ServeStreamlit

class lightning.app.components.serve.streamlit.ServeStreamlit(*args, **kwargs)

Bases: LightningWork, ABC

The ServeStreamlit work allows you to use streamlit from a work.

You can optionally build a model in the build_model hook, which will only be called once per session.

LightningWork, or Work in short, is a building block for long-running jobs.

The LightningApp runs its LightningFlow component within an infinite loop and track the LightningWork status update.

Use LightningWork for third-party services or for launching heavy jobs such as downloading data, training or serving a model.

Each LightningWork is running in its own independent process. Works are self-isolated from the rest, e.g any state changes happening within the work will be reflected within the flow but not the other way around.

Parameters

• parallel – Whether to run in parallel mode or not. When False, the flow waits for the work to finish.

• cache_calls – Whether the run method should cache its input arguments and not run again when provided with the same arguments in subsequent calls.

• raise_exception – Whether to re-raise an exception in the flow when raised from within the work run method.

• host – Bind socket to this host

• port – Bind socket to this port. Be default, this is None and should be called within your run method.

• local_build_config – The local BuildConfig isn’t used until Lightning supports DockerRuntime.

• cloud_build_config – The cloud BuildConfig enables user to easily configure machine before running this work.

• run_once – Deprecated in favor of cache_calls. This will be removed soon.

• start_with_flow – Whether the work should be started at the same time as the root flow. Only applies to works defined in __init__.

Learn More About Lightning Work Inner Workings

The Lightning Work inner workings.

Learn more Lightning Work.

Basic

build_model()

Optionally override to instantiate and return your model.

The model will be accessible under self.model.

Return type

Any

configure_layout()

Configure the UI of this LightningWork.

You can either :rtype: str

1. Return a single Frontend object to serve a user interface for this Work.

2. Return a string containing a URL to act as the user interface for this Work.

3. Return None to indicate that this Work doesn’t currently have a user interface.

Example: Serve a static directory (with at least a file index.html inside).

from lightning.app.frontend import StaticWebFrontend


class Work(LightningWork):
    def configure_layout(self):
        return StaticWebFrontend("path/to/folder/to/serve")

Example: Arrange the UI of my children in tabs (default UI by Lightning).

class Work(LightningWork):
    def configure_layout(self):
        return [
            dict(name="First Tab", content=self.child0),
            dict(name="Second Tab", content=self.child1),
            dict(name="Lightning", content="https://lightning.ai"),
        ]

If you don’t implement configure_layout, Lightning will use self.url.

Note

This hook gets called at the time of app creation and then again as part of the loop. If desired, a returned URL can depend on the state. This is not the case if the work returns a Frontend. These need to be provided at the time of app creation in order for the runtime to start the server.

on_exit()

Override this hook to add your logic when the work is exiting.

Note: This hook is not guaranteed to be called when running in the cloud.

Return type

None

abstract render()

Override with your streamlit render function.

Return type

None

run()

Override to add your own logic.

Raises

LightningPlatformException – If resource exceeds platform quotas or other constraints.

Return type

None