Initial commit: logcorrelator with unified packaging (DEB + RPM using fpm)

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/observability/logger.go

@@ -0,0 +1,85 @@
+package observability
+
+import (
+	"log"
+	"os"
+	"sync"
+)
+
+// Logger provides structured logging.
+type Logger struct {
+	mu       sync.Mutex
+	logger   *log.Logger
+	prefix   string
+	fields   map[string]any
+}
+
+// NewLogger creates a new logger.
+func NewLogger(prefix string) *Logger {
+	return &Logger{
+		logger: log.New(os.Stderr, "", log.LstdFlags|log.Lmicroseconds),
+		prefix: prefix,
+		fields: make(map[string]any),
+	}
+}
+
+// WithFields returns a new logger with additional fields.
+func (l *Logger) WithFields(fields map[string]any) *Logger {
+	newLogger := &Logger{
+		logger: l.logger,
+		prefix: l.prefix,
+		fields: make(map[string]any),
+	}
+	for k, v := range l.fields {
+		newLogger.fields[k] = v
+	}
+	for k, v := range fields {
+		newLogger.fields[k] = v
+	}
+	return newLogger
+}
+
+// Info logs an info message.
+func (l *Logger) Info(msg string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.log("INFO", msg)
+}
+
+// Error logs an error message.
+func (l *Logger) Error(msg string, err error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if err != nil {
+		l.log("ERROR", msg+" "+err.Error())
+	} else {
+		l.log("ERROR", msg)
+	}
+}
+
+// Debug logs a debug message.
+func (l *Logger) Debug(msg string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.log("DEBUG", msg)
+}
+
+func (l *Logger) log(level, msg string) {
+	prefix := l.prefix
+	if prefix != "" {
+		prefix = "[" + prefix + "] "
+	}
+
+	l.logger.SetPrefix(prefix + level + " ")
+	
+	var args []any
+	for k, v := range l.fields {
+		args = append(args, k, v)
+	}
+	
+	if len(args) > 0 {
+		l.logger.Printf(msg+" %+v", args...)
+	} else {
+		l.logger.Print(msg)
+	}
+}

internal/observability/logger_test.go

@@ -0,0 +1,111 @@
+package observability
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestNewLogger(t *testing.T) {
+	logger := NewLogger("test")
+	if logger == nil {
+		t.Fatal("expected non-nil logger")
+	}
+	if logger.prefix != "test" {
+		t.Errorf("expected prefix 'test', got %s", logger.prefix)
+	}
+}
+
+func TestLogger_Info(t *testing.T) {
+	// Capture stderr
+	oldStderr := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+
+	logger := NewLogger("test")
+	logger.Info("test message")
+
+	w.Close()
+	os.Stderr = oldStderr
+
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+	output := buf.String()
+
+	if !strings.Contains(output, "INFO") {
+		t.Error("expected INFO in output")
+	}
+	if !strings.Contains(output, "test message") {
+		t.Error("expected 'test message' in output")
+	}
+}
+
+func TestLogger_Error(t *testing.T) {
+	oldStderr := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+
+	logger := NewLogger("test")
+	logger.Error("error message", nil)
+
+	w.Close()
+	os.Stderr = oldStderr
+
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+	output := buf.String()
+
+	if !strings.Contains(output, "ERROR") {
+		t.Error("expected ERROR in output")
+	}
+	if !strings.Contains(output, "error message") {
+		t.Error("expected 'error message' in output")
+	}
+}
+
+func TestLogger_Debug(t *testing.T) {
+	oldStderr := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+
+	logger := NewLogger("test")
+	logger.Debug("debug message")
+
+	w.Close()
+	os.Stderr = oldStderr
+
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+	output := buf.String()
+
+	if !strings.Contains(output, "DEBUG") {
+		t.Error("expected DEBUG in output")
+	}
+	if !strings.Contains(output, "debug message") {
+		t.Error("expected 'debug message' in output")
+	}
+}
+
+func TestLogger_WithFields(t *testing.T) {
+	logger := NewLogger("test")
+	fieldsLogger := logger.WithFields(map[string]any{
+		"key1": "value1",
+		"key2": 42,
+	})
+
+	if fieldsLogger == logger {
+		t.Error("expected different logger instance")
+	}
+	if len(fieldsLogger.fields) != 2 {
+		t.Errorf("expected 2 fields, got %d", len(fieldsLogger.fields))
+	}
+}
+
+func TestLogger_Name(t *testing.T) {
+	logger := NewLogger("myservice")
+	if logger.prefix != "myservice" {
+		t.Errorf("expected prefix 'myservice', got %s", logger.prefix)
+	}
+}