Add feature flag

* Only raise a single warning for unexpected inputs

* Update invalid input test to raise single warning

docs/contribute.md

@@ -23,7 +23,7 @@ An ADR is an Architectural Decision Record.  This allows consensus on the direct
 
 ### Required Dev Dependencies
 
-![Win](res/win_sm.png) Git for Windows [Install Here](https://git-scm.com/downloads) (needed for dev sh script)
+![Win](res/win_sm.png) ![*nix](res/linux_sm.png)  Git for Windows and Linux [Install Here](https://git-scm.com/downloads) (needed for dev sh script)
 
 ### To Build, Test, Layout 
 
@@ -43,6 +43,7 @@ Sample developer flow:
 
 ```bash
 git clone https://github.com/actions/runner
+cd runner
 cd ./src
 ./dev.(sh/cmd) layout # the runner that built from source is in {root}/_layout
 <make code changes>
@@ -53,7 +54,7 @@ cd ./src
 ### Editors
 
 [Using Visual Studio Code](https://code.visualstudio.com/)
-[Using Visual Studio 2019](https://www.visualstudio.com/vs/)  
+[Using Visual Studio](https://code.visualstudio.com/docs)  
 
 ### Styling
 

src/Misc/dotnet-install.ps1

@@ -684,3 +684,196 @@ Prepend-Sdk-InstallRoot-To-Path -InstallRoot $InstallRoot -BinFolderRelativePath
 
 Say "Installation finished"
 exit 0
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src/Runner.Common/ConfigurationStore.cs

@@ -108,9 +108,9 @@ namespace GitHub.Runner.Common
         CredentialData GetMigratedCredentials();
         RunnerSettings GetSettings();
         void SaveCredential(CredentialData credential);
-        void SaveMigratedCredential(CredentialData credential);
         void SaveSettings(RunnerSettings settings);
         void DeleteCredential();
+        void DeleteMigratedCredential();
         void DeleteSettings();
     }
 
@@ -232,21 +232,6 @@ namespace GitHub.Runner.Common
             File.SetAttributes(_credFilePath, File.GetAttributes(_credFilePath) | FileAttributes.Hidden);
         }
 
-        public void SaveMigratedCredential(CredentialData credential)
-        {
-            Trace.Info("Saving {0} migrated credential @ {1}", credential.Scheme, _migratedCredFilePath);
-            if (File.Exists(_migratedCredFilePath))
-            {
-                // Delete existing credential file first, since the file is hidden and not able to overwrite.
-                Trace.Info("Delete exist runner migrated credential file.");
-                IOUtil.DeleteFile(_migratedCredFilePath);
-            }
-
-            IOUtil.SaveObject(credential, _migratedCredFilePath);
-            Trace.Info("Migrated Credentials Saved.");
-            File.SetAttributes(_migratedCredFilePath, File.GetAttributes(_migratedCredFilePath) | FileAttributes.Hidden);
-        }
-
         public void SaveSettings(RunnerSettings settings)
         {
             Trace.Info("Saving runner settings.");
@@ -268,6 +253,11 @@ namespace GitHub.Runner.Common
             IOUtil.Delete(_migratedCredFilePath, default(CancellationToken));
         }
 
+        public void DeleteMigratedCredential()
+        {
+            IOUtil.Delete(_migratedCredFilePath, default(CancellationToken));
+        }
+
         public void DeleteSettings()
         {
             IOUtil.Delete(_configFilePath, default(CancellationToken));

src/Runner.Common/JobServer.cs

@@ -22,6 +22,7 @@ namespace GitHub.Runner.Common
         Task<List<TimelineRecord>> UpdateTimelineRecordsAsync(Guid scopeIdentifier, string hubName, Guid planId, Guid timelineId, IEnumerable<TimelineRecord> records, CancellationToken cancellationToken);
         Task RaisePlanEventAsync<T>(Guid scopeIdentifier, string hubName, Guid planId, T eventData, CancellationToken cancellationToken) where T : JobEvent;
         Task<Timeline> GetTimelineAsync(Guid scopeIdentifier, string hubName, Guid planId, Guid timelineId, CancellationToken cancellationToken);
+        Task<ActionDownloadInfoCollection> ResolveActionDownloadInfoAsync(Guid scopeIdentifier, string hubName, Guid planId, ActionReferenceList actions, CancellationToken cancellationToken);
     }
 
     public sealed class JobServer : RunnerService, IJobServer
@@ -113,5 +114,14 @@ namespace GitHub.Runner.Common
             CheckConnection();
             return _taskClient.GetTimelineAsync(scopeIdentifier, hubName, planId, timelineId, includeRecords: true, cancellationToken: cancellationToken);
         }
+
+        //-----------------------------------------------------------------
+        // Action download info
+        //-----------------------------------------------------------------
+        public Task<ActionDownloadInfoCollection> ResolveActionDownloadInfoAsync(Guid scopeIdentifier, string hubName, Guid planId, ActionReferenceList actions, CancellationToken cancellationToken)
+        {
+            CheckConnection();
+            return _taskClient.ResolveActionDownloadInfoAsync(scopeIdentifier, hubName, planId, actions, cancellationToken: cancellationToken);
+        }
     }
 }

src/Runner.Common/RunnerServer.cs

@@ -50,10 +50,6 @@ namespace GitHub.Runner.Common
 
         // agent update
         Task<TaskAgent> UpdateAgentUpdateStateAsync(int agentPoolId, int agentId, string currentState);
-
-        // runner authorization url
-        Task<string> GetRunnerAuthUrlAsync(int runnerPoolId, int runnerId);
-        Task ReportRunnerAuthUrlErrorAsync(int runnerPoolId, int runnerId, string error);
     }
 
     public sealed class RunnerServer : RunnerService, IRunnerServer

src/Runner.Common/Terminal.cs

@@ -96,13 +96,14 @@ namespace GitHub.Runner.Common
             Trace.Info($"WRITE: {message}");
             if (!Silent)
             {
-                if(colorCode != null)
+                if (colorCode != null)
                 {
                     Console.ForegroundColor = colorCode.Value;
                     Console.Write(message);
                     Console.ResetColor();
                 }
-                else {
+                else
+                {
                     Console.Write(message);
                 }
             }
@@ -120,13 +121,14 @@ namespace GitHub.Runner.Common
             Trace.Info($"WRITE LINE: {line}");
             if (!Silent)
             {
-                if(colorCode != null)
+                if (colorCode != null)
                 {
                     Console.ForegroundColor = colorCode.Value;
                     Console.WriteLine(line);
                     Console.ResetColor();
                 }
-                else {
+                else
+                {
                     Console.WriteLine(line);
                 }
             }

src/Runner.Listener/Configuration/ConfigurationManager.cs

@@ -119,6 +119,19 @@ namespace GitHub.Runner.Listener.Configuration
                     // Determine the service deployment type based on connection data. (Hosted/OnPremises)
                     runnerSettings.IsHostedServer = runnerSettings.GitHubUrl == null || IsHostedServer(new UriBuilder(runnerSettings.GitHubUrl));
 
+                    // Warn if the Actions server url and GHES server url has different Host
+                    if (!runnerSettings.IsHostedServer)
+                    {
+                        // Example actionsServerUrl is https://my-ghes/_services/pipelines/[...]
+                        // Example githubServerUrl is https://my-ghes
+                        var actionsServerUrl = new Uri(runnerSettings.ServerUrl);
+                        var githubServerUrl = new Uri(runnerSettings.GitHubUrl);
+                        if (!string.Equals(actionsServerUrl.Authority, githubServerUrl.Authority, StringComparison.OrdinalIgnoreCase))
+                        {
+                            throw new InvalidOperationException($"GitHub Actions is not properly configured in GHES. GHES url: {runnerSettings.GitHubUrl}, Actions url: {runnerSettings.ServerUrl}.");
+                        }
+                    }
+
                     // Validate can connect.
                     await _runnerServer.ConnectAsync(new Uri(runnerSettings.ServerUrl), creds);
 
@@ -221,36 +234,11 @@ namespace GitHub.Runner.Listener.Configuration
             // Add Agent Id to settings
             runnerSettings.AgentId = agent.Id;
 
-            // respect the serverUrl resolve by server.
-            // in case of agent configured using collection url instead of account url.
-            string agentServerUrl;
-            if (agent.Properties.TryGetValidatedValue<string>("ServerUrl", out agentServerUrl) &&
-                !string.IsNullOrEmpty(agentServerUrl))
-            {
-                Trace.Info($"Agent server url resolve by server: '{agentServerUrl}'.");
-
-                // we need make sure the Schema/Host/Port component of the url remain the same.
-                UriBuilder inputServerUrl = new UriBuilder(runnerSettings.ServerUrl);
-                UriBuilder serverReturnedServerUrl = new UriBuilder(agentServerUrl);
-                if (Uri.Compare(inputServerUrl.Uri, serverReturnedServerUrl.Uri, UriComponents.SchemeAndServer, UriFormat.Unescaped, StringComparison.OrdinalIgnoreCase) != 0)
-                {
-                    inputServerUrl.Path = serverReturnedServerUrl.Path;
-                    Trace.Info($"Replace server returned url's scheme://host:port component with user input server url's scheme://host:port: '{inputServerUrl.Uri.AbsoluteUri}'.");
-                    runnerSettings.ServerUrl = inputServerUrl.Uri.AbsoluteUri;
-                }
-                else
-                {
-                    runnerSettings.ServerUrl = agentServerUrl;
-                }
-            }
-
             // See if the server supports our OAuth key exchange for credentials
             if (agent.Authorization != null &&
                 agent.Authorization.ClientId != Guid.Empty &&
                 agent.Authorization.AuthorizationUrl != null)
             {
-                UriBuilder configServerUrl = new UriBuilder(runnerSettings.ServerUrl);
-                UriBuilder oauthEndpointUrlBuilder = new UriBuilder(agent.Authorization.AuthorizationUrl);
                 var credentialData = new CredentialData
                 {
                     Scheme = Constants.Configuration.OAuth,
@@ -258,7 +246,6 @@ namespace GitHub.Runner.Listener.Configuration
                     {
                         { "clientId", agent.Authorization.ClientId.ToString("D") },
                         { "authorizationUrl", agent.Authorization.AuthorizationUrl.AbsoluteUri },
-                        { "oauthEndpointUrl", oauthEndpointUrlBuilder.Uri.AbsoluteUri },
                     },
                 };
 
@@ -464,7 +451,7 @@ namespace GitHub.Runner.Listener.Configuration
             // update should replace the existing labels
             agent.Version = BuildConstants.RunnerPackage.Version;
             agent.OSDescription = RuntimeInformation.OSDescription;
-            
+
             agent.Labels.Clear();
 
             agent.Labels.Add(new AgentLabel("self-hosted", LabelType.System));
@@ -475,7 +462,7 @@ namespace GitHub.Runner.Listener.Configuration
             {
                 agent.Labels.Add(new AgentLabel(userLabel, LabelType.User));
             }
-            
+
             return agent;
         }
 

src/Runner.Listener/Configuration/CredentialManager.cs

@@ -13,7 +13,7 @@ namespace GitHub.Runner.Listener.Configuration
     public interface ICredentialManager : IRunnerService
     {
         ICredentialProvider GetCredentialProvider(string credType);
-        VssCredentials LoadCredentials(bool preferMigrated = true);
+        VssCredentials LoadCredentials();
     }
 
     public class CredentialManager : RunnerService, ICredentialManager
@@ -40,7 +40,7 @@ namespace GitHub.Runner.Listener.Configuration
             return creds;
         }
 
-        public VssCredentials LoadCredentials(bool preferMigrated = true)
+        public VssCredentials LoadCredentials()
         {
             IConfigurationStore store = HostContext.GetService<IConfigurationStore>();
 
@@ -50,14 +50,16 @@ namespace GitHub.Runner.Listener.Configuration
             }
 
             CredentialData credData = store.GetCredentials();
-
+            var migratedCred = store.GetMigratedCredentials();
-            if (preferMigrated)
+            if (migratedCred != null)
             {
-                var migratedCred = store.GetMigratedCredentials();
+                credData = migratedCred;
-                if (migratedCred != null)
+
-                {
+                // Re-write .credentials with Token URL
-                    credData = migratedCred;
+                store.SaveCredential(credData);
-                }
+
+                // Delete .credentials_migrated
+                store.DeleteMigratedCredential();
             }
 
             ICredentialProvider credProv = GetCredentialProvider(credData.Scheme);

src/Runner.Listener/MessageListener.cs

@@ -13,10 +13,7 @@ using System.Diagnostics;
 using System.Runtime.InteropServices;
 using GitHub.Runner.Common;
 using GitHub.Runner.Sdk;
-using GitHub.Services.WebApi;
-using System.Runtime.CompilerServices;
 
-[assembly: InternalsVisibleTo("Test")]
 namespace GitHub.Runner.Listener
 {
     [ServiceLocator(Default = typeof(MessageListener))]
@@ -35,30 +32,18 @@ namespace GitHub.Runner.Listener
         private ITerminal _term;
         private IRunnerServer _runnerServer;
         private TaskAgentSession _session;
-        private ICredentialManager _credMgr;
-        private IConfigurationStore _configStore;
         private TimeSpan _getNextMessageRetryInterval;
         private readonly TimeSpan _sessionCreationRetryInterval = TimeSpan.FromSeconds(30);
         private readonly TimeSpan _sessionConflictRetryLimit = TimeSpan.FromMinutes(4);
         private readonly TimeSpan _clockSkewRetryLimit = TimeSpan.FromMinutes(30);
         private readonly Dictionary<string, int> _sessionCreationExceptionTracker = new Dictionary<string, int>();
 
-        // Whether load credentials from .credentials_migrated file
-        internal bool _useMigratedCredentials;
-
-        // need to check auth url if there is only .credentials and auth schema is OAuth
-        internal bool _needToCheckAuthorizationUrlUpdate;
-        internal Task<VssCredentials> _authorizationUrlMigrationBackgroundTask;
-        internal Task _authorizationUrlRollbackReattemptDelayBackgroundTask;
-
         public override void Initialize(IHostContext hostContext)
         {
             base.Initialize(hostContext);
 
             _term = HostContext.GetService<ITerminal>();
             _runnerServer = HostContext.GetService<IRunnerServer>();
-            _credMgr = HostContext.GetService<ICredentialManager>();
-            _configStore = HostContext.GetService<IConfigurationStore>();
         }
 
         public async Task<Boolean> CreateSessionAsync(CancellationToken token)
@@ -73,8 +58,8 @@ namespace GitHub.Runner.Listener
 
             // Create connection.
             Trace.Info("Loading Credentials");
-            _useMigratedCredentials = !StringUtil.ConvertToBoolean(Environment.GetEnvironmentVariable("GITHUB_ACTIONS_RUNNER_SPSAUTHURL"));
+            var credMgr = HostContext.GetService<ICredentialManager>();
-            VssCredentials creds = _credMgr.LoadCredentials(_useMigratedCredentials);
+            VssCredentials creds = credMgr.LoadCredentials();
 
             var agent = new TaskAgentReference
             {
@@ -89,17 +74,6 @@ namespace GitHub.Runner.Listener
             string errorMessage = string.Empty;
             bool encounteringError = false;
 
-            var originalCreds = _configStore.GetCredentials();
-            var migratedCreds = _configStore.GetMigratedCredentials();
-            if (migratedCreds == null)
-            {
-                _useMigratedCredentials = false;
-                if (originalCreds.Scheme == Constants.Configuration.OAuth)
-                {
-                    _needToCheckAuthorizationUrlUpdate = true;
-                }
-            }
-
             while (true)
             {
                 token.ThrowIfCancellationRequested();
@@ -127,12 +101,6 @@ namespace GitHub.Runner.Listener
                         encounteringError = false;
                     }
 
-                    if (_needToCheckAuthorizationUrlUpdate)
-                    {
-                        // start background task try to get new authorization url
-                        _authorizationUrlMigrationBackgroundTask = GetNewOAuthAuthorizationSetting(token);
-                    }
-
                     return true;
                 }
                 catch (OperationCanceledException) when (token.IsCancellationRequested)
@@ -164,44 +132,10 @@ namespace GitHub.Runner.Listener
                         }
                     }
 
-                    if (ex is TaskAgentSessionConflictException)
-                    {
-                        try
-                        {
-                            var newCred = await GetNewOAuthAuthorizationSetting(token, true);
-                            if (newCred != null)
-                            {
-                                await _runnerServer.ConnectAsync(new Uri(_settings.ServerUrl), newCred);
-                                Trace.Info("Updated connection to use migrated credential for next CreateSession call.");
-                                _useMigratedCredentials = true;
-                                _authorizationUrlMigrationBackgroundTask = null;
-                                _needToCheckAuthorizationUrlUpdate = false;
-                            }
-                        }
-                        catch (Exception e)
-                        {
-                            Trace.Error("Fail to refresh connection with new authorization url.");
-                            Trace.Error(e);
-                        }
-                    }
-
                     if (!IsSessionCreationExceptionRetriable(ex))
                     {
-                        if (_useMigratedCredentials && !(ex is TaskAgentSessionConflictException))
+                        _term.WriteError($"Failed to create session. {ex.Message}");
-                        {
+                        return false;
-                            // migrated credentials might cause lose permission during permission check,
-                            // we will force to use original credential and try again
-                            _useMigratedCredentials = false;
-                            var reattemptBackoff = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromHours(24), TimeSpan.FromHours(36));
-                            _authorizationUrlRollbackReattemptDelayBackgroundTask = HostContext.Delay(reattemptBackoff, token); // retry migrated creds in 24-36 hours.
-                            creds = _credMgr.LoadCredentials(false);
-                            Trace.Error("Fallback to original credentials and try again.");
-                        }
-                        else
-                        {
-                            _term.WriteError($"Failed to create session. {ex.Message}");
-                            return false;
-                        }
                     }
 
                     if (!encounteringError) //print the message only on the first error
@@ -262,51 +196,6 @@ namespace GitHub.Runner.Listener
                         encounteringError = false;
                         continuousError = 0;
                     }
-
-                    if (_needToCheckAuthorizationUrlUpdate &&
-                        _authorizationUrlMigrationBackgroundTask?.IsCompleted == true)
-                    {
-                        if (HostContext.GetService<IJobDispatcher>().Busy ||
-                            HostContext.GetService<ISelfUpdater>().Busy)
-                        {
-                            Trace.Info("Job or runner updates in progress, update credentials next time.");
-                        }
-                        else
-                        {
-                            try
-                            {
-                                var newCred = await _authorizationUrlMigrationBackgroundTask;
-                                await _runnerServer.ConnectAsync(new Uri(_settings.ServerUrl), newCred);
-                                Trace.Info("Updated connection to use migrated credential for next GetMessage call.");
-                                _useMigratedCredentials = true;
-                                _authorizationUrlMigrationBackgroundTask = null;
-                                _needToCheckAuthorizationUrlUpdate = false;
-                            }
-                            catch (Exception ex)
-                            {
-                                Trace.Error("Fail to refresh connection with new authorization url.");
-                                Trace.Error(ex);
-                            }
-                        }
-                    }
-
-                    if (_authorizationUrlRollbackReattemptDelayBackgroundTask?.IsCompleted == true)
-                    {
-                        try
-                        {
-                            // we rolled back to use original creds about 2 days before, now it's a good time to try migrated creds again.
-                            Trace.Info("Re-attempt to use migrated credential");
-                            var migratedCreds = _credMgr.LoadCredentials();
-                            await _runnerServer.ConnectAsync(new Uri(_settings.ServerUrl), migratedCreds);
-                            _useMigratedCredentials = true;
-                            _authorizationUrlRollbackReattemptDelayBackgroundTask = null;
-                        }
-                        catch (Exception ex)
-                        {
-                            Trace.Error("Fail to refresh connection with new authorization url on rollback reattempt.");
-                            Trace.Error(ex);
-                        }
-                    }
                 }
                 catch (OperationCanceledException) when (token.IsCancellationRequested)
                 {
@@ -330,21 +219,7 @@ namespace GitHub.Runner.Listener
                     }
                     else if (!IsGetNextMessageExceptionRetriable(ex))
                     {
-                        if (_useMigratedCredentials)
+                        throw;
-                        {
-                            // migrated credentials might cause lose permission during permission check,
-                            // we will force to use original credential and try again
-                            _useMigratedCredentials = false;
-                            var reattemptBackoff = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromHours(24), TimeSpan.FromHours(36));
-                            _authorizationUrlRollbackReattemptDelayBackgroundTask = HostContext.Delay(reattemptBackoff, token); // retry migrated creds in 24-36 hours.
-                            var originalCreds = _credMgr.LoadCredentials(false);
-                            await _runnerServer.ConnectAsync(new Uri(_settings.ServerUrl), originalCreds);
-                            Trace.Error("Fallback to original credentials and try again.");
-                        }
-                        else
-                        {
-                            throw;
-                        }
                     }
                     else
                     {
@@ -536,94 +411,5 @@ namespace GitHub.Runner.Listener
                 return true;
             }
         }
-
-        private async Task<VssCredentials> GetNewOAuthAuthorizationSetting(CancellationToken token, bool adhoc = false)
-        {
-            Trace.Info("Start checking oauth authorization url update.");
-            while (true)
-            {
-                try
-                {
-                    var migratedAuthorizationUrl = await _runnerServer.GetRunnerAuthUrlAsync(_settings.PoolId, _settings.AgentId);
-                    if (!string.IsNullOrEmpty(migratedAuthorizationUrl))
-                    {
-                        var credData = _configStore.GetCredentials();
-                        var clientId = credData.Data.GetValueOrDefault("clientId", null);
-                        var currentAuthorizationUrl = credData.Data.GetValueOrDefault("authorizationUrl", null);
-                        Trace.Info($"Current authorization url: {currentAuthorizationUrl}, new authorization url: {migratedAuthorizationUrl}");
-
-                        if (string.Equals(currentAuthorizationUrl, migratedAuthorizationUrl, StringComparison.OrdinalIgnoreCase))
-                        {
-                            // We don't need to update credentials.
-                            Trace.Info("No needs to update authorization url");
-                            if (adhoc)
-                            {
-                                return null;
-                            }
-                            else
-                            {
-                                await Task.Delay(TimeSpan.FromMilliseconds(-1), token);
-                            }
-                        }
-
-                        var keyManager = HostContext.GetService<IRSAKeyManager>();
-                        var signingCredentials = VssSigningCredentials.Create(() => keyManager.GetKey());
-
-                        var migratedClientCredential = new VssOAuthJwtBearerClientCredential(clientId, migratedAuthorizationUrl, signingCredentials);
-                        var migratedRunnerCredential = new VssOAuthCredential(new Uri(migratedAuthorizationUrl, UriKind.Absolute), VssOAuthGrant.ClientCredentials, migratedClientCredential);
-
-                        Trace.Info("Try connect service with Token Service OAuth endpoint.");
-                        var runnerServer = HostContext.CreateService<IRunnerServer>();
-                        await runnerServer.ConnectAsync(new Uri(_settings.ServerUrl), migratedRunnerCredential);
-                        await runnerServer.GetAgentPoolsAsync();
-                        Trace.Info($"Successfully connected service with new authorization url.");
-
-                        var migratedCredData = new CredentialData
-                        {
-                            Scheme = Constants.Configuration.OAuth,
-                            Data =
-                            {
-                                { "clientId", clientId },
-                                { "authorizationUrl", migratedAuthorizationUrl },
-                                { "oauthEndpointUrl", migratedAuthorizationUrl },
-                            },
-                        };
-
-                        _configStore.SaveMigratedCredential(migratedCredData);
-                        return migratedRunnerCredential;
-                    }
-                    else
-                    {
-                        Trace.Verbose("No authorization url updates");
-                    }
-                }
-                catch (Exception ex) when (!token.IsCancellationRequested)
-                {
-                    Trace.Error("Fail to get/test new authorization url.");
-                    Trace.Error(ex);
-
-                    try
-                    {
-                        await _runnerServer.ReportRunnerAuthUrlErrorAsync(_settings.PoolId, _settings.AgentId, ex.ToString());
-                    }
-                    catch (Exception e)
-                    {
-                        // best effort
-                        Trace.Error("Fail to report the migration error");
-                        Trace.Error(e);
-                    }
-                }
-
-                if (adhoc)
-                {
-                    return null;
-                }
-                else
-                {
-                    var backoff = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromMinutes(30), TimeSpan.FromMinutes(45));
-                    await HostContext.Delay(backoff, token);
-                }
-            }
-        }
     }
 }

src/Runner.Listener/Program.cs

@@ -102,7 +102,9 @@ namespace GitHub.Runner.Listener
                 IRunner runner = context.GetService<IRunner>();
                 try
                 {
-                    return await runner.ExecuteCommand(command);
+                    var returnCode = await runner.ExecuteCommand(command);
+                    trace.Info($"Runner execution has finished with return code {returnCode}");
+                    return returnCode;
                 }
                 catch (OperationCanceledException) when (context.RunnerShutdownToken.IsCancellationRequested)
                 {

src/Runner.Listener/Runner.cs

@@ -37,6 +37,8 @@ namespace GitHub.Runner.Listener
         {
             try
             {
+                _term.WriteLine("Runner Repo TESTING VERSION OF RUNNER...");
+                Trace.Info("Hey I'm in the log file yay!");
                 VssUtil.InitializeVssClientSettings(HostContext.UserAgents, HostContext.WebProxy);
 
                 _inConfigStage = true;

src/Runner.Sdk/ProcessInvoker.cs

@@ -318,7 +318,12 @@ namespace GitHub.Runner.Sdk
                 }
             }
 
-            using (var registration = cancellationToken.Register(async () => await CancelAndKillProcessTree(killProcessOnCancel)))
+            var cancellationFinished = new TaskCompletionSource<bool>();
+            using (var registration = cancellationToken.Register(async () =>
+            {
+                await CancelAndKillProcessTree(killProcessOnCancel);
+                cancellationFinished.TrySetResult(true);
+            }))
             {
                 Trace.Info($"Process started with process id {_proc.Id}, waiting for process exit.");
                 while (true)
@@ -344,6 +349,13 @@ namespace GitHub.Runner.Sdk
                 Trace.Info($"Finished process {_proc.Id} with exit code {_proc.ExitCode}, and elapsed time {_stopWatch.Elapsed}.");
             }
 
+            if (cancellationToken.IsCancellationRequested)
+            {
+                // Ensure cancellation also finish on the cancellationToken.Register thread.
+                await cancellationFinished.Task;
+                Trace.Info($"Process Cancellation finished.");
+            }
+
             cancellationToken.ThrowIfCancellationRequested();
 
             // Wait for process to finish.

src/Runner.Worker/ActionManager.cs

@@ -14,6 +14,7 @@ using GitHub.Runner.Common;
 using GitHub.Runner.Sdk;
 using GitHub.Runner.Worker.Container;
 using GitHub.Services.Common;
+using WebApi = GitHub.DistributedTask.WebApi;
 using Pipelines = GitHub.DistributedTask.Pipelines;
 using PipelineTemplateConstants = GitHub.DistributedTask.Pipelines.ObjectTemplating.PipelineTemplateConstants;
 
@@ -73,6 +74,11 @@ namespace GitHub.Runner.Worker
             // Clear the cache (for self-hosted runners)
             IOUtil.DeleteDirectory(HostContext.GetDirectory(WellKnownDirectory.Actions), executionContext.CancellationToken);
 
+            // todo: Remove when feature flag DistributedTask.NewActionMetadata is removed
+            var newActionMetadata = executionContext.Variables.GetBoolean("DistributedTask.NewActionMetadata") ?? false;
+
+            var repositoryActions = new List<Pipelines.ActionStep>();
+
             foreach (var action in actions)
             {
                 if (action.Reference.Type == Pipelines.ActionSourceType.ContainerRegistry)
@@ -90,7 +96,8 @@ namespace GitHub.Runner.Worker
                     Trace.Info($"Action {action.Name} ({action.Id}) needs to pull image '{containerReference.Image}'");
                     imagesToPull[containerReference.Image].Add(action.Id);
                 }
-                else if (action.Reference.Type == Pipelines.ActionSourceType.Repository)
+                // todo: Remove when feature flag DistributedTask.NewActionMetadata is removed
+                else if (action.Reference.Type == Pipelines.ActionSourceType.Repository && !newActionMetadata)
                 {
                     // only download the repository archive
                     await DownloadRepositoryActionAsync(executionContext, action);
@@ -124,6 +131,81 @@ namespace GitHub.Runner.Worker
                         }
                     }
 
+                    var repoAction = action.Reference as Pipelines.RepositoryPathReference;
+                    if (repoAction.RepositoryType != Pipelines.PipelineConstants.SelfAlias)
+                    {
+                        var definition = LoadAction(executionContext, action);
+                        if (definition.Data.Execution.HasPre)
+                        {
+                            var actionRunner = HostContext.CreateService<IActionRunner>();
+                            actionRunner.Action = action;
+                            actionRunner.Stage = ActionRunStage.Pre;
+                            actionRunner.Condition = definition.Data.Execution.InitCondition;
+
+                            Trace.Info($"Add 'pre' execution for {action.Id}");
+                            preStepTracker[action.Id] = actionRunner;
+                        }
+                    }
+                }
+                else if (action.Reference.Type == Pipelines.ActionSourceType.Repository && newActionMetadata)
+                {
+                    repositoryActions.Add(action);
+                }
+            }
+
+            if (repositoryActions.Count > 0)
+            {
+                // Get the download info
+                var downloadInfos = await GetDownloadInfoAsync(executionContext, repositoryActions);
+
+                // Download each action
+                foreach (var action in repositoryActions)
+                {
+                    var lookupKey = GetDownloadInfoLookupKey(action);
+                    if (string.IsNullOrEmpty(lookupKey))
+                    {
+                        continue;
+                    }
+
+                    if (!downloadInfos.TryGetValue(lookupKey, out var downloadInfo))
+                    {
+                        throw new Exception($"Missing download info for {lookupKey}");
+                    }
+
+                    await DownloadRepositoryActionAsync(executionContext, downloadInfo);
+                }
+
+                // More preparation based on content in the repository (action.yml)
+                foreach (var action in repositoryActions)
+                {
+                    var setupInfo = PrepareRepositoryActionAsync(executionContext, action);
+                    if (setupInfo != null)
+                    {
+                        if (!string.IsNullOrEmpty(setupInfo.Image))
+                        {
+                            if (!imagesToPull.ContainsKey(setupInfo.Image))
+                            {
+                                imagesToPull[setupInfo.Image] = new List<Guid>();
+                            }
+
+                            Trace.Info($"Action {action.Name} ({action.Id}) from repository '{setupInfo.ActionRepository}' needs to pull image '{setupInfo.Image}'");
+                            imagesToPull[setupInfo.Image].Add(action.Id);
+                        }
+                        else
+                        {
+                            ArgUtil.NotNullOrEmpty(setupInfo.ActionRepository, nameof(setupInfo.ActionRepository));
+
+                            if (!imagesToBuild.ContainsKey(setupInfo.ActionRepository))
+                            {
+                                imagesToBuild[setupInfo.ActionRepository] = new List<Guid>();
+                            }
+
+                            Trace.Info($"Action {action.Name} ({action.Id}) from repository '{setupInfo.ActionRepository}' needs to build image '{setupInfo.Dockerfile}'");
+                            imagesToBuild[setupInfo.ActionRepository].Add(action.Id);
+                            imagesToBuildInfo[setupInfo.ActionRepository] = setupInfo;
+                        }
+                    }
+
                     var repoAction = action.Reference as Pipelines.RepositoryPathReference;
                     if (repoAction.RepositoryType != Pipelines.PipelineConstants.SelfAlias)
                     {
@@ -313,6 +395,9 @@ namespace GitHub.Runner.Worker
                             Trace.Info($"Action cleanup plugin: {plugin.PluginTypeName}.");
                         }
                     }
+                    else if (definition.Data.Execution.ExecutionType == ActionExecutionType.Composite && !String.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA"))) {
+                        // Don't do anything for now
+                    }
                     else
                     {
                         throw new NotSupportedException(definition.Data.Execution.ExecutionType.ToString());
@@ -464,6 +549,143 @@ namespace GitHub.Runner.Worker
             }
         }
 
+        // This implementation is temporary and will be removed when we switch to a REST API call to the service to resolve the download info
+        private async Task<bool> RepoExistsAsync(IExecutionContext executionContext, WebApi.ActionDownloadInfo actionDownloadInfo, string token)
+        {
+            var apiUrl = GetApiUrl(executionContext);
+            var repoUrl = $"{apiUrl}/repos/{actionDownloadInfo.NameWithOwner}";
+            for (var attempt = 1; attempt <= 3; attempt++)
+            {
+                executionContext.Debug($"Checking whether repo exists: {repoUrl}");
+                try
+                {
+                    using (var httpClientHandler = HostContext.CreateHttpClientHandler())
+                    using (var httpClient = new HttpClient(httpClientHandler))
+                    {
+                        httpClient.DefaultRequestHeaders.Authorization = CreateAuthHeader(token);
+                        httpClient.DefaultRequestHeaders.UserAgent.AddRange(HostContext.UserAgents);
+                        using (var response = await httpClient.GetAsync(repoUrl))
+                        {
+                            if (response.IsSuccessStatusCode)
+                            {
+                                return true;
+                            }
+                            else if (response.StatusCode == HttpStatusCode.NotFound)
+                            {
+                                return false;
+                            }
+                            else
+                            {
+                                // Throw
+                                response.EnsureSuccessStatusCode();
+                            }
+                        }
+                    }
+                }
+                catch (Exception ex)
+                {
+                    if (attempt < 3)
+                    {
+                        executionContext.Debug($"Failed checking whether repo '{actionDownloadInfo.NameWithOwner}' exists: {ex.Message}");
+                    }
+                    else
+                    {
+                        executionContext.Error($"Failed checking whether repo '{actionDownloadInfo.NameWithOwner}' exists: {ex.Message}");
+                        throw;
+                    }
+                }
+            }
+
+            return false; // Never reaches here
+        }
+
+        // This implementation is temporary and will be replaced with a REST API call to the service to resolve
+        private async Task<IDictionary<string, WebApi.ActionDownloadInfo>> GetDownloadInfoAsync(IExecutionContext executionContext, List<Pipelines.ActionStep> actions)
+        {
+            executionContext.Output("Getting action download info");
+
+            // Convert to action reference
+            var actionReferences = actions
+                .GroupBy(x => GetDownloadInfoLookupKey(x))
+                .Where(x => !string.IsNullOrEmpty(x.Key))
+                .Select(x =>
+                {
+                    var action = x.First();
+                    var repositoryReference = action.Reference as Pipelines.RepositoryPathReference;
+                    ArgUtil.NotNull(repositoryReference, nameof(repositoryReference));
+                    return new WebApi.ActionReference
+                    {
+                        NameWithOwner = repositoryReference.Name,
+                        Ref = repositoryReference.Ref,
+                    };
+                })
+                .ToList();
+
+            // Nothing to resolve?
+            if (actionReferences.Count == 0)
+            {
+                return new Dictionary<string, WebApi.ActionDownloadInfo>();
+            }
+
+            // Resolve download info
+            var jobServer = HostContext.GetService<IJobServer>();
+            var actionDownloadInfos = default(WebApi.ActionDownloadInfoCollection);
+            for (var attempt = 1; attempt <= 3; attempt++)
+            {
+                try
+                {
+                    actionDownloadInfos = await jobServer.ResolveActionDownloadInfoAsync(executionContext.Plan.ScopeIdentifier, executionContext.Plan.PlanType, executionContext.Plan.PlanId, new WebApi.ActionReferenceList { Actions = actionReferences }, executionContext.CancellationToken);
+                    break;
+                }
+                catch (Exception ex) when (attempt < 3)
+                {
+                    executionContext.Output($"Failed to resolve action download info. Error: {ex.Message}");
+                    executionContext.Debug(ex.ToString());
+                    if (String.IsNullOrEmpty(Environment.GetEnvironmentVariable("_GITHUB_ACTION_DOWNLOAD_NO_BACKOFF")))
+                    {
+                        var backoff = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromSeconds(10), TimeSpan.FromSeconds(30));
+                        executionContext.Output($"Retrying in {backoff.TotalSeconds} seconds");
+                        await Task.Delay(backoff);
+                    }
+                }
+            }
+
+            ArgUtil.NotNull(actionDownloadInfos, nameof(actionDownloadInfos));
+            ArgUtil.NotNull(actionDownloadInfos.Actions, nameof(actionDownloadInfos.Actions));
+            var apiUrl = GetApiUrl(executionContext);
+            var defaultAccessToken = executionContext.GetGitHubContext("token");
+            var configurationStore = HostContext.GetService<IConfigurationStore>();
+            var runnerSettings = configurationStore.GetSettings();
+
+            foreach (var actionDownloadInfo in actionDownloadInfos.Actions.Values)
+            {
+                // Add secret
+                HostContext.SecretMasker.AddValue(actionDownloadInfo.Authentication?.Token);
+
+                // Temporary code: Fix token and download URL
+                if (runnerSettings.IsHostedServer)
+                {
+                    actionDownloadInfo.Authentication = new WebApi.ActionDownloadAuthentication { Token = defaultAccessToken };
+                    actionDownloadInfo.TarballUrl = actionDownloadInfo.TarballUrl.Replace("<GITHUB_API_URL>", apiUrl);
+                    actionDownloadInfo.ZipballUrl = actionDownloadInfo.ZipballUrl.Replace("<GITHUB_API_URL>", apiUrl);
+                }
+                else if (await RepoExistsAsync(executionContext, actionDownloadInfo, defaultAccessToken))
+                {
+                    actionDownloadInfo.Authentication = new WebApi.ActionDownloadAuthentication { Token = defaultAccessToken };
+                    actionDownloadInfo.TarballUrl = actionDownloadInfo.TarballUrl.Replace("<GITHUB_API_URL>", apiUrl);
+                    actionDownloadInfo.ZipballUrl = actionDownloadInfo.ZipballUrl.Replace("<GITHUB_API_URL>", apiUrl);
+                }
+                else
+                {
+                    actionDownloadInfo.TarballUrl = actionDownloadInfo.TarballUrl.Replace("<GITHUB_API_URL>", "https://api.github.com");
+                    actionDownloadInfo.ZipballUrl = actionDownloadInfo.ZipballUrl.Replace("<GITHUB_API_URL>", "https://api.github.com");
+                }
+            }
+
+            return actionDownloadInfos.Actions;
+        }
+
+        // todo: Remove when feature flag DistributedTask.NewActionMetadata is removed
         private async Task DownloadRepositoryActionAsync(IExecutionContext executionContext, Pipelines.ActionStep repositoryAction)
         {
             Trace.Entering();
@@ -507,9 +729,8 @@ namespace GitHub.Runner.Worker
             {
                 string apiUrl = GetApiUrl(executionContext);
                 string archiveLink = BuildLinkToActionArchive(apiUrl, repositoryReference.Name, repositoryReference.Ref);
-                Trace.Info($"Download archive '{archiveLink}' to '{destDirectory}'.");
                 var downloadDetails = new ActionDownloadDetails(archiveLink, ConfigureAuthorizationFromContext);
-                await DownloadRepositoryActionAsync(executionContext, downloadDetails, destDirectory);
+                await DownloadRepositoryActionAsync(executionContext, downloadDetails, null, destDirectory);
                 return;
             }
             else
@@ -533,10 +754,9 @@ namespace GitHub.Runner.Worker
 
                 foreach (var downloadAttempt in downloadAttempts)
                 {
-                    Trace.Info($"Download archive '{downloadAttempt.ArchiveLink}' to '{destDirectory}'.");
                     try
                     {
-                        await DownloadRepositoryActionAsync(executionContext, downloadAttempt, destDirectory);
+                        await DownloadRepositoryActionAsync(executionContext, downloadAttempt, null, destDirectory);
                         return;
                     }
                     catch (ActionNotFoundException)
@@ -549,6 +769,32 @@ namespace GitHub.Runner.Worker
             }
         }
 
+        private async Task DownloadRepositoryActionAsync(IExecutionContext executionContext, WebApi.ActionDownloadInfo downloadInfo)
+        {
+            Trace.Entering();
+            ArgUtil.NotNull(executionContext, nameof(executionContext));
+            ArgUtil.NotNull(downloadInfo, nameof(downloadInfo));
+            ArgUtil.NotNullOrEmpty(downloadInfo.NameWithOwner, nameof(downloadInfo.NameWithOwner));
+            ArgUtil.NotNullOrEmpty(downloadInfo.Ref, nameof(downloadInfo.Ref));
+
+            string destDirectory = Path.Combine(HostContext.GetDirectory(WellKnownDirectory.Actions), downloadInfo.NameWithOwner.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar), downloadInfo.Ref);
+            string watermarkFile = GetWatermarkFilePath(destDirectory);
+            if (File.Exists(watermarkFile))
+            {
+                executionContext.Debug($"Action '{downloadInfo.NameWithOwner}@{downloadInfo.Ref}' already downloaded at '{destDirectory}'.");
+                return;
+            }
+            else
+            {
+                // make sure we get a clean folder ready to use.
+                IOUtil.DeleteDirectory(destDirectory, executionContext.CancellationToken);
+                Directory.CreateDirectory(destDirectory);
+                executionContext.Output($"Download action repository '{downloadInfo.NameWithOwner}@{downloadInfo.Ref}'");
+            }
+
+            await DownloadRepositoryActionAsync(executionContext, null, downloadInfo, destDirectory);
+        }
+
         private string GetApiUrl(IExecutionContext executionContext)
         {
             string apiUrl = executionContext.GetGitHubContext("api_url");
@@ -569,7 +815,8 @@ namespace GitHub.Runner.Worker
 #endif
         }
 
-        private async Task DownloadRepositoryActionAsync(IExecutionContext executionContext, ActionDownloadDetails actionDownloadDetails, string destDirectory)
+        // todo: Remove the parameter "actionDownloadDetails" when feature flag DistributedTask.NewActionMetadata is removed
+        private async Task DownloadRepositoryActionAsync(IExecutionContext executionContext, ActionDownloadDetails actionDownloadDetails, WebApi.ActionDownloadInfo downloadInfo, string destDirectory)
         {
             //download and extract action in a temp folder and rename it on success
             string tempDirectory = Path.Combine(HostContext.GetDirectory(WellKnownDirectory.Actions), "_temp_" + Guid.NewGuid());
@@ -577,11 +824,12 @@ namespace GitHub.Runner.Worker
 
 #if OS_WINDOWS
             string archiveFile = Path.Combine(tempDirectory, $"{Guid.NewGuid()}.zip");
+            string link = downloadInfo?.ZipballUrl ?? actionDownloadDetails.ArchiveLink;
 #else
             string archiveFile = Path.Combine(tempDirectory, $"{Guid.NewGuid()}.tar.gz");
+            string link = downloadInfo?.TarballUrl ?? actionDownloadDetails.ArchiveLink;
 #endif
 
-            string link = actionDownloadDetails.ArchiveLink;
             Trace.Info($"Save archive '{link}' into {archiveFile}.");
             try
             {
@@ -601,7 +849,16 @@ namespace GitHub.Runner.Worker
                             using (var httpClientHandler = HostContext.CreateHttpClientHandler())
                             using (var httpClient = new HttpClient(httpClientHandler))
                             {
-                                actionDownloadDetails.ConfigureAuthorization(executionContext, httpClient);
+                                // Legacy
+                                if (downloadInfo == null)
+                                {
+                                    actionDownloadDetails.ConfigureAuthorization(executionContext, httpClient);
+                                }
+                                // FF DistributedTask.NewActionMetadata
+                                else
+                                {
+                                    httpClient.DefaultRequestHeaders.Authorization = CreateAuthHeader(downloadInfo.Authentication?.Token);
+                                }
 
                                 httpClient.DefaultRequestHeaders.UserAgent.AddRange(HostContext.UserAgents);
                                 using (var response = await httpClient.GetAsync(link))
@@ -741,6 +998,7 @@ namespace GitHub.Runner.Worker
             }
         }
 
+        // todo: Remove when feature flag DistributedTask.NewActionMetadata is removed
         private void ConfigureAuthorizationFromContext(IExecutionContext executionContext, HttpClient httpClient)
         {
             var authToken = Environment.GetEnvironmentVariable("_GITHUB_ACTION_TOKEN");
@@ -846,6 +1104,12 @@ namespace GitHub.Runner.Worker
                     Trace.Info($"Action plugin: {(actionDefinitionData.Execution as PluginActionExecutionData).Plugin}, no more preparation.");
                     return null;
                 }
+                else if (actionDefinitionData.Execution.ExecutionType == ActionExecutionType.Composite && !String.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+                {
+                    // Trace.Info($"Action composite: {(actionDefinitionData.Execution as CompositeActionExecutionData).Unknown}, no more preparation.");
+                    
+                    return null;
+                }
                 else
                 {
                     throw new NotSupportedException(actionDefinitionData.Execution.ExecutionType.ToString());
@@ -872,6 +1136,51 @@ namespace GitHub.Runner.Worker
             }
         }
 
+        private static string GetDownloadInfoLookupKey(Pipelines.ActionStep action)
+        {
+            if (action.Reference.Type != Pipelines.ActionSourceType.Repository)
+            {
+                return null;
+            }
+
+            var repositoryReference = action.Reference as Pipelines.RepositoryPathReference;
+            ArgUtil.NotNull(repositoryReference, nameof(repositoryReference));
+
+            if (string.Equals(repositoryReference.RepositoryType, Pipelines.PipelineConstants.SelfAlias, StringComparison.OrdinalIgnoreCase))
+            {
+                return null;
+            }
+
+            if (!string.Equals(repositoryReference.RepositoryType, Pipelines.RepositoryTypes.GitHub, StringComparison.OrdinalIgnoreCase))
+            {
+                throw new NotSupportedException(repositoryReference.RepositoryType);
+            }
+
+            ArgUtil.NotNullOrEmpty(repositoryReference.Name, nameof(repositoryReference.Name));
+            ArgUtil.NotNullOrEmpty(repositoryReference.Ref, nameof(repositoryReference.Ref));
+            return $"{repositoryReference.Name}@{repositoryReference.Ref}";
+        }
+
+        private static string GetDownloadInfoLookupKey(WebApi.ActionDownloadInfo info)
+        {
+            ArgUtil.NotNullOrEmpty(info.NameWithOwner, nameof(info.NameWithOwner));
+            ArgUtil.NotNullOrEmpty(info.Ref, nameof(info.Ref));
+            return $"{info.NameWithOwner}@{info.Ref}";
+        }
+
+        private AuthenticationHeaderValue CreateAuthHeader(string token)
+        {
+            if (string.IsNullOrEmpty(token))
+            {
+                return null;
+            }
+
+            var base64EncodingToken = Convert.ToBase64String(Encoding.UTF8.GetBytes($"x-access-token:{token}"));
+            HostContext.SecretMasker.AddValue(base64EncodingToken);
+            return new AuthenticationHeaderValue("Basic", base64EncodingToken);
+        }
+
+        // todo: Remove when feature flag DistributedTask.NewActionMetadata is removed
         private class ActionDownloadDetails
         {
             public string ArchiveLink { get; }
@@ -911,6 +1220,7 @@ namespace GitHub.Runner.Worker
         NodeJS,
         Plugin,
         Script,
+        Composite
     }
 
     public sealed class ContainerActionExecutionData : ActionExecutionData
@@ -967,6 +1277,25 @@ namespace GitHub.Runner.Worker
         public override bool HasPost => false;
     }
 
+    public sealed class CompositeActionExecutionData : ActionExecutionData
+    {
+        // Do I actually need this??
+        // Pre => pre execution for checking steps before, ibid for post
+        // Look at Script for dummy example
+
+        public override ActionExecutionType ExecutionType => ActionExecutionType.Composite;
+        public override bool HasPre => false;
+        public override bool HasPost => false;
+
+        public List<Pipelines.ActionStep> Steps {get; set;}
+
+        // public string Script { get; set; }
+
+        // public string Pre { get; set; }
+
+        // public string Post { get; set; }
+    }
+
     public abstract class ActionExecutionData
     {
         private string _initCondition = $"{Constants.Expressions.Always}()";

src/Runner.Worker/ActionManifestManager.cs

@@ -14,6 +14,7 @@ using YamlDotNet.Core;
 using YamlDotNet.Core.Events;
 using System.Globalization;
 using System.Linq;
+using GitHub.DistributedTask.Pipelines;
 
 namespace GitHub.Runner.Worker
 {
@@ -92,7 +93,7 @@ namespace GitHub.Runner.Worker
                             break;
 
                         case "runs":
-                            actionDefinition.Execution = ConvertRuns(context, actionPair.Value);
+                            actionDefinition.Execution = ConvertRuns(executionContext, context, actionPair.Value);
                             break;
                         default:
                             Trace.Info($"Ignore action property {propertyName}.");
@@ -294,8 +295,10 @@ namespace GitHub.Runner.Worker
         }
 
         private ActionExecutionData ConvertRuns(
+            IExecutionContext executionContext,
             TemplateContext context,
-            TemplateToken inputsToken)
+            TemplateToken inputsToken
+            )
         {
             var runsMapping = inputsToken.AssertMapping("runs");
             var usingToken = default(StringToken);
@@ -311,6 +314,15 @@ namespace GitHub.Runner.Worker
             var postToken = default(StringToken);
             var postEntrypointToken = default(StringToken);
             var postIfToken = default(StringToken);
+            // TODO: How do I represent stepsToken as a list of steps?
+            // Well for default value, we can set it to this?
+            // var stepsToken = runsMapping.AssertMapping("steps");
+            // Actually, not sure, let's just set it to MappingToken since AssertMapping("steps") 
+            // returns a MappingToken
+            // var stepsToken = default(SequenceToken);
+            var stepsLoaded = default(List<ActionStep>);
+            // It should be a array (aka sequence)
+
             foreach (var run in runsMapping)
             {
                 var runsKey = run.Key.AssertString("runs key").Value;
@@ -355,6 +367,22 @@ namespace GitHub.Runner.Worker
                     case "pre-if":
                         preIfToken = run.Value.AssertString("pre-if");
                         break;
+                    case "steps":
+                        // stepsToken = run.Value.AssertMapping("steps");
+                        // Maybe insert a for loop here instead since MappingToken is not supposed to be used in HandlerFactory.cs
+                        // Just support 1 layer of steps w/ just run
+                        var steps = run.Value.AssertSequence("steps");
+                        // foreach (var s in steps) {
+                        //     // Create list of steps
+                        //     loadS
+                        // }
+                        // foreach (var run in runsMapping)
+                        // stepsToken = List
+                        // Call load steps here
+                        // var test = new PipelineTemplateEvaluator();
+                        var evaluator = executionContext.ToPipelineTemplateEvaluator();
+                        stepsLoaded = evaluator.LoadSteps(steps, null, null);
+                        break;
                     default:
                         Trace.Info($"Ignore run property {runsKey}.");
                         break;
@@ -402,6 +430,24 @@ namespace GitHub.Runner.Worker
                         };
                     }
                 }
+                // TODO: add composite stuff here
+                else if (string.Equals(usingToken.Value, "composite", StringComparison.OrdinalIgnoreCase))
+                {
+                    // if (stepsToken.Count <= 0)
+                    // {
+                    //     throw new ArgumentNullException($"No steps provided.");
+                    // }
+                    if (stepsLoaded == null) {
+                        throw new ArgumentNullException($"No steps provided.");
+                    }
+                    else
+                    {
+                        return new CompositeActionExecutionData()
+                        {
+                            Steps = stepsLoaded
+                        };
+                    }
+                }
                 else
                 {
                     throw new ArgumentOutOfRangeException($"'using: {usingToken.Value}' is not supported, use 'docker' or 'node12' instead.");

src/Runner.Worker/ActionRunner.cs

@@ -187,13 +187,19 @@ namespace GitHub.Runner.Worker
             // Validate inputs only for actions with action.yml
             if (Action.Reference.Type == Pipelines.ActionSourceType.Repository)
             {
+                var unexpectedInputs = new List<string>();
                 foreach (var input in userInputs)
                 {
                     if (!validInputs.Contains(input))
                     {
-                        ExecutionContext.Warning($"Unexpected input '{input}', valid inputs are ['{string.Join("', '", validInputs)}']");
+                        unexpectedInputs.Add(input);
                     }
                 }
+
+                if (unexpectedInputs.Count > 0)
+                {
+                    ExecutionContext.Warning($"Unexpected input(s) '{string.Join("', '", unexpectedInputs)}', valid inputs are ['{string.Join("', '", validInputs)}']");
+                }
             }
 
             // Load the action environment.

src/Runner.Worker/ExecutionContext.cs

@@ -44,6 +44,7 @@ namespace GitHub.Runner.Worker
         TaskResult? CommandResult { get; set; }
         CancellationToken CancellationToken { get; }
         List<ServiceEndpoint> Endpoints { get; }
+        TaskOrchestrationPlanReference Plan { get; }
 
         PlanFeatures Features { get; }
         Variables Variables { get; }
@@ -141,6 +142,7 @@ namespace GitHub.Runner.Worker
         public Task ForceCompleted => _forceCompleted.Task;
         public CancellationToken CancellationToken => _cancellationTokenSource.Token;
         public List<ServiceEndpoint> Endpoints { get; private set; }
+        public TaskOrchestrationPlanReference Plan { get; private set; }
         public Variables Variables { get; private set; }
         public Dictionary<string, string> IntraActionState { get; private set; }
         public IDictionary<String, IDictionary<String, String>> JobDefaults { get; private set; }
@@ -275,6 +277,7 @@ namespace GitHub.Runner.Worker
             child.Features = Features;
             child.Variables = Variables;
             child.Endpoints = Endpoints;
+            child.Plan = Plan;
             if (intraActionState == null)
             {
                 child.IntraActionState = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
@@ -576,7 +579,8 @@ namespace GitHub.Runner.Worker
 
             _cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(token);
 
-            // Features
+            // Plan
+            Plan = message.Plan;
             Features = PlanUtil.GetFeatures(message.Plan);
 
             // Endpoints

src/Runner.Worker/Expressions/HashFilesFunction.cs

@@ -12,6 +12,8 @@ namespace GitHub.Runner.Worker.Expressions
 {
     public sealed class HashFilesFunction : Function
     {
+        private const int _hashFileTimeoutSeconds = 120;
+
         protected sealed override Object EvaluateCore(
             EvaluationContext context,
             out ResultMemory resultMemory)
@@ -89,19 +91,29 @@ namespace GitHub.Runner.Worker.Expressions
             }
             env["patterns"] = string.Join(Environment.NewLine, patterns);
 
-            int exitCode = p.ExecuteAsync(workingDirectory: githubWorkspace,
+            using (var tokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(_hashFileTimeoutSeconds)))
-                                          fileName: node,
-                                          arguments: $"\"{hashFilesScript.Replace("\"", "\\\"")}\"",
-                                          environment: env,
-                                          requireExitCodeZero: false,
-                                          cancellationToken: new CancellationTokenSource(TimeSpan.FromSeconds(120)).Token).GetAwaiter().GetResult();
-
-            if (exitCode != 0)
             {
-                throw new InvalidOperationException($"hashFiles('{ExpressionUtility.StringEscape(string.Join(", ", patterns))}') failed. Fail to hash files under directory '{githubWorkspace}'");
+                try
-            }
+                {
+                    int exitCode = p.ExecuteAsync(workingDirectory: githubWorkspace,
+                                                  fileName: node,
+                                                  arguments: $"\"{hashFilesScript.Replace("\"", "\\\"")}\"",
+                                                  environment: env,
+                                                  requireExitCodeZero: false,
+                                                  cancellationToken: tokenSource.Token).GetAwaiter().GetResult();
 
-            return hashResult;
+                    if (exitCode != 0)
+                    {
+                        throw new InvalidOperationException($"hashFiles('{ExpressionUtility.StringEscape(string.Join(", ", patterns))}') failed. Fail to hash files under directory '{githubWorkspace}'");
+                    }
+                }
+                catch (OperationCanceledException) when (tokenSource.IsCancellationRequested)
+                {
+                    throw new TimeoutException($"hashFiles('{ExpressionUtility.StringEscape(string.Join(", ", patterns))}') couldn't finish within {_hashFileTimeoutSeconds} seconds.");
+                }
+
+                return hashResult;
+            }
         }
 
         private sealed class HashFilesTrace : ITraceWriter

src/Runner.Worker/Handlers/CompositeActionHandler.cs

@@ -0,0 +1,399 @@
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using GitHub.Runner.Common;
+using GitHub.Runner.Sdk;
+using GitHub.DistributedTask.WebApi;
+using Pipelines = GitHub.DistributedTask.Pipelines;
+using System;
+using System.Linq;
+using GitHub.DistributedTask.ObjectTemplating.Tokens;
+using System.Collections.Generic;
+using GitHub.DistributedTask.Pipelines.ContextData;
+
+namespace GitHub.Runner.Worker.Handlers
+{
+    [ServiceLocator(Default = typeof(CompositeActionHandler))]
+    public interface ICompositeActionHandler : IHandler
+    {
+        CompositeActionExecutionData Data { get; set; }
+    }
+
+    // TODO: IMPLEMENT LOGIC FOR HANDLER CODE
+    public sealed class CompositeActionHandler : Handler, ICompositeActionHandler
+    {
+        public CompositeActionExecutionData Data { get; set; }
+
+        // TODO: Implement PrintActionDetails()
+        public override void PrintActionDetails(ActionRunStage stage)
+        {
+            // Just keep as same as ScriptHandler.cs for now
+            var target = Data.Steps;
+            var runStepInputs = target[0].Inputs;
+            var templateEvaluator = ExecutionContext.ToPipelineTemplateEvaluator();
+            var inputs = templateEvaluator.EvaluateStepInputs(runStepInputs, ExecutionContext.ExpressionValues, ExecutionContext.ExpressionFunctions);
+            var taskManager = HostContext.GetService<IActionManager>();
+            var userInputs = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            var runValue = "";
+            foreach (KeyValuePair<string, string> input in inputs)
+            {
+                userInputs.Add(input.Key);
+                userInputs.Add(input.Value);
+                if (input.Key.Equals("run"))
+                {
+                    runValue = input.Value;
+                }
+            }
+            var contents = runValue ?? string.Empty;
+            if (Action.Type == Pipelines.ActionSourceType.Repository)
+            {
+                var firstLine = contents.TrimStart(' ', '\t', '\r', '\n');
+                var firstNewLine = firstLine.IndexOfAny(new[] { '\r', '\n' });
+                if (firstNewLine >= 0)
+                {
+                    firstLine = firstLine.Substring(0, firstNewLine);
+                }
+
+                ExecutionContext.Output($"##[group]Run {firstLine}");
+            }
+            else
+            {
+                throw new InvalidOperationException($"Invalid action type {Action.Type} for {nameof(ScriptHandler)}");
+            }
+
+            var multiLines = contents.Replace("\r\n", "\n").TrimEnd('\n').Split('\n');
+            foreach (var line in multiLines)
+            {
+                // Bright Cyan color
+                ExecutionContext.Output($"\x1b[36;1m{line}\x1b[0m");
+            }
+
+            string argFormat;
+            string shellCommand;
+            string shellCommandPath = null;
+            bool validateShellOnHost = !(StepHost is ContainerStepHost);
+            string prependPath = string.Join(Path.PathSeparator.ToString(), ExecutionContext.PrependPath.Reverse<string>());
+            string shell = null;
+            if (!Inputs.TryGetValue("shell", out shell) || string.IsNullOrEmpty(shell))
+            {
+                // TODO: figure out how defaults interact with template later
+                // for now, we won't check job.defaults if we are inside a template.
+                if (string.IsNullOrEmpty(ExecutionContext.ScopeName) && ExecutionContext.JobDefaults.TryGetValue("run", out var runDefaults))
+                {
+                    runDefaults.TryGetValue("shell", out shell);
+                }
+            }
+            if (string.IsNullOrEmpty(shell))
+            {
+#if OS_WINDOWS
+                shellCommand = "pwsh";
+                if (validateShellOnHost)
+                {
+                    shellCommandPath = WhichUtil.Which(shellCommand, require: false, Trace, prependPath);
+                    if (string.IsNullOrEmpty(shellCommandPath))
+                    {
+                        shellCommand = "powershell";
+                        Trace.Info($"Defaulting to {shellCommand}");
+                        shellCommandPath = WhichUtil.Which(shellCommand, require: true, Trace, prependPath);
+                    }
+                }
+#else
+                shellCommand = "sh";
+                if (validateShellOnHost)
+                {
+                    shellCommandPath = WhichUtil.Which("bash", false, Trace, prependPath) ?? WhichUtil.Which("sh", true, Trace, prependPath);
+                }
+#endif
+                argFormat = ScriptHandlerHelpers.GetScriptArgumentsFormat(shellCommand);
+            }
+            else
+            {
+                var parsed = ScriptHandlerHelpers.ParseShellOptionString(shell);
+                shellCommand = parsed.shellCommand;
+                if (validateShellOnHost)
+                {
+                    shellCommandPath = WhichUtil.Which(parsed.shellCommand, true, Trace, prependPath);
+                }
+
+                argFormat = $"{parsed.shellArgs}".TrimStart();
+                if (string.IsNullOrEmpty(argFormat))
+                {
+                    argFormat = ScriptHandlerHelpers.GetScriptArgumentsFormat(shellCommand);
+                }
+            }
+
+            if (!string.IsNullOrEmpty(shellCommandPath))
+            {
+                ExecutionContext.Output($"shell: {shellCommandPath} {argFormat}");
+            }
+            else
+            {
+                ExecutionContext.Output($"shell: {shellCommand} {argFormat}");
+            }
+
+            if (this.Environment?.Count > 0)
+            {
+                ExecutionContext.Output("env:");
+                foreach (var env in this.Environment)
+                {
+                    ExecutionContext.Output($"  {env.Key}: {env.Value}");
+                }
+            }
+
+            ExecutionContext.Output("##[endgroup]");
+        }
+
+        public async Task RunAsync(ActionRunStage stage)
+        {
+            // DELETE LATER
+            // await Task.Yield();
+
+
+            // Basically, the only difference from ScriptHandler.cs is that "contents" is not just each step under "run: "
+            // It might make more sense to:
+            // 1) Abstract the core functionality of the ScriptHandler.cs that we need for BOTH CompositeActionHandler.cs and ScriptHandler.cs
+            // 2) Call those functions in both handlers
+            // * There is already a file called ScriptHandlerHelpers.cs that might be a good location to add more functions. 
+
+            // Copied from ScriptHandler.cs
+            // Validate args.
+            Trace.Entering();
+            ArgUtil.NotNull(ExecutionContext, nameof(ExecutionContext));
+            ArgUtil.NotNull(Inputs, nameof(Inputs));
+
+            var githubContext = ExecutionContext.ExpressionValues["github"] as GitHubContext;
+            ArgUtil.NotNull(githubContext, nameof(githubContext));
+
+            var tempDirectory = HostContext.GetDirectory(WellKnownDirectory.Temp);
+
+            // Resolve steps
+            var target = Data.Steps;
+            if (target == null) {
+                Trace.Error("Data.Steps in CompositeActionHandler is null");
+            } else {
+                Trace.Info($"Data Steps Value for Composite Actions is: {target}.");
+            }
+
+
+            // For now, just assume it is 1 Run step
+            // We will adapt this in the future. 
+            // Copied from ActionRunner.cs RunAsync() function => Maybe we don't need a handler and need to avoid this preplicatoin in the future?
+            var runStepInputs = target[0].Inputs;
+            if (runStepInputs == null) {
+                Trace.Error("runStepInputs in CompositeActionHandler is null");
+            } else {
+                Trace.Info($"runStepInputs Value for Composite Actions is: {runStepInputs}.");
+            }
+            var templateEvaluator = ExecutionContext.ToPipelineTemplateEvaluator();
+            var inputs = templateEvaluator.EvaluateStepInputs(runStepInputs, ExecutionContext.ExpressionValues, ExecutionContext.ExpressionFunctions);
+            var taskManager = HostContext.GetService<IActionManager>();
+
+            var userInputs = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            var runValue = "";
+            foreach (KeyValuePair<string, string> input in inputs)
+            {
+                userInputs.Add(input.Key);
+                userInputs.Add(input.Value);
+                Trace.Info($"Composite Action Handler. Key: {input.Key} Value: {input.Value}");
+                // Why is the key should not be "run" => because the "run" keyword is recorgnized as something that will be a "script"?
+                // Or should we create another key that delineates between "script" and "run"?
+                // ^ Perhaps we can explore this in the next version with the changes the to action.yaml template
+                if (input.Key.Equals("script"))
+                {
+                    runValue = input.Value;
+                }
+
+                // string message = "";
+                // if (definition.Data?.Deprecated?.TryGetValue(input.Key, out message) == true)
+                // {
+                //     ExecutionContext.Warning(String.Format("Input '{0}' has been deprecated with message: {1}", input.Key, message));
+                // }
+
+                // Get the run bash value that we want to run
+                // In the future, we would apply and validate the template => maybe using the manifest manager to recursively load the json schema.
+            }
+
+            Trace.Info($"Run Value for Composite Actions is: {runValue}.");
+
+            // Let's think about validating inputs later
+            // Validate inputs only for actions with action.yml
+            // var unexpectedInputs = new List<string>();
+            // foreach (var input in userInputs)
+            // {
+            //     if (!validInputs.Contains(input))
+            //     {
+            //         unexpectedInputs.Add(input);
+            //     }
+            // }
+
+            // if (unexpectedInputs.Count > 0)
+            // {
+            //     ExecutionContext.Warning($"Unexpected input(s) '{string.Join("', '", unexpectedInputs)}', valid inputs are ['{string.Join("', '", validInputs)}']");
+            // }
+
+
+            //TODO:
+            // 6/11/20 EOD thoughts
+            // => What functions do I need to use from ScriptHandlerHelpers.cs?
+            // Do I need to Reverse the string for prepending the path??
+            //      ^ why or why not?
+            // How do I process the Inputs?
+            //      => It's a TemplateToken
+            // How do I incorporate Async? we call the StepHost for Async when you call ExecuteAsync()
+
+            // Detect operating system for fileName + arguments
+
+            var contents = runValue ?? string.Empty;
+
+            string workingDirectory = null;
+            if (!Inputs.TryGetValue("workingDirectory", out workingDirectory))
+            {
+                // TODO: figure out how defaults interact with template later
+                // for now, we won't check job.defaults if we are inside a template.
+                if (string.IsNullOrEmpty(ExecutionContext.ScopeName) && ExecutionContext.JobDefaults.TryGetValue("run", out var runDefaults))
+                {
+                    if (runDefaults.TryGetValue("working-directory", out workingDirectory))
+                    {
+                        ExecutionContext.Debug("Overwrite 'working-directory' base on job defaults.");
+                    }
+                }
+            }
+            var workspaceDir = githubContext["workspace"] as StringContextData;
+            workingDirectory = Path.Combine(workspaceDir, workingDirectory ?? string.Empty);
+
+
+            string shell = null;
+            if (!Inputs.TryGetValue("shell", out shell) || string.IsNullOrEmpty(shell))
+            {
+                // TODO: figure out how defaults interact with template later
+                // for now, we won't check job.defaults if we are inside a template.
+                if (string.IsNullOrEmpty(ExecutionContext.ScopeName) && ExecutionContext.JobDefaults.TryGetValue("run", out var runDefaults))
+                {
+                    if (runDefaults.TryGetValue("shell", out shell))
+                    {
+                        ExecutionContext.Debug("Overwrite 'shell' base on job defaults.");
+                    }
+                }
+            }
+
+            var isContainerStepHost = StepHost is ContainerStepHost;
+
+            string prependPath = string.Join(Path.PathSeparator.ToString(), ExecutionContext.PrependPath.Reverse<string>());
+            string commandPath, argFormat, shellCommand;
+
+            if (string.IsNullOrEmpty(shell))
+            {
+#if OS_WINDOWS
+                shellCommand = "pwsh";
+                commandPath = WhichUtil.Which(shellCommand, require: false, Trace, prependPath);
+                if (string.IsNullOrEmpty(commandPath))
+                {
+                    shellCommand = "powershell";
+                    Trace.Info($"Defaulting to {shellCommand}");
+                    commandPath = WhichUtil.Which(shellCommand, require: true, Trace, prependPath);
+                }
+                ArgUtil.NotNullOrEmpty(commandPath, "Default Shell");
+#else
+                shellCommand = "sh";
+                commandPath = WhichUtil.Which("bash", false, Trace, prependPath) ?? WhichUtil.Which("sh", true, Trace, prependPath);
+#endif
+                argFormat = ScriptHandlerHelpers.GetScriptArgumentsFormat(shellCommand);
+            }
+            else
+            {
+                var parsed = ScriptHandlerHelpers.ParseShellOptionString(shell);
+                shellCommand = parsed.shellCommand;
+                // For non-ContainerStepHost, the command must be located on the host by Which
+                commandPath = WhichUtil.Which(parsed.shellCommand, !isContainerStepHost, Trace, prependPath);
+                argFormat = $"{parsed.shellArgs}".TrimStart();
+                if (string.IsNullOrEmpty(argFormat))
+                {
+                    argFormat = ScriptHandlerHelpers.GetScriptArgumentsFormat(shellCommand);
+                }
+            }
+
+            // No arg format was given, shell must be a built-in
+            if (string.IsNullOrEmpty(argFormat) || !argFormat.Contains("{0}"))
+            {
+                throw new ArgumentException("Invalid shell option. Shell must be a valid built-in (bash, sh, cmd, powershell, pwsh) or a format string containing '{0}'");
+            }
+
+            // We do not not the full path until we know what shell is being used, so that we can determine the file extension
+            var scriptFilePath = Path.Combine(tempDirectory, $"{Guid.NewGuid()}{ScriptHandlerHelpers.GetScriptFileExtension(shellCommand)}");
+            var resolvedScriptPath = $"{StepHost.ResolvePathForStepHost(scriptFilePath).Replace("\"", "\\\"")}";
+
+            // Format arg string with script path
+            var arguments = string.Format(argFormat, resolvedScriptPath);
+
+            // Fix up and write the script
+            contents = ScriptHandlerHelpers.FixUpScriptContents(shellCommand, contents);
+#if OS_WINDOWS
+            // Normalize Windows line endings
+            contents = contents.Replace("\r\n", "\n").Replace("\n", "\r\n");
+            var encoding = ExecutionContext.Variables.Retain_Default_Encoding && Console.InputEncoding.CodePage != 65001
+                ? Console.InputEncoding
+                : new UTF8Encoding(false);
+#else
+            // Don't add a BOM. It causes the script to fail on some operating systems (e.g. on Ubuntu 14).
+            var encoding = new UTF8Encoding(false);
+#endif
+            // Script is written to local path (ie host) but executed relative to the StepHost, which may be a container
+            File.WriteAllText(scriptFilePath, contents, encoding);
+
+            // Prepend PATH
+            AddPrependPathToEnvironment();
+
+            // expose context to environment
+            foreach (var context in ExecutionContext.ExpressionValues)
+            {
+                if (context.Value is IEnvironmentContextData runtimeContext && runtimeContext != null)
+                {
+                    foreach (var env in runtimeContext.GetRuntimeEnvironmentVariables())
+                    {
+                        Environment[env.Key] = env.Value;
+                    }
+                }
+            }
+
+            // dump out the command
+            var fileName = isContainerStepHost ? shellCommand : commandPath;
+#if OS_OSX
+            if (Environment.ContainsKey("DYLD_INSERT_LIBRARIES"))  // We don't check `isContainerStepHost` because we don't support container on macOS
+            {
+                // launch `node macOSRunInvoker.js shell args` instead of `shell args` to avoid macOS SIP remove `DYLD_INSERT_LIBRARIES` when launch process
+                string node12 = Path.Combine(HostContext.GetDirectory(WellKnownDirectory.Externals), "node12", "bin", $"node{IOUtil.ExeExtension}");
+                string macOSRunInvoker = Path.Combine(HostContext.GetDirectory(WellKnownDirectory.Bin), "macos-run-invoker.js");
+                arguments = $"\"{macOSRunInvoker.Replace("\"", "\\\"")}\" \"{fileName.Replace("\"", "\\\"")}\" {arguments}";
+                fileName = node12;
+            }
+#endif
+            ExecutionContext.Debug($"{fileName} {arguments}");
+
+            using (var stdoutManager = new OutputManager(ExecutionContext, ActionCommandManager))
+            using (var stderrManager = new OutputManager(ExecutionContext, ActionCommandManager))
+            {
+                StepHost.OutputDataReceived += stdoutManager.OnDataReceived;
+                StepHost.ErrorDataReceived += stderrManager.OnDataReceived;
+
+                // Execute
+                int exitCode = await StepHost.ExecuteAsync(workingDirectory: StepHost.ResolvePathForStepHost(workingDirectory),
+                                            fileName: fileName,
+                                            arguments: arguments,
+                                            environment: Environment,
+                                            requireExitCodeZero: false,
+                                            outputEncoding: null,
+                                            killProcessOnCancel: false,
+                                            inheritConsoleHandler: !ExecutionContext.Variables.Retain_Default_Encoding,
+                                            cancellationToken: ExecutionContext.CancellationToken);
+
+                // Error
+                if (exitCode != 0)
+                {
+                    ExecutionContext.Error($"Process completed with exit code {exitCode}.");
+                    ExecutionContext.Result = TaskResult.Failed;
+                }
+            }
+        }
+
+    }
+}

src/Runner.Worker/Handlers/HandlerFactory.cs

@@ -66,6 +66,14 @@ namespace GitHub.Runner.Worker.Handlers
                 handler = HostContext.CreateService<IRunnerPluginHandler>();
                 (handler as IRunnerPluginHandler).Data = data as PluginActionExecutionData;
             }
+            else if (data.ExecutionType == ActionExecutionType.Composite)
+            {
+                // TODO
+                // Runner plugin
+                handler = HostContext.CreateService<ICompositeActionHandler>();
+                // handler = CompositeHandler;
+                (handler as ICompositeActionHandler).Data = data as CompositeActionExecutionData;
+            }
             else
             {
                 // This should never happen.

src/Runner.Worker/JobExtension.cs

@@ -239,6 +239,7 @@ namespace GitHub.Runner.Worker
                             }
 
                             actionRunner.TryEvaluateDisplayName(contextData, context);
+
                             jobSteps.Add(actionRunner);
 
                             if (prepareResult.PreStepTracker.TryGetValue(step.Id, out var preStep))
@@ -284,6 +285,13 @@ namespace GitHub.Runner.Worker
                             intraActionStates.TryGetValue(actionStep.Action.Id, out var intraActionState);
                             actionStep.ExecutionContext = jobContext.CreateChild(actionStep.Action.Id, actionStep.DisplayName, actionStep.Action.Name, actionStep.Action.ScopeName, actionStep.Action.ContextName, intraActionState);
                         }
+
+                        // TODO: Maybe add EvaluateStep stuff here too?
+                        // TODO: INSERT CONVERTSTEPS FUNCTION HERE FOR EVALUATING STEPS
+                            // Maybe we don't need to do this here do we need to initialize the job?
+                            // context.Debug("Evaluating job evaluating steps");
+                            // var stepsEvaluation = templateEvaluator.EvaluateSteps(contextData, context, context.ExpressionFunctions);
+                            ////////
                     }
 
                     List<IStep> steps = new List<IStep>();

src/Runner.Worker/JobRunner.cs

@@ -5,21 +5,13 @@ using GitHub.Services.Common;
 using GitHub.Services.WebApi;
 using System;
 using System.Collections.Generic;
-using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Net.Http;
-using System.Text;
-using System.IO.Compression;
-using System.Diagnostics;
-using Newtonsoft.Json.Linq;
-using GitHub.DistributedTask.ObjectTemplating.Tokens;
 using GitHub.Runner.Common;
 using GitHub.Runner.Sdk;
-using GitHub.DistributedTask.Pipelines.ContextData;
-using GitHub.DistributedTask.ObjectTemplating;
 
 namespace GitHub.Runner.Worker
 {
@@ -68,9 +60,11 @@ namespace GitHub.Runner.Worker
             {
                 // Create the job execution context.
                 jobContext = HostContext.CreateService<IExecutionContext>();
+                // HERE
                 jobContext.InitializeJob(message, jobRequestCancellationToken);
                 Trace.Info("Starting the job execution context.");
                 jobContext.Start();
+                // User will see this message too
                 jobContext.Debug($"Starting: {message.JobDisplayName}");
 
                 runnerShutdownRegistration = HostContext.RunnerShutdownToken.Register(() =>
@@ -122,13 +116,6 @@ namespace GitHub.Runner.Worker
                 _tempDirectoryManager = HostContext.GetService<ITempDirectoryManager>();
                 _tempDirectoryManager.InitializeTempDirectory(jobContext);
 
-                // // Expand container properties
-                // jobContext.Container?.ExpandProperties(jobContext.Variables);
-                // foreach (var sidecar in jobContext.SidecarContainers)
-                // {
-                //     sidecar.ExpandProperties(jobContext.Variables);
-                // }
-
                 // Get the job extension.
                 Trace.Info("Getting job extension.");
                 IJobExtension jobExtension = HostContext.CreateService<IJobExtension>();

src/Runner.Worker/action_yaml.json

@@ -32,7 +32,8 @@
             "one-of": [
                 "container-runs",
                 "node12-runs",
-                "plugin-runs"
+                "plugin-runs",
+                "composite-runs"
             ]
         },
         "container-runs": {
@@ -83,6 +84,31 @@
                 }
             }
         },
+        "composite-runs": {
+            "mapping" : {
+                "properties": {
+                    "using": "non-empty-string",
+                    "steps": "steps"
+                }
+            }
+        },
+        "steps": {
+            "sequence": {
+                "item-type": "steps-item"
+            }
+        },
+        "steps-item": {
+            "one-of": [
+                "run-step"
+            ]
+        },
+        "run-step": {
+            "mapping": {
+              "properties": {
+                "run": "non-empty-string"
+              }
+            }
+        },
         "container-runs-context": {
             "context": [
                 "inputs"

src/Sdk/DTGenerated/Generated/TaskHttpClientBase.cs

@@ -317,5 +317,37 @@ namespace GitHub.DistributedTask.WebApi
                 userState: userState,
                 cancellationToken: cancellationToken);
         }
+
+        /// <summary>
+        /// [Preview API] Resolves information required to download actions (URL, token) defined in an orchestration.
+        /// </summary>
+        /// <param name="scopeIdentifier">The project GUID to scope the request</param>
+        /// <param name="hubName">The name of the server hub: "build" for the Build server or "rm" for the Release Management server</param>
+        /// <param name="planId"></param>
+        /// <param name="actionReferenceList"></param>
+        /// <param name="userState"></param>
+        /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
+        public virtual Task<ActionDownloadInfoCollection> ResolveActionDownloadInfoAsync(
+            Guid scopeIdentifier,
+            string hubName,
+            Guid planId,
+            ActionReferenceList actionReferenceList,
+            object userState = null,
+            CancellationToken cancellationToken = default)
+        {
+            HttpMethod httpMethod = new HttpMethod("POST");
+            Guid locationId = new Guid("27d7f831-88c1-4719-8ca1-6a061dad90eb");
+            object routeValues = new { scopeIdentifier = scopeIdentifier, hubName = hubName, planId = planId };
+            HttpContent content = new ObjectContent<ActionReferenceList>(actionReferenceList, new VssJsonMediaTypeFormatter(true));
+
+            return SendAsync<ActionDownloadInfoCollection>(
+                httpMethod,
+                locationId,
+                routeValues: routeValues,
+                version: new ApiResourceVersion(6.0, 1),
+                userState: userState,
+                cancellationToken: cancellationToken,
+                content: content);
+        }
     }
 }

src/Sdk/DTPipelines/Pipelines/ObjectTemplating/PipelineTemplateConverter.cs

@@ -16,6 +16,7 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
 {
     internal static class PipelineTemplateConverter
     {
+
         internal static Boolean ConvertToIfResult(
             TemplateContext context,
             TemplateToken ifResult)
@@ -29,7 +30,6 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             var evaluationResult = EvaluationResult.CreateIntermediateResult(null, ifResult);
             return evaluationResult.IsTruthy;
         }
-
         internal static Boolean? ConvertToStepContinueOnError(
             TemplateContext context,
             TemplateToken token,
@@ -264,5 +264,351 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
 
             return result;
         }
+
+        //Note: originally was List<Step> but we need to change to List<ActionStep> to use the "Inputs" attribute
+        internal static List<ActionStep> ConvertToSteps(
+            TemplateContext context,
+            TemplateToken steps)
+        {
+            var stepsSequence = steps.AssertSequence($"job {PipelineTemplateConstants.Steps}");
+
+            var result = new List<ActionStep>();
+            foreach (var stepsItem in stepsSequence)
+            {
+                var step = ConvertToStep(context, stepsItem);
+                if (step != null) // step = null means we are hitting error during step conversion, there should be an error in context.errors
+                {
+                    if (step.Enabled)
+                    {
+                        result.Add(step);
+                    }
+                }
+            }
+
+            return result;
+        }
+
+        private static ActionStep ConvertToStep(
+            TemplateContext context,
+            TemplateToken stepsItem)
+        {
+            var step = stepsItem.AssertMapping($"{PipelineTemplateConstants.Steps} item");
+            var continueOnError = default(ScalarToken);
+            var env = default(TemplateToken);
+            var id = default(StringToken);
+            var ifCondition = default(String);
+            var ifToken = default(ScalarToken);
+            var name = default(ScalarToken);
+            var run = default(ScalarToken);
+            var scope = default(StringToken);
+            var timeoutMinutes = default(ScalarToken);
+            var uses = default(StringToken);
+            var with = default(TemplateToken);
+            var workingDir = default(ScalarToken);
+            var path = default(ScalarToken);
+            var clean = default(ScalarToken);
+            var fetchDepth = default(ScalarToken);
+            var lfs = default(ScalarToken);
+            var submodules = default(ScalarToken);
+            var shell = default(ScalarToken);
+
+            foreach (var stepProperty in step)
+            {
+                var propertyName = stepProperty.Key.AssertString($"{PipelineTemplateConstants.Steps} item key");
+
+                switch (propertyName.Value)
+                {
+                    case PipelineTemplateConstants.Clean:
+                        clean = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Clean}");
+                        break;
+
+                    case PipelineTemplateConstants.ContinueOnError:
+                        ConvertToStepContinueOnError(context, stepProperty.Value, allowExpressions: true); // Validate early if possible
+                        continueOnError = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} {PipelineTemplateConstants.ContinueOnError}");
+                        break;
+
+                    case PipelineTemplateConstants.Env:
+                        ConvertToStepEnvironment(context, stepProperty.Value, StringComparer.Ordinal, allowExpressions: true); // Validate early if possible
+                        env = stepProperty.Value;
+                        break;
+
+                    case PipelineTemplateConstants.FetchDepth:
+                        fetchDepth = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.FetchDepth}");
+                        break;
+
+                    case PipelineTemplateConstants.Id:
+                        id = stepProperty.Value.AssertString($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Id}");
+                        if (!NameValidation.IsValid(id.Value, true))
+                        {
+                            context.Error(id, $"Step id {id.Value} is invalid. Ids must start with a letter or '_' and contain only alphanumeric characters, '-', or '_'");
+                        }
+                        break;
+
+                    case PipelineTemplateConstants.If:
+                        ifToken = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.If}");
+                        break;
+
+                    case PipelineTemplateConstants.Lfs:
+                        lfs = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Lfs}");
+                        break;
+
+                    case PipelineTemplateConstants.Name:
+                        name = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Name}");
+                        break;
+
+                    case PipelineTemplateConstants.Path:
+                        path = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Path}");
+                        break;
+
+                    case PipelineTemplateConstants.Run:
+                        run = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Run}");
+                        break;
+
+                    case PipelineTemplateConstants.Shell:
+                        shell = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Shell}");
+                        break;
+
+                    case PipelineTemplateConstants.Scope:
+                        scope = stepProperty.Value.AssertString($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Scope}");
+                        break;
+
+                    case PipelineTemplateConstants.Submodules:
+                        submodules = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Submodules}");
+                        break;
+
+                    case PipelineTemplateConstants.TimeoutMinutes:
+                        ConvertToStepTimeout(context, stepProperty.Value, allowExpressions: true); // Validate early if possible
+                        timeoutMinutes = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.TimeoutMinutes}");
+                        break;
+
+                    case PipelineTemplateConstants.Uses:
+                        uses = stepProperty.Value.AssertString($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Uses}");
+                        break;
+
+                    case PipelineTemplateConstants.With:
+                        ConvertToStepInputs(context, stepProperty.Value, allowExpressions: true); // Validate early if possible
+                        with = stepProperty.Value;
+                        break;
+
+                    case PipelineTemplateConstants.WorkingDirectory:
+                        workingDir = stepProperty.Value.AssertScalar($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.WorkingDirectory}");
+                        break;
+
+                    default:
+                        propertyName.AssertUnexpectedValue($"{PipelineTemplateConstants.Steps} item key"); // throws
+                        break;
+                }
+            }
+
+            // Fixup the if-condition
+            var isDefaultScope = String.IsNullOrEmpty(scope?.Value);
+            ifCondition = ConvertToIfCondition(context, ifToken, false, isDefaultScope);
+
+            if (run != null)
+            {
+                var result = new ActionStep
+                {
+                    ScopeName = scope?.Value,
+                    ContextName = id?.Value,
+                    ContinueOnError = continueOnError,
+                    DisplayNameToken = name,
+                    Condition = ifCondition,
+                    TimeoutInMinutes = timeoutMinutes,
+                    Environment = env,
+                    Reference = new ScriptReference(),
+                };
+
+                var inputs = new MappingToken(null, null, null);
+                inputs.Add(new StringToken(null, null, null, PipelineConstants.ScriptStepInputs.Script), run);
+
+                if (workingDir != null)
+                {
+                    inputs.Add(new StringToken(null, null, null, PipelineConstants.ScriptStepInputs.WorkingDirectory), workingDir);
+                }
+
+                if (shell != null)
+                {
+                    inputs.Add(new StringToken(null, null, null, PipelineConstants.ScriptStepInputs.Shell), shell);
+                }
+
+                result.Inputs = inputs;
+
+                return result;
+            }
+            else
+            {
+                uses.AssertString($"{PipelineTemplateConstants.Steps} item {PipelineTemplateConstants.Uses}");
+                var result = new ActionStep
+                {
+                    ScopeName = scope?.Value,
+                    ContextName = id?.Value,
+                    ContinueOnError = continueOnError,
+                    DisplayNameToken = name,
+                    Condition = ifCondition,
+                    TimeoutInMinutes = timeoutMinutes,
+                    Inputs = with,
+                    Environment = env,
+                };
+
+                if (uses.Value.StartsWith("docker://", StringComparison.Ordinal))
+                {
+                    var image = uses.Value.Substring("docker://".Length);
+                    result.Reference = new ContainerRegistryReference { Image = image };
+                }
+                else if (uses.Value.StartsWith("./") || uses.Value.StartsWith(".\\"))
+                {
+                    result.Reference = new RepositoryPathReference
+                    {
+                        RepositoryType = PipelineConstants.SelfAlias,
+                        Path = uses.Value
+                    };
+                }
+                else
+                {
+                    var usesSegments = uses.Value.Split('@');
+                    var pathSegments = usesSegments[0].Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);
+                    var gitRef = usesSegments.Length == 2 ? usesSegments[1] : String.Empty;
+
+                    if (usesSegments.Length != 2 ||
+                        pathSegments.Length < 2 ||
+                        String.IsNullOrEmpty(pathSegments[0]) ||
+                        String.IsNullOrEmpty(pathSegments[1]) ||
+                        String.IsNullOrEmpty(gitRef))
+                    {
+                        // todo: loc
+                        context.Error(uses, $"Expected format {{org}}/{{repo}}[/path]@ref. Actual '{uses.Value}'");
+                    }
+                    else
+                    {
+                        var repositoryName = $"{pathSegments[0]}/{pathSegments[1]}";
+                        var directoryPath = pathSegments.Length > 2 ? String.Join("/", pathSegments.Skip(2)) : String.Empty;
+
+                        result.Reference = new RepositoryPathReference
+                        {
+                            RepositoryType = RepositoryTypes.GitHub,
+                            Name = repositoryName,
+                            Ref = gitRef,
+                            Path = directoryPath,
+                        };
+                    }
+                }
+
+                return result;
+            }
+        }
+
+        /// <summary>
+        /// When empty, default to "success()".
+        /// When a status function is not referenced, format as "success() &amp;&amp; &lt;CONDITION&gt;".
+        /// </summary>
+        private static String ConvertToIfCondition(
+            TemplateContext context,
+            TemplateToken token,
+            Boolean isJob,
+            Boolean isDefaultScope)
+        {
+            String condition;
+            if (token is null)
+            {
+                condition = null;
+            }
+            else if (token is BasicExpressionToken expressionToken)
+            {
+                condition = expressionToken.Expression;
+            }
+            else
+            {
+                var stringToken = token.AssertString($"{(isJob ? "job" : "step")} {PipelineTemplateConstants.If}");
+                condition = stringToken.Value;
+            }
+
+            if (String.IsNullOrWhiteSpace(condition))
+            {
+                return $"{PipelineTemplateConstants.Success}()";
+            }
+
+            var expressionParser = new ExpressionParser();
+            var functions = default(IFunctionInfo[]);
+            var namedValues = default(INamedValueInfo[]);
+            if (isJob)
+            {
+                namedValues = s_jobIfNamedValues;
+                // TODO: refactor into seperate functions
+                // functions = PhaseCondition.FunctionInfo;
+            }
+            else
+            {
+                namedValues = isDefaultScope ? s_stepNamedValues : s_stepInTemplateNamedValues;
+                functions = s_stepConditionFunctions;
+            }
+
+            var node = default(ExpressionNode);
+            try
+            {
+                node = expressionParser.CreateTree(condition, null, namedValues, functions) as ExpressionNode;
+            }
+            catch (Exception ex)
+            {
+                context.Error(token, ex);
+                return null;
+            }
+
+            if (node == null)
+            {
+                return $"{PipelineTemplateConstants.Success}()";
+            }
+
+            var hasStatusFunction = node.Traverse().Any(x =>
+            {
+                if (x is Function function)
+                {
+                    return String.Equals(function.Name, PipelineTemplateConstants.Always, StringComparison.OrdinalIgnoreCase) ||
+                        String.Equals(function.Name, PipelineTemplateConstants.Cancelled, StringComparison.OrdinalIgnoreCase) ||
+                        String.Equals(function.Name, PipelineTemplateConstants.Failure, StringComparison.OrdinalIgnoreCase) ||
+                        String.Equals(function.Name, PipelineTemplateConstants.Success, StringComparison.OrdinalIgnoreCase);
+                }
+
+                return false;
+            });
+
+            return hasStatusFunction ? condition : $"{PipelineTemplateConstants.Success}() && ({condition})";
+        }
+
+        private static readonly INamedValueInfo[] s_jobIfNamedValues = new INamedValueInfo[]
+        {
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.GitHub),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Needs),
+        };
+        private static readonly INamedValueInfo[] s_stepNamedValues = new INamedValueInfo[]
+        {
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Strategy),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Matrix),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Steps),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.GitHub),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Job),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Runner),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Env),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Needs),
+        };
+        private static readonly INamedValueInfo[] s_stepInTemplateNamedValues = new INamedValueInfo[]
+        {
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Strategy),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Matrix),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Steps),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Inputs),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.GitHub),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Job),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Runner),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Env),
+            new NamedValueInfo<NoOperationNamedValue>(PipelineTemplateConstants.Needs),
+        };
+        private static readonly IFunctionInfo[] s_stepConditionFunctions = new IFunctionInfo[]
+        {
+            new FunctionInfo<NoOperation>(PipelineTemplateConstants.Always, 0, 0),
+            new FunctionInfo<NoOperation>(PipelineTemplateConstants.Cancelled, 0, 0),
+            new FunctionInfo<NoOperation>(PipelineTemplateConstants.Failure, 0, 0),
+            new FunctionInfo<NoOperation>(PipelineTemplateConstants.Success, 0, 0),
+            new FunctionInfo<NoOperation>(PipelineTemplateConstants.HashFiles, 1, Byte.MaxValue),
+        };
     }
 }

src/Sdk/DTPipelines/Pipelines/ObjectTemplating/PipelineTemplateEvaluator.cs

@@ -159,6 +159,44 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             return result;
         }
 
+        // TODO: Add function here that says Evaluate Steps but it will return whatever ConvertToSteps returns.
+        // return: List<ActionStep>
+        // used to be evaluatesteps
+        public List<ActionStep> LoadSteps(
+            TemplateToken token,
+            DictionaryContextData contextData,
+            IList<IFunctionInfo> expressionFunctions
+        )
+        {
+            // Similar to EvaluateStepDisplayName() except that we pass in PipelineTemplateConstants.Steps as the type for evaluation
+            var result = default(List<ActionStep>);
+
+            if (token != null && token.Type != TokenType.Null)
+            {
+                var context = CreateContext(contextData, expressionFunctions, setMissingContext: false);
+                // This will keep it from preexpanding
+                // TODO: we might want to to have a bool to prevent it from filling in with missing context w/ dummy variables
+                // context.ExpressionFunctions.Clear();
+                // context.ExpressionValues.Clear();
+
+                try
+                {
+                    token = TemplateEvaluator.Evaluate(context, PipelineTemplateConstants.Steps, token, 0, null, omitHeader: true);
+                    context.Errors.Check();
+                    result = PipelineTemplateConverter.ConvertToSteps(context, token);
+                }
+                catch (Exception ex) when (!(ex is TemplateValidationException))
+                {
+                    context.Errors.Add(ex);
+                }
+
+                context.Errors.Check();
+            }
+
+            return result;
+        }
+
+
         public Dictionary<String, String> EvaluateStepEnvironment(
             TemplateToken token,
             DictionaryContextData contextData,
@@ -400,7 +438,8 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
         private TemplateContext CreateContext(
             DictionaryContextData contextData,
             IList<IFunctionInfo> expressionFunctions,
-            IEnumerable<KeyValuePair<String, Object>> expressionState = null)
+            IEnumerable<KeyValuePair<String, Object>> expressionState = null,
+            bool setMissingContext = true)
         {
             var result = new TemplateContext
             {
@@ -449,18 +488,21 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             //   - Evaluating early when all referenced contexts are available, even though all allowed
             //     contexts may not yet be available. For example, evaluating step display name can often
             //     be performed early.
-            foreach (var name in s_expressionValueNames)
+            if (setMissingContext)
             {
-                if (!result.ExpressionValues.ContainsKey(name))
+                foreach (var name in s_expressionValueNames)
                 {
-                    result.ExpressionValues[name] = null;
+                    if (!result.ExpressionValues.ContainsKey(name))
+                    {
+                        result.ExpressionValues[name] = null;
+                    }
                 }
-            }
+                foreach (var name in s_expressionFunctionNames)
-            foreach (var name in s_expressionFunctionNames)
-            {
-                if (!functionNames.Contains(name))
                 {
-                    result.ExpressionFunctions.Add(new FunctionInfo<NoOperation>(name, 0, Int32.MaxValue));
+                    if (!functionNames.Contains(name))
+                    {
+                        result.ExpressionFunctions.Add(new FunctionInfo<NoOperation>(name, 0, Int32.MaxValue));
+                    }
                 }
             }
 

src/Sdk/DTPipelines/Pipelines/PipelineConstants.cs

@@ -94,5 +94,12 @@ namespace GitHub.DistributedTask.Pipelines
             public static readonly String Resources = "resources";
             public static readonly String All = "all";
         }
+
+        public static class ScriptStepInputs
+        {
+            public static readonly String Script = "script";
+            public static readonly String WorkingDirectory = "workingDirectory";
+            public static readonly String Shell = "shell";
+        }
     }
 }

src/Sdk/DTWebApi/WebApi/ActionDownloadInfo.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    [DataContract]
+    public class ActionDownloadInfo
+    {
+        [DataMember(EmitDefaultValue = false)]
+        public ActionDownloadAuthentication Authentication { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string NameWithOwner { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string ResolvedNameWithOwner { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string ResolvedSha { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string TarballUrl { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string Ref { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string ZipballUrl { get; set; }
+    }
+
+    [DataContract]
+    public class ActionDownloadAuthentication
+    {
+        [DataMember(EmitDefaultValue = false)]
+        public DateTime ExpiresAt { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string Token { get; set; }
+    }
+}

src/Sdk/DTWebApi/WebApi/ActionDownloadInfoCollection.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+using System.Runtime.Serialization;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    [DataContract]
+    public class ActionDownloadInfoCollection
+    {
+        [DataMember]
+        public IDictionary<string, ActionDownloadInfo> Actions
+        {
+            get;
+            set;
+        }
+    }
+}

src/Sdk/DTWebApi/WebApi/ActionReference.cs

@@ -0,0 +1,22 @@
+using System.Runtime.Serialization;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    [DataContract]
+    public class ActionReference
+    {
+        [DataMember]
+        public string NameWithOwner
+        {
+            get;
+            set;
+        }
+
+        [DataMember]
+        public string Ref
+        {
+            get;
+            set;
+        }
+    }
+}

src/Sdk/DTWebApi/WebApi/ActionReferenceList.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+using System.Runtime.Serialization;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    [DataContract]
+    public class ActionReferenceList
+    {
+        [DataMember]
+        public IList<ActionReference> Actions
+        {
+            get;
+            set;
+        }
+    }
+}

src/Test/L0/Worker/ActionRunnerL0.cs

@@ -328,8 +328,7 @@ namespace GitHub.Runner.Common.Tests.Worker
             Assert.Equal("invalid1", finialInputs["invalid1"]);
             Assert.Equal("invalid2", finialInputs["invalid2"]);
 
-            _ec.Verify(x => x.AddIssue(It.Is<Issue>(s => s.Message.Contains("Unexpected input 'invalid1'")), It.IsAny<string>()), Times.Once);
+            _ec.Verify(x => x.AddIssue(It.Is<Issue>(s => s.Message.Contains("Unexpected input(s) 'invalid1', 'invalid2'")), It.IsAny<string>()), Times.Once);
-            _ec.Verify(x => x.AddIssue(It.Is<Issue>(s => s.Message.Contains("Unexpected input 'invalid2'")), It.IsAny<string>()), Times.Once);
         }
 
         private void Setup([CallerMemberName] string name = "")