real init

src/lib/logger/logger.go

@@ -0,0 +1,88 @@
+package logger
+
+import (
+	"io"
+	"log"
+	"os"
+	"sync"
+	"time"
+)
+
+var (
+	infoLogger  *log.Logger
+	warnLogger  *log.Logger
+	errorLogger *log.Logger
+	debugLogger *log.Logger
+
+	once sync.Once
+)
+
+func initLogger() {
+	if err := os.MkdirAll("logs", 0755); err != nil {
+		log.Printf("Failed to create logs directory: %v. Falling back to standard output.", err)
+	}
+
+	// 1. Setup Info Logger
+	var infoOutput io.Writer = os.Stdout
+	if infoFile, err := os.OpenFile("logs/info.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666); err == nil {
+		infoOutput = io.MultiWriter(os.Stdout, infoFile)
+		writeHeader(infoFile)
+	}
+	infoLogger = log.New(infoOutput, "INFO: ", log.Ldate|log.Ltime|log.LUTC)
+
+	// 2. Setup Warn Logger
+	var warnOutput io.Writer = os.Stdout
+	if warnFile, err := os.OpenFile("logs/warn.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666); err == nil {
+		warnOutput = io.MultiWriter(os.Stdout, warnFile)
+		writeHeader(warnFile)
+	}
+	warnLogger = log.New(warnOutput, "WARN: ", log.Ldate|log.Ltime|log.LUTC)
+
+	// 3. Setup Error Logger
+	var errorOutput io.Writer = os.Stderr
+	if errorFile, err := os.OpenFile("logs/error.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666); err == nil {
+		errorOutput = io.MultiWriter(os.Stderr, errorFile)
+		writeHeader(errorFile)
+	}
+	// Note: increased call depth isn't an issue for Lshortfile here because
+	// log.Logger.Printf correctly tracks the caller frame right above it.
+	errorLogger = log.New(errorOutput, "ERROR: ", log.Ldate|log.Ltime|log.LUTC|log.Lshortfile)
+
+	// 4. Setup Debug Logger
+	var debugOutput io.Writer = os.Stdout
+	if debugFile, err := os.OpenFile("logs/debug.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666); err == nil {
+		debugOutput = io.MultiWriter(os.Stdout, debugFile)
+		writeHeader(debugFile)
+	}
+	debugLogger = log.New(debugOutput, "DEBUG: ", log.Ldate|log.Ltime|log.LUTC)
+}
+
+func writeHeader(file *os.File) {
+	file.WriteString("========== Start Log ==========\n")
+	file.WriteString("[INFO] Logger initialized\n")
+	file.WriteString("[" + time.Now().Format(time.RFC3339) + "]\n")
+}
+
+// Info accepts a format string and an optional, arbitrary number of arguments.
+func Info(format string, v ...any) {
+	once.Do(initLogger)
+	infoLogger.Printf(format, v...)
+}
+
+// Warn accepts a format string and an optional, arbitrary number of arguments.
+func Warn(format string, v ...any) {
+	once.Do(initLogger)
+	warnLogger.Printf(format, v...)
+}
+
+// Error accepts a format string and an optional, arbitrary number of arguments.
+func Error(format string, v ...any) {
+	once.Do(initLogger)
+	errorLogger.Printf(format, v...)
+}
+
+// Debug accepts a format string and an optional, arbitrary number of arguments.
+func Debug(format string, v ...any) {
+	once.Do(initLogger)
+	debugLogger.Printf(format, v...)
+}