Add structured logging with log/slog

Replace fmt.Printf logging calls with slog.Info/slog.Error for structured
JSON output to stderr. Add internal/log package to initialize the default
slog handler from the config log level. Fix .gitignore to only ignore the
binary at the repo root, not the cmd/eng-pad-server directory.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1,4 +1,4 @@
-eng-pad-server
+/eng-pad-server
 /srv/
 *.db
 *.db-wal

cmd/eng-pad-server/server.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"git.wntrmute.dev/kyle/eng-pad-server/internal/config"
+	"git.wntrmute.dev/kyle/eng-pad-server/internal/db"
+	"git.wntrmute.dev/kyle/eng-pad-server/internal/grpcserver"
+	applog "git.wntrmute.dev/kyle/eng-pad-server/internal/log"
+	"git.wntrmute.dev/kyle/eng-pad-server/internal/server"
+	"git.wntrmute.dev/kyle/eng-pad-server/internal/webserver"
+	"github.com/spf13/cobra"
+)
+
+var serverCmd = &cobra.Command{
+	Use:   "server",
+	Short: "Start the eng-pad server",
+	RunE:  runServer,
+}
+
+func init() {
+	rootCmd.AddCommand(serverCmd)
+}
+
+func runServer(cmd *cobra.Command, args []string) error {
+	cfg, err := config.Load(cfgFile)
+	if err != nil {
+		return err
+	}
+
+	applog.Init(cfg.Log.Level)
+
+	database, err := db.Open(cfg.Database.Path)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = database.Close() }()
+
+	if err := db.Migrate(database); err != nil {
+		return fmt.Errorf("migrate: %w", err)
+	}
+
+	slog.Info("eng-pad-server starting", "version", version)
+
+	// Start gRPC server
+	grpcSrv, err := grpcserver.Start(grpcserver.Config{
+		Addr:    cfg.Server.GRPCAddr,
+		TLSCert: cfg.Server.TLSCert,
+		TLSKey:  cfg.Server.TLSKey,
+		DB:      database,
+		BaseURL: cfg.Web.BaseURL,
+	})
+	if err != nil {
+		return fmt.Errorf("start grpc: %w", err)
+	}
+
+	// Start REST API server
+	restSrv, err := server.Start(server.Config{
+		Addr:    cfg.Server.ListenAddr,
+		TLSCert: cfg.Server.TLSCert,
+		TLSKey:  cfg.Server.TLSKey,
+		DB:      database,
+		BaseURL: cfg.Web.BaseURL,
+	})
+	if err != nil {
+		return fmt.Errorf("start rest: %w", err)
+	}
+
+	// Start Web UI server
+	webSrv, err := webserver.Start(webserver.Config{
+		Addr:    cfg.Web.ListenAddr,
+		DB:      database,
+		BaseURL: cfg.Web.BaseURL,
+	})
+	if err != nil {
+		return fmt.Errorf("start web: %w", err)
+	}
+
+	// Wait for shutdown signal
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
+	sig := <-sigCh
+	slog.Info("received shutdown signal", "signal", sig.String())
+
+	// Graceful shutdown with 30-second timeout
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// Stop gRPC server gracefully
+	grpcSrv.GracefulStop()
+
+	// Shutdown REST and web servers
+	if err := restSrv.Shutdown(ctx); err != nil {
+		slog.Error("REST server shutdown error", "error", err)
+	}
+	if err := webSrv.Shutdown(ctx); err != nil {
+		slog.Error("web server shutdown error", "error", err)
+	}
+
+	// Close the database
+	if err := database.Close(); err != nil {
+		slog.Error("database close error", "error", err)
+	}
+
+	slog.Info("shutdown complete")
+	return nil
+}

internal/grpcserver/server.go

@@ -4,6 +4,7 @@ import (
 	"crypto/tls"
 	"database/sql"
 	"fmt"
+	"log/slog"
 	"net"
 
 	pb "git.wntrmute.dev/kyle/eng-pad-server/gen/engpad/v1"
@@ -46,7 +47,7 @@ func Start(cfg Config) (*grpc.Server, error) {
 	syncSvc := &SyncService{DB: cfg.DB, BaseURL: cfg.BaseURL}
 	pb.RegisterEngPadSyncServer(srv, syncSvc)
 
-	fmt.Printf("gRPC listening on %s\n", cfg.Addr)
+	slog.Info("gRPC server started", "addr", cfg.Addr)
 	go func() { _ = srv.Serve(lis) }()
 
 	return srv, nil

internal/log/log.go

@@ -0,0 +1,23 @@
+package log
+
+import (
+	"log/slog"
+	"os"
+	"strings"
+)
+
+func Init(level string) {
+	var lvl slog.Level
+	switch strings.ToLower(level) {
+	case "debug":
+		lvl = slog.LevelDebug
+	case "warn":
+		lvl = slog.LevelWarn
+	case "error":
+		lvl = slog.LevelError
+	default:
+		lvl = slog.LevelInfo
+	}
+	handler := slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{Level: lvl})
+	slog.SetDefault(slog.New(handler))
+}

internal/server/server.go

@@ -4,6 +4,7 @@ import (
 	"crypto/tls"
 	"database/sql"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"time"
 
@@ -42,7 +43,7 @@ func Start(cfg Config) (*http.Server, error) {
 		IdleTimeout:  120 * time.Second,
 	}
 
-	fmt.Printf("REST API listening on %s\n", cfg.Addr)
+	slog.Info("REST API started", "addr", cfg.Addr)
 	go func() { _ = srv.ListenAndServeTLS("", "") }()
 
 	return srv, nil

internal/webserver/server.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"html/template"
 	"io/fs"
+	"log/slog"
 	"net/http"
 	"time"
 
@@ -85,10 +86,10 @@ func Start(cfg Config) (*http.Server, error) {
 			Certificates: []tls.Certificate{tlsCert},
 			MinVersion:   tls.VersionTLS13,
 		}
-		fmt.Printf("Web UI listening on %s (TLS)\n", cfg.Addr)
+		slog.Info("web UI started", "addr", cfg.Addr, "tls", true)
 		go func() { _ = srv.ListenAndServeTLS("", "") }()
 	} else {
-		fmt.Printf("Web UI listening on %s\n", cfg.Addr)
+		slog.Info("web UI started", "addr", cfg.Addr, "tls", false)
 		go func() { _ = srv.ListenAndServe() }()
 	}