Merge pull request #326 from bookingcom/dams/info-500

return 404 instead of 500 when info-ing a non-existing metric

Author: dams

app/carbonapi/http_handlers.go

@@ -951,6 +951,14 @@ func (app *App) infoHandler(w http.ResponseWriter, r *http.Request) {
 	request.IncCall()
 	infos, err := app.backend.Info(ctx, request)
 	if err != nil {
+		var notFound dataTypes.ErrNotFound
+		if errors.As(err, &notFound) {
+			http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
+			toLog.HttpCode = http.StatusNotFound
+			toLog.Reason = "info not found"
+			logAsError = true
+			return
+		}
 		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 		toLog.HttpCode = http.StatusInternalServerError
 		toLog.Reason = err.Error()

app/carbonzipper/http_handlers.go

@@ -456,6 +456,18 @@ func (app *App) infoHandler(w http.ResponseWriter, req *http.Request) {
 	infos, errs := backend.Infos(ctx, bs, request)
 	err = errorsFanIn(ctx, errs, len(bs))
 	if err != nil {
+
+		var notFound types.ErrNotFound
+		if errors.As(err, &notFound) {
+			accessLogger.Error("info not found",
+				zap.Int("http_code", http.StatusNotFound),
+				zap.Error(err),
+				zap.Duration("runtime_seconds", time.Since(t0)),
+			)
+			http.Error(w, "info: not found", http.StatusNotFound)
+			return
+		}
+
 		accessLogger.Error("info failed",
 			zap.Int("http_code", http.StatusInternalServerError),
 			zap.Error(err),

pkg/backend/net/net.go

@@ -392,6 +392,11 @@ func (b Backend) Info(ctx context.Context, request types.InfoRequest) ([]types.I
 	request.Trace.AddMarshal(t0)
 
 	_, resp, err := b.call(ctx, request.Trace, u, body)
+
+	if code, ok := err.(ErrHTTPCode); ok && code == http.StatusNotFound {
+		return nil, types.ErrInfoNotFound
+	}
+
 	if err != nil {
 		return nil, errors.Wrap(err, "HTTP call failed")
 	}