Merge "Add warning about out-directory usage with RBE builds" am: f43eee4b9b

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1453658

Change-Id: Ie3d91d3762ff8f8746fd211005dbe9c1ed2040ee

cmd/soong_ui/main.go

@@ -173,6 +173,7 @@ func main() {
 	rbeMetricsFile := filepath.Join(logsDir, c.logsPrefix+"rbe_metrics.pb")
 	soongMetricsFile := filepath.Join(logsDir, c.logsPrefix+"soong_metrics")
 	defer build.UploadMetrics(buildCtx, config, c.simpleOutput, buildStarted, buildErrorFile, rbeMetricsFile, soongMetricsFile)
+	build.PrintOutDirWarning(buildCtx, config)
 
 	os.MkdirAll(logsDir, 0777)
 	log.SetOutput(filepath.Join(logsDir, c.logsPrefix+"soong.log"))

ui/build/rbe.go

@@ -34,6 +34,8 @@ const (
 
 	// RBE metrics proto buffer file
 	rbeMetricsPBFilename = "rbe_metrics.pb"
+
+	defaultOutDir = "out"
 )
 
 func rbeCommand(ctx Context, config Config, rbeCmd string) string {
@@ -151,3 +153,16 @@ func DumpRBEMetrics(ctx Context, config Config, filename string) {
 		ctx.Fatalf("failed to copy %q to %q: %v\n", metricsFile, filename, err)
 	}
 }
+
+// PrintOutDirWarning prints a warning to indicate to the user that
+// setting output directory to a path other than "out" in an RBE enabled
+// build can cause slow builds.
+func PrintOutDirWarning(ctx Context, config Config) {
+	if config.UseRBE() && config.OutDir() != defaultOutDir {
+		fmt.Fprintln(ctx.Writer, "")
+		fmt.Fprintln(ctx.Writer, "\033[33mWARNING:\033[0m")
+		fmt.Fprintln(ctx.Writer, fmt.Sprintf("Setting OUT_DIR to a path other than %v may result in slow RBE builds.", defaultOutDir))
+		fmt.Fprintln(ctx.Writer, "See http://go/android_rbe_out_dir for a workaround.")
+		fmt.Fprintln(ctx.Writer, "")
+	}
+}