Added OpenTelemetry and use structured logging

internal/telemetry/logger.go

@@ -0,0 +1,32 @@
+package telemetry
+
+import (
+	"context"
+	"log/slog"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+type TraceHandler struct {
+	slog.Handler
+}
+
+func (h *TraceHandler) Handle(ctx context.Context, r slog.Record) error {
+	spanCtx := trace.SpanContextFromContext(ctx)
+	if spanCtx.HasTraceID() {
+		r.AddAttrs(
+			slog.String("trace_id", spanCtx.TraceID().String()),
+			slog.String("span_id", spanCtx.SpanID().String()),
+		)
+	}
+
+	return h.Handler.Handle(ctx, r)
+}
+
+func (h *TraceHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return &TraceHandler{Handler: h.Handler.WithAttrs(attrs)}
+}
+
+func (h *TraceHandler) WithGroup(name string) slog.Handler {
+	return &TraceHandler{Handler: h.Handler.WithGroup(name)}
+}