[App] Resolve inconsistency where the flow.flows property isn't recursive leading to flow overrides (#15466)

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Author: tchaton

src/lightning_app/CHANGELOG.md

@@ -19,7 +19,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 
--
+- Changed the `flow.flows` to be recursive wont to align the behavior with the `flow.works` ([#15466](https://github.com/Lightning-AI/lightning/pull/15466))
 
 -
 
@@ -46,6 +46,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 
+
 - Fixed writing app name and id in connect.txt file for the command CLI ([#15443](https://github.com/Lightning-AI/lightning/pull/15443))
 
 -

src/lightning_app/cli/commands/app_commands.py

@@ -94,6 +94,7 @@ def _handle_command_without_client(command: str, metadata: Dict, url: str) -> No
     query_parameters = "&".join(provided_params)
     resp = requests.post(url + f"/command/{command}?{query_parameters}")
     assert resp.status_code == 200, resp.json()
+    print(resp.json())
 
 
 def _handle_command_with_client(command: str, metadata: Dict, app_name: str, app_id: Optional[str], url: str):

src/lightning_app/core/app.py

@@ -284,7 +284,7 @@ def check_error_queue(self) -> None:
     @property
     def flows(self) -> List["LightningFlow"]:
         """Returns all the flows defined within this application."""
-        return [self.root] + self.root.get_all_children()
+        return list(self.root.flows.values())
 
     @property
     def works(self) -> List[LightningWork]:

src/lightning_app/core/flow.py

@@ -207,22 +207,19 @@ def _attach_backend(flow: "LightningFlow", backend):
         """Attach the backend to all flows and its children."""
         flow._backend = backend
 
-        for child_flow in flow.flows.values():
-            LightningFlow._attach_backend(child_flow, backend)
-
-        for struct_name in flow._structures:
-            structure = getattr(flow, struct_name)
-            for flow in structure.flows:
-                LightningFlow._attach_backend(flow, backend)
-            for work in structure.works:
-                backend._wrap_run_method(_LightningAppRef().get_current(), work)
-                work._backend = backend
-
         for name in flow._structures:
             getattr(flow, name)._backend = backend
 
-        for work in flow.works(recurse=False):
-            backend._wrap_run_method(_LightningAppRef().get_current(), work)
+        for child_flow in flow.flows.values():
+            child_flow._backend = backend
+            for name in child_flow._structures:
+                getattr(child_flow, name)._backend = backend
+
+        app = _LightningAppRef().get_current()
+
+        for child_work in flow.works():
+            child_work._backend = backend
+            backend._wrap_run_method(app, child_work)
 
     def __getattr__(self, item):
         if item in self.__dict__.get("_paths", {}):
@@ -274,12 +271,15 @@ def state_with_changes(self):
         }
 
     @property
-    def flows(self):
+    def flows(self) -> Dict[str, "LightningFlow"]:
         """Return its children LightningFlow."""
-        flows = {el: getattr(self, el) for el in sorted(self._flows)}
+        flows = {}
+        for el in sorted(self._flows):
+            flow = getattr(self, el)
+            flows[flow.name] = flow
+            flows.update(flow.flows)
         for struct_name in sorted(self._structures):
-            for flow in getattr(self, struct_name).flows:
-                flows[flow.name] = flow
+            flows.update(getattr(self, struct_name).flows)
         return flows
 
     def works(self, recurse: bool = True) -> List[LightningWork]:
@@ -297,28 +297,7 @@ def works(self, recurse: bool = True) -> List[LightningWork]:
 
     def named_works(self, recurse: bool = True) -> List[Tuple[str, LightningWork]]:
         """Return its :class:`~lightning_app.core.work.LightningWork` with their names."""
-        named_works = [(el, getattr(self, el)) for el in sorted(self._works)]
-        if not recurse:
-            return named_works
-        for child_name in sorted(self._flows):
-            for w in getattr(self, child_name).works(recurse=recurse):
-                named_works.append(w)
-        for struct_name in sorted(self._structures):
-            for w in getattr(self, struct_name).works:
-                named_works.append((w.name, w))
-        return named_works
-
-    def get_all_children_(self, children):
-        sorted_children = sorted(self._flows)
-        children.extend([getattr(self, el) for el in sorted_children])
-        for child in sorted_children:
-            getattr(self, child).get_all_children_(children)
-        return children
-
-    def get_all_children(self):
-        children = []
-        self.get_all_children_(children)
-        return children
+        return [(w.name, w) for w in self.works(recurse=recurse)]
 
     def set_state(self, provided_state: Dict, recurse: bool = True) -> None:
         """Method to set the state to this LightningFlow, its children and

src/lightning_app/core/queues.py

@@ -234,6 +234,18 @@ def __init__(
         self.redis = redis.Redis(host=host, port=port, password=password)
 
     def put(self, item: Any) -> None:
+        from lightning_app import LightningWork
+
+        is_work = isinstance(item, LightningWork)
+
+        # TODO: Be careful to handle with a lock if another thread needs
+        # to access the work backend one day.
+        # The backend isn't picklable
+        # Raises a TypeError: cannot pickle '_thread.RLock' object
+        if is_work:
+            backend = item._backend
+            item._backend = None
+
         value = pickle.dumps(item)
         queue_len = self.length()
         if queue_len >= WARNING_QUEUE_SIZE:
@@ -252,6 +264,10 @@ def put(self, item: Any) -> None:
                 "If the issue persists, please contact [email protected]"
             )
 
+        # The backend isn't pickable.
+        if is_work:
+            item._backend = backend
+
     def get(self, timeout: int = None):
         """Returns the left most element of the redis queue.
 

src/lightning_app/structures/dict.py

@@ -86,12 +86,17 @@ def works(self):
     @property
     def flows(self):
         from lightning_app import LightningFlow
-
-        flows = []
-        for flow in [item for item in self.values() if isinstance(item, LightningFlow)]:
-            flows.append(flow)
-            for child_flow in flow.flows:
-                flows.append(child_flow)
+        from lightning_app.structures import Dict, List
+
+        flows = {}
+        for item in self.values():
+            if isinstance(item, LightningFlow):
+                flows[item.name] = item
+                for child_flow in item.flows.values():
+                    flows[child_flow.name] = child_flow
+            if isinstance(item, (Dict, List)):
+                for child_flow in item.flows.values():
+                    flows[child_flow.name] = child_flow
         return flows
 
     @property

src/lightning_app/structures/list.py

@@ -89,12 +89,17 @@ def works(self):
     @property
     def flows(self):
         from lightning_app import LightningFlow
-
-        flows = []
-        for flow in [item for item in self if isinstance(item, LightningFlow)]:
-            flows.append(flow)
-            for child_flow in flow.flows:
-                flows.append(child_flow)
+        from lightning_app.structures import Dict, List
+
+        flows = {}
+        for item in self:
+            if isinstance(item, LightningFlow):
+                flows[item.name] = item
+                for child_flow in item.flows.values():
+                    flows[child_flow.name] = child_flow
+            if isinstance(item, (Dict, List)):
+                for child_flow in item.flows.values():
+                    flows[child_flow.name] = child_flow
         return flows
 
     @property

src/lightning_app/utilities/app_helpers.py

@@ -267,10 +267,12 @@ def _set_child_name(component: "Component", child: "Component", new_name: str) -
 
     # the name changed, so recursively update the names of the children of this child
     if isinstance(child, lightning_app.core.LightningFlow):
-        for n, c in child.flows.items():
+        for n in child._flows:
+            c = getattr(child, n)
+            _set_child_name(child, c, n)
+        for n in child._works:
+            c = getattr(child, n)
             _set_child_name(child, c, n)
-        for n, w in child.named_works(recurse=False):
-            _set_child_name(child, w, n)
         for n in child._structures:
             s = getattr(child, n)
             _set_child_name(child, s, n)

src/lightning_app/utilities/tree.py

@@ -17,16 +17,6 @@ def breadth_first(root: "Component", types: Type["ComponentTuple"] = None):
     yield from _BreadthFirstVisitor(root, types)
 
 
-def depth_first(root: "Component", types: Type["ComponentTuple"] = None):
-    """Returns a generator that walks through the tree of components depth-first.
-
-    Arguments:
-        root: The root component of the tree
-        types: If provided, only the component types in this list will be visited.
-    """
-    yield from _DepthFirstVisitor(root, types)
-
-
 class _BreadthFirstVisitor:
     def __init__(self, root: "Component", types: Type["ComponentTuple"] = None) -> None:
         self.queue = [root]
@@ -36,11 +26,23 @@ def __iter__(self):
         return self
 
     def __next__(self):
+        from lightning_app.structures import Dict
+
         while self.queue:
             component = self.queue.pop(0)
 
             if isinstance(component, lightning_app.LightningFlow):
-                self.queue += list(component.flows.values())
+                components = [getattr(component, el) for el in sorted(component._flows)]
+                for struct_name in sorted(component._structures):
+                    structure = getattr(component, struct_name)
+                    if isinstance(structure, Dict):
+                        values = sorted(structure.items(), key=lambda x: x[0])
+                    else:
+                        values = sorted(((v.name, v) for v in structure), key=lambda x: x[0])
+                    for _, value in values:
+                        if isinstance(value, lightning_app.LightningFlow):
+                            components.append(value)
+                self.queue += components
                 self.queue += component.works(recurse=False)
 
             if any(isinstance(component, t) for t in self.types):

tests/tests_app/core/lightning_app/test_configure_layout.py

@@ -126,9 +126,9 @@ def __init__(self):
     root = TestContentComponent()
     LightningApp(root)
     assert root._layout == [
-        dict(name="component0", content="root.component0"),
-        dict(name="component1", content="root.component1"),
-        dict(name="component2", content="root.component2"),
+        dict(name="root.component0", content="root.component0"),
+        dict(name="root.component1", content="root.component1"),
+        dict(name="root.component2", content="root.component2"),
     ]