prefect.server.api.server

Defines the Prefect REST API FastAPI app.

Functions

validation_exception_handler ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L199" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

validation_exception_handler(request: Request, exc: RequestValidationError) -> JSONResponse

Provide a detailed message for request validation errors.

integrity_exception_handler ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L215" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

integrity_exception_handler(request: Request, exc: Exception) -> JSONResponse

Capture database integrity errors.

is_client_retryable_exception ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L230" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

is_client_retryable_exception(exc: Exception) -> bool

replace_placeholder_string_in_files ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L259" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

replace_placeholder_string_in_files(directory: str, placeholder: str, replacement: str, allowed_extensions: list[str] | None = None) -> None

Recursively loops through all files in the given directory and replaces a placeholder string.

copy_directory ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L286" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

copy_directory(directory: str, path: str) -> None

custom_internal_exception_handler ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L306" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

custom_internal_exception_handler(request: Request, exc: Exception) -> JSONResponse

Log a detailed exception for internal server errors before returning.

Send 503 for errors clients can retry on.

prefect_object_not_found_exception_handler ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L331" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

prefect_object_not_found_exception_handler(request: Request, exc: ObjectNotFoundError) -> JSONResponse

Return 404 status code on object not found exceptions.

create_api_app ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L343" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

create_api_app(dependencies: list[Any] | None = None, health_check_path: str = '/health', version_check_path: str = '/version', fast_api_app_kwargs: dict[str, Any] | None = None, final: bool = False, ignore_cache: bool = False) -> FastAPI

Create a FastAPI app that includes the Prefect REST API

Args:

• dependencies: a list of global dependencies to add to each Prefect REST API router
• health_check_path: the health check route path
• fast_api_app_kwargs: kwargs to pass to the FastAPI constructor
• final: whether this will be the last instance of the Prefect server to be created in this process, so that additional optimizations may be applied
• ignore_cache: if set, a new app will be created even if the settings and fast_api_app_kwargs match an existing app in the cache

Returns:

• a FastAPI app that serves the Prefect REST API

create_ui_app ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L479" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

create_ui_app(ephemeral: bool) -> FastAPI

create_app ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L663" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

create_app(settings: Optional[prefect.settings.Settings] = None, ephemeral: bool = False, webserver_only: bool = False, final: bool = False, ignore_cache: bool = False) -> FastAPI

Create a FastAPI app that includes the Prefect REST API and UI

Args:

• settings: The settings to use to create the app. If not set, settings are pulled from the context.
• ephemeral: If set, the application will be treated as ephemeral. The UI and services will be disabled.
• webserver_only: If set, the webserver and UI will be available but all background services will be disabled.
• final: whether this will be the last instance of the Prefect server to be created in this process, so that additional optimizations may be applied
• ignore_cache: If set, a new application will be created even if the settings match. Otherwise, an application is returned from the cache.

Classes

SPAStaticFiles ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L166" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Implementation of StaticFiles for serving single page applications.

Adds get_response handling to ensure that when a resource isn't found the application still returns the index.

Methods:

get_response ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L174" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_response(self, path: str, scope: Any) -> Response

RequestLimitMiddleware ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L181" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

A middleware that limits the number of concurrent requests handled by the API.

This is a blunt tool for limiting SQLite concurrent writes which will cause failures at high volume. Ideally, we would only apply the limit to routes that perform writes.

SubprocessASGIServer ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L867" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Methods:

address ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L911" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

address(self) -> str

api_url ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L915" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

api_url(self) -> str

find_available_port ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L890" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

find_available_port(self) -> int

is_port_available ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L900" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

is_port_available(port: int) -> bool

start ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L918" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

start(self, timeout: Optional[int] = None) -> None

Start the server in a separate process. Safe to call multiple times; only starts the server once.

Args:

• timeout: The maximum time to wait for the server to start

stop ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/server/api/server.py#L1012" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

stop(self) -> None