feat: init logging middleware on server mode

Signed-off-by: Matthis Holleville <matthish29@gmail.com>

pkg/server/log.go

@@ -0,0 +1,77 @@
+package server
+
+import (
+	"bytes"
+	"net/http"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+type loggingResponseWriter struct {
+	http.ResponseWriter
+	statusCode int
+	buf        *bytes.Buffer
+}
+
+func NewLoggingResponseWriter(w http.ResponseWriter) *loggingResponseWriter {
+	return &loggingResponseWriter{
+		w,
+		http.StatusOK,
+		&bytes.Buffer{},
+	}
+}
+
+func (lrw *loggingResponseWriter) WriteHeader(code int) {
+	lrw.statusCode = code
+	lrw.ResponseWriter.WriteHeader(code)
+}
+
+func (lrw *loggingResponseWriter) Write(b []byte) (int, error) {
+	return lrw.buf.Write(b)
+}
+
+func (lrw *loggingResponseWriter) Flush() {
+	if f, ok := lrw.ResponseWriter.(http.Flusher); ok {
+		f.Flush()
+	}
+	lrw.ResponseWriter.Write(lrw.buf.Bytes())
+}
+
+func logRequest(logger *zap.Logger, fields []zap.Field, statusCode int, message string) {
+	if statusCode >= 400 {
+		logger.Error(message, fields...)
+	} else {
+		logger.Info("request completed", fields...)
+	}
+}
+
+func loggingMiddleware(next http.Handler) http.Handler {
+	config := zap.NewProductionConfig()
+	config.DisableCaller = true
+	logger, err := config.Build()
+	if err != nil {
+		panic(err)
+	}
+	defer logger.Sync()
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		lrw := NewLoggingResponseWriter(w)
+		start := time.Now()
+		defer func() {
+			duration := time.Since(start).Milliseconds()
+			fields := []zap.Field{
+				zap.Int64("duration_ms", duration),
+				zap.String("method", r.Method),
+				zap.String("remote_addr", r.RemoteAddr),
+				zap.Int("status_code", lrw.statusCode),
+				zap.String("url", r.URL.Path),
+			}
+			logRequest(logger, fields, lrw.statusCode, lrw.buf.String())
+		}()
+
+		next.ServeHTTP(lrw, r)
+
+		lrw.Flush()
+	})
+}