Add graph text description handler

Signed-off-by: Yuriy Losev <yuriy.losev@flant.com>

Author: yalosev

pkg/addon-operator/debug_server.go

@@ -51,18 +51,39 @@ func (op *AddonOperator) RegisterDebugGlobalRoutes(dbgSrv *debug.Server) {
 }
 
 func (op *AddonOperator) RegisterDebugGraphRoutes(dbgSrv *debug.Server) {
-	dbgSrv.RegisterHandler(http.MethodGet, "/graph", func(_ *http.Request) (interface{}, error) {
+	dbgSrv.Router.Get("/graph", func(w http.ResponseWriter, req *http.Request) {
+		format := req.URL.Query().Get("format")
+		if format == "text" {
+			dotDesc, err := op.ModuleManager.GetGraphDOTDescription()
+			if err != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				_, _ = w.Write([]byte(err.Error()))
+				return
+			}
+
+			w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+			w.WriteHeader(http.StatusOK)
+			_, _ = w.Write(dotDesc)
+			return
+		}
+
 		image, err := op.ModuleManager.GetGraphImage()
 		if err != nil {
-			return nil, fmt.Errorf("couldn't get graph's image")
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte(err.Error()))
+			return
 		}
 
 		buf := new(bytes.Buffer)
 		if err = png.Encode(buf, image); err != nil {
-			return nil, fmt.Errorf("couldn't encode graph's image")
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte(fmt.Errorf("couldn't encode png graph's image").Error()))
+			return
 		}
 
-		return buf.String(), nil
+		w.Header().Set("Content-Type", "image/png")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write(buf.Bytes())
 	})
 }
 

pkg/module_manager/module_manager.go

@@ -436,6 +436,10 @@ func (mm *ModuleManager) GetGraphImage() (image.Image, error) {
 	return mm.moduleScheduler.GetGraphImage()
 }
 
+func (mm *ModuleManager) GetGraphDOTDescription() ([]byte, error) {
+	return mm.moduleScheduler.GetGraphDOTDescription()
+}
+
 // SetGlobalDiscoveryAPIVersions applies global values patch to .global.discovery.apiVersions key
 // if non-default moduleLoader is in use
 func (mm *ModuleManager) SetGlobalDiscoveryAPIVersions(apiVersions []string) {

pkg/module_manager/scheduler/scheduler.go

@@ -108,34 +108,48 @@ func (s *Scheduler) EventCh() chan extenders.ExtenderEvent {
 	return s.extCh
 }
 
-// GetGraphImage draws current graph's image
-func (s *Scheduler) GetGraphImage() (image.Image, error) {
-	if s.graphImage != nil {
-		return s.graphImage, nil
-	}
+// GetGraphDOTDescription returns DOT(graph description language) description of the current graph
+func (s *Scheduler) GetGraphDOTDescription() ([]byte, error) {
+	return s.getGraphDOTDescription()
+}
 
+func (s *Scheduler) getGraphDOTDescription() ([]byte, error) {
 	var b bytes.Buffer
 	writer := bufio.NewWriter(&b)
 
 	if err := draw.DOT(s.dag, writer, draw.GraphAttribute("label", "Module Scheduler's Graph")); err != nil {
-		return nil, fmt.Errorf("Couldn't write graph file: %w", err)
+		return nil, fmt.Errorf("couldn't write graph file: %w", err)
 	}
 	writer.Flush()
 
-	graph, err := graphviz.ParseBytes(b.Bytes())
+	return b.Bytes(), nil
+}
+
+// GetGraphImage draws current graph's image
+func (s *Scheduler) GetGraphImage() (image.Image, error) {
+	if s.graphImage != nil {
+		return s.graphImage, nil
+	}
+
+	dotDesc, err := s.getGraphDOTDescription()
+	if err != nil {
+		return nil, err
+	}
+
+	graphvizGraph, err := graphviz.ParseBytes(dotDesc)
 	if err != nil {
-		return nil, fmt.Errorf("Couldn't parse graph file: %w", err)
+		return nil, fmt.Errorf("couldn't parse graph file: %w", err)
 	}
 
 	g := graphviz.New()
 
-	image, err := g.RenderImage(graph)
+	graphvizImage, err := g.RenderImage(graphvizGraph)
 	if err != nil {
-		return nil, fmt.Errorf("Couldn't render graph image: %w", err)
+		return nil, fmt.Errorf("couldn't render graph image: %w", err)
 	}
-	s.graphImage = image
+	s.graphImage = graphvizImage
 
-	return image, nil
+	return graphvizImage, nil
 }
 
 // AddModuleVertex adds a new vertex of type Module to the graph