Make es.uri optional by setting default to empty string check if it's empty and if so, don't parse it

Signed-off-by: pincher95 <[email protected]>

Author: pincher95

main.go

@@ -61,7 +61,7 @@ func main() {
 		toolkitFlags = webflag.AddFlags(kingpin.CommandLine, ":9114")
 		esURI        = kingpin.Flag("es.uri",
 			"HTTP API address of an Elasticsearch node.").
-			Default("http://localhost:9200").String()
+			Default("").String()
 		esTimeout = kingpin.Flag("es.timeout",
 			"Timeout for trying to get stats from Elasticsearch.").
 			Default("5s").Duration()
@@ -143,114 +143,118 @@ func main() {
 	promslogConfig.Writer = w
 	logger := promslog.New(promslogConfig)
 
-	esURL, err := url.Parse(*esURI)
-	if err != nil {
-		logger.Error("failed to parse es.uri", "err", err)
-		os.Exit(1)
-	}
+	// version metric
+	prometheus.MustRegister(versioncollector.NewCollector(name))
 
-	esUsername := os.Getenv("ES_USERNAME")
-	esPassword := os.Getenv("ES_PASSWORD")
+	// Create a context that is cancelled on SIGKILL or SIGINT.
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, os.Kill)
+	defer cancel()
 
-	if esUsername != "" && esPassword != "" {
-		esURL.User = url.UserPassword(esUsername, esPassword)
-	}
+	if *esURI != "" {
+		esURL, err := url.Parse(*esURI)
+		if err != nil {
+			logger.Error("failed to parse es.uri", "err", err)
+			os.Exit(1)
+		}
 
-	// returns nil if not provided and falls back to simple TCP.
-	tlsConfig := createTLSConfig(*esCA, *esClientCert, *esClientPrivateKey, *esInsecureSkipVerify)
+		esUsername := os.Getenv("ES_USERNAME")
+		esPassword := os.Getenv("ES_PASSWORD")
 
-	var httpTransport http.RoundTripper
+		if esUsername != "" && esPassword != "" {
+			esURL.User = url.UserPassword(esUsername, esPassword)
+		}
 
-	httpTransport = &http.Transport{
-		TLSClientConfig: tlsConfig,
-		Proxy:           http.ProxyFromEnvironment,
-	}
+		// returns nil if not provided and falls back to simple TCP.
+		tlsConfig := createTLSConfig(*esCA, *esClientCert, *esClientPrivateKey, *esInsecureSkipVerify)
 
-	esAPIKey := os.Getenv("ES_API_KEY")
+		var httpTransport http.RoundTripper
 
-	if esAPIKey != "" {
-		httpTransport = &transportWithAPIKey{
-			underlyingTransport: httpTransport,
-			apiKey:              esAPIKey,
+		httpTransport = &http.Transport{
+			TLSClientConfig: tlsConfig,
+			Proxy:           http.ProxyFromEnvironment,
 		}
-	}
 
-	httpClient := &http.Client{
-		Timeout:   *esTimeout,
-		Transport: httpTransport,
-	}
+		esAPIKey := os.Getenv("ES_API_KEY")
 
-	if *awsRegion != "" {
-		httpClient.Transport, err = roundtripper.NewAWSSigningTransport(httpTransport, *awsRegion, *awsRoleArn, logger)
-		if err != nil {
-			logger.Error("failed to create AWS transport", "err", err)
-			os.Exit(1)
+		if esAPIKey != "" {
+			httpTransport = &transportWithAPIKey{
+				underlyingTransport: httpTransport,
+				apiKey:              esAPIKey,
+			}
 		}
-	}
 
-	// version metric
-	prometheus.MustRegister(versioncollector.NewCollector(name))
+		httpClient := &http.Client{
+			Timeout:   *esTimeout,
+			Transport: httpTransport,
+		}
 
-	// create the exporter
-	exporter, err := collector.NewElasticsearchCollector(
-		logger,
-		[]string{},
-		collector.WithElasticsearchURL(esURL),
-		collector.WithHTTPClient(httpClient),
-	)
-	if err != nil {
-		logger.Error("failed to create Elasticsearch collector", "err", err)
-		os.Exit(1)
-	}
-	prometheus.MustRegister(exporter)
-
-	// TODO(@sysadmind): Remove this when we have a better way to get the cluster name to down stream collectors.
-	// cluster info retriever
-	clusterInfoRetriever := clusterinfo.New(logger, httpClient, esURL, *esClusterInfoInterval)
-
-	prometheus.MustRegister(collector.NewClusterHealth(logger, httpClient, esURL))
-	prometheus.MustRegister(collector.NewNodes(logger, httpClient, esURL, *esAllNodes, *esNode))
-
-	if *esExportIndices || *esExportShards {
-		sC := collector.NewShards(logger, httpClient, esURL)
-		prometheus.MustRegister(sC)
-		iC := collector.NewIndices(logger, httpClient, esURL, *esExportShards, *esExportIndexAliases)
-		prometheus.MustRegister(iC)
-		if registerErr := clusterInfoRetriever.RegisterConsumer(iC); registerErr != nil {
-			logger.Error("failed to register indices collector in cluster info")
-			os.Exit(1)
+		if *awsRegion != "" {
+			var err error
+			httpClient.Transport, err = roundtripper.NewAWSSigningTransport(httpTransport, *awsRegion, *awsRoleArn, logger)
+			if err != nil {
+				logger.Error("failed to create AWS transport", "err", err)
+				os.Exit(1)
+			}
 		}
-		if registerErr := clusterInfoRetriever.RegisterConsumer(sC); registerErr != nil {
-			logger.Error("failed to register shards collector in cluster info")
+
+		// create the exporter
+		exporter, err := collector.NewElasticsearchCollector(
+			logger,
+			[]string{},
+			collector.WithElasticsearchURL(esURL),
+			collector.WithHTTPClient(httpClient),
+		)
+		if err != nil {
+			logger.Error("failed to create Elasticsearch collector", "err", err)
 			os.Exit(1)
 		}
-	}
+		prometheus.MustRegister(exporter)
 
-	if *esExportIndicesSettings {
-		prometheus.MustRegister(collector.NewIndicesSettings(logger, httpClient, esURL))
-	}
+		// TODO(@sysadmind): Remove this when we have a better way to get the cluster name to down stream collectors.
+		// cluster info retriever
+		clusterInfoRetriever := clusterinfo.New(logger, httpClient, esURL, *esClusterInfoInterval)
 
-	if *esExportIndicesMappings {
-		prometheus.MustRegister(collector.NewIndicesMappings(logger, httpClient, esURL))
-	}
+		prometheus.MustRegister(collector.NewClusterHealth(logger, httpClient, esURL))
+		prometheus.MustRegister(collector.NewNodes(logger, httpClient, esURL, *esAllNodes, *esNode))
 
-	// Create a context that is cancelled on SIGKILL or SIGINT.
-	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, os.Kill)
-	defer cancel()
+		if *esExportIndices || *esExportShards {
+			sC := collector.NewShards(logger, httpClient, esURL)
+			prometheus.MustRegister(sC)
+			iC := collector.NewIndices(logger, httpClient, esURL, *esExportShards, *esExportIndexAliases)
+			prometheus.MustRegister(iC)
+			if registerErr := clusterInfoRetriever.RegisterConsumer(iC); registerErr != nil {
+				logger.Error("failed to register indices collector in cluster info")
+				os.Exit(1)
+			}
+			if registerErr := clusterInfoRetriever.RegisterConsumer(sC); registerErr != nil {
+				logger.Error("failed to register shards collector in cluster info")
+				os.Exit(1)
+			}
+		}
 
-	// start the cluster info retriever
-	switch runErr := clusterInfoRetriever.Run(ctx); runErr {
-	case nil:
-		logger.Info("started cluster info retriever", "interval", (*esClusterInfoInterval).String())
-	case clusterinfo.ErrInitialCallTimeout:
-		logger.Info("initial cluster info call timed out")
-	default:
-		logger.Error("failed to run cluster info retriever", "err", err)
-		os.Exit(1)
-	}
+		if *esExportIndicesSettings {
+			prometheus.MustRegister(collector.NewIndicesSettings(logger, httpClient, esURL))
+		}
 
-	// register cluster info retriever as prometheus collector
-	prometheus.MustRegister(clusterInfoRetriever)
+		if *esExportIndicesMappings {
+			prometheus.MustRegister(collector.NewIndicesMappings(logger, httpClient, esURL))
+		}
+
+		// start the cluster info retriever
+		switch runErr := clusterInfoRetriever.Run(ctx); runErr {
+		case nil:
+			logger.Info("started cluster info retriever", "interval", (*esClusterInfoInterval).String())
+		case clusterinfo.ErrInitialCallTimeout:
+			logger.Info("initial cluster info call timed out")
+		default:
+			var err error
+			logger.Error("failed to run cluster info retriever", "err", err)
+			os.Exit(1)
+		}
+
+		// register cluster info retriever as prometheus collector
+		prometheus.MustRegister(clusterInfoRetriever)
+	}
 
 	http.HandleFunc(*metricsPath, func(w http.ResponseWriter, r *http.Request) {
 		// If query has target param treat like probe endpoint
@@ -366,7 +370,7 @@ func main() {
 
 	server := &http.Server{}
 	go func() {
-		if err = web.ListenAndServe(server, toolkitFlags, logger); err != nil {
+		if err := web.ListenAndServe(server, toolkitFlags, logger); err != nil {
 			logger.Error("http server quit", "err", err)
 			os.Exit(1)
 		}