Merge changes I1fb78d7c,Ic836282f

* changes:
  Background distGzipFile to speed up CI builds
  Fix some problems with soong metrics loading

ui/build/build.go

@@ -18,6 +18,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"sync"
 	"text/template"
 
 	"android/soong/ui/metrics"
@@ -205,6 +206,8 @@ func Build(ctx Context, config Config) {
 		return
 	}
 
+	defer waitForDist(ctx)
+
 	// checkProblematicFiles aborts the build if Android.mk or CleanSpec.mk are found at the root of the tree.
 	checkProblematicFiles(ctx)
 
@@ -329,8 +332,18 @@ func Build(ctx Context, config Config) {
 	}
 }
 
+var distWaitGroup sync.WaitGroup
+
+// waitForDist waits for all backgrounded distGzipFile and distFile writes to finish
+func waitForDist(ctx Context) {
+	ctx.BeginTrace("soong_ui", "dist")
+	defer ctx.EndTrace()
+
+	distWaitGroup.Wait()
+}
+
 // distGzipFile writes a compressed copy of src to the distDir if dist is enabled.  Failures
-// are printed but non-fatal.
+// are printed but non-fatal. Uses the distWaitGroup func for backgrounding (optimization).
 func distGzipFile(ctx Context, config Config, src string, subDirs ...string) {
 	if !config.Dist() {
 		return
@@ -343,13 +356,17 @@ func distGzipFile(ctx Context, config Config, src string, subDirs ...string) {
 		ctx.Printf("failed to mkdir %s: %s", destDir, err.Error())
 	}
 
-	if err := gzipFileToDir(src, destDir); err != nil {
+	distWaitGroup.Add(1)
-		ctx.Printf("failed to dist %s: %s", filepath.Base(src), err.Error())
+	go func() {
-	}
+		defer distWaitGroup.Done()
+		if err := gzipFileToDir(src, destDir); err != nil {
+			ctx.Printf("failed to dist %s: %s", filepath.Base(src), err.Error())
+		}
+	}()
 }
 
 // distFile writes a copy of src to the distDir if dist is enabled.  Failures are printed but
-// non-fatal.
+// non-fatal. Uses the distWaitGroup func for backgrounding (optimization).
 func distFile(ctx Context, config Config, src string, subDirs ...string) {
 	if !config.Dist() {
 		return
@@ -362,7 +379,11 @@ func distFile(ctx Context, config Config, src string, subDirs ...string) {
 		ctx.Printf("failed to mkdir %s: %s", destDir, err.Error())
 	}
 
-	if _, err := copyFile(src, filepath.Join(destDir, filepath.Base(src))); err != nil {
+	distWaitGroup.Add(1)
-		ctx.Printf("failed to dist %s: %s", filepath.Base(src), err.Error())
+	go func() {
-	}
+		defer distWaitGroup.Done()
+		if _, err := copyFile(src, filepath.Join(destDir, filepath.Base(src))); err != nil {
+			ctx.Printf("failed to dist %s: %s", filepath.Base(src), err.Error())
+		}
+	}()
 }

ui/build/soong.go

@@ -15,7 +15,9 @@
 package build
 
 import (
+	"errors"
 	"fmt"
+	"io/fs"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -491,10 +493,14 @@ func runSoong(ctx Context, config Config) {
 
 	ninja("bootstrap", "bootstrap.ninja", targets...)
 
-	var soongBuildMetrics *soong_metrics_proto.SoongBuildMetrics
 	if shouldCollectBuildSoongMetrics(config) {
 		soongBuildMetrics := loadSoongBuildMetrics(ctx, config)
-		logSoongBuildMetrics(ctx, soongBuildMetrics)
+		if soongBuildMetrics != nil {
+			logSoongBuildMetrics(ctx, soongBuildMetrics)
+			if ctx.Metrics != nil {
+				ctx.Metrics.SetSoongBuildMetrics(soongBuildMetrics)
+			}
+		}
 	}
 
 	distGzipFile(ctx, config, config.SoongNinjaFile(), "soong")
@@ -504,9 +510,6 @@ func runSoong(ctx Context, config Config) {
 		distGzipFile(ctx, config, config.SoongMakeVarsMk(), "soong")
 	}
 
-	if shouldCollectBuildSoongMetrics(config) && ctx.Metrics != nil {
-		ctx.Metrics.SetSoongBuildMetrics(soongBuildMetrics)
-	}
 	if config.JsonModuleGraph() {
 		distGzipFile(ctx, config, config.ModuleGraphFile(), "soong")
 	}
@@ -538,8 +541,12 @@ func shouldCollectBuildSoongMetrics(config Config) bool {
 
 func loadSoongBuildMetrics(ctx Context, config Config) *soong_metrics_proto.SoongBuildMetrics {
 	soongBuildMetricsFile := filepath.Join(config.LogsDir(), "soong_build_metrics.pb")
-	buf, err := ioutil.ReadFile(soongBuildMetricsFile)
+	buf, err := os.ReadFile(soongBuildMetricsFile)
-	if err != nil {
+	if errors.Is(err, fs.ErrNotExist) {
+		// Soong may not have run during this invocation
+          ctx.Verbosef("Failed to read metrics file, %s: %s", soongBuildMetricsFile, err)
+		return nil
+	} else if err != nil {
 		ctx.Fatalf("Failed to load %s: %s", soongBuildMetricsFile, err)
 	}
 	soongBuildMetrics := &soong_metrics_proto.SoongBuildMetrics{}