add logs using log/slog (#23)

api/logger.go

@@ -1,34 +1,74 @@
 package api
 
 import (
+	"bytes"
 	"fmt"
+	"io"
 	"log/slog"
 	"time"
 
 	"github.com/gin-gonic/gin"
 )
 
-func Logger(logger *slog.Logger) gin.HandlerFunc {
+type responseBodyWriter struct {
+	gin.ResponseWriter
+	body *bytes.Buffer
+}
+
+func (r responseBodyWriter) Write(b []byte) (int, error) {
+	r.body.Write(b)
+	return r.ResponseWriter.Write(b)
+}
+
+func Logger() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		t := time.Now()
-		var log []slog.Attr
 
+		var body []byte
+		var w *responseBodyWriter
+
+		if c.Request.Method != "GET" {
+			body, _ = io.ReadAll(c.Request.Body)
+			w = &responseBodyWriter{body: &bytes.Buffer{}, ResponseWriter: c.Writer}
+			c.Writer = w
+			c.Request.Body = io.NopCloser(bytes.NewReader(body))
+		}
 		c.Next()
 
 		duration := time.Since(t).Milliseconds()
 
-		log = append(log,
+		if c.Request.Method != "GET" {
-			slog.Int("STATUS", c.Writer.Status()),
+			slog.LogAttrs(
-			slog.String("METHOD", c.Request.Method),
+				c,
-			slog.String("PATH", c.Request.RequestURI),
+				slog.LevelDebug,
-			slog.String("DURATION", fmt.Sprintf("%d ms", duration)),
+				"http",
-		)
+				slog.Group(
+					"request",
+					slog.Int("STATUS", c.Writer.Status()),
+					slog.String("METHOD", c.Request.Method),
+					slog.String("PATH", c.Request.RequestURI),
+					slog.String("DURATION", fmt.Sprintf("%d ms", duration)),
+					slog.String("BODY", string(body)),
+				),
+				slog.Group(
+					"response",
+					slog.String("BODY", w.body.String()),
+				),
+			)
+		} else {
+			slog.LogAttrs(
+				c,
+				slog.LevelDebug,
+				"http",
+				slog.Group(
+					"request",
+					slog.Int("STATUS", c.Writer.Status()),
+					slog.String("METHOD", c.Request.Method),
+					slog.String("PATH", c.Request.RequestURI),
+					slog.String("DURATION", fmt.Sprintf("%d ms", duration)),
+				),
+			)
 
-		logger.LogAttrs(
+		}
-			c,
-			slog.LevelDebug,
-			"http",
-			log...,
-		)
 	}
 }

api/server.go

@@ -31,12 +31,19 @@ func NewServer(config util.Config, store db.Store) *Server {
 	opts := slog.HandlerOptions{
 		Level: logLevel,
 	}
-	logger := slog.New(slog.NewJSONHandler(os.Stdout, &opts))
+	logger := slog.New(slog.NewTextHandler(os.Stdout, &opts))
+
+	if config.LogOutput == "json" {
+		logger = slog.New(slog.NewJSONHandler(os.Stdout, &opts))
+	}
+
+	slog.SetDefault(logger)
+
 	router := gin.New()
 
 	router.Use(gin.Recovery())
 
-	router.Use(Logger(logger))
+	router.Use(Logger())
 
 	router.POST("/accounts", server.createAccount)
 	router.GET("/accounts/:id", server.getAccount)

app.env

@@ -2,3 +2,4 @@ DB_SOURCE=postgresql://root:secret@localhost:5432/df?sslmode=disable
 DB_DRIVER=postgres
 SERVER_ADDRESS=0.0.0.0:8080
 ENVIRONMENT=development
+LOG_OUTPUT=text

util/config.go

@@ -7,6 +7,7 @@ type Config struct {
 	DBDriver      string `mapstructure:"DB_DRIVER"`
 	ServerAddress string `mapstructure:"SERVER_ADDRESS"`
 	Environment   string `mapstructure:"ENVIRONMENT"`
+	LogOutput     string `mapstructure:"LOG_OUTPUT"`
 }
 
 func LoadConfig(path string) (config Config, err error) {