Fix default CloudCompute for flows (#15371)

* Fix default CloudCompute for flows
* Unit test added

src/lightning_app/CHANGELOG.md

@@ -38,6 +38,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed a bug where the upload files endpoint would raise an error when running locally ([#14924](https://github.com/Lightning-AI/lightning/pull/14924))
 - Fixed BYOC cluster region selector -> hiding it from help since only us-east-1 has been tested and is recommended ([#15277]https://github.com/Lightning-AI/lightning/pull/15277)
 - Fixed a bug when launching an app on multiple clusters ([#15226](https://github.com/Lightning-AI/lightning/pull/15226))
+- Fixed a bug with a default CloudCompute for Lightning flows ([#15371](https://github.com/Lightning-AI/lightning/pull/15371))
 
 ## [0.6.2] - 2022-09-21
 

src/lightning_app/core/app.py

@@ -103,7 +103,7 @@ class LightningApp:
 
         _validate_root_flow(root)
         self._root = root
-        self.flow_cloud_compute = flow_cloud_compute or lightning_app.CloudCompute()
+        self.flow_cloud_compute = flow_cloud_compute or lightning_app.CloudCompute(name="flow-lite")
 
         # queues definition.
         self.delta_queue: Optional[BaseQueue] = None

tests/tests_app/runners/test_cloud.py

@@ -68,6 +68,28 @@ class WorkWithTwoDrives(LightningWork):
         pass
 
 
+def get_cloud_runtime_request_body(**kwargs) -> "Body8":
+    default_request_body = dict(
+        app_entrypoint_file=mock.ANY,
+        enable_app_server=True,
+        flow_servers=[],
+        image_spec=None,
+        works=[],
+        local_source=True,
+        dependency_cache_key=mock.ANY,
+        user_requested_flow_compute_config=V1UserRequestedFlowComputeConfig(
+            name="flow-lite",
+            preemptible=False,
+            shm_size=0,
+        ),
+    )
+
+    if kwargs.get("user_requested_flow_compute_config") is not None:
+        default_request_body["user_requested_flow_compute_config"] = kwargs["user_requested_flow_compute_config"]
+
+    return Body8(**default_request_body)
+
+
 class TestAppCreationClient:
     """Testing the calls made using GridRestClient to create the app."""
 
@@ -138,8 +160,9 @@ class TestAppCreationClient:
             body=V1ProjectClusterBinding(cluster_id=new_cluster, project_id="default-project-id"),
         )
 
+    @pytest.mark.parametrize("flow_cloud_compute", [None, CloudCompute(name="t2.medium")])
     @mock.patch("lightning_app.runners.backends.cloud.LightningClient", mock.MagicMock())
-    def test_run_with_custom_flow_compute_config(self, monkeypatch):
+    def test_run_with_default_flow_compute_config(self, monkeypatch, flow_cloud_compute):
         mock_client = mock.MagicMock()
         mock_client.projects_service_list_memberships.return_value = V1ListMembershipsResponse(
             memberships=[V1Membership(name="test-project", project_id="test-project-id")]
@@ -155,30 +178,30 @@ class TestAppCreationClient:
         cloud_backend.client = mock_client
         monkeypatch.setattr(backends, "CloudBackend", mock.MagicMock(return_value=cloud_backend))
         monkeypatch.setattr(cloud, "LocalSourceCodeDir", mock.MagicMock())
-        app = mock.MagicMock()
-        app.flows = []
-        app.frontend = {}
-        app.flow_cloud_compute = CloudCompute(name="t2.medium")
+
+        dummy_flow = mock.MagicMock()
+        monkeypatch.setattr(dummy_flow, "run", lambda *args, **kwargs: None)
+        if flow_cloud_compute is None:
+            app = LightningApp(dummy_flow)
+        else:
+            app = LightningApp(dummy_flow, flow_cloud_compute=flow_cloud_compute)
+
         cloud_runtime = cloud.CloudRuntime(app=app, entrypoint_file="entrypoint.py")
         cloud_runtime._check_uploaded_folder = mock.MagicMock()
 
         monkeypatch.setattr(Path, "is_file", lambda *args, **kwargs: False)
         monkeypatch.setattr(cloud, "Path", Path)
         cloud_runtime.dispatch()
-        body = Body8(
-            app_entrypoint_file=mock.ANY,
-            enable_app_server=True,
-            flow_servers=[],
-            image_spec=None,
-            works=[],
-            local_source=True,
-            dependency_cache_key=mock.ANY,
-            user_requested_flow_compute_config=V1UserRequestedFlowComputeConfig(
-                name="t2.medium",
+
+        user_requested_flow_compute_config = None
+        if flow_cloud_compute is not None:
+            user_requested_flow_compute_config = V1UserRequestedFlowComputeConfig(
+                name=flow_cloud_compute.name,
                 preemptible=False,
                 shm_size=0,
-            ),
-        )
+            )
+
+        body = get_cloud_runtime_request_body(user_requested_flow_compute_config=user_requested_flow_compute_config)
         cloud_runtime.backend.client.lightningapp_v2_service_create_lightningapp_release.assert_called_once_with(
             project_id="test-project-id", app_id=mock.ANY, body=body
         )