logger: replace WithTap with WithTee

.changeset/logger-with-tee.md

@@ -0,0 +1,8 @@
+---
+"github.com/livekit/protocol": minor
+"@livekit/protocol": patch
+---
+
+Replace logger.WithTap with logger.WithTee, which duplicates every log entry to a caller-supplied zaputil.Tee. The tee's core is built from the level each derived logger resolves, so the copy follows component levels rather than carrying a level of its own.
+
+Replace ZapLogger.WithMinLevel with WithComponentLeveler, which attaches a zaputil.ComponentLeveler to a branch of the logger tree. A leveler owns the per-component level and write-enabler cache for one configuration source and can only widen its parent, so a caller can resolve levels per (tenant, component) without rebuilding loggers on a config change. ZapLogger.Leveler exposes the leveler a branch resolves through, for use as the parent of a derived one.

livekit/egress_test.go

@@ -18,7 +18,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-	"go.uber.org/zap/zapcore"
 
 	"github.com/livekit/protocol/logger"
 	"github.com/livekit/protocol/logger/testutil"
@@ -32,7 +31,7 @@ type TestEgressLogOutput struct {
 
 func TestLoggerProto(t *testing.T) {
 	ws := &testutil.BufferedWriteSyncer{}
-	l, err := logger.NewZapLogger(&logger.Config{}, logger.WithTap(zaputil.NewWriteEnabler(ws, zapcore.DebugLevel)))
+	l, err := logger.NewZapLogger(&logger.Config{Level: "debug"}, logger.WithTee(zaputil.NewTee(testutil.NewJSONCoreFactory(ws))))
 	require.NoError(t, err)
 
 	s3 := &S3Upload{

logger/config.go

@@ -14,7 +14,12 @@
 
 package logger
 
-import "sync"
+import (
+	"strings"
+	"sync"
+
+	"go.uber.org/zap/zapcore"
+)
 
 type Config struct {
 	JSON  bool   `yaml:"json,omitempty"`
@@ -72,3 +77,18 @@ func (c *Config) AddUpdateObserver(cb ConfigObserver) {
 	defer c.lock.Unlock()
 	c.onUpdatedCallbacks = append(c.onUpdatedCallbacks, cb)
 }
+
+// ResolveComponentLevel always resolves: an unconfigured component takes Level.
+func (c *Config) ResolveComponentLevel(component string) (zapcore.Level, bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	parts := strings.Split(component, ".")
+	for len(parts) > 0 {
+		if lvl, ok := c.ComponentLevels[strings.Join(parts, ".")]; ok {
+			return ParseZapLevel(lvl), true
+		}
+		parts = parts[:len(parts)-1]
+	}
+	return ParseZapLevel(c.Level), true
+}

logger/config_test.go

@@ -0,0 +1,25 @@
+package logger
+
+import (
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zapcore"
+
+	"github.com/livekit/protocol/logger/zaputil"
+)
+
+func TestConfigResolveComponentLevel(t *testing.T) {
+	conf := &Config{Level: "info", ComponentLevels: map[string]string{"rtc.room": "debug"}}
+	root := zaputil.NewRootComponentLeveler(zapcore.AddSync(io.Discard), conf)
+
+	require.True(t, root.ComponentLevel("rtc.room").Enabled(zapcore.DebugLevel))
+	require.True(t, root.ComponentLevel("rtc.room.track").Enabled(zapcore.DebugLevel))
+	require.False(t, root.ComponentLevel("rtc").Enabled(zapcore.DebugLevel))
+	require.True(t, root.ComponentLevel("rtc").Enabled(zapcore.InfoLevel))
+
+	lvl, ok := (&Config{}).ResolveComponentLevel("anything")
+	require.True(t, ok)
+	require.Equal(t, zapcore.InfoLevel, lvl)
+}