refactor(main): migrate to zerolog structured logging

main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"log"
 	"net/http"
 	"os"
 	"os/signal"
@@ -12,18 +11,27 @@ import (
 
 	"github.com/fujin/anthropic-proxy/internal/auth"
 	"github.com/fujin/anthropic-proxy/internal/config"
+	"github.com/fujin/anthropic-proxy/internal/logging"
 	"github.com/fujin/anthropic-proxy/internal/proxy"
 	"github.com/fujin/anthropic-proxy/internal/server"
+	"github.com/rs/zerolog/log"
 )
 
 func run() error {
-	log.SetFlags(log.LstdFlags)
-
 	cfg, err := config.Load("config.yaml")
 	if err != nil {
 		return fmt.Errorf("load config: %w", err)
 	}
 
+	logging.Setup(logging.Config{
+		Level:      cfg.Logging.Level,
+		File:       cfg.Logging.File,
+		MaxSizeMB:  cfg.Logging.MaxSizeMB,
+		MaxBackups: cfg.Logging.MaxBackups,
+		MaxAgeDays: cfg.Logging.MaxAgeDays,
+		Compress:   cfg.Logging.Compress,
+	})
+
 	// Load credentials from ~/.claude/.credentials.json
 	creds, err := config.LoadDefaultCredentials()
 	if err != nil {
@@ -35,15 +43,15 @@ func run() error {
 		cred = creds[0]
 		// If token is expired, try refresh first
 		if !cred.ExpiresAt.IsZero() && time.Now().After(cred.ExpiresAt) {
-			log.Printf("token expired, attempting refresh...")
+			log.Info().Msg("token expired, attempting refresh")
 			refreshCtx, refreshCancel := context.WithTimeout(context.Background(), 15*time.Second)
 			refreshErr := auth.RefreshToken(refreshCtx, cred)
 			refreshCancel()
 			if refreshErr != nil {
-				log.Printf("refresh failed: %v — initiating login", refreshErr)
+				log.Warn().Err(refreshErr).Msg("refresh failed, initiating login")
 				cred = nil // fall through to login
 			} else {
-				log.Printf("token refreshed successfully")
+				log.Info().Msg("token refreshed")
 			}
 		}
 	}
@@ -54,14 +62,14 @@ func run() error {
 		if statErr == nil && (fi.Mode()&os.ModeCharDevice) == 0 {
 			return fmt.Errorf("no valid credentials found; run the proxy interactively for initial login")
 		}
-		log.Printf("no valid credentials found, starting OAuth login flow...")
+		log.Info().Msg("no credentials found, starting OAuth login")
 		cred, err = auth.Login(context.Background())
 		if err != nil {
 			return fmt.Errorf("login failed: %w", err)
 		}
 	}
 
-	log.Printf("loaded credential for %s", cred.Email)
+	log.Info().Str("credential", cred.Email).Msg("credential loaded")
 
 	pool := auth.NewPool([]*auth.Credential{cred})
 
@@ -73,14 +81,14 @@ func run() error {
 
 	var profile *proxy.SniffedProfile
 	if cfg.ClaudeBinary != "" {
-		log.Printf("sniffing claude-code at %s...", cfg.ClaudeBinary)
+		log.Info().Str("binary", cfg.ClaudeBinary).Msg("sniffing claude-code")
 		profile, err = proxy.SniffClaudeCode(cfg.ClaudeBinary)
 		if err != nil {
-			log.Printf("warning: sniff failed, using defaults: %v", err)
+			log.Warn().Err(err).Msg("sniff failed, using defaults")
 		}
 	}
 
-	log.Printf("starting server on port %d", cfg.Port)
+	log.Info().Int("port", cfg.Port).Msg("starting server")
 	srv := server.New(cfg, pool, profile)
 
 	quit := make(chan os.Signal, 1)
@@ -88,14 +96,14 @@ func run() error {
 
 	go func() {
 		<-quit
-		log.Printf("shutting down...")
+		log.Info().Msg("shutting down")
 		cancel()
 
 		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 10*time.Second)
 		defer shutdownCancel()
 
 		if err := srv.Shutdown(shutdownCtx); err != nil {
-			log.Printf("shutdown error: %v", err)
+			log.Error().Err(err).Msg("shutdown error")
 		}
 	}()
 
@@ -108,7 +116,7 @@ func run() error {
 
 func main() {
 	if err := run(); err != nil {
-		log.Printf("error: %v", err)
+		log.Error().Err(err).Msg("fatal error")
 		os.Exit(1)
 	}
 }