Merge pull request #552 from jacobweinstock/use-slog

Move to slog logr implementation:

## Description

slog is one less import and by default provides improved time format and file, function, and line number attributes.

<!--- Please describe what this PR is going to change -->

## Why is this needed

<!--- Link to issue you have raised -->

Fixes: #

## How Has This Been Tested?
<!--- Please describe in detail how you tested your changes. -->
<!--- Include details of your testing environment, and the tests you ran to -->
<!--- see how your change affects other areas of the code, etc. -->


## How are existing users impacted? What migration steps/scripts do we need?

<!--- Fixes a bug, unblocks installation, removes a component of the stack etc -->
<!--- Requires a DB migration script, etc. -->


## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [ ] added unit or e2e tests
- [ ] provided instructions on how to upgrade

cmd/smee/main.go

@@ -5,18 +5,19 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"log/slog"
 	"net"
 	"net/netip"
 	"net/url"
 	"os"
 	"os/signal"
 	"path"
+	"path/filepath"
 	"strings"
 	"syscall"
 	"time"
 
 	"github.com/go-logr/logr"
-	"github.com/go-logr/zapr"
 	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/insomniacslk/dhcp/dhcpv4/server4"
 	"github.com/tinkerbell/ipxedust"
@@ -31,8 +32,6 @@ import (
 	"github.com/tinkerbell/smee/internal/metric"
 	"github.com/tinkerbell/smee/internal/otel"
 	"github.com/tinkerbell/smee/internal/syslog"
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
 	"golang.org/x/sync/errgroup"
 )
 
@@ -488,22 +487,40 @@ func (c *config) dhcpHandler(ctx context.Context, log logr.Logger) (server.Handl
 	return nil, errors.New("invalid dhcp mode")
 }
 
-// defaultLogger is zap logr implementation.
+// defaultLogger uses the slog logr implementation.
 func defaultLogger(level string) logr.Logger {
-	config := zap.NewProductionConfig()
-	config.OutputPaths = []string{"stdout"}
+	// source file and function can be long. This makes the logs less readable.
+	// truncate source file and function to last 3 parts for improved readability.
+	customAttr := func(_ []string, a slog.Attr) slog.Attr {
+		if a.Key == slog.SourceKey {
+			ss, ok := a.Value.Any().(*slog.Source)
+			if !ok || ss == nil {
+				return a
+			}
+			f := strings.Split(ss.Function, "/")
+			if len(f) > 3 {
+				ss.Function = filepath.Join(f[len(f)-3:]...)
+			}
+			p := strings.Split(ss.File, "/")
+			if len(p) > 3 {
+				ss.File = filepath.Join(p[len(p)-3:]...)
+			}
+
+			return a
+		}
+
+		return a
+	}
+	opts := &slog.HandlerOptions{AddSource: true, ReplaceAttr: customAttr}
 	switch level {
 	case "debug":
-		config.Level = zap.NewAtomicLevelAt(zapcore.DebugLevel)
+		opts.Level = slog.LevelDebug
 	default:
-		config.Level = zap.NewAtomicLevelAt(zapcore.InfoLevel)
-	}
-	zapLogger, err := config.Build()
-	if err != nil {
-		panic(fmt.Sprintf("who watches the watchmen (%v)?", err))
+		opts.Level = slog.LevelInfo
 	}
+	log := slog.New(slog.NewJSONHandler(os.Stdout, opts))
 
-	return zapr.NewLogger(zapLogger)
+	return logr.FromSlogHandler(log.Handler())
 }
 
 func parseTrustedProxies(trustedProxies string) (result []string) {

go.mod

@@ -10,7 +10,6 @@ require (
 	github.com/ghodss/yaml v1.0.0
 	github.com/go-logr/logr v1.4.2
 	github.com/go-logr/stdr v1.2.2
-	github.com/go-logr/zapr v1.3.0
 	github.com/google/go-cmp v0.6.0
 	github.com/insomniacslk/dhcp v0.0.0-20240829085014-a3a4c1f04475
 	github.com/packethost/xff v0.0.0-20190305172552-d3e9190c41b3
@@ -24,7 +23,6 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.32.0
 	go.opentelemetry.io/otel/sdk v1.32.0
 	go.opentelemetry.io/otel/trace v1.32.0
-	go.uber.org/zap v1.27.0
 	golang.org/x/net v0.31.0
 	golang.org/x/sync v0.9.0
 	golang.org/x/sys v0.27.0
@@ -87,7 +85,6 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.32.0 // indirect
 	go.opentelemetry.io/otel/metric v1.32.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.3.1 // indirect
-	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/crypto v0.29.0 // indirect
 	golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa // indirect
 	golang.org/x/oauth2 v0.23.0 // indirect