Cleanup cAdvisor error responses with proper headers & response codes

api/handler.go

@@ -85,7 +85,7 @@ func handleRequest(supportedApiVersions map[string]ApiVersion, m manager.Manager
 			versions = append(versions, v)
 		}
 		sort.Strings(versions)
-		fmt.Fprintf(w, "Supported API versions: %s", strings.Join(versions, ","))
+		http.Error(w, fmt.Sprintf("Supported API versions: %s", strings.Join(versions, ",")), http.StatusBadRequest)
 		return nil
 	}
 
@@ -109,7 +109,7 @@ func handleRequest(supportedApiVersions map[string]ApiVersion, m manager.Manager
 	if requestType == "" {
 		requestTypes := versionHandler.SupportedRequestTypes()
 		sort.Strings(requestTypes)
-		fmt.Fprintf(w, "Supported request types: %q", strings.Join(requestTypes, ","))
+		http.Error(w, fmt.Sprintf("Supported request types: %q", strings.Join(requestTypes, ",")), http.StatusBadRequest)
 		return nil
 	}
 

http/handlers.go

@@ -44,7 +44,7 @@ func RegisterHandlers(mux httpmux.Mux, containerManager manager.Manager, httpAut
 	mux.HandleFunc(validate.ValidatePage, func(w http.ResponseWriter, r *http.Request) {
 		err := validate.HandleRequest(w, containerManager)
 		if err != nil {
-			fmt.Fprintf(w, "%s", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
 		}
 	})
 
@@ -104,15 +104,9 @@ func RegisterPrometheusHandler(mux httpmux.Mux, containerManager manager.Manager
 }
 
 func staticHandlerNoAuth(w http.ResponseWriter, r *http.Request) {
-	err := static.HandleRequest(w, r.URL)
+	static.HandleRequest(w, r.URL)
-	if err != nil {
-		fmt.Fprintf(w, "%s", err)
-	}
 }
 
 func staticHandler(w http.ResponseWriter, r *auth.AuthenticatedRequest) {
-	err := static.HandleRequest(w, r.URL)
+	static.HandleRequest(w, r.URL)
-	if err != nil {
-		fmt.Fprintf(w, "%s", err)
-	}
 }

pages/containers.go

@@ -163,7 +163,7 @@ func printUnit(bytes uint64) string {
 	return ByteSize(bytes).Unit()
 }
 
-func serveContainersPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error {
+func serveContainersPage(m manager.Manager, w http.ResponseWriter, u *url.URL) {
 	start := time.Now()
 
 	// The container name is the path after the handler
@@ -175,14 +175,16 @@ func serveContainersPage(m manager.Manager, w http.ResponseWriter, u *url.URL) e
 	}
 	cont, err := m.GetContainerInfo(containerName, &reqParams)
 	if err != nil {
-		return fmt.Errorf("failed to get container %q with error: %v", containerName, err)
+		http.Error(w, fmt.Sprintf("failed to get container %q with error: %v", containerName, err), http.StatusNotFound)
+		return
 	}
 	displayName := getContainerDisplayName(cont.ContainerReference)
 
 	// Get the MachineInfo
 	machineInfo, err := m.GetMachineInfo()
 	if err != nil {
-		return err
+		http.Error(w, fmt.Sprintf("failed to get machine info: %v", err), http.StatusInternalServerError)
+		return
 	}
 
 	rootDir := getRootDir(containerName)
@@ -241,7 +243,6 @@ func serveContainersPage(m manager.Manager, w http.ResponseWriter, u *url.URL) e
 	}
 
 	glog.V(5).Infof("Request took %s", time.Since(start))
-	return nil
 }
 
 // Build a relative path to the root of the container page.

pages/docker.go

@@ -51,7 +51,7 @@ func toStatusKV(status info.DockerStatus) ([]keyVal, []keyVal) {
 	}, ds
 }
 
-func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error {
+func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) {
 	start := time.Now()
 
 	// The container name is the path after the handler
@@ -66,7 +66,8 @@ func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error
 		}
 		conts, err := m.AllDockerContainers(&reqParams)
 		if err != nil {
-			return fmt.Errorf("failed to get container %q with error: %v", containerName, err)
+			http.Error(w, fmt.Sprintf("failed to get container %q with error: %v", containerName, err), http.StatusNotFound)
+			return
 		}
 		subcontainers := make([]link, 0, len(conts))
 		for _, cont := range conts {
@@ -79,14 +80,16 @@ func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error
 		// Get Docker status
 		status, err := m.DockerInfo()
 		if err != nil {
-			return err
+			http.Error(w, fmt.Sprintf("failed to get docker info: %v", err), http.StatusInternalServerError)
+			return
 		}
 
 		dockerStatus, driverStatus := toStatusKV(status)
 		// Get Docker Images
 		images, err := m.DockerImages()
 		if err != nil {
-			return err
+			http.Error(w, fmt.Sprintf("failed to get docker images: %v", err), http.StatusInternalServerError)
+			return
 		}
 
 		dockerContainersText := "Docker Containers"
@@ -110,7 +113,8 @@ func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error
 		}
 		cont, err := m.DockerContainer(containerName[1:], &reqParams)
 		if err != nil {
-			return fmt.Errorf("failed to get container %q with error: %v", containerName, err)
+			http.Error(w, fmt.Sprintf("failed to get container %q with error: %v", containerName, err), http.StatusNotFound)
+			return
 		}
 		displayName := getContainerDisplayName(cont.ContainerReference)
 
@@ -128,7 +132,8 @@ func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error
 		// Get the MachineInfo
 		machineInfo, err := m.GetMachineInfo()
 		if err != nil {
-			return err
+			http.Error(w, fmt.Sprintf("failed to get machine info: %v", err), http.StatusInternalServerError)
+			return
 		}
 		data = &pageData{
 			DisplayName:            displayName,
@@ -153,5 +158,5 @@ func serveDockerPage(m manager.Manager, w http.ResponseWriter, u *url.URL) error
 	}
 
 	glog.V(5).Infof("Request took %s", time.Since(start))
-	return nil
+	return
 }

pages/pages.go

@@ -77,37 +77,25 @@ func init() {
 
 func containerHandlerNoAuth(containerManager manager.Manager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		err := serveContainersPage(containerManager, w, r.URL)
+		serveContainersPage(containerManager, w, r.URL)
-		if err != nil {
-			fmt.Fprintf(w, "%s", err)
-		}
 	}
 }
 
 func containerHandler(containerManager manager.Manager) auth.AuthenticatedHandlerFunc {
 	return func(w http.ResponseWriter, r *auth.AuthenticatedRequest) {
-		err := serveContainersPage(containerManager, w, r.URL)
+		serveContainersPage(containerManager, w, r.URL)
-		if err != nil {
-			fmt.Fprintf(w, "%s", err)
-		}
 	}
 }
 
 func dockerHandlerNoAuth(containerManager manager.Manager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		err := serveDockerPage(containerManager, w, r.URL)
+		serveDockerPage(containerManager, w, r.URL)
-		if err != nil {
-			fmt.Fprintf(w, "%s", err)
-		}
 	}
 }
 
 func dockerHandler(containerManager manager.Manager) auth.AuthenticatedHandlerFunc {
 	return func(w http.ResponseWriter, r *auth.AuthenticatedRequest) {
-		err := serveDockerPage(containerManager, w, r.URL)
+		serveDockerPage(containerManager, w, r.URL)
-		if err != nil {
-			fmt.Fprintf(w, "%s", err)
-		}
 	}
 }
 

pages/static/static.go

@@ -22,6 +22,8 @@ import (
 	"net/http"
 	"net/url"
 	"path"
+
+	"github.com/golang/glog"
 )
 
 const StaticResource = "/static/"
@@ -47,16 +49,18 @@ var staticFiles = map[string][]byte{
 	"jquery-1.10.2.min.js":          jqueryJs,
 }
 
-func HandleRequest(w http.ResponseWriter, u *url.URL) error {
+func HandleRequest(w http.ResponseWriter, u *url.URL) {
 	if len(u.Path) <= len(StaticResource) {
-		return fmt.Errorf("unknown static resource %q", u.Path)
+		http.Error(w, fmt.Sprintf("unknown static resource %q", u.Path), http.StatusNotFound)
+		return
 	}
 
 	// Get the static content if it exists.
 	resource := u.Path[len(StaticResource):]
 	content, ok := staticFiles[resource]
 	if !ok {
-		return fmt.Errorf("unknown static resource %q", resource)
+		http.Error(w, fmt.Sprintf("unknown static resource %q", u.Path), http.StatusNotFound)
+		return
 	}
 
 	// Set Content-Type if we were able to detect it.
@@ -65,6 +69,7 @@ func HandleRequest(w http.ResponseWriter, u *url.URL) error {
 		w.Header().Set("Content-Type", contentType)
 	}
 
-	_, err := w.Write(content)
+	if _, err := w.Write(content); err != nil {
-	return err
+		glog.Errorf("Failed to write response: %v", err)
+	}
 }