Merge "implement USE_BAZEL_VERSION for m"

bazel/bazel_proxy.go

@@ -26,10 +26,11 @@ import (
 	"time"
 )
 
-// Logs fatal events of ProxyServer.
+// Logs events of ProxyServer.
 type ServerLogger interface {
 	Fatal(v ...interface{})
 	Fatalf(format string, v ...interface{})
+	Println(v ...interface{})
 }
 
 // CmdRequest is a request to the Bazel Proxy server.
@@ -74,6 +75,7 @@ type ProxyServer struct {
 	logger          ServerLogger
 	outDir          string
 	workspaceDir    string
+	bazeliskVersion string
 	// The server goroutine will listen on this channel and stop handling requests
 	// once it is written to.
 	done chan struct{}
@@ -119,12 +121,17 @@ func (b *ProxyClient) IssueCommand(req CmdRequest) (CmdResponse, error) {
 }
 
 // NewProxyServer is a constructor for a ProxyServer.
-func NewProxyServer(logger ServerLogger, outDir string, workspaceDir string) *ProxyServer {
+func NewProxyServer(logger ServerLogger, outDir string, workspaceDir string, bazeliskVersion string) *ProxyServer {
+	if len(bazeliskVersion) > 0 {
+		logger.Println("** Using Bazelisk for this build, due to env var USE_BAZEL_VERSION=" + bazeliskVersion + " **")
+	}
+
 	return &ProxyServer{
 		logger:          logger,
 		outDir:          outDir,
 		workspaceDir:    workspaceDir,
 		done:            make(chan struct{}),
+		bazeliskVersion: bazeliskVersion,
 	}
 }
 
@@ -155,6 +162,9 @@ func (b *ProxyServer) handleRequest(conn net.Conn) error {
 		return fmt.Errorf("Error decoding request: %s", err)
 	}
 
+	if len(b.bazeliskVersion) > 0 {
+		req.Env = append(req.Env, "USE_BAZEL_VERSION="+b.bazeliskVersion)
+	}
 	stdout, stderr, cmdErr := ExecBazel("./build/bazel/bin/bazel", b.workspaceDir, req)
 	errorString := ""
 	if cmdErr != nil {

cmd/soong_build/main.go

@@ -552,6 +552,12 @@ func main() {
 		}
 		writeMetrics(configuration, ctx.EventHandler, metricsDir)
 	}
+
+	// Register this environment variablesas being an implicit dependencies of
+	// soong_build. Changes to this environment variable will result in
+	// retriggering soong_build.
+	configuration.Getenv("USE_BAZEL_VERSION")
+
 	writeUsedEnvironmentFile(configuration)
 
 	// Touch the output file so that it's the newest file created by soong_build.

ui/build/config.go

@@ -1642,6 +1642,16 @@ func (c *configImpl) IsPersistentBazelEnabled() bool {
 	return c.Environment().IsEnvTrue("USE_PERSISTENT_BAZEL")
 }
 
+// GetBazeliskBazelVersion returns the Bazel version to use for this build,
+// or the empty string if the current canonical prod Bazel should be used.
+// This environment variable should only be set to debug the build system.
+// The Bazel version, if set, will be passed to Bazelisk, and Bazelisk will
+// handle downloading and invoking the correct Bazel binary.
+func (c *configImpl) GetBazeliskBazelVersion() string {
+	value, _ := c.Environment().Get("USE_BAZEL_VERSION")
+	return value
+}
+
 func (c *configImpl) BazelModulesForceEnabledByFlag() string {
 	return c.bazelForceEnabledModules
 }

ui/build/soong.go

@@ -533,7 +533,7 @@ func runSoong(ctx Context, config Config) {
 		defer ctx.EndTrace()
 
 		if config.IsPersistentBazelEnabled() {
-			bazelProxy := bazel.NewProxyServer(ctx.Logger, config.OutDir(), filepath.Join(config.SoongOutDir(), "workspace"))
+			bazelProxy := bazel.NewProxyServer(ctx.Logger, config.OutDir(), filepath.Join(config.SoongOutDir(), "workspace"), config.GetBazeliskBazelVersion())
 			bazelProxy.Start()
 			defer bazelProxy.Close()
 		}