`prefect.server.api.server`

Defines the Prefect REST API FastAPI app.

Functions

`validation_exception_handler`

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

Provide a detailed message for request validation errors.

`integrity_exception_handler`

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

Capture database integrity errors.

`is_client_retryable_exception`

is_client_retryable_exception(exc: Exception) -> bool

`replace_placeholder_string_in_files`

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`

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

`custom_internal_exception_handler`

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`

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

Return 404 status code on object not found exceptions.

`create_api_app`

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`

create_ui_app(ephemeral: bool) -> FastAPI

`create_app`

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

`RequestLimitMiddleware`

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`

Methods:

`address`

address(self) -> str

`api_url`

api_url(self) -> str

`find_available_port`

find_available_port(self) -> int

`is_port_available`

is_port_available(port: int) -> bool

`start`

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`

stop(self) -> None

​prefect.server.api.server

​Functions

​validation_exception_handler

​integrity_exception_handler

​is_client_retryable_exception

​replace_placeholder_string_in_files

​copy_directory

​custom_internal_exception_handler

​prefect_object_not_found_exception_handler

​create_api_app

​create_ui_app

​create_app

​Classes

​RequestLimitMiddleware

​SubprocessASGIServer

​address

​api_url

​find_available_port

​is_port_available

​start

​stop