chore!: adopt log/slog, drop go-kit/log

.circleci/config.yml

@@ -6,7 +6,7 @@ executors:
   # This must match .promu.yml.
   golang:
     docker:
-      - image: cimg/go:1.22.6
+      - image: cimg/go:1.23
 jobs:
   test:
     executor: golang

.golangci.yml

@@ -2,6 +2,7 @@
 linters:
   enable:
     - revive
+    - sloglint
 
 issues:
   exclude-rules:
@@ -11,7 +12,7 @@ issues:
 
 linters-settings:
   errcheck:
-    exclude: scripts/errcheck_excludes.txt
+    exclude-functions: scripts/errcheck_excludes.txt
   revive:
     rules:
       # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter

.promu.yml

@@ -1,6 +1,6 @@
 go:
     # This must match .circle/config.yml.
-    version: 1.22
+    version: 1.23
 repository:
     path: github.com/prometheus-community/elasticsearch_exporter
 build:

collector/cluster_health.go

@@ -17,12 +17,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"path"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -46,7 +45,7 @@ type clusterHealthStatusMetric struct {
 
 // ClusterHealth type defines the collector struct
 type ClusterHealth struct {
-	logger log.Logger
+	logger *slog.Logger
 	client *http.Client
 	url    *url.URL
 
@@ -55,7 +54,7 @@ type ClusterHealth struct {
 }
 
 // NewClusterHealth returns a new Collector exposing ClusterHealth stats.
-func NewClusterHealth(logger log.Logger, client *http.Client, url *url.URL) *ClusterHealth {
+func NewClusterHealth(logger *slog.Logger, client *http.Client, url *url.URL) *ClusterHealth {
 	subsystem := "cluster_health"
 
 	return &ClusterHealth{
@@ -225,8 +224,8 @@ func (c *ClusterHealth) fetchAndDecodeClusterHealth() (clusterHealthResponse, er
 	defer func() {
 		err = res.Body.Close()
 		if err != nil {
-			level.Warn(c.logger).Log(
-				"msg", "failed to close http.Client",
+			c.logger.Warn(
+				"failed to close http.Client",
 				"err", err,
 			)
 		}
@@ -252,8 +251,8 @@ func (c *ClusterHealth) fetchAndDecodeClusterHealth() (clusterHealthResponse, er
 func (c *ClusterHealth) Collect(ch chan<- prometheus.Metric) {
 	clusterHealthResp, err := c.fetchAndDecodeClusterHealth()
 	if err != nil {
-		level.Warn(c.logger).Log(
-			"msg", "failed to fetch and decode cluster health",
+		c.logger.Warn(
+			"failed to fetch and decode cluster health",
 			"err", err,
 		)
 		return

collector/cluster_health_test.go

@@ -22,8 +22,8 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/prometheus/common/promslog"
 )
 
 func TestClusterHealth(t *testing.T) {
@@ -189,7 +189,7 @@ func TestClusterHealth(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			c := NewClusterHealth(log.NewNopLogger(), http.DefaultClient, u)
+			c := NewClusterHealth(promslog.NewNopLogger(), http.DefaultClient, u)
 			if err != nil {
 				t.Fatal(err)
 			}

collector/cluster_info.go

@@ -17,11 +17,11 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 
 	"github.com/blang/semver/v4"
-	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -30,12 +30,12 @@ func init() {
 }
 
 type ClusterInfoCollector struct {
-	logger log.Logger
+	logger *slog.Logger
 	u      *url.URL
 	hc     *http.Client
 }
 
-func NewClusterInfo(logger log.Logger, u *url.URL, hc *http.Client) (Collector, error) {
+func NewClusterInfo(logger *slog.Logger, u *url.URL, hc *http.Client) (Collector, error) {
 	return &ClusterInfoCollector{
 		logger: logger,
 		u:      u,

collector/cluster_info_test.go

@@ -22,8 +22,8 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/prometheus/common/promslog"
 )
 
 func TestClusterInfo(t *testing.T) {
@@ -80,7 +80,7 @@ func TestClusterInfo(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			c, err := NewClusterInfo(log.NewNopLogger(), u, http.DefaultClient)
+			c, err := NewClusterInfo(promslog.NewNopLogger(), u, http.DefaultClient)
 			if err != nil {
 				t.Fatal(err)
 			}

collector/cluster_settings.go

@@ -18,13 +18,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/imdario/mergo"
 	"github.com/prometheus/client_golang/prometheus"
 )
@@ -34,12 +33,12 @@ func init() {
 }
 
 type ClusterSettingsCollector struct {
-	logger log.Logger
+	logger *slog.Logger
 	u      *url.URL
 	hc     *http.Client
 }
 
-func NewClusterSettings(logger log.Logger, u *url.URL, hc *http.Client) (Collector, error) {
+func NewClusterSettings(logger *slog.Logger, u *url.URL, hc *http.Client) (Collector, error) {
 	return &ClusterSettingsCollector{
 		logger: logger,
 		u:      u,
@@ -226,7 +225,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 	if strings.HasSuffix(merged.Cluster.Routing.Allocation.Disk.Watermark.High, "b") {
 		flooodStageBytes, err := getValueInBytes(merged.Cluster.Routing.Allocation.Disk.Watermark.FloodStage)
 		if err != nil {
-			level.Error(c.logger).Log("msg", "failed to parse flood_stage bytes", "err", err)
+			c.logger.Error("failed to parse flood_stage bytes", "err", err)
 		} else {
 			ch <- prometheus.MustNewConstMetric(
 				clusterSettingsDesc["floodStageBytes"],
@@ -237,7 +236,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 
 		highBytes, err := getValueInBytes(merged.Cluster.Routing.Allocation.Disk.Watermark.High)
 		if err != nil {
-			level.Error(c.logger).Log("msg", "failed to parse high bytes", "err", err)
+			c.logger.Error("failed to parse high bytes", "err", err)
 		} else {
 			ch <- prometheus.MustNewConstMetric(
 				clusterSettingsDesc["highBytes"],
@@ -248,7 +247,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 
 		lowBytes, err := getValueInBytes(merged.Cluster.Routing.Allocation.Disk.Watermark.Low)
 		if err != nil {
-			level.Error(c.logger).Log("msg", "failed to parse low bytes", "err", err)
+			c.logger.Error("failed to parse low bytes", "err", err)
 		} else {
 			ch <- prometheus.MustNewConstMetric(
 				clusterSettingsDesc["lowBytes"],
@@ -263,7 +262,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 	// Watermark ratio metrics
 	floodRatio, err := getValueAsRatio(merged.Cluster.Routing.Allocation.Disk.Watermark.FloodStage)
 	if err != nil {
-		level.Error(c.logger).Log("msg", "failed to parse flood_stage ratio", "err", err)
+		c.logger.Error("failed to parse flood_stage ratio", "err", err)
 	} else {
 		ch <- prometheus.MustNewConstMetric(
 			clusterSettingsDesc["floodStageRatio"],
@@ -274,7 +273,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 
 	highRatio, err := getValueAsRatio(merged.Cluster.Routing.Allocation.Disk.Watermark.High)
 	if err != nil {
-		level.Error(c.logger).Log("msg", "failed to parse high ratio", "err", err)
+		c.logger.Error("failed to parse high ratio", "err", err)
 	} else {
 		ch <- prometheus.MustNewConstMetric(
 			clusterSettingsDesc["highRatio"],
@@ -285,7 +284,7 @@ func (c *ClusterSettingsCollector) Update(ctx context.Context, ch chan<- prometh
 
 	lowRatio, err := getValueAsRatio(merged.Cluster.Routing.Allocation.Disk.Watermark.Low)
 	if err != nil {
-		level.Error(c.logger).Log("msg", "failed to parse low ratio", "err", err)
+		c.logger.Error("failed to parse low ratio", "err", err)
 	} else {
 		ch <- prometheus.MustNewConstMetric(
 			clusterSettingsDesc["lowRatio"],

collector/cluster_settings_test.go

@@ -22,8 +22,8 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/prometheus/common/promslog"
 )
 
 func TestClusterSettingsStats(t *testing.T) {
@@ -136,7 +136,7 @@ elasticsearch_clustersettings_allocation_watermark_low_bytes 5.24288e+07
 				t.Fatal(err)
 			}
 
-			c, err := NewClusterSettings(log.NewNopLogger(), u, http.DefaultClient)
+			c, err := NewClusterSettings(promslog.NewNopLogger(), u, http.DefaultClient)
 			if err != nil {
 				t.Fatal(err)
 			}

collector/collector.go

@@ -18,14 +18,13 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"sync"
 	"time"
 
 	"github.com/alecthomas/kingpin/v2"
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -37,7 +36,7 @@ const (
 	defaultDisabled = false
 )
 
-type factoryFunc func(logger log.Logger, u *url.URL, hc *http.Client) (Collector, error)
+type factoryFunc func(logger *slog.Logger, u *url.URL, hc *http.Client) (Collector, error)
 
 var (
 	factories              = make(map[string]factoryFunc)
@@ -90,15 +89,15 @@ func registerCollector(name string, isDefaultEnabled bool, createFunc factoryFun
 
 type ElasticsearchCollector struct {
 	Collectors map[string]Collector
-	logger     log.Logger
+	logger     *slog.Logger
 	esURL      *url.URL
 	httpClient *http.Client
 }
 
 type Option func(*ElasticsearchCollector) error
 
 // NewElasticsearchCollector creates a new ElasticsearchCollector
-func NewElasticsearchCollector(logger log.Logger, filters []string, options ...Option) (*ElasticsearchCollector, error) {
+func NewElasticsearchCollector(logger *slog.Logger, filters []string, options ...Option) (*ElasticsearchCollector, error) {
 	e := &ElasticsearchCollector{logger: logger}
 	// Apply options to customize the collector
 	for _, o := range options {
@@ -128,7 +127,7 @@ func NewElasticsearchCollector(logger log.Logger, filters []string, options ...O
 		if collector, ok := initiatedCollectors[key]; ok {
 			collectors[key] = collector
 		} else {
-			collector, err := factories[key](log.With(logger, "collector", key), e.esURL, e.httpClient)
+			collector, err := factories[key](logger.With("collector", key), e.esURL, e.httpClient)
 			if err != nil {
 				return nil, err
 			}
@@ -176,21 +175,21 @@ func (e ElasticsearchCollector) Collect(ch chan<- prometheus.Metric) {
 	wg.Wait()
 }
 
-func execute(ctx context.Context, name string, c Collector, ch chan<- prometheus.Metric, logger log.Logger) {
+func execute(ctx context.Context, name string, c Collector, ch chan<- prometheus.Metric, logger *slog.Logger) {
 	begin := time.Now()
 	err := c.Update(ctx, ch)
 	duration := time.Since(begin)
 	var success float64
 
 	if err != nil {
 		if IsNoDataError(err) {
-			level.Debug(logger).Log("msg", "collector returned no data", "name", name, "duration_seconds", duration.Seconds(), "err", err)
+			logger.Debug("collector returned no data", "name", name, "duration_seconds", duration.Seconds(), "err", err)
 		} else {
-			level.Error(logger).Log("msg", "collector failed", "name", name, "duration_seconds", duration.Seconds(), "err", err)
+			logger.Error("collector failed", "name", name, "duration_seconds", duration.Seconds(), "err", err)
 		}
 		success = 0
 	} else {
-		level.Debug(logger).Log("msg", "collector succeeded", "name", name, "duration_seconds", duration.Seconds())
+		logger.Debug("collector succeeded", "name", name, "duration_seconds", duration.Seconds())
 		success = 1
 	}
 	ch <- prometheus.MustNewConstMetric(scrapeDurationDesc, prometheus.GaugeValue, duration.Seconds(), name)

collector/data_stream.go

@@ -17,12 +17,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"path"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -42,15 +41,15 @@ var (
 
 // DataStream Information Struct
 type DataStream struct {
-	logger log.Logger
+	logger *slog.Logger
 	client *http.Client
 	url    *url.URL
 
 	dataStreamMetrics []*dataStreamMetric
 }
 
 // NewDataStream defines DataStream Prometheus metrics
-func NewDataStream(logger log.Logger, client *http.Client, url *url.URL) *DataStream {
+func NewDataStream(logger *slog.Logger, client *http.Client, url *url.URL) *DataStream {
 	return &DataStream{
 		logger: logger,
 		client: client,
@@ -106,8 +105,8 @@ func (ds *DataStream) fetchAndDecodeDataStreamStats() (DataStreamStatsResponse,
 	defer func() {
 		err = res.Body.Close()
 		if err != nil {
-			level.Warn(ds.logger).Log(
-				"msg", "failed to close http.Client",
+			ds.logger.Warn(
+				"failed to close http.Client",
 				"err", err,
 			)
 		}
@@ -134,8 +133,8 @@ func (ds *DataStream) Collect(ch chan<- prometheus.Metric) {
 
 	dataStreamStatsResp, err := ds.fetchAndDecodeDataStreamStats()
 	if err != nil {
-		level.Warn(ds.logger).Log(
-			"msg", "failed to fetch and decode data stream stats",
+		ds.logger.Warn(
+			"failed to fetch and decode data stream stats",
 			"err", err,
 		)
 		return