prototype support for step retries

src/Runner.Worker/ActionRunner.cs

@@ -64,6 +64,8 @@ namespace GitHub.Runner.Worker
 
         public Pipelines.ActionStep Action { get; set; }
 
+        public Int32 Retries => Action?.Retries ?? 0;
+
         public TemplateToken Timeout => Action?.TimeoutInMinutes;
 
         public async Task RunAsync()

src/Runner.Worker/JobExtensionRunner.cs

@@ -26,6 +26,7 @@ namespace GitHub.Runner.Worker
         public TemplateToken ContinueOnError => new BooleanToken(null, null, null, false);
         public string DisplayName { get; set; }
         public IExecutionContext ExecutionContext { get; set; }
+        public Int32 Retries => 0;
         public TemplateToken Timeout => new NumberToken(null, null, null, 0);
         public object Data => _data;
 

src/Runner.Worker/StepsRunner.cs

@@ -24,6 +24,7 @@ namespace GitHub.Runner.Worker
         TemplateToken ContinueOnError { get; }
         string DisplayName { get; set; }
         IExecutionContext ExecutionContext { get; set; }
+        Int32 Retries { get; }
         TemplateToken Timeout { get; }
         Task RunAsync();
     }
@@ -280,73 +281,96 @@ namespace GitHub.Runner.Worker
                 step.ExecutionContext.Error("An error occurred when attempting to determine the step timeout.");
                 step.ExecutionContext.Error(ex);
             }
-            if (timeoutMinutes > 0)
-            {
-                var timeout = TimeSpan.FromMinutes(timeoutMinutes);
-                step.ExecutionContext.SetTimeout(timeout);
-            }
 
-            await EncodingUtil.SetEncoding(HostContext, Trace, step.ExecutionContext.CancellationToken);
-
-            try
+            int attempt = 1;
+            while (true)
             {
-                await step.RunAsync();
-            }
-            catch (OperationCanceledException ex)
-            {
-                if (step.ExecutionContext.CancellationToken.IsCancellationRequested &&
-                    !jobCancellationToken.IsCancellationRequested)
+                if (timeoutMinutes > 0)
                 {
-                    Trace.Error($"Caught timeout exception from step: {ex.Message}");
-                    step.ExecutionContext.Error("The action has timed out.");
-                    step.ExecutionContext.Result = TaskResult.Failed;
+                    var timeout = TimeSpan.FromMinutes(timeoutMinutes);
+                    step.ExecutionContext.SetTimeout(timeout);
                 }
-                else
-                {
-                    // Log the exception and cancel the step.
-                    Trace.Error($"Caught cancellation exception from step: {ex}");
-                    step.ExecutionContext.Error(ex);
-                    step.ExecutionContext.Result = TaskResult.Canceled;
-                }
-            }
-            catch (Exception ex)
-            {
-                // Log the error and fail the step.
-                Trace.Error($"Caught exception from step: {ex}");
-                step.ExecutionContext.Error(ex);
-                step.ExecutionContext.Result = TaskResult.Failed;
-            }
 
-            // Merge execution context result with command result
-            if (step.ExecutionContext.CommandResult != null)
-            {
-                step.ExecutionContext.Result = TaskResultUtil.MergeTaskResults(step.ExecutionContext.Result, step.ExecutionContext.CommandResult.Value);
-            }
+                await EncodingUtil.SetEncoding(HostContext, Trace, step.ExecutionContext.CancellationToken);
 
-            // Fixup the step result if ContinueOnError.
-            if (step.ExecutionContext.Result == TaskResult.Failed)
-            {
-                var continueOnError = false;
                 try
                 {
-                    continueOnError = templateEvaluator.EvaluateStepContinueOnError(step.ContinueOnError, step.ExecutionContext.ExpressionValues, step.ExecutionContext.ExpressionFunctions);
+                    await step.RunAsync();
+                }
+                catch (OperationCanceledException ex)
+                {
+                    if (step.ExecutionContext.CancellationToken.IsCancellationRequested &&
+                        !jobCancellationToken.IsCancellationRequested)
+                    {
+                        Trace.Error($"Caught timeout exception from step: {ex.Message}");
+                        step.ExecutionContext.Error("The action has timed out.");
+                        step.ExecutionContext.Result = TaskResult.Failed;
+                    }
+                    else
+                    {
+                        // Log the exception and cancel the step.
+                        Trace.Error($"Caught cancellation exception from step: {ex}");
+                        step.ExecutionContext.Error(ex);
+                        step.ExecutionContext.Result = TaskResult.Canceled;
+                    }
                 }
                 catch (Exception ex)
                 {
-                    Trace.Info("The step failed and an error occurred when attempting to determine whether to continue on error.");
-                    Trace.Error(ex);
-                    step.ExecutionContext.Error("The step failed and an error occurred when attempting to determine whether to continue on error.");
+                    // Log the error and fail the step.
+                    Trace.Error($"Caught exception from step: {ex}");
                     step.ExecutionContext.Error(ex);
+                    step.ExecutionContext.Result = TaskResult.Failed;
                 }
 
-                if (continueOnError)
+                // Merge execution context result with command result
+                if (step.ExecutionContext.CommandResult != null)
                 {
-                    step.ExecutionContext.Outcome = step.ExecutionContext.Result;
-                    step.ExecutionContext.Result = TaskResult.Succeeded;
-                    Trace.Info($"Updated step result (continue on error)");
+                    step.ExecutionContext.Result = TaskResultUtil.MergeTaskResults(step.ExecutionContext.Result, step.ExecutionContext.CommandResult.Value);
                 }
+
+                // Fixup the step result if ContinueOnError.
+                if (step.ExecutionContext.Result == TaskResult.Failed)
+                {
+                    var continueOnError = false;
+                    try
+                    {
+                        continueOnError = templateEvaluator.EvaluateStepContinueOnError(step.ContinueOnError, step.ExecutionContext.ExpressionValues, step.ExecutionContext.ExpressionFunctions);
+                    }
+                    catch (Exception ex)
+                    {
+                        Trace.Info("The step failed and an error occurred when attempting to determine whether to continue on error.");
+                        Trace.Error(ex);
+                        step.ExecutionContext.Error("The step failed and an error occurred when attempting to determine whether to continue on error.");
+                        step.ExecutionContext.Error(ex);
+                    }
+
+                    if (continueOnError)
+                    {
+                        step.ExecutionContext.Outcome = step.ExecutionContext.Result;
+                        step.ExecutionContext.Result = TaskResult.Succeeded;
+                        Trace.Info($"Updated step result (continue on error)");
+                    }
+                }
+                Trace.Info($"Step result: {step.ExecutionContext.Result}");
+
+                if (step.ExecutionContext.Result == TaskResult.Failed && attempt <= step.Retries)
+                {
+                    attempt++;
+                    step.ExecutionContext.Result = null;
+                    step.ExecutionContext.ResultCode = null;
+                    // todo: replace the step cancellation token source
+                    // todo: reset the step.ExecutionContext.CommandResult
+                    // todo: create a new timeline record, e.g. "My display name (#2)"
+                    // todo: clear outputs? What will we do on a job? probably clear outputs since merging from separate timeline attempts would otherwise be complex
+                    // todo: consider intrastate - i guess it makes sense this doesn't get cleared
+                    // todo: reconcile all of the above wrt composite steps
+                    // todo: reconcile all of the above wrt pre/post
+                    // todo: distinguish retryable vs non-retryable failures? e.g. if an exception bubbles from the handler
+                    continue;
+                }
+
+                break;
             }
-            Trace.Info($"Step result: {step.ExecutionContext.Result}");
 
             // Complete the step context.
             step.ExecutionContext.Debug($"Finishing: {step.DisplayName}");

src/Sdk/DTPipelines/Pipelines/ActionStep.cs

@@ -22,6 +22,7 @@ namespace GitHub.DistributedTask.Pipelines
             this.Reference = actionToClone.Reference?.Clone();
 
             Environment = actionToClone.Environment?.Clone();
+            Retries = actionToClone.Retries;
             Inputs = actionToClone.Inputs?.Clone();
             ContextName = actionToClone?.ContextName;
             DisplayNameToken = actionToClone.DisplayNameToken?.Clone();
@@ -46,6 +47,9 @@ namespace GitHub.DistributedTask.Pipelines
         [DataMember(EmitDefaultValue = false)]
         public TemplateToken Environment { get; set; }
 
+        [DataMember(EmitDefaultValue = false)]
+        public Int32 Retries { get; set; }
+
         [DataMember(EmitDefaultValue = false)]
         public TemplateToken Inputs { get; set; }