chore: add metrics config enabled

CHANGELOG.md

@@ -37,6 +37,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Improvements
 
+- [#138](https://github.com/babylonlabs-io/btc-staker/pull/138) Adds prometheus metrics
+configuration to enabled it (disabled by default).
 - [#114](https://github.com/babylonlabs-io/btc-staker/pull/114) **Multi-staking support**.
 This PR contains a series of PRs on multi-staking support and BTC staking integration.
 

README.md

@@ -476,6 +476,23 @@ ZMQPubRawBlock = tcp://127.0.0.1:29001
 ZMQPubRawTx = tcp://127.0.0.1:29002
 ```
 
+#### Metrics configuration
+
+by default prometheus metrics are disabled, although it is possible to enabled it
+in the config file.
+
+```bash
+[metricsconfig]
+# if it should be enabled.
+Enabled = false
+
+# host of prometheus server.
+Host = 127.0.0.1
+
+# port of prometheus server.
+ServerPort = 2112
+```
+
 To see the complete list of configuration options, check the `stakerd.conf` file.
 
 ## 4. Starting staker daemon

cmd/stakerd/main.go

@@ -93,8 +93,10 @@ func main() {
 		dbBackend,
 	)
 
-	addr := fmt.Sprintf("%s:%d", cfg.MetricsConfig.Host, cfg.MetricsConfig.ServerPort)
-	metrics.Start(cfgLogger, addr, stakerMetrics.Registry)
+	if cfg.MetricsConfig.Enabled {
+		addr := fmt.Sprintf("%s:%d", cfg.MetricsConfig.Host, cfg.MetricsConfig.ServerPort)
+		metrics.Start(cfgLogger, addr, stakerMetrics.Registry)
+	}
 
 	if err = service.RunUntilShutdown(ctx); err != nil {
 		_, _ = fmt.Fprintln(os.Stderr, err)

metrics/prometheus.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"errors"
 	"net/http"
+
 	//nolint:revive
 	_ "net/http/pprof"
 	"regexp"
@@ -14,18 +15,27 @@ import (
 )
 
 func Start(logger *logrus.Logger, addr string, reg *prometheus.Registry) {
-	go start(logger, addr, reg)
+	svr := Server(logger, addr, reg)
+
+	go func() {
+		err := svr.ListenAndServe()
+		if err != nil && !errors.Is(err, http.ErrServerClosed) {
+			logger.Errorf("prometheus server got err: %v", err)
+		}
+	}()
 }
 
-func start(logger *logrus.Logger, addr string, reg *prometheus.Registry) {
+func Server(logger *logrus.Logger, addr string, reg *prometheus.Registry) *http.Server {
 	// Add Go module build info.
 	reg.MustRegister(collectors.NewBuildInfoCollector())
 	reg.MustRegister(collectors.NewGoCollector(
 		collectors.WithGoCollectorRuntimeMetrics(collectors.GoRuntimeMetricsRule{Matcher: regexp.MustCompile("/.*")})),
 	)
 
+	mux := http.NewServeMux()
+
 	// Expose the registered metrics via HTTP.
-	http.Handle("/metrics", promhttp.HandlerFor(
+	mux.Handle("/metrics", promhttp.HandlerFor(
 		reg,
 		promhttp.HandlerOpts{
 			// Opt into OpenMetrics to support exemplars.
@@ -35,9 +45,5 @@ func start(logger *logrus.Logger, addr string, reg *prometheus.Registry) {
 
 	logger.Infof("Successfully started Prometheus metrics server at %s", addr)
 
-	err := http.ListenAndServe(addr, nil)
-
-	if err != nil && !errors.Is(err, http.ErrServerClosed) {
-		logger.Errorf("prometheus server got err: %v", err)
-	}
+	return &http.Server{Addr: addr, Handler: mux}
 }

metrics/prometheus_test.go

@@ -0,0 +1,48 @@
+package metrics_test
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+
+	//nolint:revive
+
+	"net/http"
+	"net/http/httptest"
+	_ "net/http/pprof"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/babylonlabs-io/btc-staker/itest/testutil"
+	"github.com/babylonlabs-io/btc-staker/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
+)
+
+func TestMetrics(t *testing.T) {
+	t.Parallel()
+	addr := fmt.Sprintf("127.0.0.1:%d", testutil.AllocateUniquePort(t))
+	testRegistry := prometheus.NewRegistry()
+
+	server := metrics.Server(logrus.New(), addr, testRegistry)
+
+	// Use httptest to simulate a real HTTP server
+	testServer := httptest.NewServer(server.Handler)
+	defer testServer.Close()
+
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, testServer.URL+"/metrics", nil)
+	require.NoError(t, err)
+
+	resp, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+	require.Equal(t, http.StatusOK, resp.StatusCode)
+	defer resp.Body.Close()
+
+	fullBody, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+
+	bodyString := string(fullBody)
+	require.True(t, strings.Contains(bodyString, "metrics"))
+}

stakercfg/metrics.go

@@ -12,6 +12,8 @@ const (
 
 // MetricsConfig defines the server's basic configuration
 type MetricsConfig struct {
+	// Enalbed if the prometheus server should be enabled
+	Enabled bool `long:"enabled" description:"if it should be enabled."`
 	// IP of the prometheus server
 	Host string `long:"host" description:"host of prometheus server."`
 	// Port of the prometheus server
@@ -33,6 +35,7 @@ func (cfg *MetricsConfig) Validate() error {
 
 func DefaultMetricsConfig() MetricsConfig {
 	return MetricsConfig{
+		Enabled:    false,
 		ServerPort: defaultMetricsServerPort,
 		Host:       defaultMetricsHost,
 	}