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"""
Rest gateway provider.
"""
import asyncio
import logging
import typing
import uvicorn
from starlette import applications, exceptions
from starlette import requests as reqmod
from starlette import responses as respmod
from starlette import routing
import forml
from forml import io, runtime, setup
from forml.io import asset, layout
LOGGER = logging.getLogger(__name__)
class Apply(routing.Route):
"""Application endpoint route."""
PATH = '/{application:str}'
DEFAULT_ENCODING = 'application/octet-stream'
INSTANCE_HEADER = 'x-forml-instance'
def __init__(self, handler: typing.Callable[[str, layout.Request], typing.Awaitable[layout.Response]]):
super().__init__(self.PATH, self.__endpoint, methods=['POST'])
self.__handler: typing.Callable[[str, layout.Request], typing.Awaitable[layout.Response]] = handler
async def __endpoint(self, request: reqmod.Request) -> respmod.Response:
"""Route endpoint implementation.
Args:
request: Input instance.
Returns:
Output instance.
"""
application = request.path_params['application']
encoding = layout.Encoding.parse(request.headers.get('content-type', self.DEFAULT_ENCODING))[0]
accept = request.headers.get('accept')
if accept:
accept = layout.Encoding.parse(accept)
payload = await request.body()
try:
result = await self.__handler(application, layout.Request(payload, encoding, request.query_params, accept))
except layout.Encoding.Unsupported as err:
raise exceptions.HTTPException(status_code=415, detail=str(err))
except forml.MissingError as err:
raise exceptions.HTTPException(status_code=404, detail=str(err))
except forml.InvalidError as err:
raise exceptions.HTTPException(status_code=400, detail=str(err))
except forml.FailedError as err:
raise exceptions.HTTPException(status_code=500, detail=str(err))
return respmod.Response(
result.payload.data,
media_type=result.payload.encoding.header,
headers={self.INSTANCE_HEADER: str(result.instance).lower()},
)
class Stats(routing.Route):
"""Stats endpoint route."""
PATH = '/stats'
def __init__(self, handler: typing.Callable[[], typing.Awaitable[runtime.Stats]]):
super().__init__(self.PATH, self.__endpoint, methods=['GET'])
self.__handler: typing.Callable[[], typing.Awaitable[runtime.Stats]] = handler
async def __endpoint(self, _: reqmod.Request) -> respmod.Response:
"""Route endpoint implementation.
Returns:
Output instance.
"""
result = await self.__handler()
return respmod.Response(str(result), media_type='text/plain')
[docs]class Gateway(runtime.Gateway, alias='rest'):
"""Gateway(inventory: typing.Optional[asset.Inventory] = None, registry: typing.Optional[asset.Registry] = None, feeds: typing.Optional[io.Importer] = None, processes: typing.Optional[int] = None, loop: typing.Optional[asyncio.AbstractEventLoop] = None, server: typing.Callable[[applications.Starlette, ...], None] = uvicorn.run, **options)
Serving gateway implemented as a RESTful API.
The frontend provides the following HTTP endpoints:
================== ====== ==================================================================
Path Method Description
================== ====== ==================================================================
``/stats`` GET Retrieve the Engine-provided performance :class:`metrics report
<forml.runtime.Stats>`.
``/<application>`` POST Prediction request for the given :ref:`application <application>`.
The entire request *body* is passed to the :ref:`Engine <serving>`
as the :class:`layout.Payload.data <forml.io.layout.Payload>`
with the declared ``content-type`` indicated via the ``.encoding``
and any potential query parameters bundled within the ``.params``.
================== ====== ==================================================================
Args:
inventory: Inventory of applications to be served (default as per the platform
configuration).
registry: Model registry of project artifacts to be served (default as per the platform
configuration).
feeds: Feeds to be used for potential feature augmentation (default as per the platform
configuration).
processes: Process pool size for each model sandbox.
loop: Explicit event loop instance.
server: Serving loop main function accepting the provided `application instance
<https://www.starlette.io/applications/>`_ (defaults to `uvicorn.run
<https://www.uvicorn.org/deployment/#running-programmatically>`_).
options: Additional serving loop keyword arguments (i.e. `Uvicorn settings
<https://www.uvicorn.org/settings/>`_).
The provider can be enabled using the following :ref:`platform configuration <platform-config>`:
.. code-block:: toml
:caption: config.toml
[GATEWAY.http]
provider = "rest"
port = 8080
processes = 3
Important:
Select the ``rest`` :ref:`extras to install <install-extras>` ForML together with the
Starlette/Uvicorn support.
""" # pylint: disable=line-too-long # noqa: E501
setup.LOGGING.endswith = lambda _: False # temporal Uvicorn workaround until PR #1716 is merged
OPTIONS = {'headers': [('server', f'ForML {forml.__version__}')], 'log_config': setup.LOGGING}
"""Default server loop options."""
def __init__(
self,
inventory: typing.Optional[asset.Inventory] = None,
registry: typing.Optional[asset.Registry] = None,
feeds: typing.Optional[io.Importer] = None,
processes: typing.Optional[int] = None,
loop: typing.Optional[asyncio.AbstractEventLoop] = None,
server: typing.Callable[[applications.Starlette, ...], None] = uvicorn.run,
**options,
):
super().__init__(inventory, registry, feeds, processes=processes, loop=loop, server=server, options=options)
@classmethod
def run(
cls,
apply: typing.Callable[[str, layout.Request], typing.Awaitable[layout.Response]],
stats: typing.Callable[[], typing.Awaitable[runtime.Stats]],
**kwargs,
) -> None:
routes = [Apply(apply), Stats(stats)]
app = applications.Starlette(routes=routes, debug=False)
kwargs['server'](app, **(cls.OPTIONS | kwargs['options']))