importccl: Correctly handle cancelled context when importing

pkg/storage/cloud/external_storage.go

@@ -559,6 +559,10 @@ func checkHTTPContentRangeHeader(h string, pos int64) error {
 func (r *resumingHTTPReader) sendRequest(
 	reqHeaders map[string]string,
 ) (resp *http.Response, err error) {
+	// Initialize err to the context.Canceled: if our context is canceled, we will
+	// never enter the loop below; in this case we want to return "nil, canceled"
+	err = context.Canceled
+
 	for attempt, retries := 0,
 		retry.StartWithCtx(r.ctx, httpRetryOptions); retries.Next(); attempt++ {
 		resp, err = r.client.req(r.ctx, "GET", r.url, nil, reqHeaders)
@@ -570,7 +574,7 @@ func (r *resumingHTTPReader) sendRequest(
 		log.Errorf(r.ctx, "HTTP:Req error: err=%s (attempt %d)", err, attempt)
 
 		if _, ok := err.(*retryableHTTPError); !ok {
-			break
+			return
 		}
 	}
 

pkg/storage/cloud/external_storage_test.go

@@ -878,3 +878,22 @@ func TestHttpGet(t *testing.T) {
 		})
 	}
 }
+
+func TestHttpGetWithCancelledContext(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+
+	s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
+	defer s.Close()
+
+	store, err := makeHTTPStorage(s.URL, testSettings)
+	require.NoError(t, err)
+	defer func() {
+		require.NoError(t, store.Close())
+	}()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	_, err = store.ReadFile(ctx, "/something")
+	require.Error(t, context.Canceled, err)
+}