Draft framework and model for refactoring composite actions

* Composite Action Run Steps

* Env Flow => Able to get env variables and overwrite current env variables => but it doesn't 'stick'

* clean up

* Clean up trace messages + add Trace debug in ActionManager

* Add debugging message

* Optimize runtime of code

* Change String to string

* Add comma to Composite

* Change JobSteps to a List, Change Register Step function name

* Add TODO, remove unn. content

* Remove unnecessary code

* Fix unit tests

* Fix env format

* Remove comment

* Remove TODO message for context

* Add verbose trace logs which are only viewable by devs

* Initial Start for FileTable stuff

* Progress towards passing FileTable or FileID or FileName

* Sort usings in Composite Action Handler

* Change 0 to location

* Update context variables in composite action yaml

* Add helpful error message for null steps

* Pass fileID to all children token of root action token

* Change confusing term context => templateContext, Eliminate _fileTable and only use ExecutionContext.FileTable + update this table when need be

* Remove unnessary FileID attribute from CompositeActionExecutionData

* Clean up file path for error message

* Remove todo

* Fix Workflow Step Env overiding Parent Env

* Remove env in composite action scope

* Clean up

* Revert back

* revert back

* add back envToken

* Remove unnecessary code

* Add file length check

* Clean up

* Figure out how to handle set-env edge cases

* formatting

* fix unit tests

* Fix windows unit test syntax error

* Fix period

* Sanity check for fileTable add + remove unn. code

* revert back

* Add back line break

* Fix null errors

* Address situation if FileTable is null + add sanity check for adding file to fileTable

* add line

* Revert

* Fix unit tests to instantiate a FileTable

* Fix logic for trimming manifestfile path

* Add null check

* Add filetable to testing file, remove ? since we know filetable should never be non null

docs/contribute.md

@@ -51,6 +51,19 @@ cd ./src
 ./dev.(sh/cmd) test # run all unit tests before git commit/push
 ```
 
+View logs:
+```bash
+cd runner/_layout/_diag
+ls
+cat (Runner/Worker)_TIMESTAMP.log # view your log file
+```
+
+Run Runner:
+```bash
+cd runner/_layout
+./run.sh # run your custom runner
+```
+
 ### Editors
 
 [Using Visual Studio Code](https://code.visualstudio.com/)

releaseNote.md

@@ -1,7 +1,6 @@
 ## Features
   - Resolve action download info from server (#508, #515, #550)
   - Print runner and machine name to log. (#539)
-  - Allow runner to register against non-default runner groups (#517)
 ## Bugs
   - Reduce input validation warnings (#506) 
   - Fix null ref exception in SecretMasker caused by `hashfiles` timeout. (#516)
@@ -9,7 +8,6 @@
   - Fix DataContract with Token service (#532)
   - Skip search $PATH on command with fully qualified path (#526)
   - Restore SELinux context on service file when SELinux is enabled (#525)
-  - Fix trailing '.0' for Int64 values in ContextData (#572)
 ## Misc
   - Remove SPS/Token migration code. Remove GHES url manipulate code. (#513) 
   - Add sub-step for developer flow for clarity (#523)

releaseVersion

@@ -1 +1 @@
-2.267.2
+<Update to ./src/runnerversion when creating release>

src/Misc/dotnet-install.ps1

@@ -885,4 +885,4 @@ exit 0
 # DsQOUWk8J6ojDurhrP536WI+3arg8PcnppHBLd/xNKYdlsTb+6qndgzKXkDDt1CV
 # 4zCyuZ7bO8eyZAmNoSZz22k7vus9UjBz/CDhXylo20N43nr29rWPItUgH4uvOGQn
 # t26Y/yjBaQImz32psrfJEMbQ7cl789s8WOx8
-# SIG # End signature block
+# SIG # End signature block

src/Runner.Common/Constants.cs

@@ -90,7 +90,7 @@ namespace GitHub.Runner.Common
                     public static readonly string Labels = "labels";
                     public static readonly string MonitorSocketAddress = "monitorsocketaddress";
                     public static readonly string Name = "name";
-                    public static readonly string RunnerGroup = "runnergroup";
+                    public static readonly string Pool = "pool";
                     public static readonly string StartupType = "startuptype";
                     public static readonly string Url = "url";
                     public static readonly string UserName = "username";

src/Runner.Listener/CommandSettings.cs

@@ -42,7 +42,7 @@ namespace GitHub.Runner.Listener
             Constants.Runner.CommandLine.Args.Labels,
             Constants.Runner.CommandLine.Args.MonitorSocketAddress,
             Constants.Runner.CommandLine.Args.Name,
-            Constants.Runner.CommandLine.Args.RunnerGroup,
+            Constants.Runner.CommandLine.Args.Pool,
             Constants.Runner.CommandLine.Args.StartupType,
             Constants.Runner.CommandLine.Args.Token,
             Constants.Runner.CommandLine.Args.Url,
@@ -169,15 +169,6 @@ namespace GitHub.Runner.Listener
                 validator: Validators.NonEmptyValidator);
         }
 
-        public string GetRunnerGroupName(string defaultPoolName = null)
-        {
-            return GetArgOrPrompt(
-                name: Constants.Runner.CommandLine.Args.RunnerGroup,
-                description: "Enter the name of the runner group to add this runner to:",
-                defaultValue: defaultPoolName ?? "default",
-                validator: Validators.NonEmptyValidator);
-        }
-
         public string GetToken()
         {
             return GetArgOrPrompt(

src/Runner.Listener/Configuration/ConfigurationManager.cs

@@ -159,34 +159,17 @@ namespace GitHub.Runner.Listener.Configuration
 
             _term.WriteSection("Runner Registration");
 
-            // If we have more than one runner group available, allow the user to specify which one to be added into
-            string poolName = null;
-            TaskAgentPool agentPool = null;
+            //Get all the agent pools, and select the first private pool
             List<TaskAgentPool> agentPools = await _runnerServer.GetAgentPoolsAsync();
-            TaskAgentPool defaultPool = agentPools?.Where(x => x.IsInternal).FirstOrDefault();
+            TaskAgentPool agentPool = agentPools?.Where(x => x.IsHosted == false).FirstOrDefault();
 
-            if (agentPools?.Where(x => !x.IsHosted).Count() > 1)
+            if (agentPool == null)
             {
-                poolName = command.GetRunnerGroupName(defaultPool?.Name);
-                _term.WriteLine();
-                agentPool = agentPools.Where(x => string.Equals(poolName, x.Name, StringComparison.OrdinalIgnoreCase) && !x.IsHosted).FirstOrDefault();
+                throw new TaskAgentPoolNotFoundException($"Could not find any private pool. Contact support.");
             }
             else
             {
-                agentPool = defaultPool;
-            }
-
-            if (agentPool == null && poolName == null)
-            {
-                throw new TaskAgentPoolNotFoundException($"Could not find any self-hosted runner groups. Contact support.");
-            }
-            else if (agentPool == null && poolName != null)
-            {
-                throw new TaskAgentPoolNotFoundException($"Could not find any self-hosted runner group named \"{poolName}\".");
-            }
-            else
-            {
-                Trace.Info("Found a self-hosted runner group with id {1} and name {2}", agentPool.Id, agentPool.Name);
+                Trace.Info("Found a private pool with id {1} and name {2}", agentPool.Id, agentPool.Name);
                 runnerSettings.PoolId = agentPool.Id;
                 runnerSettings.PoolName = agentPool.Name;
             }

src/Runner.Worker/ActionManager.cs

@@ -395,6 +395,12 @@ namespace GitHub.Runner.Worker
                             Trace.Info($"Action cleanup plugin: {plugin.PluginTypeName}.");
                         }
                     }
+                    else if (definition.Data.Execution.ExecutionType == ActionExecutionType.Composite && !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+                    {
+                        var compositeAction = definition.Data.Execution as CompositeActionExecutionData;
+                        Trace.Info($"Load {compositeAction.Steps.Count} action steps.");
+                        Trace.Verbose($"Details: {StringUtil.ConvertToJson(compositeAction.Steps)}");
+                    }
                     else
                     {
                         throw new NotSupportedException(definition.Data.Execution.ExecutionType.ToString());
@@ -1038,6 +1044,11 @@ namespace GitHub.Runner.Worker
                     Trace.Info($"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).Steps}, no more preparation.");
+                    return null;
+                }
                 else
                 {
                     throw new NotSupportedException(actionDefinitionData.Execution.ExecutionType.ToString());
@@ -1148,6 +1159,7 @@ namespace GitHub.Runner.Worker
         NodeJS,
         Plugin,
         Script,
+        Composite,
     }
 
     public sealed class ContainerActionExecutionData : ActionExecutionData
@@ -1204,6 +1216,14 @@ namespace GitHub.Runner.Worker
         public override bool HasPost => false;
     }
 
+    public sealed class CompositeActionExecutionData : ActionExecutionData
+    {
+        public override ActionExecutionType ExecutionType => ActionExecutionType.Composite;
+        public override bool HasPre => false;
+        public override bool HasPost => false;
+        public List<Pipelines.ActionStep> Steps { 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 Pipelines = GitHub.DistributedTask.Pipelines;
 
 namespace GitHub.Runner.Worker
 {
@@ -32,8 +33,6 @@ namespace GitHub.Runner.Worker
     public sealed class ActionManifestManager : RunnerService, IActionManifestManager
     {
         private TemplateSchema _actionManifestSchema;
-        private IReadOnlyList<String> _fileTable;
-
         public override void Initialize(IHostContext hostContext)
         {
             base.Initialize(hostContext);
@@ -54,22 +53,39 @@ namespace GitHub.Runner.Worker
 
         public ActionDefinitionData Load(IExecutionContext executionContext, string manifestFile)
         {
-            var context = CreateContext(executionContext);
+            var templateContext = CreateContext(executionContext);
             ActionDefinitionData actionDefinition = new ActionDefinitionData();
+
+            // Clean up file name real quick
+            // Instead of using Regex which can be computationally expensive, 
+            // we can just remove the # of characters from the fileName according to the length of the basePath
+            string basePath = HostContext.GetDirectory(WellKnownDirectory.Actions);
+            string fileRelativePath = manifestFile;
+            if (manifestFile.Contains(basePath))
+            {
+                fileRelativePath = manifestFile.Remove(0, basePath.Length + 1);
+            }
+
             try
             {
                 var token = default(TemplateToken);
 
                 // Get the file ID
-                var fileId = context.GetFileId(manifestFile);
-                _fileTable = context.GetFileTable();
+                var fileId = templateContext.GetFileId(fileRelativePath);
+
+                // Add this file to the FileTable in executionContext if it hasn't been added already
+                // we use > since fileID is 1 indexed
+                if (fileId > executionContext.FileTable.Count)
+                {
+                    executionContext.FileTable.Add(fileRelativePath);
+                }
 
                 // Read the file
                 var fileContent = File.ReadAllText(manifestFile);
                 using (var stringReader = new StringReader(fileContent))
                 {
-                    var yamlObjectReader = new YamlObjectReader(null, stringReader);
-                    token = TemplateReader.Read(context, "action-root", yamlObjectReader, fileId, out _);
+                    var yamlObjectReader = new YamlObjectReader(fileId, stringReader);
+                    token = TemplateReader.Read(templateContext, "action-root", yamlObjectReader, fileId, out _);
                 }
 
                 var actionMapping = token.AssertMapping("action manifest root");
@@ -88,11 +104,11 @@ namespace GitHub.Runner.Worker
                             break;
 
                         case "inputs":
-                            ConvertInputs(context, actionPair.Value, actionDefinition);
+                            ConvertInputs(templateContext, actionPair.Value, actionDefinition);
                             break;
 
                         case "runs":
-                            actionDefinition.Execution = ConvertRuns(context, actionPair.Value);
+                            actionDefinition.Execution = ConvertRuns(executionContext, templateContext, actionPair.Value);
                             break;
                         default:
                             Trace.Info($"Ignore action property {propertyName}.");
@@ -103,24 +119,24 @@ namespace GitHub.Runner.Worker
             catch (Exception ex)
             {
                 Trace.Error(ex);
-                context.Errors.Add(ex);
+                templateContext.Errors.Add(ex);
             }
 
-            if (context.Errors.Count > 0)
+            if (templateContext.Errors.Count > 0)
             {
-                foreach (var error in context.Errors)
+                foreach (var error in templateContext.Errors)
                 {
                     Trace.Error($"Action.yml load error: {error.Message}");
                     executionContext.Error(error.Message);
                 }
 
-                throw new ArgumentException($"Fail to load {manifestFile}");
+                throw new ArgumentException($"Fail to load {fileRelativePath}");
             }
 
             if (actionDefinition.Execution == null)
             {
                 executionContext.Debug($"Loaded action.yml file: {StringUtil.ConvertToJson(actionDefinition)}");
-                throw new ArgumentException($"Top level 'runs:' section is required for {manifestFile}");
+                throw new ArgumentException($"Top level 'runs:' section is required for {fileRelativePath}");
             }
             else
             {
@@ -281,19 +297,17 @@ namespace GitHub.Runner.Worker
                 result.ExpressionFunctions.Add(item);
             }
 
-            // Add the file table
-            if (_fileTable?.Count > 0)
+            // Add the file table from the Execution Context
+            for (var i = 0; i < executionContext.FileTable.Count; i++)
             {
-                for (var i = 0 ; i < _fileTable.Count ; i++)
-                {
-                    result.GetFileId(_fileTable[i]);
-                }
+                result.GetFileId(executionContext.FileTable[i]);
             }
 
             return result;
         }
 
         private ActionExecutionData ConvertRuns(
+            IExecutionContext executionContext,
             TemplateContext context,
             TemplateToken inputsToken)
         {
@@ -311,6 +325,8 @@ namespace GitHub.Runner.Worker
             var postToken = default(StringToken);
             var postEntrypointToken = default(StringToken);
             var postIfToken = default(StringToken);
+            var stepsLoaded = default(List<Pipelines.Step>);
+
             foreach (var run in runsMapping)
             {
                 var runsKey = run.Key.AssertString("runs key").Value;
@@ -355,6 +371,16 @@ namespace GitHub.Runner.Worker
                     case "pre-if":
                         preIfToken = run.Value.AssertString("pre-if");
                         break;
+                    case "steps":
+                        if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+                        {
+                            var steps = run.Value.AssertSequence("steps");
+                            var evaluator = executionContext.ToPipelineTemplateEvaluator();
+                            // TODO: Change this so that we process each type of step
+                            stepsLoaded = evaluator.LoadCompositeSteps(steps);
+                            break;
+                        }
+                        throw new Exception("You aren't supposed to be using Composite Actions yet!");
                     default:
                         Trace.Info($"Ignore run property {runsKey}.");
                         break;
@@ -402,6 +428,21 @@ namespace GitHub.Runner.Worker
                         };
                     }
                 }
+                else if (string.Equals(usingToken.Value, "composite", StringComparison.OrdinalIgnoreCase) && !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+                {
+                    if (stepsLoaded == null)
+                    {
+                        // TODO: Add a more helpful error message + including file name, etc. to show user that it's because of their yaml file
+                        throw new ArgumentNullException($"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/ExecutionContext.cs

@@ -63,7 +63,7 @@ namespace GitHub.Runner.Worker
         JobContext JobContext { get; }
 
         // Only job level ExecutionContext has JobSteps
-        Queue<IStep> JobSteps { get; }
+        List<IStep> JobSteps { get; }
 
         // Only job level ExecutionContext has PostJobSteps
         Stack<IStep> PostJobSteps { get; }
@@ -105,6 +105,7 @@ namespace GitHub.Runner.Worker
         // others
         void ForceTaskComplete();
         void RegisterPostJobStep(IStep step);
+        void RegisterNestedStep(IStep step, DictionaryContextData inputsData, int location, Dictionary<string, string> envData);
     }
 
     public sealed class ExecutionContext : RunnerService, IExecutionContext
@@ -159,7 +160,7 @@ namespace GitHub.Runner.Worker
         public List<ContainerInfo> ServiceContainers { get; private set; }
 
         // Only job level ExecutionContext has JobSteps
-        public Queue<IStep> JobSteps { get; private set; }
+        public List<IStep> JobSteps { get; private set; }
 
         // Only job level ExecutionContext has PostJobSteps
         public Stack<IStep> PostJobSteps { get; private set; }
@@ -169,7 +170,6 @@ namespace GitHub.Runner.Worker
 
         public bool EchoOnActionCommand { get; set; }
 
-
         public TaskResult? Result
         {
             get
@@ -266,6 +266,35 @@ namespace GitHub.Runner.Worker
             Root.PostJobSteps.Push(step);
         }
 
+        /// <summary>
+        /// Helper function used in CompositeActionHandler::RunAsync to
+        /// add a child node, aka a step, to the current job to the Root.JobSteps based on the location. 
+        /// </summary>
+        public void RegisterNestedStep(IStep step, DictionaryContextData inputsData, int location, Dictionary<string, string> envData)
+        {
+            // TODO: For UI purposes, look at figuring out how to condense steps in one node => maybe use the same previous GUID
+            var newGuid = Guid.NewGuid();
+            step.ExecutionContext = Root.CreateChild(newGuid, step.DisplayName, newGuid.ToString("N"), null, null);
+            step.ExecutionContext.ExpressionValues["inputs"] = inputsData;
+
+            // Add the composite action environment variables to each step.
+            // If the key already exists, we override it since the composite action env variables will have higher precedence
+            // Note that for each composite action step, it's environment variables will be set in the StepRunner automatically
+            // step.ExecutionContext.SetEnvironmentVariables(envData);
+#if OS_WINDOWS
+            var envContext = new DictionaryContextData();
+#else
+            var envContext = new CaseSensitiveDictionaryContextData();
+#endif
+            foreach (var pair in envData)
+            {
+                envContext[pair.Key] = new StringContextData(pair.Value ?? string.Empty);
+            }
+            step.ExecutionContext.ExpressionValues["env"] = envContext;
+
+            Root.JobSteps.Insert(location, step);
+        }
+
         public IExecutionContext CreateChild(Guid recordId, string displayName, string refName, string scopeName, string contextName, Dictionary<string, string> intraActionState = null, int? recordOrder = null)
         {
             Trace.Entering();
@@ -660,7 +689,7 @@ namespace GitHub.Runner.Worker
             PrependPath = new List<string>();
 
             // JobSteps for job ExecutionContext
-            JobSteps = new Queue<IStep>();
+            JobSteps = new List<IStep>();
 
             // PostJobSteps for job ExecutionContext
             PostJobSteps = new Stack<IStep>();

src/Runner.Worker/Handlers/CompositeActionHandler.cs

@@ -0,0 +1,141 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using GitHub.DistributedTask.ObjectTemplating.Tokens;
+using GitHub.DistributedTask.Pipelines.ContextData;
+using GitHub.DistributedTask.WebApi;
+using GitHub.Runner.Common;
+using GitHub.Runner.Sdk;
+using Pipelines = GitHub.DistributedTask.Pipelines;
+
+
+namespace GitHub.Runner.Worker.Handlers
+{
+    [ServiceLocator(Default = typeof(CompositeActionHandler))]
+    public interface ICompositeActionHandler : IHandler
+    {
+        CompositeActionExecutionData Data { get; set; }
+    }
+    public sealed class CompositeActionHandler : Handler, ICompositeActionHandler
+    {
+        public CompositeActionExecutionData Data { get; set; }
+
+        public Task RunAsync(ActionRunStage stage)
+        {
+            // 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);
+
+            // Create Context Data to reuse for each composite action step
+            var inputsData = new DictionaryContextData();
+            foreach (var i in Inputs)
+            {
+                inputsData[i.Key] = new StringContextData(i.Value);
+            }
+
+            // Add each composite action step to the front of the queue
+            int location = 0;
+
+            // Resolve action steps
+            var compositeSteps = Data.Steps;
+
+            // TODO: Assume that each step is not an actionStep
+            // How do we handle all types of steps?????
+
+            // While loop till we have reached the last layer?
+            List<Pipelines.Step> stepsToAppend = new List<Pipelines.Step>();
+
+            // First put each step in stepsToAppend
+            foreach (var step in compositeSteps)
+            {
+                stepsToAppend.Append(step);
+            }
+
+            // We go through each step and push to the top of the stack its children. 
+            // That way, we go through each steps, steps of steps in order
+            // This is an ITERATIVE approach. While a recursive approach may be more elegant, 
+            // that would use a lot more memory in the call stack.
+            // Ex: 
+            // Let's say we have 4 composite steps with the first step that has 3 children
+            // A (composite step)=> a1, a2, a3
+            // B (non composite)
+            // C (non composite)
+            // D (non composite)
+            // It would be executed in this order => a1, a2, a3, A (steps within A), B, C, D
+            while (stepsToAppend != null)
+            {
+                var currentStep = stepsToAppend[0];
+
+                // TODO: Create another StepsContext?
+                // In the original StepsRunner, we could lock the thread and only proceed after we finish processing these steps
+                // Then, we invoke the CompositeStepsRunner class?
+
+                // TODO: We have to create another Execution Context for Composite Actions
+                // See below
+
+                // TODO: Append to StepsRunner
+                // by invoking a RegisterNestedStep on the Composite Action Exeuction Context for Composite Action Steps
+
+
+            }
+
+            // foreach (Pipelines.Step aStep in actionSteps)
+            // {
+            //     // Ex: 
+            //     // runs:
+            //     //      using: "composite"
+            //     //      steps:
+            //     //          - uses: example/test-composite@v2 (a)
+            //     //          - run echo hello world (b)
+            //     //          - run echo hello world 2 (c)
+            //     // 
+            //     // ethanchewy/test-composite/action.yaml
+            //     // runs:
+            //     //      using: "composite"
+            //     //      steps: 
+            //     //          - run echo hello world 3 (d)
+            //     //          - run echo hello world 4 (e)
+            //     // 
+            //     // Steps processed as follow:
+            //     // | a |
+            //     // | a | => | d |
+            //     // (Run step d)
+            //     // | a | 
+            //     // | a | => | e |
+            //     // (Run step e)
+            //     // | a | 
+            //     // (Run step a)
+            //     // | b | 
+            //     // (Run step b)
+            //     // | c |
+            //     // (Run step c)
+            //     // Done.
+
+            //     // TODO: how are we going to order each step?
+            //     // How is this going to look in the UI (will we have a bunch of nesting)
+            //     // ^ We need to focus on how we are going to get the steps to run in the right order. 
+
+            //     var actionRunner = HostContext.CreateService<IActionRunner>();
+            //     actionRunner.Action = aStep;
+            //     actionRunner.Stage = stage;
+            //     actionRunner.Condition = aStep.Condition;
+            //     actionRunner.DisplayName = aStep.DisplayName;
+
+            //     ExecutionContext.RegisterNestedStep(actionRunner, inputsData, location, Environment);
+            //     location++;
+            // }
+
+            return Task.CompletedTask;
+        }
+
+    }
+}

src/Runner.Worker/Handlers/HandlerFactory.cs

@@ -66,6 +66,11 @@ namespace GitHub.Runner.Worker.Handlers
                 handler = HostContext.CreateService<IRunnerPluginHandler>();
                 (handler as IRunnerPluginHandler).Data = data as PluginActionExecutionData;
             }
+            else if (data.ExecutionType == ActionExecutionType.Composite)
+            {
+                handler = HostContext.CreateService<ICompositeActionHandler>();
+                (handler as ICompositeActionHandler).Data = data as CompositeActionExecutionData;
+            }
             else
             {
                 // This should never happen.

src/Runner.Worker/JobRunner.cs

@@ -152,7 +152,7 @@ namespace GitHub.Runner.Worker
                 {
                     foreach (var step in jobSteps)
                     {
-                        jobContext.JobSteps.Enqueue(step);
+                        jobContext.JobSteps.Add(step);
                     }
 
                     await stepsRunner.RunAsync(jobContext);

src/Runner.Worker/StepsRunner.cs

@@ -59,14 +59,15 @@ namespace GitHub.Runner.Worker
                     checkPostJobActions = true;
                     while (jobContext.PostJobSteps.TryPop(out var postStep))
                     {
-                        jobContext.JobSteps.Enqueue(postStep);
+                        jobContext.JobSteps.Add(postStep);
                     }
 
                     continue;
                 }
 
-                var step = jobContext.JobSteps.Dequeue();
-                var nextStep = jobContext.JobSteps.Count > 0 ? jobContext.JobSteps.Peek() : null;
+                var step = jobContext.JobSteps[0];
+                jobContext.JobSteps.RemoveAt(0);
+                var nextStep = jobContext.JobSteps.Count > 0 ? jobContext.JobSteps[0] : null;
 
                 Trace.Info($"Processing step: DisplayName='{step.DisplayName}'");
                 ArgUtil.NotNull(step.ExecutionContext, nameof(step.ExecutionContext));
@@ -92,12 +93,28 @@ namespace GitHub.Runner.Worker
 #else
                     var envContext = new CaseSensitiveDictionaryContextData();
 #endif
-                    step.ExecutionContext.ExpressionValues["env"] = envContext;
+                    // Global env
                     foreach (var pair in step.ExecutionContext.EnvironmentVariables)
                     {
                         envContext[pair.Key] = new StringContextData(pair.Value ?? string.Empty);
                     }
 
+                    // Stomps over with outside step env
+                    if (step.ExecutionContext.ExpressionValues.TryGetValue("env", out var envContextData))
+                    {
+#if OS_WINDOWS
+                        var dict = envContextData as DictionaryContextData;
+#else
+                        var dict = envContextData as CaseSensitiveDictionaryContextData;
+#endif
+                        foreach (var pair in dict)
+                        {
+                            envContext[pair.Key] = pair.Value;
+                        }
+                    }
+
+                    step.ExecutionContext.ExpressionValues["env"] = envContext;
+
                     bool evaluateStepEnvFailed = false;
                     if (step is IActionRunner actionStep)
                     {
@@ -409,7 +426,11 @@ namespace GitHub.Runner.Worker
                     scope = scopesToInitialize.Pop();
                     executionContext.Debug($"Initializing scope '{scope.Name}'");
                     executionContext.ExpressionValues["steps"] = stepsContext.GetScope(scope.ParentName);
-                    executionContext.ExpressionValues["inputs"] = !String.IsNullOrEmpty(scope.ParentName) ? scopeInputs[scope.ParentName] : null;
+                    // TODO: Fix this temporary workaround for Composite Actions
+                    if (!executionContext.ExpressionValues.ContainsKey("inputs") && !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+                    {
+                        executionContext.ExpressionValues["inputs"] = !String.IsNullOrEmpty(scope.ParentName) ? scopeInputs[scope.ParentName] : null;
+                    }
                     var templateEvaluator = executionContext.ToPipelineTemplateEvaluator();
                     var inputs = default(DictionaryContextData);
                     try
@@ -432,7 +453,11 @@ namespace GitHub.Runner.Worker
             // Setup expression values
             var scopeName = executionContext.ScopeName;
             executionContext.ExpressionValues["steps"] = stepsContext.GetScope(scopeName);
-            executionContext.ExpressionValues["inputs"] = string.IsNullOrEmpty(scopeName) ? null : scopeInputs[scopeName];
+            // TODO: Fix this temporary workaround for Composite Actions
+            if (!executionContext.ExpressionValues.ContainsKey("inputs") && !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TESTING_COMPOSITE_ACTIONS_ALPHA")))
+            {
+                executionContext.ExpressionValues["inputs"] = string.IsNullOrEmpty(scopeName) ? null : scopeInputs[scopeName];
+            }
 
             return true;
         }

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 +84,36 @@
                 }
             }
         },
+        "composite-runs": {
+            "mapping": {
+                "properties": {
+                    "using": "non-empty-string",
+                    "steps": "composite-steps"
+                }
+            }
+        },
+        "composite-steps": {
+            "context": [
+                "github",
+                "needs",
+                "strategy",
+                "matrix",
+                "secrets",
+                "steps",
+                "inputs",
+                "job",
+                "runner",
+                "env",
+                "always(0,0)",
+                "failure(0,0)",
+                "cancelled(0,0)",
+                "success(0,0)",
+                "hashFiles(1,255)"
+            ],
+            "sequence": {
+                "item-type": "any"
+            }
+        },
         "container-runs-context": {
             "context": [
                 "inputs"

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

@@ -65,6 +65,7 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
         public const String StepEnv = "step-env";
         public const String StepIfResult = "step-if-result";
         public const String Steps = "steps";
+        public const String StepsInTemplate = "steps-in-template";
         public const String StepsScopeInputs = "steps-scope-inputs";
         public const String StepsScopeOutputs = "steps-scope-outputs";
         public const String StepsTemplateRoot = "steps-template-root";

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

@@ -29,7 +29,6 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             var evaluationResult = EvaluationResult.CreateIntermediateResult(null, ifResult);
             return evaluationResult.IsTruthy;
         }
-
         internal static Boolean? ConvertToStepContinueOnError(
             TemplateContext context,
             TemplateToken token,
@@ -264,5 +263,350 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
 
             return result;
         }
+
+        internal static List<Step> ConvertToSteps(
+            TemplateContext context,
+            TemplateToken steps)
+        {
+            var stepsSequence = steps.AssertSequence($"job {PipelineTemplateConstants.Steps}");
+
+            var result = new List<Step>();
+            foreach (var stepsItem in stepsSequence)
+            {
+                var step = ConvertToStep(context, stepsItem);
+                if (step != null) // step = null means we are hitting error during step conversion, there should be an error in context.errors
+                {
+                    if (step.Enabled)
+                    {
+                        result.Add(step);
+                    }
+                }
+            }
+
+            return result;
+        }
+
+        private static Step ConvertToStep(
+            TemplateContext context,
+            TemplateToken stepsItem)
+        {
+            var step = stepsItem.AssertMapping($"{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 +159,32 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             return result;
         }
 
+        // TODO: Change to return a variety of steps.
+        public List<Step> LoadCompositeSteps(
+            TemplateToken token)
+        {
+            var result = default(List<Step>);
+            if (token != null && token.Type != TokenType.Null)
+            {
+                var context = CreateContext(null, null, setMissingContext: false);
+                // TODO: we might want to to have a bool to prevent it from filling in with missing context w/ dummy variables
+                try
+                {
+                    token = TemplateEvaluator.Evaluate(context, PipelineTemplateConstants.StepsInTemplate, 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 +426,8 @@ 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 +476,21 @@ 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)
-            {
-                if (!functionNames.Contains(name))
+                foreach (var name in s_expressionFunctionNames)
                 {
-                    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/TaskAgentPoolReference.cs

@@ -29,7 +29,6 @@ namespace GitHub.DistributedTask.WebApi
             this.PoolType = referenceToBeCloned.PoolType;
             this.Size = referenceToBeCloned.Size;
             this.IsLegacy = referenceToBeCloned.IsLegacy;
-            this.IsInternal = referenceToBeCloned.IsInternal;
         }
 
         public TaskAgentPoolReference Clone()
@@ -68,16 +67,6 @@ namespace GitHub.DistributedTask.WebApi
             set;
         }
 
-        /// <summary>
-        /// Gets or sets a value indicating whether or not this pool is internal and can't be modified by users
-        /// </summary>
-        [DataMember]
-        public bool IsInternal
-        {
-            get;
-            set;
-        }
-
         /// <summary>
         /// Gets or sets the type of the pool
         /// </summary>

src/Test/L0/Listener/Configuration/ConfigurationManagerL0.cs

@@ -39,12 +39,10 @@ namespace GitHub.Runner.Common.Tests.Listener.Configuration
         private string _expectedToken = "expectedToken";
         private string _expectedServerUrl = "https://codedev.ms";
         private string _expectedAgentName = "expectedAgentName";
-        private string _defaultRunnerGroupName = "defaultRunnerGroup";
-        private string _secondRunnerGroupName = "secondRunnerGroup";
+        private string _expectedPoolName = "poolName";
         private string _expectedAuthType = "pat";
         private string _expectedWorkFolder = "_work";
-        private int _defaultRunnerGroupId = 1;
-        private int _secondRunnerGroupId = 2;
+        private int _expectedPoolId = 1;
         private RSACryptoServiceProvider rsa = null;
         private RunnerSettings _configMgrAgentSettings = new RunnerSettings();
 
@@ -99,7 +97,7 @@ namespace GitHub.Runner.Common.Tests.Listener.Configuration
             _serviceControlManager.Setup(x => x.GenerateScripts(It.IsAny<RunnerSettings>()));
 #endif
 
-            var expectedPools = new List<TaskAgentPool>() { new TaskAgentPool(_defaultRunnerGroupName) { Id = _defaultRunnerGroupId, IsInternal = true }, new TaskAgentPool(_secondRunnerGroupName) { Id = _secondRunnerGroupId } };
+            var expectedPools = new List<TaskAgentPool>() { new TaskAgentPool(_expectedPoolName) { Id = _expectedPoolId } };
             _runnerServer.Setup(x => x.GetAgentPoolsAsync(It.IsAny<string>(), It.IsAny<TaskAgentPoolType>())).Returns(Task.FromResult(expectedPools));
 
             var expectedAgents = new List<TaskAgent>();
@@ -157,7 +155,7 @@ namespace GitHub.Runner.Common.Tests.Listener.Configuration
                        "configure",                
                        "--url", _expectedServerUrl,
                        "--name", _expectedAgentName,
-                       "--runnergroup", _secondRunnerGroupName,
+                       "--pool", _expectedPoolName,
                        "--work", _expectedWorkFolder,
                        "--auth", _expectedAuthType,
                        "--token", _expectedToken,
@@ -177,7 +175,7 @@ namespace GitHub.Runner.Common.Tests.Listener.Configuration
                 Assert.NotNull(s);
                 Assert.True(s.ServerUrl.Equals(_expectedServerUrl));
                 Assert.True(s.AgentName.Equals(_expectedAgentName));
-                Assert.True(s.PoolId.Equals(_secondRunnerGroupId));
+                Assert.True(s.PoolId.Equals(_expectedPoolId));
                 Assert.True(s.WorkFolder.Equals(_expectedWorkFolder));
 
                 // validate GetAgentPoolsAsync gets called twice with automation pool type

src/Test/L0/Worker/ActionManagerL0.cs

@@ -3584,6 +3584,7 @@ runs:
             _ec.Setup(x => x.Variables).Returns(new Variables(_hc, variables));
             _ec.Setup(x => x.ExpressionValues).Returns(new DictionaryContextData());
             _ec.Setup(x => x.ExpressionFunctions).Returns(new List<IFunctionInfo>());
+            _ec.Setup(x => x.FileTable).Returns(new List<String>());
             _ec.Setup(x => x.Plan).Returns(new TaskOrchestrationPlanReference());
             _ec.Setup(x => x.Write(It.IsAny<string>(), It.IsAny<string>())).Callback((string tag, string message) => { _hc.GetTrace().Info($"[{tag}]{message}"); });
             _ec.Setup(x => x.AddIssue(It.IsAny<Issue>(), It.IsAny<string>())).Callback((Issue issue, string message) => { _hc.GetTrace().Info($"[{issue.Type}]{issue.Message ?? message}"); });

src/Test/L0/Worker/ActionManifestManagerL0.cs

@@ -759,6 +759,7 @@ namespace GitHub.Runner.Common.Tests.Worker
             _ec.Setup(x => x.Variables).Returns(new Variables(_hc, new Dictionary<string, VariableValue>()));
             _ec.Setup(x => x.ExpressionValues).Returns(new DictionaryContextData());
             _ec.Setup(x => x.ExpressionFunctions).Returns(new List<IFunctionInfo>());
+            _ec.Setup(x => x.FileTable).Returns(new List<String>());
             _ec.Setup(x => x.Write(It.IsAny<string>(), It.IsAny<string>())).Callback((string tag, string message) => { _hc.GetTrace().Info($"{tag}{message}"); });
             _ec.Setup(x => x.AddIssue(It.IsAny<Issue>(), It.IsAny<string>())).Callback((Issue issue, string message) => { _hc.GetTrace().Info($"[{issue.Type}]{issue.Message ?? message}"); });
         }

src/Test/L0/Worker/ActionRunnerL0.cs

@@ -379,6 +379,7 @@ namespace GitHub.Runner.Common.Tests.Worker
             _ec.Setup(x => x.ExpressionFunctions).Returns(new List<IFunctionInfo>());
             _ec.Setup(x => x.IntraActionState).Returns(new Dictionary<string, string>());
             _ec.Setup(x => x.EnvironmentVariables).Returns(new Dictionary<string, string>());
+            _ec.Setup(x => x.FileTable).Returns(new List<String>());
             _ec.Setup(x => x.SetGitHubContext(It.IsAny<string>(), It.IsAny<string>()));
             _ec.Setup(x => x.GetGitHubContext(It.IsAny<string>())).Returns("{\"foo\":\"bar\"}");
             _ec.Setup(x => x.CancellationToken).Returns(_ecTokenSource.Token);

src/Test/L0/Worker/StepsRunnerL0.cs

@@ -80,7 +80,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -115,7 +115,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -154,7 +154,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -208,7 +208,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -287,7 +287,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Steps.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -330,7 +330,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Step.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Step.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -361,7 +361,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -391,7 +391,7 @@ namespace GitHub.Runner.Common.Tests.Worker
                 {
                     _ec.Object.Result = null;
 
-                    _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(variableSet.Select(x => x.Object).ToList()));
+                    _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(variableSet.Select(x => x.Object).ToList()));
 
                     // Act.
                     await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -417,7 +417,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 _ec.Object.Result = null;
 
-                _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(new[] { step1.Object }));
+                _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(new[] { step1.Object }));
 
                 // Act.
                 await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -426,11 +426,11 @@ namespace GitHub.Runner.Common.Tests.Worker
                 Assert.Equal(TaskResult.Succeeded, _ec.Object.Result ?? TaskResult.Succeeded);
 
 #if OS_WINDOWS
-                Assert.Equal("100", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("100"));
-                Assert.Equal("github_actions", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env2"].AssertString("github_actions"));
+                Assert.Equal("100", step1.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("100"));
+                Assert.Equal("github_actions", step1.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env2"].AssertString("github_actions"));
 #else
-                Assert.Equal("100", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("100"));
-                Assert.Equal("github_actions", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env2"].AssertString("github_actions"));
+                Assert.Equal("100", step1.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("100"));
+                Assert.Equal("github_actions", step1.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env2"].AssertString("github_actions"));
 #endif
             }
         }
@@ -455,7 +455,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 _ec.Object.Result = null;
 
-                _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(new[] { step1.Object, step2.Object }));
+                _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(new[] { step1.Object, step2.Object }));
 
                 // Act.
                 await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -463,13 +463,13 @@ namespace GitHub.Runner.Common.Tests.Worker
                 // Assert.
                 Assert.Equal(TaskResult.Succeeded, _ec.Object.Result ?? TaskResult.Succeeded);
 #if OS_WINDOWS
-                Assert.Equal("1000", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("1000"));
-                Assert.Equal("github_actions", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env3"].AssertString("github_actions"));
-                Assert.False(_ec.Object.ExpressionValues["env"].AssertDictionary("env").ContainsKey("env2"));
+                Assert.Equal("1000", step2.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("1000"));
+                Assert.Equal("github_actions", step2.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env3"].AssertString("github_actions"));
+                Assert.False(step2.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env").ContainsKey("env2"));
 #else
-                Assert.Equal("1000", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("1000"));
-                Assert.Equal("github_actions", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env3"].AssertString("github_actions"));
-                Assert.False(_ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env").ContainsKey("env2"));
+                Assert.Equal("1000", step2.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("1000"));
+                Assert.Equal("github_actions", step2.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env3"].AssertString("github_actions"));
+                Assert.False(step2.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env").ContainsKey("env2"));
 #endif
             }
         }
@@ -493,7 +493,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 _ec.Object.Result = null;
 
-                _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(new[] { step1.Object, step2.Object }));
+                _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(new[] { step1.Object, step2.Object }));
 
                 // Act.
                 await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -501,11 +501,11 @@ namespace GitHub.Runner.Common.Tests.Worker
                 // Assert.
                 Assert.Equal(TaskResult.Succeeded, _ec.Object.Result ?? TaskResult.Succeeded);
 #if OS_WINDOWS
-                Assert.Equal("1000", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("1000"));
-                Assert.Equal("something", _ec.Object.ExpressionValues["env"].AssertDictionary("env")["env2"].AssertString("something"));
+                Assert.Equal("1000", step2.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env1"].AssertString("1000"));
+                Assert.Equal("something", step2.Object.ExecutionContext.ExpressionValues["env"].AssertDictionary("env")["env2"].AssertString("something"));
 #else
-                Assert.Equal("1000", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("1000"));
-                Assert.Equal("something", _ec.Object.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env2"].AssertString("something"));
+                Assert.Equal("1000", step2.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env1"].AssertString("1000"));
+                Assert.Equal("something", step2.Object.ExecutionContext.ExpressionValues["env"].AssertCaseSensitiveDictionary("env")["env2"].AssertString("something"));
 #endif
             }
         }
@@ -524,7 +524,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 _ec.Object.Result = null;
 
-                _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(new[] { step1.Object, step2.Object, step3.Object }));
+                _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(new[] { step1.Object, step2.Object, step3.Object }));
 
                 // Act.
                 await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -560,7 +560,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 _ec.Object.Result = null;
 
-                _ec.Setup(x => x.JobSteps).Returns(new Queue<IStep>(new[] { step1.Object, step2.Object, step3.Object }));
+                _ec.Setup(x => x.JobSteps).Returns(new List<IStep>(new[] { step1.Object, step2.Object, step3.Object }));
 
                 // Act.
                 await _stepsRunner.RunAsync(jobContext: _ec.Object);
@@ -602,7 +602,7 @@ namespace GitHub.Runner.Common.Tests.Worker
             stepContext.Setup(x => x.WriteDebug).Returns(true);
             stepContext.Setup(x => x.Variables).Returns(_variables);
             stepContext.Setup(x => x.EnvironmentVariables).Returns(_env);
-            stepContext.Setup(x => x.ExpressionValues).Returns(_contexts);
+            stepContext.Setup(x => x.ExpressionValues).Returns(new DictionaryContextData());
             stepContext.Setup(x => x.ExpressionFunctions).Returns(new List<IFunctionInfo>());
             stepContext.Setup(x => x.JobContext).Returns(_jobContext);
             stepContext.Setup(x => x.StepsContext).Returns(_stepContext);

src/runnerversion

@@ -1 +1 @@
-2.267.2
+2.267.0