Set up initial project structure with essential files and directories

internal/httpapp/middleware.go

@@ -0,0 +1,46 @@
+package httpapp
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"log"
+	"net/http"
+	"time"
+)
+
+type ctxKey string
+
+const requestIDKey ctxKey = "reqid"
+
+func requestID(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		id := r.Header.Get("X-Request-Id")
+		if id == "" {
+			id = newReqID()
+		}
+		w.Header().Set("X-Request-Id", id)
+		ctx := context.WithValue(r.Context(), requestIDKey, id)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func logging(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		next.ServeHTTP(w, r)
+		d := time.Since(start)
+		id, _ := r.Context().Value(requestIDKey).(string)
+		log.Printf("%s %s %s rid=%s dur=%s", r.RemoteAddr, r.Method, r.URL.Path, id, d)
+	})
+}
+
+func newReqID() string {
+	var b [16]byte
+	if _, err := rand.Read(b[:]); err != nil {
+		// Fallback to timestamp-based ID if crypto/rand fails (extremely rare)
+		log.Printf("rand.Read failed, using fallback: %v", err)
+		return hex.EncodeToString([]byte(time.Now().Format(time.RFC3339Nano)))
+	}
+	return hex.EncodeToString(b[:])
+}