Add option --scrape-timeout.

exporter.go

@@ -17,15 +17,17 @@ import (
 type Exporter struct {
 	sync.Mutex
 	endpoint           string
+	scrapeTimeout      time.Duration
 	registry           *prometheus.Registry
 	totalScrapes       prometheus.Counter
 	metricDescriptions map[string]*prometheus.Desc
 }
 
-func NewExporter(endpoint string) *Exporter {
+func NewExporter(endpoint string, scrapeTimeout time.Duration) *Exporter {
 	e := Exporter{
-		endpoint: endpoint,
-		registry: prometheus.NewRegistry(),
+		endpoint:      endpoint,
+		scrapeTimeout: scrapeTimeout,
+		registry:      prometheus.NewRegistry(),
 
 		totalScrapes: prometheus.NewCounter(prometheus.CounterOpts{
 			Namespace: "v2ray",
@@ -82,12 +84,12 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 }
 
 func (e *Exporter) scrapeV2Ray(ch chan<- prometheus.Metric) error {
-	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), e.scrapeTimeout)
 	defer cancel()
 
 	conn, err := grpc.DialContext(ctx, e.endpoint, grpc.WithInsecure(), grpc.WithBlock())
 	if err != nil {
-		return fmt.Errorf("failed to dial: %w", err)
+		return fmt.Errorf("failed to dial: %w, timeout: %v", err, e.scrapeTimeout)
 	}
 	defer conn.Close()
 

main.go

@@ -4,17 +4,19 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"time"
 
 	flags "github.com/jessevdk/go-flags"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	log "github.com/sirupsen/logrus"
 )
 
 var opts struct {
-	Listen        string `short:"l" long:"listen" description:"Listen address" value-name:"[ADDR]:PORT" default:":9550"`
-	MetricsPath   string `short:"m" long:"metrics-path" description:"Metrics path" value-name:"PATH" default:"/scrape"`
-	V2RayEndpoint string `short:"e" long:"v2ray-endpoint" description:"V2Ray API endpoint" value-name:"HOST:PORT" default:"127.0.0.1:8080"`
-	Version       bool   `long:"version" description:"Show version"`
+	Listen                 string `short:"l" long:"listen" description:"Listen address" value-name:"[ADDR]:PORT" default:":9550"`
+	MetricsPath            string `short:"m" long:"metrics-path" description:"Metrics path" value-name:"PATH" default:"/scrape"`
+	V2RayEndpoint          string `short:"e" long:"v2ray-endpoint" description:"V2Ray API endpoint" value-name:"HOST:PORT" default:"127.0.0.1:8080"`
+	ScrapeTimeoutInSeconds int64  `short:"t" long:"scrape-timeout" description:"The timeout in seconds for every individual scrape" value-name:"N" default:"3"`
+	Version                bool   `long:"version" description:"Show version"`
 }
 
 var (
@@ -42,7 +44,8 @@ func main() {
 		os.Exit(0)
 	}
 
-	exporter = NewExporter(opts.V2RayEndpoint)
+	scrapeTimeout := time.Duration(opts.ScrapeTimeoutInSeconds) * time.Second
+	exporter = NewExporter(opts.V2RayEndpoint, scrapeTimeout)
 
 	http.Handle("/metrics", promhttp.Handler())
 	http.HandleFunc("/scrape", scrapeHandler)