Add context for everything

Signed-off-by: Asai Neko <sugar@sne.moe>

logger/slog.go

@@ -1,12 +1,19 @@
 package logger
 
 import (
+	"context"
 	"io"
 	"log/slog"
 	"os"
 	"strings"
+
+	"go.opentelemetry.io/otel/trace"
 )
 
+type otlpHandler struct {
+	slog.Handler
+}
+
 func Init() {
 	levelStr := strings.ToLower(os.Getenv("LOG_LEVEL"))
 	var level slog.Level
@@ -22,14 +29,9 @@ func Init() {
 	}
 
 	var writer io.Writer = os.Stdout
-
 	if level == slog.LevelDebug {
-		file, err := os.OpenFile("app.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0666)
-		if err != nil {
-			slog.Error("Failed to open log file for debug mode", "err", err)
-		} else {
-			writer = io.MultiWriter(os.Stdout, file)
-		}
+		file, _ := os.OpenFile("app.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0666)
+		writer = io.MultiWriter(os.Stdout, file)
 	}
 
 	opts := &slog.HandlerOptions{
@@ -43,7 +45,19 @@ func Init() {
 		},
 	}
 
-	handler := slog.NewJSONHandler(writer, opts)
+	baseHandler := slog.NewJSONHandler(writer, opts)
+	handler := &otlpHandler{baseHandler}
 	logger := slog.New(handler)
 	slog.SetDefault(logger)
 }
+
+func (h *otlpHandler) Handle(ctx context.Context, r slog.Record) error {
+	span := trace.SpanFromContext(ctx)
+	if span.SpanContext().HasTraceID() {
+		r.AddAttrs(
+			slog.String("trace_id", span.SpanContext().TraceID().String()),
+			slog.String("span_id", span.SpanContext().SpanID().String()),
+		)
+	}
+	return h.Handler.Handle(ctx, r)
+}