feat: add request logger middleware

internal/server/observability.go

@@ -0,0 +1,37 @@
+package server
+
+import (
+	"log"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func RequestLogger() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		start := time.Now()
+		path := c.Request.URL.Path
+		query := c.Request.URL.RawQuery
+
+		c.Next()
+
+		route := c.FullPath()
+		if route == "" {
+			route = path
+		}
+
+		log.Printf(
+			"http_request method=%s route=%s path=%s query=%s status=%d duration_ms=%.2f bytes=%d client_ip=%s errors=%s",
+			c.Request.Method,
+			strconv.Quote(route),
+			strconv.Quote(path),
+			strconv.Quote(query),
+			c.Writer.Status(),
+			float64(time.Since(start).Microseconds())/1000,
+			c.Writer.Size(),
+			strconv.Quote(c.ClientIP()),
+			strconv.Quote(c.Errors.ByType(gin.ErrorTypePrivate).String()),
+		)
+	}
+}

internal/server/server.go

@@ -22,7 +22,7 @@ func ProvideRouter(htmlRender render.HTMLRender) *gin.Engine {
 		gin.SetMode(gin.ReleaseMode)
 	}
 	r := gin.New()
-	r.Use(CORSMiddleware(), gin.Logger(), gin.Recovery())
+	r.Use(CORSMiddleware(), RequestLogger(), gin.Recovery())
 	r.Static("/static", "./static")
 	r.Static("/dist", "./dist")
 	r.HTMLRender = htmlRender

internal/server/server_test.go

@@ -1,9 +1,16 @@
 package server
 
 import (
+	"bytes"
+	"io"
+	"log"
 	"net/http"
+	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
+
+	"github.com/gin-gonic/gin"
 )
 
 func TestNewHTTPServer_TimeoutsAndAddr(t *testing.T) {
@@ -25,3 +32,35 @@ func TestNewHTTPServer_TimeoutsAndAddr(t *testing.T) {
 		t.Fatalf("IdleTimeout: got %s want %s", srv.IdleTimeout, 2*time.Minute)
 	}
 }
+
+func TestRequestLoggerUsesMatchedRoute(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	var logs bytes.Buffer
+	previousOutput := log.Writer()
+	log.SetOutput(&logs)
+	defer log.SetOutput(previousOutput)
+
+	router := gin.New()
+	router.Use(RequestLogger())
+	router.GET("/anime/:id", func(c *gin.Context) {
+		c.String(http.StatusOK, "ok")
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/anime/1?section=characters", nil)
+	rec := httptest.NewRecorder()
+	router.ServeHTTP(rec, req)
+
+	output, err := io.ReadAll(&logs)
+	if err != nil {
+		t.Fatalf("read logs: %v", err)
+	}
+
+	logLine := string(output)
+	if !strings.Contains(logLine, `route="/anime/:id"`) {
+		t.Fatalf("log line missing route: %s", logLine)
+	}
+	if !strings.Contains(logLine, `status=200`) {
+		t.Fatalf("log line missing status: %s", logLine)
+	}
+}