Add debug mode to log

Makefile

@@ -5,4 +5,4 @@ serve:
 	go build && ./pye serve
 
 dev:
-	go build && ./pye serve --db dev-data.db
+	go build && ./pye serve --db dev-data.db  --debug

README.md

@@ -11,15 +11,17 @@ in a state that proves I am competent Go developer.
 
 ## Commands
 
-## `pye serve [--config] [--port] [--db]`
+## JWT server
 
-Serve a simple JWT auth system
+Serve a simple JWT auth system  
+**Usage**: `pye serve [--config] [--port] [--db]`
 
 * `POST /register` - register a user with Basic Auth
 * `POST /login` - get a JWT token by Basic Auth
 * `GET /pem` - get PEM-encoded public RS256 key
 * Data and RS256 key persistently stored in an SQLite database and a PEM file
 
-## `pye verify <jwt> <pem file>`
+## JWT verification
 
-Verify a JWT with a public key from a PEM file
+Verify a JWT with a public key from a PEM file  
+**Usage**: `pye verify <jwt> <pem_file>`

cmd/main.go

@@ -9,16 +9,19 @@ import (
 	"git.a71.su/Andrew71/pye/cmd/serve"
 	"git.a71.su/Andrew71/pye/cmd/verify"
 	"git.a71.su/Andrew71/pye/config"
+	"git.a71.su/Andrew71/pye/logging"
 )
 
-func Run() {	
+func Run() {
 
 	serveCmd := flag.NewFlagSet("serve", flag.ExitOnError)
 	serveConfig := serveCmd.String("config", "", "override config file")
 	servePort := serveCmd.Int("port", 0, "override port")
 	serveDb := serveCmd.String("db", "", "override sqlite database")
+	serveDebug := serveCmd.Bool("debug", false, "debug logging")
 
 	verifyCmd := flag.NewFlagSet("verify", flag.ExitOnError)
+	verifyDebug := verifyCmd.Bool("debug", false, "debug logging")
 
 	if len(os.Args) < 2 {
 		fmt.Println("expected 'serve' or 'verify' subcommands")
@@ -28,6 +31,7 @@ func Run() {
 	switch os.Args[1] {
 	case "serve":
 		serveCmd.Parse(os.Args[2:])
+		logging.LogInit(*serveDebug)
 		if *serveConfig != "" {
 			err := config.LoadConfig(*serveConfig)
 			if err != nil {
@@ -43,8 +47,9 @@ func Run() {
 		serve.Serve()
 	case "verify":
 		verifyCmd.Parse(os.Args[2:])
+		logging.LogInit(*verifyDebug)
 		if len(os.Args) != 4 {
-			fmt.Println("Usage: <jwt> <pem file>")
+			fmt.Println("Usage: <jwt> <pem file>  [--debug]")
 		}
 		verify.Verify(os.Args[2], os.Args[3])
 	default:

cmd/serve/main.go

@@ -28,5 +28,6 @@ func Serve() {
 	router.HandleFunc("GET /login", func(w http.ResponseWriter, r *http.Request) { auth.Login(w, r, data) })
 
 	slog.Info("🪐 pye started", "port", config.Cfg.Port)
+	slog.Debug("debug mode active")
 	http.ListenAndServe(":"+strconv.Itoa(config.Cfg.Port), router)
 }

config/config.go

@@ -10,12 +10,16 @@ type Config struct {
 	Port       int    `json:"port"`
 	KeyFile    string `json:"key-file"`
 	SQLiteFile string `json:"sqlite-file"`
+	LogToFile  bool   `json:"log-to-file"`
+	LogFile    string `json:"log-file"`
 }
 
 var DefaultConfig = Config{
 	Port:       7102,
 	KeyFile:    "private.key",
 	SQLiteFile: "data.db",
+	LogToFile:  false,
+	LogFile:    "pye.log",
 }
 
 var (

logging/log.go

@@ -0,0 +1,34 @@
+package logging
+
+import (
+	"io"
+	"log"
+	"log/slog"
+	"os"
+
+	"git.a71.su/Andrew71/pye/config"
+)
+
+// LogInit makes slog output to both os.Stdout and a file if needed, and sets slog.LevelDebug if enabled.
+func LogInit(debugMode bool) {
+	var w io.Writer
+	if config.Cfg.LogToFile {
+		f, err := os.OpenFile(config.Cfg.LogFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+		if err != nil {
+			slog.Error("error opening log file, logging to stdout only", "path", config.Cfg.LogFile, "error", err)
+			return
+		}
+		// No defer f.Close() because that breaks the MultiWriter
+		w = io.MultiWriter(f, os.Stdout)
+	} else {
+		w = os.Stdout
+	}
+
+	// Make slog use intended format
+	var opts *slog.HandlerOptions
+	if debugMode {
+		opts = &slog.HandlerOptions{Level: slog.LevelDebug}
+	}
+	slog.SetDefault(slog.New(slog.NewTextHandler(w, opts)))
+	log.SetFlags(log.LstdFlags | log.Lshortfile)
+}

storage/sqlite/sqlite.go

@@ -18,6 +18,7 @@ const create string = `
 	PRIMARY KEY("uuid")
   );`
 
+// SQLiteStorage is a storage.Storage implementation with SQLite3
 type SQLiteStorage struct {
 	db *sql.DB
 }
@@ -64,14 +65,14 @@ func MustLoadSQLite(dataFile string) SQLiteStorage {
 	}
 	db, err := sql.Open("sqlite3", dataFile)
 	if err != nil {
-		slog.Error("error opening database", "error", err)
+		slog.Error("error opening sqlite3 database", "error", err)
 		os.Exit(1)
 	}
 
 	statement, err := db.Prepare(create)
 	if err != nil {
 		if err.Error() != "table \"users\" already exists" {
-			slog.Info("error initialising database table", "error", err)
+			slog.Info("error initialising sqlite3 database table", "error", err)
 			os.Exit(1)
 		}
 	} else {