Milo: Pending swarming builds

appengine/cmd/milo/swarming/build.go

Index: appengine/cmd/milo/swarming/build.go
diff --git a/appengine/cmd/milo/swarming/build.go b/appengine/cmd/milo/swarming/build.go
index 7decfc96c2d518776e8823ec268d0ea0b8589cbf..a1c5b27fb05e6d6c3dc94c6cfeb8b1408f63b1bb 100644
--- a/appengine/cmd/milo/swarming/build.go
+++ b/appengine/cmd/milo/swarming/build.go
@@ -114,8 +114,10 @@ func getSwarmingResult(sc *swarming.Service, taskID string) (
 	return srtr, nil
 }
 
+// getSwarming fetches both the swarming task data and log data, and returns
+// the task result, the log string, task error, and log error.
 func getSwarming(c context.Context, server string, taskID string) (
-	*swarming.SwarmingRpcsTaskResult, string, error) {
+	*swarming.SwarmingRpcsTaskResult, string, error, error) {
 
 	var log string
 	var sr *swarming.SwarmingRpcsTaskResult
@@ -125,15 +127,12 @@ func getSwarming(c context.Context, server string, taskID string) (
 	if server == "debug" {
 		sr, errRes = getDebugSwarmingResult(taskID)
 		log, errLog = getDebugTaskOutput(taskID)
-		if errLog != nil {
-			return sr, log, errLog
-		}
-		return sr, log, errRes
+		return sr, log, errRes, errLog
 	}
 
 	sc, err := getSwarmingClient(c, server)
 	if err != nil {
-		return nil, "", err
+		return nil, "", err, nil
 	}
 
 	var wg sync.WaitGroup
@@ -148,10 +147,7 @@ func getSwarming(c context.Context, server string, taskID string) (
 		sr, errRes = getSwarmingResult(sc, taskID)
 	}()
 	wg.Wait()
-	if errRes != nil {
-		return sr, log, errRes
-	}
-	return sr, log, errLog
+	return sr, log, errRes, errLog
 }
 
 func taskProperties(sr *swarming.SwarmingRpcsTaskResult) *resp.PropertyGroup {
@@ -292,9 +288,18 @@ func streamsFromAnnotatedLog(ctx context.Context, log string) (*logdog.Streams,
 
 func swarmingBuildImpl(c context.Context, URL string, server string, taskID string) (*resp.MiloBuild, error) {
 	// Fetch the data from Swarming
-	sr, body, err := getSwarming(c, server, taskID)
-	if err != nil {
-		return nil, err
+	sr, body, errRes, errLog := getSwarming(c, server, taskID)
+	// Swarming result must come back.
+	if errRes != nil {
+		return nil, errRes
+	}
+	switch sr.State {
+	case TaskCompleted, TaskRunning, TaskCanceled:
+		if errLog != nil {
+			// If the task is completed, running, or canceled, we'd expect a log.
+			// If not, we don't necessarily expect the log to come back.

[nodir, 2016/06/28 20:36:49]

I think getSwarming is a better place for this logic (since perhaps all users of
getSwarming will have to replicate it)
this would simplify getSwarming func signature too (won't have to have two
errors)

+			return nil, errLog
+		}
 	}
 
 	allowMilo := false
@@ -316,20 +321,22 @@ func swarmingBuildImpl(c context.Context, URL string, server string, taskID stri
 	// Decode the data using annotee. The logdog stream returned here is assumed
 	// to be consistent, which is why the following block of code are not
 	// expected to ever err out.
-	lds, err := streamsFromAnnotatedLog(c, body)
-	if err != nil {
-		build.Components = []*resp.BuildComponent{{
-			Type:   resp.Summary,
-			Label:  "Milo annotation parser",
-			Text:   []string{err.Error()},
-			Status: resp.InfraFailure,
-			SubLink: []*resp.Link{{
-				Label: "swarming task",
-				URL:   taskPageURL(server, taskID),
-			}},
-		}}
-	} else {
-		logdog.AddLogDogToBuild(c, URL, lds, build)
+	if errLog != nil && body != "" {
+		lds, err := streamsFromAnnotatedLog(c, body)
+		if err != nil {
+			build.Components = []*resp.BuildComponent{{
+				Type:   resp.Summary,
+				Label:  "Milo annotation parser",
+				Text:   []string{err.Error()},
+				Status: resp.InfraFailure,
+				SubLink: []*resp.Link{{
+					Label: "swarming task",
+					URL:   taskPageURL(server, taskID),
+				}},
+			}}
+		} else {
+			logdog.AddLogDogToBuild(c, URL, lds, build)
+		}
 	}
 
 	return build, nil