cmd/coordinator: fix local development environment

Previously the server would fail to start if a valid token could not
be found. The local development environment still doesn't do much, but
it should let you view and edit the HTML and confirm that the server
starts, so ignore the error if we are running in dev mode.

Add a short README explaining how to start and view the coordinator
server locally.

Fixes golang/go#19828.
Fixes golang/go#18291.

Change-Id: I91a3ce49e1e9ea18ca19f3867edb2c71fc1b5124
Reviewed-on: https://go-review.googlesource.com/39297
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: kevinburke

cmd/coordinator/README.md

@@ -0,0 +1,12 @@
+# Coordinator
+
+## Running locally
+
+Run
+
+    go install golang.org/x/build/cmd/coordinator && coordinator --mode=dev
+
+to start a server on https://localhost:8119. Proceed past the TLS warning and
+you should get the homepage. Some features won't work when running locally,
+but you should be able to view the homepage and the builders page and do basic
+sanity checks.

cmd/coordinator/coordinator.go

@@ -264,6 +264,9 @@ func (fn loggerFunc) createSpan(event string, optText ...string) eventSpan {
 func main() {
 	flag.Parse()
 
+	if Version == "" && *mode == "dev" {
+		Version = "dev"
+	}
 	log.Printf("coordinator version %q starting", Version)
 	err := initGCE()
 	if err != nil {
@@ -281,7 +284,7 @@ func main() {
 	err = initKube()
 	if err != nil {
 		kubeErr = err
-		log.Printf("Kube support disabled due to eror initializing Kubernetes: %v", err)
+		log.Printf("Kube support disabled due to error initializing Kubernetes: %v", err)
 	}
 
 	go updateInstanceRecord()

cmd/coordinator/gce.go

@@ -120,12 +120,19 @@ func initGCE() error {
 
 	dsClient, err = datastore.NewClient(ctx, buildEnv.ProjectName)
 	if err != nil {
-		// TODO(bradfitz): make fatal later, once working.
-		log.Printf("Error creating datastore client: %v", err)
+		if *mode == "dev" {
+			log.Printf("Error creating datastore client: %v", err)
+		} else {
+			log.Fatalf("Error creating datastore client: %v", err)
+		}
 	}
 
 	tokenSource, err = google.DefaultTokenSource(ctx, compute.CloudPlatformScope)
 	if err != nil {
+		if *mode == "dev" {
+			// don't try to do anything else with GCE, as it will likely fail
+			return nil
+		}
 		log.Fatalf("failed to get a token source: %v", err)
 	}
 	httpClient := oauth2.NewClient(ctx, tokenSource)
@@ -197,7 +204,7 @@ func (p *gceBuildletPool) pollQuotaLoop() {
 		return
 	}
 	if buildEnv.ProjectName == "" {
-		log.Printf("pollQuotaLoop: no GCE project name confingured; not checking quota.")
+		log.Printf("pollQuotaLoop: no GCE project name configured; not checking quota.")
 		return
 	}
 	for {