Merge pull request #4062 from liubin/fix/4061-add-links-for-kata-monitor

kata-monitor: add some links when generating pages for browsers

src/runtime/cmd/kata-monitor/main.go

@@ -175,6 +175,15 @@ func main() {
 }
 
 func indexPage(w http.ResponseWriter, r *http.Request) {
+	htmlResponse := kataMonitor.IfReturnHTMLResponse(w, r)
+	if htmlResponse {
+		indexPageHTML(w, r)
+	} else {
+		indexPageText(w, r)
+	}
+}
+
+func indexPageText(w http.ResponseWriter, r *http.Request) {
 	w.Write([]byte("Available HTTP endpoints:\n"))
 
 	spacing := 0
@@ -184,13 +193,35 @@ func indexPage(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 	spacing = spacing + 3
+	formatter := fmt.Sprintf("%%-%ds: %%s\n", spacing)
 
-	formattedString := fmt.Sprintf("%%-%ds: %%s\n", spacing)
 	for _, endpoint := range endpoints {
-		w.Write([]byte(fmt.Sprintf(formattedString, endpoint.path, endpoint.desc)))
+		w.Write([]byte(fmt.Sprintf(formatter, endpoint.path, endpoint.desc)))
 	}
 }
 
+func indexPageHTML(w http.ResponseWriter, r *http.Request) {
+
+	w.Write([]byte("<h1>Available HTTP endpoints:</h1>\n"))
+
+	var formattedString string
+	needLinkPaths := []string{"/metrics", "/sandboxes"}
+
+	w.Write([]byte("<ul>"))
+	for _, endpoint := range endpoints {
+		formattedString = fmt.Sprintf("<b>%s</b>: %s\n", endpoint.path, endpoint.desc)
+		for _, linkPath := range needLinkPaths {
+			if linkPath == endpoint.path {
+				formattedString = fmt.Sprintf("<b><a href='%s'>%s</a></b>: %s\n", endpoint.path, endpoint.path, endpoint.desc)
+				break
+			}
+		}
+		formattedString = fmt.Sprintf("<li>%s</li>", formattedString)
+		w.Write([]byte(formattedString))
+	}
+	w.Write([]byte("</ul>"))
+}
+
 // initLog setup logger
 func initLog() {
 	kataMonitorLog := logrus.WithFields(logrus.Fields{

src/runtime/pkg/kata-monitor/metrics.go

@@ -78,6 +78,21 @@ func (km *KataMonitor) ProcessMetricsRequest(w http.ResponseWriter, r *http.Requ
 		scrapeDurationsHistogram.Observe(float64(time.Since(start).Nanoseconds() / int64(time.Millisecond)))
 	}()
 
+	// this is likely the same as `kata-runtime metrics <SANDBOX>`.
+	sandboxID, err := getSandboxIDFromReq(r)
+	if err == nil && sandboxID != "" {
+		metrics, err := GetSandboxMetrics(sandboxID)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+			return
+		}
+		w.Write([]byte(metrics))
+		return
+	}
+
+	// if no sandbox provided, will get all sandbox's metrics.
+
 	// prepare writer for writing response.
 	contentType := expfmt.Negotiate(r.Header)
 

src/runtime/pkg/kata-monitor/monitor.go

@@ -27,6 +27,7 @@ const (
 	RuntimeCRIO                 = "cri-o"
 	fsMonitorRetryDelaySeconds  = 60
 	podCacheRefreshDelaySeconds = 5
+	contentTypeHtml             = "text/html"
 )
 
 // SetLogger sets the logger for katamonitor package.
@@ -194,7 +195,41 @@ func (km *KataMonitor) GetAgentURL(w http.ResponseWriter, r *http.Request) {
 // ListSandboxes list all sandboxes running in Kata
 func (km *KataMonitor) ListSandboxes(w http.ResponseWriter, r *http.Request) {
 	sandboxes := km.sandboxCache.getSandboxList()
+	htmlResponse := IfReturnHTMLResponse(w, r)
+	if htmlResponse {
+		listSandboxesHtml(sandboxes, w)
+	} else {
+		listSandboxesText(sandboxes, w)
+	}
+}
+
+func listSandboxesText(sandboxes []string, w http.ResponseWriter) {
 	for _, s := range sandboxes {
 		w.Write([]byte(fmt.Sprintf("%s\n", s)))
 	}
 }
+func listSandboxesHtml(sandboxes []string, w http.ResponseWriter) {
+	w.Write([]byte("<h1>Sandbox list</h1>\n"))
+	w.Write([]byte("<ul>\n"))
+	for _, s := range sandboxes {
+		w.Write([]byte(fmt.Sprintf("<li>%s: <a href='/debug/pprof/?sandbox=%s'>pprof</a>, <a href='/metrics?sandbox=%s'>metrics</a>, <a href='/agent-url?sandbox=%s'>agent-url</a></li>\n", s, s, s, s)))
+	}
+	w.Write([]byte("</ul>\n"))
+}
+
+// IfReturnHTMLResponse returns true if request accepts html response
+// NOTE: IfReturnHTMLResponse will also set response header to `text/html`
+func IfReturnHTMLResponse(w http.ResponseWriter, r *http.Request) bool {
+	accepts := r.Header["Accept"]
+	for _, accept := range accepts {
+		fields := strings.Split(accept, ",")
+		for _, field := range fields {
+			if field == contentTypeHtml {
+				w.Header().Set("Content-Type", contentTypeHtml)
+				return true
+			}
+		}
+	}
+
+	return false
+}

src/runtime/pkg/kata-monitor/pprof.go

@@ -55,8 +55,10 @@ func (km *KataMonitor) proxyRequest(w http.ResponseWriter, r *http.Request) {
 	}
 
 	uri := fmt.Sprintf("http://shim%s", r.URL.String())
+	monitorLog.Debugf("proxyRequest to: %s, uri: %s", socketAddress, uri)
 	resp, err := client.Get(uri)
 	if err != nil {
+		serveError(w, http.StatusInternalServerError, fmt.Sprintf("failed to request %s through %s", uri, socketAddress))
 		return
 	}