refactor: enhance logging with caller information and structured output

logger.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
+	"runtime"
 )
 
 // Logger interface is used throughout gorush
@@ -19,9 +21,9 @@ type Logger interface {
 // NewLogger for simple logger.
 func NewLogger() Logger {
 	return defaultLogger{
-		infoLogger:  log.New(os.Stderr, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile),
-		errorLogger: log.New(os.Stderr, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile),
-		fatalLogger: log.New(os.Stderr, "FATAL: ", log.Ldate|log.Ltime|log.Lshortfile),
+		infoLogger:  log.New(os.Stderr, "INFO: ", log.Ldate|log.Ltime),
+		errorLogger: log.New(os.Stderr, "ERROR: ", log.Ldate|log.Ltime),
+		fatalLogger: log.New(os.Stderr, "FATAL: ", log.Ldate|log.Ltime),
 	}
 }
 
@@ -35,24 +37,45 @@ func (l defaultLogger) Infof(format string, args ...interface{}) {
 	l.infoLogger.Printf(format, args...)
 }
 
+func (l defaultLogger) logWithCallerf(logger *log.Logger, format string, args ...interface{}) {
+	_, file, line, ok := runtime.Caller(2)
+	if ok {
+		shortFile := filepath.Base(file)
+		logger.Printf("%s:%d: %s", shortFile, line, fmt.Sprintf(format, args...))
+		return
+	}
+	logger.Printf(format, args...)
+}
+
+func (l defaultLogger) logWithCaller(logger *log.Logger, args ...interface{}) {
+	_, file, line, ok := runtime.Caller(2)
+	if ok {
+		shortFile := filepath.Base(file)
+		logger.Printf("%s:%d: %s", shortFile, line, fmt.Sprint(args...))
+		return
+	}
+	logger.Println(fmt.Sprint(args...))
+}
+
 func (l defaultLogger) Errorf(format string, args ...interface{}) {
-	l.errorLogger.Printf(format, args...)
+	l.logWithCallerf(l.errorLogger, format, args...)
 }
 
 func (l defaultLogger) Fatalf(format string, args ...interface{}) {
-	l.fatalLogger.Fatalf(format, args...)
+	l.logWithCallerf(l.fatalLogger, format, args...)
+	os.Exit(1)
 }
 
 func (l defaultLogger) Info(args ...interface{}) {
 	l.infoLogger.Println(fmt.Sprint(args...))
 }
 
 func (l defaultLogger) Error(args ...interface{}) {
-	l.errorLogger.Println(fmt.Sprint(args...))
+	l.logWithCaller(l.errorLogger, args...)
 }
 
 func (l defaultLogger) Fatal(args ...interface{}) {
-	l.fatalLogger.Println(fmt.Sprint(args...))
+	l.logWithCaller(l.fatalLogger, args...)
 	os.Exit(1)
 }