Make soong lock file sync time configurable..

- Add SOONG_LOCK_TIMEOUT environmental variable for users to set a
duration (e.g. 1h), which defaults to the current 10 seconds.
- Instead of logging once per second waiting to acquire the lock,
only log once before the first wait

Fixes: 131854539
Test: make; open another tab and make
Change-Id: I0a02a1b071964f74473a5f55034f916526e1b309

ui/build/proc_sync.go

@@ -34,6 +34,14 @@ func BecomeSingletonOrFail(ctx Context, config Config) (lock *fileLock) {
 	if err != nil {
 		ctx.Logger.Fatal(err)
 	}
+	lockfilePollDuration := time.Second
+	lockfileTimeout := time.Second * 10
+	if envTimeout := os.Getenv("SOONG_LOCK_TIMEOUT"); envTimeout != "" {
+		lockfileTimeout, err = time.ParseDuration(envTimeout)
+		if err != nil {
+			ctx.Logger.Fatalf("failure parsing SOONG_LOCK_TIMEOUT %q: %s", envTimeout, err)
+		}
+	}
 	err = lockSynchronous(*lockingInfo, newSleepWaiter(lockfilePollDuration, lockfileTimeout), ctx.Logger)
 	if err != nil {
 		ctx.Logger.Fatal(err)
@@ -41,9 +49,6 @@ func BecomeSingletonOrFail(ctx Context, config Config) (lock *fileLock) {
 	return lockingInfo
 }
 
-var lockfileTimeout = time.Second * 10
-var lockfilePollDuration = time.Second
-
 type lockable interface {
 	tryLock() error
 	Unlock() error
@@ -80,15 +85,18 @@ func lockSynchronous(lock lockable, waiter waiter, logger logger.Logger) (err er
 			return nil
 		}
 
-		waited = true
-
 		done, description := waiter.checkDeadline()
 
+		if !waited {
+			logger.Printf("Waiting up to %s to lock %v to ensure no other Soong process is running in the same output directory\n", description, lock.description())
+		}
+
+		waited = true
+
 		if done {
 			return fmt.Errorf("Tried to lock %s, but timed out %s . Make sure no other Soong process is using it",
 				lock.description(), waiter.summarize())
 		} else {
-			logger.Printf("Waiting up to %s to lock %v to ensure no other Soong process is running in the same output directory\n", description, lock.description())
 			waiter.wait()
 		}
 	}