feat: backend service

backend/internal/server/middleware/logging/logging.go

@@ -0,0 +1,44 @@
+// Package logging emits a single info-level access log entry per HTTP request,
+// enriched with the active OpenTelemetry trace fields and the resolved request
+// id when present.
+package logging
+
+import (
+	"time"
+
+	"galaxy/backend/internal/server/middleware/requestid"
+	"galaxy/backend/internal/telemetry"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+)
+
+// Middleware returns the access-log gin middleware. The provided logger should
+// already carry the per-process service-name field; the middleware adds the
+// request method, matched route, status, latency, request id, and trace
+// fields.
+func Middleware(logger *zap.Logger) gin.HandlerFunc {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+
+	return func(c *gin.Context) {
+		start := time.Now()
+		c.Next()
+		duration := time.Since(start)
+
+		fields := make([]zap.Field, 0, 6)
+		fields = append(fields,
+			zap.String("method", c.Request.Method),
+			zap.String("path", c.FullPath()),
+			zap.Int("status", c.Writer.Status()),
+			zap.Duration("duration", duration),
+		)
+		if requestID, ok := requestid.FromGin(c); ok {
+			fields = append(fields, zap.String("request_id", requestID))
+		}
+		fields = append(fields, telemetry.TraceFieldsFromContext(c.Request.Context())...)
+
+		logger.Info("http request", fields...)
+	}
+}