Update

internal/http/logging.go

@@ -0,0 +1,95 @@
+package httpapi
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+// WithRequestLogging wraps h with a handler that logs each request to dir/access.log.
+// Uses dir "var/logs" by default. Returns h unchanged if dir is empty.
+func WithRequestLogging(dir string, h http.Handler) (http.Handler, error) {
+	if dir == "" {
+		return h, nil
+	}
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return nil, err
+	}
+	f, err := os.OpenFile(filepath.Join(dir, "access.log"), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return nil, err
+	}
+	return &requestLogger{handler: h, file: f}, nil
+}
+
+type requestLogger struct {
+	handler http.Handler
+	file    *os.File
+	mu      sync.Mutex
+}
+
+func (l *requestLogger) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	start := time.Now()
+	ip := clientIP(r)
+	method := r.Method
+	path := r.URL.Path
+	userAgent := r.Header.Get("User-Agent")
+	if userAgent == "" {
+		userAgent = "-"
+	}
+
+	wrapped := &responseRecorder{ResponseWriter: w, status: http.StatusOK}
+	l.handler.ServeHTTP(wrapped, r)
+
+	elapsed := time.Since(start).Milliseconds()
+	line := formatLogLine(ip, method, path, wrapped.status, elapsed, strings.ReplaceAll(userAgent, "\"", "'"))
+
+	l.mu.Lock()
+	_, _ = l.file.WriteString(line)
+	l.mu.Unlock()
+}
+
+type responseRecorder struct {
+	http.ResponseWriter
+	status int
+}
+
+func (r *responseRecorder) WriteHeader(code int) {
+	r.status = code
+	r.ResponseWriter.WriteHeader(code)
+}
+
+func formatLogLine(ip, method, path string, status int, elapsedMs int64, userAgent string) string {
+	// Common log format: ip - - [timestamp] "method path protocol" status size "referer" "user-agent" elapsed_ms
+	t := time.Now().UTC().Format("02/Jan/2006:15:04:05 -0700")
+	return fmt.Sprintf("%s - - [%s] \"%s %s\" %d %d \"-\" \"%s\" %dms\n",
+		ip, t, method, path, status, 0, userAgent, elapsedMs)
+}
+
+func clientIP(r *http.Request) string {
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
+		// First IP in the list is the original client
+		for i := 0; i < len(xff); i++ {
+			if xff[i] == ',' {
+				return xff[:i]
+			}
+		}
+		return xff
+	}
+	if xri := r.Header.Get("X-Real-IP"); xri != "" {
+		return xri
+	}
+	host, _ := splitHostPort(r.RemoteAddr)
+	return host
+}
+
+func splitHostPort(addr string) (host, port string) {
+	if idx := strings.LastIndex(addr, ":"); idx >= 0 {
+		return addr[:idx], addr[idx+1:]
+	}
+	return addr, ""
+}