refactor(metadata handler): uses req context instead of context.Backg…

…round

pkg/cmd/agent/metadata.go

@@ -22,7 +22,7 @@ func newMetadataHandler(logger log.Logger) http.HandlerFunc {
 	)
 
 	// Caches only successful result of GetInstanceMetadata.
-	lazyGetMetadata := func() (cloudmeta.InstanceMetadata, error) {
+	lazyGetMetadata := func(ctx context.Context) (cloudmeta.InstanceMetadata, error) {
 		m.Lock()
 		defer m.Unlock()
 		if loaded {
@@ -34,7 +34,7 @@ func newMetadataHandler(logger log.Logger) http.HandlerFunc {
 			return cloudmeta.InstanceMetadata{}, errors.Wrap(err, "NewCloudMeta")
 		}
 
-		metadata, err = metaSvc.GetInstanceMetadata(context.Background())
+		metadata, err = metaSvc.GetInstanceMetadata(ctx)
 		if err != nil {
 			return cloudmeta.InstanceMetadata{}, err
 		}
@@ -44,12 +44,13 @@ func newMetadataHandler(logger log.Logger) http.HandlerFunc {
 	}
 
 	return func(w http.ResponseWriter, r *http.Request) {
-		instanceMeta, err := lazyGetMetadata()
+		ctx := r.Context()
+		instanceMeta, err := lazyGetMetadata(ctx)
 		if err != nil {
 			// Metadata may not be available for several reasons:
 			// 1. running on-premise 2. disabled 3. smth went wrong with metadata server.
 			// As we cannot distinguish between these cases, we can only log err.
-			logger.Error(r.Context(), "GetInstanceMetadata", "err", err)
+			logger.Error(ctx, "GetInstanceMetadata", "err", err)
 			render.Respond(w, r, models.InstanceMetadata{})
 			return
 		}