rebase

collector/collector.go

@@ -171,6 +171,56 @@ func GetServerIDFromVarz(endpoint string, retryInterval time.Duration) string {
 	return id
 }
 
+func GetServerNameFromVarz(endpoint string, retryInterval time.Duration) string {
+	getServerName := func() (string, error) {
+		resp, err := http.DefaultClient.Get(endpoint + "/varz")
+		if err != nil {
+			return "", err
+		}
+		defer resp.Body.Close()
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return "", err
+		}
+		var response map[string]interface{}
+		err = json.Unmarshal(body, &response)
+		if err != nil {
+			return "", err
+		}
+		serverName, ok := response["server_name"]
+		if !ok {
+			Fatalf("Could not find server name in /varz")
+		}
+		id, ok := serverName.(string)
+		if !ok {
+			Fatalf("Invalid server_name type in /varz: %+v", serverName)
+		}
+
+		return id, nil
+	}
+
+	var id string
+	var err error
+	id, err = getServerName()
+	if err == nil {
+		return id
+	}
+
+	// Retry periodically until available, in case it never starts
+	// then a liveness check against the NATS Server itself should
+	// detect that an restart the server, in terms of the exporter
+	// we just wait for it to eventually be available.
+	for range time.NewTicker(retryInterval).C {
+		id, err = getServerName()
+		if err != nil {
+			Errorf("Could not find server id: %s", err)
+			continue
+		}
+		break
+	}
+	return id
+}
+
 // Describe the metric to the Prometheus server.
 func (nc *NATSCollector) Describe(ch chan<- *prometheus.Desc) {
 	nc.Lock()

exporter/exporter.go

@@ -41,31 +41,32 @@ const (
 // NATSExporterOptions are options to configure the NATS collector
 type NATSExporterOptions struct {
 	collector.LoggerOptions
-	ListenAddress        string
-	ListenPort           int
-	ScrapePath           string
-	GetHealthz           bool
-	GetConnz             bool
-	GetConnzDetailed     bool
-	GetVarz              bool
-	GetSubz              bool
-	GetRoutez            bool
-	GetGatewayz          bool
-	GetLeafz             bool
-	GetReplicatorVarz    bool
-	GetStreamingChannelz bool
-	GetStreamingServerz  bool
-	GetJszFilter         string
-	RetryInterval        time.Duration
-	CertFile             string
-	KeyFile              string
-	CaFile               string
-	NATSServerURL        string
-	NATSServerTag        string
-	HTTPUser             string // User in metrics scrape by prometheus.
-	HTTPPassword         string
-	Prefix               string
-	UseInternalServerID  bool
+	ListenAddress         string
+	ListenPort            int
+	ScrapePath            string
+	GetHealthz            bool
+	GetConnz              bool
+	GetConnzDetailed      bool
+	GetVarz               bool
+	GetSubz               bool
+	GetRoutez             bool
+	GetGatewayz           bool
+	GetLeafz              bool
+	GetReplicatorVarz     bool
+	GetStreamingChannelz  bool
+	GetStreamingServerz   bool
+	GetJszFilter          string
+	RetryInterval         time.Duration
+	CertFile              string
+	KeyFile               string
+	CaFile                string
+	NATSServerURL         string
+	NATSServerTag         string
+	HTTPUser              string // User in metrics scrape by prometheus.
+	HTTPPassword          string
+	Prefix                string
+	UseInternalServerID   bool
+	UseInternalServerName bool
 }
 
 // NATSExporter collects NATS metrics
@@ -175,7 +176,7 @@ func (ne *NATSExporter) InitializeCollectors() error {
 	}
 
 	getJsz := opts.GetJszFilter != ""
-	if !opts.GetHealthz && !opts.GetConnz && !opts.GetConnzDetailed && !opts.GetRoutez &&
+	if !opts.GetConnz && !opts.GetRoutez &&
 		!opts.GetSubz && !opts.GetVarz && !opts.GetGatewayz && !opts.GetLeafz &&
 		!opts.GetStreamingChannelz && !opts.GetStreamingServerz && !opts.GetReplicatorVarz && !getJsz {
 		return fmt.Errorf("no Collectors specfied")

main.go

@@ -130,6 +130,7 @@ func main() {
 	flag.StringVar(&opts.HTTPPassword, "http_pass", "", "Set the password for HTTP scrapes. NATS bcrypt supported.")
 	flag.StringVar(&opts.Prefix, "prefix", "", "Replace the default prefix for all the metrics.")
 	flag.BoolVar(&opts.UseInternalServerID, "use_internal_server_id", false, "Enables using ServerID from /varz")
+	flag.BoolVar(&opts.UseInternalServerName, "use_internal_server_name", false, "Enables using ServerName from /varz")
 	flag.Parse()
 
 	opts.RetryInterval = time.Duration(retryInterval) * time.Second
@@ -165,6 +166,13 @@ necessary.`)
 		if err := exp.AddServer(id, url); err != nil {
 			collector.Fatalf("Unable to setup server in exporter: %s, %s: %v", id, url, err)
 		}
+	} else if len(args) == 1 && opts.UseInternalServerID {
+		// Pick the server id from the /varz endpoint info.
+		url := flag.Args()[0]
+		id := collector.GetServerNameFromVarz(url, opts.RetryInterval)
+		if err := exp.AddServer(id, url); err != nil {
+			collector.Fatalf("Unable to setup server in exporter: %s, %s: %v", id, url, err)
+		}
 	} else {
 		// For each URL specified, add the NATS server with the optional ID.
 		for _, arg := range args {