Catch write errors

control-plane/subcommand/consul-sidecar/command.go

@@ -296,16 +296,13 @@ func (c *Command) mergedMetricsHandler(rw http.ResponseWriter, _ *http.Request)
 		http.Error(rw, fmt.Sprintf("Received non-2xx status code scraping Envoy proxy metrics: %d: %s", envoyMetrics.StatusCode, string(envoyMetricsBody)), http.StatusInternalServerError)
 		return
 	}
-	_, err = rw.Write(envoyMetricsBody)
-	if err != nil {
-		c.logger.Error(fmt.Sprintf("Error writing envoy metrics body: %s", err.Error()))
-	}
+	writeResponse(rw, envoyMetricsBody, "envoy metrics", c.logger)
 
 	serviceMetricsAddr := fmt.Sprintf("http://127.0.0.1:%s%s", c.flagServiceMetricsPort, c.flagServiceMetricsPath)
 	serviceMetrics, err := c.serviceMetricsGetter.Get(serviceMetricsAddr)
 	if err != nil {
 		c.logger.Warn("Error scraping service metrics", "err", err)
-		rw.Write(serviceMetricSuccess(false))
+		writeResponse(rw, serviceMetricSuccess(false), "service metrics success", c.logger)
 		// Since we've already written the Envoy metrics to the response, we can
 		// return at this point if we were unable to get service metrics.
 		return
@@ -322,21 +319,24 @@ func (c *Command) mergedMetricsHandler(rw http.ResponseWriter, _ *http.Request)
 	serviceMetricsBody, err := ioutil.ReadAll(serviceMetrics.Body)
 	if err != nil {
 		c.logger.Error("Could not read service metrics", "err", err)
-		rw.Write(serviceMetricSuccess(false))
+		writeResponse(rw, serviceMetricSuccess(false), "service metrics success", c.logger)
 		return
 	}
 	if non2xxCode(serviceMetrics.StatusCode) {
 		c.logger.Error("Received non-2xx status code scraping service metrics", "code", serviceMetrics.StatusCode, "response", string(serviceMetricsBody))
-		rw.Write(serviceMetricSuccess(false))
+		writeResponse(rw, serviceMetricSuccess(false), "service metrics success", c.logger)
 		return
 	}
-	_, err = rw.Write(serviceMetricsBody)
-	if err != nil {
-		c.logger.Error(fmt.Sprintf("Error writing service metrics body: %s", err.Error()))
-	}
-	_, err = rw.Write(serviceMetricSuccess(true))
+	writeResponse(rw, serviceMetricsBody, "service metrics", c.logger)
+	writeResponse(rw, serviceMetricSuccess(true), "service metrics success", c.logger)
+}
+
+// writeResponse is a helper method to write resp to rw and log if there is an error writing.
+// respName is the name of this response that will be used in the error log.
+func writeResponse(rw http.ResponseWriter, resp []byte, respName string, logger hclog.Logger) {
+	_, err := rw.Write(resp)
 	if err != nil {
-		c.logger.Error(fmt.Sprintf("Error writing service metrics success: %s", err.Error()))
+		logger.Error(fmt.Sprintf("Error writing %s: %s", respName, err.Error()))
 	}
 }