[App] Support for headless apps

.azure/app-cloud-e2e.yml

@@ -93,7 +93,7 @@ jobs:
         'App: custom_work_dependencies':
           name: "custom_work_dependencies"
           dir: "local"
-    timeoutInMinutes: "10"
+    timeoutInMinutes: "15"
     cancelTimeoutInMinutes: "1"
     # values: https://docs.microsoft.com/en-us/azure/devops/pipelines/process/phases?view=azure-devops&tabs=yaml#workspace
     workspace:

requirements/app/base.txt

@@ -1,4 +1,4 @@
-lightning-cloud>=0.5.11
+lightning-cloud>=0.5.12
 packaging
 typing-extensions>=4.0.0, <=4.4.0
 deepdiff>=5.7.0, <=5.8.1

src/lightning_app/CHANGELOG.md

@@ -19,8 +19,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 ### Changed
 
 - The `MultiNode` components now warn the user when running with `num_nodes > 1` locally ([#15806](https://github.com/Lightning-AI/lightning/pull/15806))
+
 - Cluster creation and deletion now waits by default [#15458](https://github.com/Lightning-AI/lightning/pull/15458)
 
+- Running an app without a UI locally no longer opens the browser ([#15875](https://github.com/Lightning-AI/lightning/pull/15875))
+
+- Apps without UIs no longer activate the "Open App" button when running in the cloud ([#15875](https://github.com/Lightning-AI/lightning/pull/15875))
+
 
 ### Deprecated
 

src/lightning_app/cli/lightning_cli.py

@@ -2,13 +2,13 @@
 import shutil
 import sys
 from pathlib import Path
-from typing import Any, Tuple, Union
+from typing import Tuple, Union
 
 import arrow
 import click
 import inquirer
 import rich
-from lightning_cloud.openapi import Externalv1LightningappInstance, V1LightningappInstanceState, V1LightningworkState
+from lightning_cloud.openapi import V1LightningappInstanceState, V1LightningworkState
 from lightning_cloud.openapi.rest import ApiException
 from lightning_utilities.core.imports import RequirementCache
 from requests.exceptions import ConnectionError
@@ -48,15 +48,6 @@
 logger = Logger(__name__)
 
 
-def get_app_url(runtime_type: RuntimeType, *args: Any, need_credits: bool = False) -> str:
-    if runtime_type == RuntimeType.CLOUD:
-        lit_app: Externalv1LightningappInstance = args[0]
-        action = "?action=add_credits" if need_credits else ""
-        return f"{get_lightning_cloud_url()}/me/apps/{lit_app.id}{action}"
-    else:
-        return os.getenv("APP_SERVER_HOST", "http://127.0.0.1:7501/view")
-
-
 def main() -> None:
     # Check environment and versions if not in the cloud
     if "LIGHTNING_APP_STATE_URL" not in os.environ:
@@ -269,10 +260,6 @@ def _run_app(
 
     secrets = _format_input_env_variables(secret)
 
-    def on_before_run(*args: Any, **kwargs: Any) -> None:
-        if open_ui and not without_server:
-            click.launch(get_app_url(runtime_type, *args, **kwargs))
-
     click.echo("Your Lightning App is starting. This won't take long.")
 
     # TODO: Fixme when Grid utilities are available.
@@ -284,7 +271,7 @@ def on_before_run(*args: Any, **kwargs: Any) -> None:
         start_server=not without_server,
         no_cache=no_cache,
         blocking=blocking,
-        on_before_run=on_before_run,
+        open_ui=open_ui,
         name=name,
         env_vars=env_vars,
         secrets=secrets,

src/lightning_app/core/app.py

@@ -29,6 +29,8 @@
 from lightning_app.utilities import frontend
 from lightning_app.utilities.app_helpers import (
     _delta_to_app_state_delta,
+    _handle_is_headless,
+    _is_headless,
     _LightningAppRef,
     _should_dispatch_app,
     Logger,
@@ -148,6 +150,8 @@ def __init__(
 
         self._update_layout()
 
+        self.is_headless: Optional[bool] = None
+
         self._original_state = None
         self._last_state = self.state
         self.state_accumulate_wait = STATE_ACCUMULATE_WAIT
@@ -412,6 +416,7 @@ def run_once(self):
             self.backend.update_work_statuses(self.works)
 
         self._update_layout()
+        self._update_is_headless()
         self.maybe_apply_changes()
 
         if self.checkpointing and self._should_snapshot():
@@ -510,6 +515,16 @@ def _update_layout(self) -> None:
             layout = _collect_layout(self, component)
             component._layout = layout
 
+    def _update_is_headless(self) -> None:
+        is_headless = _is_headless(self)
+
+        # If `is_headless` changed, handle it.
+        # This ensures support for apps which dynamically add a UI at runtime.
+        if self.is_headless != is_headless:
+            self.is_headless = is_headless
+
+            _handle_is_headless(self)
+
     def _apply_restarting(self) -> bool:
         self._reset_original_state()
         # apply stage after restoring the original state.

src/lightning_app/runners/cloud.py

@@ -7,8 +7,9 @@
 from dataclasses import dataclass
 from pathlib import Path
 from textwrap import dedent
-from typing import Any, Callable, List, Optional, Union
+from typing import Any, List, Optional, Union
 
+import click
 from lightning_cloud.openapi import (
     Body3,
     Body4,
@@ -56,12 +57,13 @@
     ENABLE_MULTIPLE_WORKS_IN_NON_DEFAULT_CONTAINER,
     ENABLE_PULLING_STATE_ENDPOINT,
     ENABLE_PUSHING_STATE_ENDPOINT,
+    get_lightning_cloud_url,
 )
 from lightning_app.runners.backends.cloud import CloudBackend
 from lightning_app.runners.runtime import Runtime
 from lightning_app.source_code import LocalSourceCodeDir
 from lightning_app.storage import Drive, Mount
-from lightning_app.utilities.app_helpers import Logger
+from lightning_app.utilities.app_helpers import _is_headless, Logger
 from lightning_app.utilities.cloud import _get_project
 from lightning_app.utilities.dependency_caching import get_hash
 from lightning_app.utilities.load_app import load_app_from_file
@@ -192,9 +194,9 @@ class CloudRuntime(Runtime):
 
     def dispatch(
         self,
-        on_before_run: Optional[Callable] = None,
         name: str = "",
         cluster_id: str = None,
+        open_ui: bool = True,
         **kwargs: Any,
     ) -> None:
         """Method to dispatch and run the :class:`~lightning_app.core.app.LightningApp` in the cloud."""
@@ -405,6 +407,7 @@ def dispatch(
                 local_source=True,
                 dependency_cache_key=app_spec.dependency_cache_key,
                 user_requested_flow_compute_config=app_spec.user_requested_flow_compute_config,
+                is_headless=_is_headless(self.app),
             )
 
             # create / upload the new app release
@@ -464,12 +467,12 @@ def dispatch(
             logger.error(e.body)
             sys.exit(1)
 
-        if on_before_run:
-            on_before_run(lightning_app_instance, need_credits=not has_sufficient_credits)
-
         if lightning_app_instance.status.phase == V1LightningappInstanceState.FAILED:
             raise RuntimeError("Failed to create the application. Cannot upload the source code.")
 
+        if open_ui:
+            click.launch(self._get_app_url(lightning_app_instance, not has_sufficient_credits))
+
         if cleanup_handle:
             cleanup_handle()
 
@@ -538,6 +541,11 @@ def load_app_from_file(cls, filepath: str) -> "LightningApp":
             app = LightningApp(EmptyFlow())
         return app
 
+    @staticmethod
+    def _get_app_url(lightning_app_instance: Externalv1LightningappInstance, need_credits: bool = False) -> str:
+        action = "?action=add_credits" if need_credits else ""
+        return f"{get_lightning_cloud_url()}/me/apps/{lightning_app_instance.id}{action}"
+
 
 def _create_mount_drive_spec(work_name: str, mount: Mount) -> V1LightningworkDrives:
     if mount.protocol == "s3://":

src/lightning_app/runners/multiprocess.py

@@ -1,15 +1,17 @@
 import multiprocessing
 import os
 from dataclasses import dataclass
-from typing import Any, Callable, Optional, Union
+from typing import Any, Union
+
+import click
 
 from lightning_app.api.http_methods import _add_tags_to_api, _validate_api
 from lightning_app.core.api import start_server
 from lightning_app.core.constants import APP_SERVER_IN_CLOUD
 from lightning_app.runners.backends import Backend
 from lightning_app.runners.runtime import Runtime
 from lightning_app.storage.orchestrator import StorageOrchestrator
-from lightning_app.utilities.app_helpers import is_overridden
+from lightning_app.utilities.app_helpers import _is_headless, is_overridden
 from lightning_app.utilities.commands.base import _commands_to_api, _prepare_commands
 from lightning_app.utilities.component import _set_flow_context, _set_frontend_context
 from lightning_app.utilities.load_app import extract_metadata_from_app
@@ -29,7 +31,7 @@ class MultiProcessRuntime(Runtime):
     backend: Union[str, Backend] = "multiprocessing"
     _has_triggered_termination: bool = False
 
-    def dispatch(self, *args: Any, on_before_run: Optional[Callable] = None, **kwargs: Any):
+    def dispatch(self, *args: Any, open_ui: bool = True, **kwargs: Any):
         """Method to dispatch and run the LightningApp."""
         try:
             _set_flow_context()
@@ -101,8 +103,8 @@ def dispatch(self, *args: Any, on_before_run: Optional[Callable] = None, **kwarg
                 # wait for server to be ready
                 has_started_queue.get()
 
-            if on_before_run:
-                on_before_run(self, self.app)
+            if open_ui and not _is_headless(self.app):
+                click.launch(self._get_app_url())
 
             # Connect the runtime to the application.
             self.app.connect(self)
@@ -125,3 +127,7 @@ def terminate(self):
             for port in ports:
                 disable_port(port)
         super().terminate()
+
+    @staticmethod
+    def _get_app_url() -> str:
+        return os.getenv("APP_SERVER_HOST", "http://127.0.0.1:7501/view")

src/lightning_app/runners/runtime.py

@@ -4,7 +4,7 @@
 from dataclasses import dataclass, field
 from pathlib import Path
 from threading import Thread
-from typing import Any, Callable, Dict, List, Optional, Type, TYPE_CHECKING, Union
+from typing import Any, Dict, List, Optional, Type, TYPE_CHECKING, Union
 
 from lightning_app import LightningApp, LightningFlow
 from lightning_app.core.constants import APP_SERVER_HOST, APP_SERVER_PORT
@@ -28,7 +28,7 @@ def dispatch(
     host: str = APP_SERVER_HOST,
     port: int = APP_SERVER_PORT,
     blocking: bool = True,
-    on_before_run: Optional[Callable] = None,
+    open_ui: bool = True,
     name: str = "",
     env_vars: Dict[str, str] = None,
     secrets: Dict[str, str] = None,
@@ -45,7 +45,7 @@ def dispatch(
         host: Server host address
         port: Server port
         blocking: Whether for the wait for the UI to start running.
-        on_before_run: Callable to be executed before run.
+        open_ui: Whether to open the UI in the browser.
         name: Name of app execution
         env_vars: Dict of env variables to be set on the app
         secrets: Dict of secrets to be passed as environment variables to the app
@@ -82,7 +82,7 @@ def dispatch(
     )
     # a cloud dispatcher will return the result while local
     # dispatchers will be running the app in the main process
-    return runtime.dispatch(on_before_run=on_before_run, name=name, no_cache=no_cache, cluster_id=cluster_id)
+    return runtime.dispatch(open_ui=open_ui, name=name, no_cache=no_cache, cluster_id=cluster_id)
 
 
 @dataclass

src/lightning_app/runners/singleprocess.py

@@ -1,9 +1,13 @@
 import multiprocessing as mp
-from typing import Any, Callable, Optional
+import os
+from typing import Any
+
+import click
 
 from lightning_app.core.api import start_server
 from lightning_app.core.queues import QueuingSystem
 from lightning_app.runners.runtime import Runtime
+from lightning_app.utilities.app_helpers import _is_headless
 from lightning_app.utilities.load_app import extract_metadata_from_app
 
 
@@ -13,7 +17,7 @@ class SingleProcessRuntime(Runtime):
     def __post_init__(self):
         pass
 
-    def dispatch(self, *args, on_before_run: Optional[Callable] = None, **kwargs: Any):
+    def dispatch(self, *args, open_ui: bool = True, **kwargs: Any):
         """Method to dispatch and run the LightningApp."""
         queue = QueuingSystem.SINGLEPROCESS
 
@@ -42,8 +46,8 @@ def dispatch(self, *args, on_before_run: Optional[Callable] = None, **kwargs: An
             # wait for server to be ready.
             has_started_queue.get()
 
-        if on_before_run:
-            on_before_run()
+        if open_ui and not _is_headless(self.app):
+            click.launch(self._get_app_url())
 
         try:
             self.app._run()
@@ -52,3 +56,7 @@ def dispatch(self, *args, on_before_run: Optional[Callable] = None, **kwargs: An
             raise
         finally:
             self.terminate()
+
+    @staticmethod
+    def _get_app_url() -> str:
+        return os.getenv("APP_SERVER_HOST", "http://127.0.0.1:7501/view")

src/lightning_app/testing/testing.py

@@ -394,15 +394,18 @@ def run_app_in_cloud(
             process = Process(target=_print_logs, kwargs={"app_id": app_id})
             process.start()
 
-        while True:
-            try:
-                with admin_page.context.expect_page() as page_catcher:
-                    admin_page.locator('[data-cy="open"]').click()
-                view_page = page_catcher.value
-                view_page.wait_for_load_state(timeout=0)
-                break
-            except (playwright._impl._api_types.Error, playwright._impl._api_types.TimeoutError):
-                pass
+        if not app.spec.is_headless:
+            while True:
+                try:
+                    with admin_page.context.expect_page() as page_catcher:
+                        admin_page.locator('[data-cy="open"]').click()
+                    view_page = page_catcher.value
+                    view_page.wait_for_load_state(timeout=0)
+                    break
+                except (playwright._impl._api_types.Error, playwright._impl._api_types.TimeoutError):
+                    pass
+        else:
+            view_page = None
 
         # TODO: is re-creating this redundant?
         lit_apps = [