adding compile-time const whether to use the broker service

src/Directory.Build.props

@@ -47,6 +47,11 @@
     <DefineConstants>$(DefineConstants);DEBUG</DefineConstants>
   </PropertyGroup>
 
+  <!-- Set USE_BROKER vars -->
+  <PropertyGroup Condition="'$(USE_BROKER)' == 'true'">
+    <DefineConstants>$(DefineConstants);USE_BROKER</DefineConstants>
+  </PropertyGroup>
+
   <!-- Set Treat tarnings as errors -->
   <PropertyGroup>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

src/Runner.Common/BrokerServer.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using GitHub.Runner.Common.Util;
+using GitHub.Services.WebApi;
+using GitHub.Services.Common;
+using GitHub.Runner.Sdk;
+using System.Net.Http;
+
+namespace GitHub.Runner.Common
+{
+    [ServiceLocator(Default = typeof(BrokerServer))]
+    public interface IBrokerServer : IRunnerService
+    {
+        Task ConnectAsync(Uri serverUrl);
+        Task<GitHub.DistributedTask.WebApi.TaskAgentMessage> GetMessageAsync(Int32 poolId, Guid sessionId, Int64? lastMessageId, CancellationToken cancellationToken);
+    }
+
+    public sealed class BrokerServer : RunnerService, IBrokerServer
+    {
+        private HttpClient _httpClient;
+
+        public async Task ConnectAsync(Uri serverUrl)
+        {
+            _httpClient = new HttpClient();
+            _httpClient.BaseAddress = serverUrl;
+            _httpClient.Timeout = TimeSpan.FromSeconds(50);
+            await _httpClient.GetAsync("health");
+        }
+
+        public async Task<GitHub.DistributedTask.WebApi.TaskAgentMessage> GetMessageAsync(Int32 poolId, Guid sessionId, Int64? lastMessageId, CancellationToken cancellationToken)
+        {
+            await _httpClient.GetAsync("message");
+            return null;
+        }
+    }
+}

src/Runner.Listener/Configuration/CredentialManager.cs

@@ -40,6 +40,12 @@ namespace GitHub.Runner.Listener.Configuration
             return creds;
         }
 
+#if USE_BROKER
+        public VssCredentials LoadCredentials()
+        {
+            return new VssCredentials();
+        }
+#else
         public VssCredentials LoadCredentials()
         {
             IConfigurationStore store = HostContext.GetService<IConfigurationStore>();
@@ -69,6 +75,7 @@ namespace GitHub.Runner.Listener.Configuration
 
             return creds;
         }
+#endif
     }
 
     [DataContract]

src/Runner.Listener/MessageListener.cs

@@ -31,6 +31,7 @@ namespace GitHub.Runner.Listener
         private RunnerSettings _settings;
         private ITerminal _term;
         private IRunnerServer _runnerServer;
+        private IBrokerServer _brokerServer;
         private TaskAgentSession _session;
         private TimeSpan _getNextMessageRetryInterval;
         private bool _accessTokenRevoked = false;
@@ -45,8 +46,44 @@ namespace GitHub.Runner.Listener
 
             _term = HostContext.GetService<ITerminal>();
             _runnerServer = HostContext.GetService<IRunnerServer>();
+            _brokerServer = HostContext.GetService<IBrokerServer>();
         }
 
+#if USE_BROKER
+        public async Task<Boolean> CreateSessionAsync(CancellationToken token)
+        {
+            Trace.Entering();
+
+            // Settings
+            var configManager = HostContext.GetService<IConfigurationManager>();
+            _settings = configManager.LoadSettings();
+            var serverUrl = _settings.ServerUrl;
+            Trace.Info(_settings);
+
+            // Connect
+            token.ThrowIfCancellationRequested();
+            Trace.Info($"Attempt to create session.");
+            Trace.Info("Connecting to the Runner Server...");
+            _term.WriteLine($"Connecting to {new Uri(serverUrl)}");
+            await _brokerServer.ConnectAsync(new Uri(serverUrl));
+            _term.WriteLine();
+            _term.WriteSuccessMessage("Connected to GitHub");
+            _term.WriteLine();
+
+            // Session info
+            var agent = new TaskAgentReference
+            {
+                Id = _settings.AgentId,
+                Name = _settings.AgentName,
+                Version = BuildConstants.RunnerPackage.Version,
+                OSDescription = RuntimeInformation.OSDescription,
+            };
+            string sessionName = $"{Environment.MachineName ?? "RUNNER"}";
+            _session = new TaskAgentSession(sessionName, agent);
+
+            return true;
+        }
+#else
         public async Task<Boolean> CreateSessionAsync(CancellationToken token)
         {
             Trace.Entering();
@@ -151,6 +188,7 @@ namespace GitHub.Runner.Listener
                 }
             }
         }
+#endif
 
         public async Task DeleteSessionAsync()
         {
@@ -170,6 +208,116 @@ namespace GitHub.Runner.Listener
             }
         }
 
+#if USE_BROKER
+        public async Task<TaskAgentMessage> GetNextMessageAsync(CancellationToken token)
+        {
+            Trace.Entering();
+            ArgUtil.NotNull(_session, nameof(_session));
+            ArgUtil.NotNull(_settings, nameof(_settings));
+            bool encounteringError = false;
+            int continuousError = 0;
+            string errorMessage = string.Empty;
+            Stopwatch heartbeat = new Stopwatch();
+            heartbeat.Restart();
+            while (true)
+            {
+                token.ThrowIfCancellationRequested();
+                TaskAgentMessage message = null;
+                try
+                {
+                    message = await _brokerServer.GetMessageAsync(_settings.PoolId, _session.SessionId, _lastMessageId, token);
+
+                    // Decrypt the message body if the session is using encryption
+                    message = DecryptMessage(message);
+
+                    if (message != null)
+                    {
+                        _lastMessageId = message.MessageId;
+                    }
+
+                    if (encounteringError) //print the message once only if there was an error
+                    {
+                        _term.WriteLine($"{DateTime.UtcNow:u}: Runner reconnected.");
+                        encounteringError = false;
+                        continuousError = 0;
+                    }
+                }
+                catch (OperationCanceledException) when (token.IsCancellationRequested)
+                {
+                    Trace.Info("Get next message has been cancelled.");
+                    throw;
+                }
+                catch (TaskAgentAccessTokenExpiredException)
+                {
+                    Trace.Info("Runner OAuth token has been revoked. Unable to pull message.");
+                    _accessTokenRevoked = true;
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    Trace.Error("Catch exception during get next message.");
+                    Trace.Error(ex);
+
+                    // don't retry if SkipSessionRecover = true, DT service will delete agent session to stop agent from taking more jobs.
+                    if (ex is TaskAgentSessionExpiredException && !_settings.SkipSessionRecover && await CreateSessionAsync(token))
+                    {
+                        Trace.Info($"{nameof(TaskAgentSessionExpiredException)} received, recovered by recreate session.");
+                    }
+                    else if (!IsGetNextMessageExceptionRetriable(ex))
+                    {
+                        throw;
+                    }
+                    else
+                    {
+                        continuousError++;
+                        //retry after a random backoff to avoid service throttling
+                        //in case of there is a service error happened and all agents get kicked off of the long poll and all agent try to reconnect back at the same time.
+                        if (continuousError <= 5)
+                        {
+                            // random backoff [15, 30]
+                            _getNextMessageRetryInterval = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromSeconds(15), TimeSpan.FromSeconds(30), _getNextMessageRetryInterval);
+                        }
+                        else
+                        {
+                            // more aggressive backoff [30, 60]
+                            _getNextMessageRetryInterval = BackoffTimerHelper.GetRandomBackoff(TimeSpan.FromSeconds(30), TimeSpan.FromSeconds(60), _getNextMessageRetryInterval);
+                        }
+
+                        if (!encounteringError)
+                        {
+                            //print error only on the first consecutive error
+                            _term.WriteError($"{DateTime.UtcNow:u}: Runner connect error: {ex.Message}. Retrying until reconnected.");
+                            encounteringError = true;
+                        }
+
+                        // re-create VssConnection before next retry
+                        await _runnerServer.RefreshConnectionAsync(RunnerConnectionType.MessageQueue, TimeSpan.FromSeconds(60));
+
+                        Trace.Info("Sleeping for {0} seconds before retrying.", _getNextMessageRetryInterval.TotalSeconds);
+                        await HostContext.Delay(_getNextMessageRetryInterval, token);
+                    }
+                }
+
+                if (message == null)
+                {
+                    if (heartbeat.Elapsed > TimeSpan.FromMinutes(30))
+                    {
+                        Trace.Info($"No message retrieved from session '{_session.SessionId}' within last 30 minutes.");
+                        heartbeat.Restart();
+                    }
+                    else
+                    {
+                        Trace.Verbose($"No message retrieved from session '{_session.SessionId}'.");
+                    }
+
+                    continue;
+                }
+
+                Trace.Info($"Message '{message.MessageId}' received from session '{_session.SessionId}'.");
+                return message;
+            }
+        }
+#else
         public async Task<TaskAgentMessage> GetNextMessageAsync(CancellationToken token)
         {
             Trace.Entering();
@@ -281,6 +429,7 @@ namespace GitHub.Runner.Listener
                 return message;
             }
         }
+#endif
 
         public async Task DeleteMessageAsync(TaskAgentMessage message)
         {

src/dev.sh

@@ -2,7 +2,7 @@
 
 ###############################################################################
 #  
-#  ./dev.sh build/layout/test/package [Debug/Release]
+#  ./dev.sh build/layout/test/package [Debug/Release] [linux-x64|linux-x86|linux-arm64|linux-arm|osx-x64|win-x64|win-x86] [use-broker]
 #
 ###############################################################################
 
@@ -11,6 +11,7 @@ set -e
 DEV_CMD=$1
 DEV_CONFIG=$2
 DEV_TARGET_RUNTIME=$3
+DEV_USE_BROKER=$4
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 LAYOUT_DIR="$SCRIPT_DIR/../_layout"
@@ -81,6 +82,13 @@ elif [[ "$CURRENT_PLATFORM" == 'darwin' ]]; then
     fi
 fi
 
+if [ -n "$DEV_USE_BROKER" ]; then
+    USE_BROKER='-p:USE_BROKER="true"'
+else
+    USE_BROKER=''
+fi
+
+
 function failed()
 {
     local error=${1:-Undefined error}
@@ -114,13 +122,13 @@ function heading()
 function build ()
 {
     heading "Building ..."
-    dotnet msbuild -t:Build -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:RunnerVersion="${RUNNER_VERSION}" ./dir.proj || failed build
+    dotnet msbuild -t:Build -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:RunnerVersion="${RUNNER_VERSION}" $USE_BROKER ./dir.proj || failed build
 }
 
 function layout ()
 {
     heading "Create layout ..."
-    dotnet msbuild -t:layout -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:RunnerVersion="${RUNNER_VERSION}" ./dir.proj || failed build
+    dotnet msbuild -t:layout -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:RunnerVersion="${RUNNER_VERSION}" $USE_BROKER ./dir.proj || failed build
 
     #change execution flag to allow running with sudo
     if [[ ("$CURRENT_PLATFORM" == "linux") || ("$CURRENT_PLATFORM" == "darwin") ]]; then