replace promlog with go-kit (#6052)

cmd/nginx-ingress/main.go

@@ -29,7 +29,6 @@ import (
 	"github.com/nginxinc/nginx-plus-go-client/client"
 	nginxCollector "github.com/nginxinc/nginx-prometheus-exporter/collector"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/promlog"
 	api_v1 "k8s.io/api/core/v1"
 	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	util_version "k8s.io/apimachinery/pkg/util/version"
@@ -39,6 +38,9 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+
+	kitlog "github.com/go-kit/log"
+	"github.com/go-kit/log/level"
 )
 
 // Injected during build
@@ -736,15 +738,8 @@ func createPlusAndLatencyCollectors(
 			streamServerZoneVariableLabels := []string{"resource_type", "resource_name", "resource_namespace"}
 			variableLabelNames := nginxCollector.NewVariableLabelNames(upstreamServerVariableLabels, serverZoneVariableLabels, upstreamServerPeerVariableLabelNames,
 				streamUpstreamServerVariableLabels, streamServerZoneVariableLabels, streamUpstreamServerPeerVariableLabelNames, nil, nil)
-			infoLevel := new(promlog.AllowedLevel)
-			err := infoLevel.Set("info")
-			if err != nil {
-				glog.Error("Error setting prometheus exporter log level")
-			}
-			promlogConfig := &promlog.Config{
-				Level: infoLevel,
-			}
-			logger := promlog.New(promlogConfig)
+			logger := kitlog.NewLogfmtLogger(os.Stdout)
+			logger = level.NewFilter(logger, level.AllowError())
 			plusCollector = nginxCollector.NewNginxPlusCollector(plusClient, "nginx_ingress_nginxplus", variableLabelNames, constLabels, logger)
 			go metrics.RunPrometheusListenerForNginxPlus(*prometheusMetricsListenPort, plusCollector, registry, prometheusSecret)
 		} else {

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/dlclark/regexp2 v1.11.2
 	github.com/gkampitakis/go-snaps v0.5.4
 	github.com/go-chi/chi/v5 v5.1.0
+	github.com/go-kit/log v0.2.1
 	github.com/golang-jwt/jwt/v4 v4.5.0
 	github.com/golang/glog v1.2.0
 	github.com/google/go-cmp v0.6.0
@@ -19,7 +20,6 @@ require (
 	github.com/nginxinc/nginx-service-mesh v1.7.0
 	github.com/nginxinc/telemetry-exporter v0.1.0
 	github.com/prometheus/client_golang v1.18.0
-	github.com/prometheus/common v0.47.0
 	github.com/spiffe/go-spiffe/v2 v2.3.0
 	github.com/stretchr/testify v1.9.0
 	go.opentelemetry.io/otel v1.28.0
@@ -63,7 +63,6 @@ require (
 	github.com/gkampitakis/go-diff v1.3.2 // indirect
 	github.com/go-asn1-ber/asn1-ber v1.5.6 // indirect
 	github.com/go-jose/go-jose/v4 v4.0.2 // indirect
-	github.com/go-kit/log v0.2.1 // indirect
 	github.com/go-ldap/ldap/v3 v3.4.8 // indirect
 	github.com/go-logfmt/logfmt v0.5.1 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
@@ -96,6 +95,7 @@ require (
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
+	github.com/prometheus/common v0.47.0 // indirect
 	github.com/prometheus/procfs v0.15.0 // indirect
 	github.com/rogpeppe/go-internal v1.12.0 // indirect
 	github.com/spf13/cobra v1.8.0 // indirect

internal/metrics/listener.go

@@ -6,16 +6,18 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"os"
 	"strconv"
 	"time"
 
 	"github.com/go-chi/chi/v5"
+	kitlog "github.com/go-kit/log"
+	"github.com/go-kit/log/level"
 	"github.com/golang/glog"
 	prometheusClient "github.com/nginxinc/nginx-prometheus-exporter/client"
 	nginxCollector "github.com/nginxinc/nginx-prometheus-exporter/collector"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/prometheus/common/promlog"
 	v1 "k8s.io/api/core/v1"
 )
 
@@ -26,16 +28,8 @@ func NewNginxMetricsClient(httpClient *http.Client) *prometheusClient.NginxClien
 
 // RunPrometheusListenerForNginx runs an http server to expose Prometheus metrics for NGINX
 func RunPrometheusListenerForNginx(port int, client *prometheusClient.NginxClient, registry *prometheus.Registry, constLabels map[string]string, prometheusSecret *v1.Secret) {
-	infoLevel := new(promlog.AllowedLevel)
-	err := infoLevel.Set("info")
-	if err != nil {
-		glog.Error("Error setting prometheus exporter log level")
-	}
-	promlogConfig := &promlog.Config{
-		Level: infoLevel,
-	}
-
-	logger := promlog.New(promlogConfig)
+	logger := kitlog.NewLogfmtLogger(os.Stdout)
+	logger = level.NewFilter(logger, level.AllowError())
 	registry.MustRegister(nginxCollector.NewNginxCollector(client, "nginx_ingress_nginx", constLabels, logger))
 	runServer(strconv.Itoa(port), registry, prometheusSecret)
 }