feat: replace go-kit logger by slog

promhippie · Sep 14, 2024 · c9b5eab · c9b5eab
1 parent 0ea6a3d
commit c9b5eab
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Showing 15 changed files with 135 additions and 216 deletions.
diff --git a/changelog/unreleased/logging-library.md b/changelog/unreleased/logging-library.md
@@ -0,0 +1,7 @@
+Change: Switch to official logging library
+
+Since there have been a structured logger part of the Go standard library we
+thought it's time to replace the library with that. Be aware that log messages
+should change a little bit.
+
+https://github.com/promhippie/hcloud_exporter/issues/258
diff --git a/pkg/action/metrics.go b/pkg/action/metrics.go
@@ -2,9 +2,8 @@ package action
 
 import (
 	"fmt"
+	"log/slog"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
 	"github.com/promhippie/hcloud_exporter/pkg/version"
@@ -49,11 +48,9 @@ func init() {
 }
 
 type promLogger struct {
-	logger log.Logger
+	logger *slog.Logger
 }
 
 func (pl promLogger) Println(v ...interface{}) {
-	level.Error(pl.logger).Log(
-		"msg", fmt.Sprintln(v...),
-	)
+	pl.logger.Error(fmt.Sprintln(v...))
 }
diff --git a/pkg/action/server.go b/pkg/action/server.go
@@ -3,14 +3,13 @@ package action
 import (
 	"context"
 	"io"
+	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
 	"time"
 
 	"github.com/go-chi/chi/v5"
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/hetznercloud/hcloud-go/v2/hcloud"
 	"github.com/oklog/run"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -22,9 +21,8 @@ import (
 )
 
 // Server handles the server sub-command.
-func Server(cfg *config.Config, logger log.Logger) error {
-	level.Info(logger).Log(
-		"msg", "Launching HetznerCloud Exporter",
+func Server(cfg *config.Config, logger *slog.Logger) error {
+	logger.Info("Launching HetznerCloud Exporter",
 		"version", version.String,
 		"revision", version.Revision,
 		"date", version.Date,
@@ -34,8 +32,7 @@ func Server(cfg *config.Config, logger log.Logger) error {
 	token, err := config.Value(cfg.Target.Token)
 
 	if err != nil {
-		level.Error(logger).Log(
-			"msg", "Failed to load token from file",
+		logger.Error("Failed to load token from file",
 			"err", err,
 		)
 
@@ -63,9 +60,8 @@ func Server(cfg *config.Config, logger log.Logger) error {
 		}
 
 		gr.Add(func() error {
-			level.Info(logger).Log(
-				"msg", "Starting metrics server",
-				"addr", cfg.Server.Addr,
+			logger.Info("Starting metrics server",
+				"address", cfg.Server.Addr,
 			)
 
 			return web.ListenAndServe(
@@ -82,16 +78,14 @@ func Server(cfg *config.Config, logger log.Logger) error {
 			defer cancel()
 
 			if err := server.Shutdown(ctx); err != nil {
-				level.Error(logger).Log(
-					"msg", "Failed to shutdown metrics gracefully",
+				logger.Error("Failed to shutdown metrics gracefully",
 					"err", err,
 				)
 
 				return
 			}
 
-			level.Info(logger).Log(
-				"msg", "Metrics shutdown gracefully",
+			logger.Info("Metrics shutdown gracefully",
 				"reason", reason,
 			)
 		})
@@ -114,7 +108,7 @@ func Server(cfg *config.Config, logger log.Logger) error {
 	return gr.Run()
 }
 
-func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.Mux {
+func handler(cfg *config.Config, logger *slog.Logger, client *hcloud.Client) *chi.Mux {
 	mux := chi.NewRouter()
 	mux.Use(middleware.Recoverer(logger))
 	mux.Use(middleware.RealIP)
@@ -126,9 +120,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.FloatingIPs {
-		level.Debug(logger).Log(
-			"msg", "Floating IP collector registered",
-		)
+		logger.Debug("Floating IP collector registered")
 
 		registry.MustRegister(exporter.NewFloatingIPCollector(
 			logger,
@@ -140,9 +132,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.Images {
-		level.Debug(logger).Log(
-			"msg", "Image collector registered",
-		)
+		logger.Debug("Image collector registered")
 
 		registry.MustRegister(exporter.NewImageCollector(
 			logger,
@@ -154,9 +144,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.Pricing {
-		level.Debug(logger).Log(
-			"msg", "Pricing collector registered",
-		)
+		logger.Debug("Pricing collector registered")
 
 		registry.MustRegister(exporter.NewPricingCollector(
 			logger,
@@ -168,9 +156,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.Servers {
-		level.Debug(logger).Log(
-			"msg", "Server collector registered",
-		)
+		logger.Debug("Server collector registered")
 
 		registry.MustRegister(exporter.NewServerCollector(
 			logger,
@@ -182,9 +168,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.ServerMetrics {
-		level.Debug(logger).Log(
-			"msg", "Server metrics collector registered",
-		)
+		logger.Debug("Server metrics collector registered")
 
 		registry.MustRegister(exporter.NewServerMetricsCollector(
 			logger,
@@ -196,9 +180,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.LoadBalancers {
-		level.Debug(logger).Log(
-			"msg", "Load balancer collector registered",
-		)
+		logger.Debug("Load balancer collector registered")
 
 		registry.MustRegister(exporter.NewLoadBalancerCollector(
 			logger,
@@ -210,9 +192,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.SSHKeys {
-		level.Debug(logger).Log(
-			"msg", "SSH key collector registered",
-		)
+		logger.Debug("SSH key collector registered")
 
 		registry.MustRegister(exporter.NewSSHKeyCollector(
 			logger,
@@ -224,9 +204,7 @@ func handler(cfg *config.Config, logger log.Logger, client *hcloud.Client) *chi.
 	}
 
 	if cfg.Collector.Volumes {
-		level.Debug(logger).Log(
-			"msg", "Volumes collector registered",
-		)
+		logger.Debug("Volumes collector registered")
 
 		registry.MustRegister(exporter.NewVolumeCollector(
 			logger,

diff --git a/pkg/command/command.go b/pkg/command/command.go
@@ -5,7 +5,6 @@ import (
 	"os"
 	"time"
 
-	"github.com/go-kit/log/level"
 	"github.com/promhippie/hcloud_exporter/pkg/action"
 	"github.com/promhippie/hcloud_exporter/pkg/config"
 	"github.com/promhippie/hcloud_exporter/pkg/version"
@@ -34,10 +33,7 @@ func Run() error {
 			logger := setupLogger(cfg)
 
 			if cfg.Target.Token == "" {
-				level.Error(logger).Log(
-					"msg", "Missing required hcloud.token",
-				)
-
+				logger.Error("Missing required hcloud.token")
 				return fmt.Errorf("missing required hcloud.token")
 			}
 

diff --git a/pkg/command/health.go b/pkg/command/health.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"net/http"
 
-	"github.com/go-kit/log/level"
 	"github.com/promhippie/hcloud_exporter/pkg/config"
 	"github.com/urfave/cli/v2"
 )
@@ -26,8 +25,7 @@ func Health(cfg *config.Config) *cli.Command {
 			)
 
 			if err != nil {
-				level.Error(logger).Log(
-					"msg", "Failed to request health check",
+				logger.Error("Failed to request health check",
 					"err", err,
 				)
 
@@ -37,15 +35,18 @@ func Health(cfg *config.Config) *cli.Command {
 			defer resp.Body.Close()
 
 			if resp.StatusCode != 200 {
-				level.Error(logger).Log(
-					"msg", "Health check seems to be in bad state",
+				logger.Error("Health check seems to be in bad state",
 					"err", err,
 					"code", resp.StatusCode,
 				)
 
 				return err
 			}
 
+			logger.Debug("Health check seems to be fine",
+				"code", resp.StatusCode,
+			)
+
 			return nil
 		},
 	}

diff --git a/pkg/command/setup.go b/pkg/command/setup.go
@@ -1,42 +1,40 @@
 package command
 
 import (
+	"log/slog"
 	"os"
 	"strings"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/promhippie/hcloud_exporter/pkg/config"
 )
 
-func setupLogger(cfg *config.Config) log.Logger {
-	var logger log.Logger
-
+func setupLogger(cfg *config.Config) *slog.Logger {
 	if cfg.Logs.Pretty {
-		logger = log.NewSyncLogger(
-			log.NewLogfmtLogger(os.Stdout),
-		)
-	} else {
-		logger = log.NewSyncLogger(
-			log.NewJSONLogger(os.Stdout),
+		return slog.New(
+			slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+				Level: loggerLevel(cfg),
+			}),
 		)
 	}
 
+	return slog.New(
+		slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+			Level: loggerLevel(cfg),
+		}),
+	)
+}
+
+func loggerLevel(cfg *config.Config) slog.Leveler {
 	switch strings.ToLower(cfg.Logs.Level) {
 	case "error":
-		logger = level.NewFilter(logger, level.AllowError())
+		return slog.LevelError
 	case "warn":
-		logger = level.NewFilter(logger, level.AllowWarn())
+		return slog.LevelWarn
 	case "info":
-		logger = level.NewFilter(logger, level.AllowInfo())
+		return slog.LevelInfo
 	case "debug":
-		logger = level.NewFilter(logger, level.AllowDebug())
-	default:
-		logger = level.NewFilter(logger, level.AllowInfo())
+		return slog.LevelDebug
 	}
 
-	return log.With(
-		logger,
-		"ts", log.DefaultTimestampUTC,
-	)
+	return slog.LevelInfo
 }
diff --git a/pkg/exporter/floating_ip.go b/pkg/exporter/floating_ip.go
@@ -2,11 +2,10 @@ package exporter
 
 import (
 	"context"
+	"log/slog"
 	"strconv"
 	"time"
 
-	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/hetznercloud/hcloud-go/v2/hcloud"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/promhippie/hcloud_exporter/pkg/config"
@@ -15,7 +14,7 @@ import (
 // FloatingIPCollector collects metrics about the floating IPs.
 type FloatingIPCollector struct {
 	client   *hcloud.Client
-	logger   log.Logger
+	logger   *slog.Logger
 	failures *prometheus.CounterVec
 	duration *prometheus.HistogramVec
 	config   config.Target
@@ -24,15 +23,15 @@ type FloatingIPCollector struct {
 }
 
 // NewFloatingIPCollector returns a new FloatingIPCollector.
-func NewFloatingIPCollector(logger log.Logger, client *hcloud.Client, failures *prometheus.CounterVec, duration *prometheus.HistogramVec, cfg config.Target) *FloatingIPCollector {
+func NewFloatingIPCollector(logger *slog.Logger, client *hcloud.Client, failures *prometheus.CounterVec, duration *prometheus.HistogramVec, cfg config.Target) *FloatingIPCollector {
 	if failures != nil {
 		failures.WithLabelValues("floating_ip").Add(0)
 	}
 
 	labels := []string{"id", "server", "location", "type", "ip"}
 	return &FloatingIPCollector{
 		client:   client,
-		logger:   log.With(logger, "collector", "floating-ip"),
+		logger:   logger.With("collector", "floating-ip"),
 		failures: failures,
 		duration: duration,
 		config:   cfg,
@@ -67,17 +66,15 @@ func (c *FloatingIPCollector) Collect(ch chan<- prometheus.Metric) {
 	ips, err := c.client.FloatingIP.All(ctx)
 
 	if err != nil {
-		level.Error(c.logger).Log(
-			"msg", "Failed to fetch floating IPs",
+		c.logger.Error("Failed to fetch floating IPs",
 			"err", err,
 		)
 
 		c.failures.WithLabelValues("floating_ip").Inc()
 		return
 	}
 
-	level.Debug(c.logger).Log(
-		"msg", "Fetched floating IPs",
+	c.logger.Debug("Fetched floating IPs",
 		"count", len(ips),
 	)
 
@@ -108,8 +105,7 @@ func (c *FloatingIPCollector) Collect(ch chan<- prometheus.Metric) {
 		)
 	}
 
-	level.Debug(c.logger).Log(
-		"msg", "Processed floating IP collector",
+	c.logger.Debug("Processed floating IP collector",
 		"duration", time.Since(now),
 	)