!47 isula-build: fix goroutine leak because of Status channels waiting

Merge pull request !47 from Vanient/master

daemon/build.go

@@ -62,6 +62,7 @@ func (b *Backend) Build(req *pb.BuildRequest, stream pb.Control_BuildServer) (er
 	eg, ctx = errgroup.WithContext(ctx)
 	eg.Go(func() error {
 		b.syncBuildStatus(req.BuildID) <- struct{}{}
+		close(b.status[req.BuildID].startBuild)
 		imageID, err = builder.Build()
 
 		// in case there is error during Build stage, the backend will always waiting for content write into

daemon/status.go

@@ -32,7 +32,12 @@ func (b *Backend) Status(req *pb.StatusRequest, stream pb.Control_StatusServer)
 	}).Info("StatusRequest received")
 
 	// waiting for Build start first so that the builder with req.BuildID will be set already
-	<-b.syncBuildStatus(req.BuildID)
+	select {
+	case <-b.syncBuildStatus(req.BuildID):
+	case <-stream.Context().Done():
+		b.deleteStatus(req.BuildID)
+		return nil
+	}
 
 	builder, err := b.daemon.Builder(req.BuildID)
 	if err != nil {