from collections import OrderedDict, namedtuple
from datetime import datetime
from decimal import Decimal
import functools
import io
from pathlib import Path
from typing import Any, Callable, Mapping, Sequence, Union
import aiohttp
import aiohttp.web
from dateutil.tz import tzutc
from multidict import CIMultiDict
import json as modjson
from .auth import generate_signature
from .exceptions import BackendClientError, BackendAPIError
from .session import BaseSession, Session as SyncSession, AsyncSession
__all__ = [
'Request',
'Response',
]
RequestContent = Union[
bytes, bytearray, str,
aiohttp.StreamReader,
io.IOBase,
None,
]
'''
The type alias for the set of allowed types for request content.
'''
AttachedFile = namedtuple('AttachedFile', 'filename stream content_type')
'''
A struct that represents an attached file to the API request.
:param str filename: The name of file to store. It may include paths
and the server will create parent directories
if required.
:param Any stream: A file-like object that allows stream-reading bytes.
:param str content_type: The content type for the stream. For arbitrary
binary data, use "application/octet-stream".
'''
_default_request_timeout = aiohttp.ClientTimeout(
total=None, connect=None,
sock_connect=30.0, sock_read=None,
)
class ExtendedJSONEncoder(modjson.JSONEncoder):
def default(self, obj):
if isinstance(obj, Path):
return str(obj)
if isinstance(obj, Decimal):
return str(obj)
return super().default(obj)
[docs]class Request:
'''
The API request object.
'''
__slots__ = (
'config', 'session', 'method', 'path',
'date', 'headers', 'params', 'content_type',
'_content', '_attached_files',
'reporthook',
)
_allowed_methods = frozenset([
'GET', 'HEAD', 'POST',
'PUT', 'PATCH', 'DELETE',
'OPTIONS'])
def __init__(self, session: BaseSession,
method: str = 'GET',
path: str = None,
content: RequestContent = None, *,
content_type: str = None,
params: Mapping[str, str] = None,
reporthook: Callable = None) -> None:
'''
Initialize an API request.
:param BaseSession session: The session where this request is executed on.
:param str path: The query path. When performing requests, the version number
prefix will be automatically perpended if required.
:param RequestContent content: The API query body which will be encoded as
JSON.
:param str content_type: Explicitly set the content type. See also
:func:`Request.set_content`.
'''
self.session = session
self.config = session.config
self.method = method
if path.startswith('/'):
path = path[1:]
self.path = path
self.params = params
self.date = None
self.headers = CIMultiDict([
('User-Agent', self.config.user_agent),
('X-BackendAI-Version', self.config.version),
])
self._attached_files = None
self.set_content(content, content_type=content_type)
self.reporthook = reporthook
@property
def content(self) -> RequestContent:
'''
Retrieves the content in the original form.
Private codes should NOT use this as it incurs duplicate
encoding/decoding.
'''
return self._content
[docs] def set_content(self, value: RequestContent, *,
content_type: str = None):
'''
Sets the content of the request.
'''
assert self._attached_files is None, \
'cannot set content because you already attached files.'
guessed_content_type = 'application/octet-stream'
if value is None:
guessed_content_type = 'text/plain'
self._content = b''
elif isinstance(value, str):
guessed_content_type = 'text/plain'
self._content = value.encode('utf-8')
else:
guessed_content_type = 'application/octet-stream'
self._content = value
self.content_type = (content_type if content_type is not None
else guessed_content_type)
[docs] def set_json(self, value: object):
'''
A shortcut for set_content() with JSON objects.
'''
self.set_content(modjson.dumps(value, cls=ExtendedJSONEncoder),
content_type='application/json')
[docs] def attach_files(self, files: Sequence[AttachedFile]):
'''
Attach a list of files represented as AttachedFile.
'''
assert not self._content, 'content must be empty to attach files.'
self.content_type = 'multipart/form-data'
self._attached_files = files
def _sign(self, rel_url, access_key=None, secret_key=None, hash_type=None):
'''
Calculates the signature of the given request and adds the
Authorization HTTP header.
It should be called at the very end of request preparation and before
sending the request to the server.
'''
if access_key is None:
access_key = self.config.access_key
if secret_key is None:
secret_key = self.config.secret_key
if hash_type is None:
hash_type = self.config.hash_type
hdrs, _ = generate_signature(
self.method, self.config.version, self.config.endpoint,
self.date, str(rel_url), self.content_type, self._content,
access_key, secret_key, hash_type)
self.headers.update(hdrs)
def _pack_content(self):
if self._attached_files is not None:
data = aiohttp.FormData()
for f in self._attached_files:
data.add_field('src',
f.stream,
filename=f.filename,
content_type=f.content_type)
assert data.is_multipart, 'Failed to pack files as multipart.'
# Let aiohttp fill up the content-type header including
# multipart boundaries.
self.headers.pop('Content-Type', None)
return data
else:
return self._content
def _build_url(self):
base_url = self.config.endpoint.path.rstrip('/')
query_path = self.path.lstrip('/') if len(self.path) > 0 else ''
path = '{0}/{1}'.format(base_url, query_path)
url = self.config.endpoint.with_path(path)
if self.params:
url = url.with_query(self.params)
return url
# TODO: attach rate-limit information
[docs] def fetch(self, **kwargs) -> 'FetchContextManager':
'''
Sends the request to the server and reads the response.
You may use this method either with plain synchronous Session or
AsyncSession. Both the followings patterns are valid:
.. code-block:: python3
from ai.backend.client.request import Request
from ai.backend.client.session import Session
with Session() as sess:
rqst = Request(sess, 'GET', ...)
with rqst.fetch() as resp:
print(resp.text())
.. code-block:: python3
from ai.backend.client.request import Request
from ai.backend.client.session import AsyncSession
async with AsyncSession() as sess:
rqst = Request(sess, 'GET', ...)
async with rqst.fetch() as resp:
print(await resp.text())
'''
assert self.method in self._allowed_methods, \
'Disallowed HTTP method: {}'.format(self.method)
self.date = datetime.now(tzutc())
self.headers['Date'] = self.date.isoformat()
if self.content_type is not None:
self.headers['Content-Type'] = self.content_type
full_url = self._build_url()
self._sign(full_url.relative())
rqst_ctx = self.session.aiohttp_session.request(
self.method,
str(full_url),
data=self._pack_content(),
timeout=_default_request_timeout,
headers=self.headers)
return FetchContextManager(self.session, rqst_ctx, **kwargs)
[docs] def connect_websocket(self, **kwargs) -> 'WebSocketContextManager':
'''
Creates a WebSocket connection.
.. warning::
This method only works with
:class:`~ai.backend.client.session.AsyncSession`.
'''
assert isinstance(self.session, AsyncSession), \
'Cannot use websockets with sessions in the synchronous mode'
assert self.method == 'GET', 'Invalid websocket method'
self.date = datetime.now(tzutc())
self.headers['Date'] = self.date.isoformat()
# websocket is always a "binary" stream.
self.content_type = 'application/octet-stream'
full_url = self._build_url()
self._sign(full_url.relative())
ws_ctx = self.session.aiohttp_session.ws_connect(
str(full_url),
autoping=True, heartbeat=30.0,
headers=self.headers)
return WebSocketContextManager(self.session, ws_ctx, **kwargs)
[docs]class Response:
'''
Represents the Backend.AI API response.
Also serves as a high-level wrapper of :class:`aiohttp.ClientResponse`.
The response objects are meant to be created by the SDK, not the callers.
:func:`text`, :func:`json` methods return the resolved content directly with
plain synchronous Session while they return the coroutines with AsyncSession.
'''
__slots__ = (
'_session', '_raw_response', '_async_mode',
)
def __init__(self, session: BaseSession,
underlying_response: aiohttp.ClientResponse, *,
async_mode: bool = False):
self._session = session
self._raw_response = underlying_response
self._async_mode = async_mode
@property
def session(self) -> BaseSession:
return self._session
@property
def status(self) -> int:
return self._raw_response.status
@property
def reason(self) -> str:
return self._raw_response.reason
@property
def headers(self) -> Mapping[str, str]:
return self._raw_response.headers
@property
def raw_response(self) -> aiohttp.ClientResponse:
return self._raw_response
@property
def content_type(self) -> str:
return self._raw_response.content_type
@property
def content_length(self) -> int:
return self._raw_response.content_length
@property
def content(self) -> aiohttp.StreamReader:
return self._raw_response.content
def text(self) -> str:
if self._async_mode:
return self._raw_response.text()
else:
return self._session.worker_thread.execute(self._raw_response.text())
def json(self, *, loads=modjson.loads) -> Any:
loads = functools.partial(loads, object_pairs_hook=OrderedDict)
if self._async_mode:
return self._raw_response.json(loads=loads)
else:
return self._session.worker_thread.execute(
self._raw_response.json(loads=loads))
def read(self, n=-1) -> bytes:
return self._session.worker_thread.execute(self.aread(n))
async def aread(self, n=-1) -> bytes:
return await self._raw_response.content.read(n)
def readall(self) -> bytes:
return self._session.worker_thread.execute(self._areadall())
async def areadall(self) -> bytes:
return await self._raw_response.content.read(-1)
[docs]class FetchContextManager:
'''
The context manager returned by :func:`Request.fetch`.
It provides both synchronouse and asynchronous contex manager interfaces.
'''
__slots__ = (
'session', 'rqst_ctx', 'response_cls',
'check_status',
'_async_mode',
)
def __init__(self, session, rqst_ctx, *,
response_cls: Response = Response,
check_status: bool = True):
self.session = session
self.rqst_ctx = rqst_ctx
self.response_cls = response_cls
self.check_status = check_status
self._async_mode = True
def __enter__(self):
assert isinstance(self.session, SyncSession)
self._async_mode = False
return self.session.worker_thread.execute(self.__aenter__())
async def __aenter__(self):
try:
raw_resp = await self.rqst_ctx.__aenter__()
if self.check_status and raw_resp.status // 100 != 2:
msg = await raw_resp.text()
raise BackendAPIError(raw_resp.status, raw_resp.reason, msg)
return self.response_cls(self.session, raw_resp,
async_mode=self._async_mode)
except aiohttp.ClientError as e:
msg = 'Request to the API endpoint has failed.\n' \
'Check your network connection and/or the server status.\n' \
'\u279c {!r}'.format(e)
raise BackendClientError(msg) from e
def __exit__(self, *args):
return self.session.worker_thread.execute(self.__aexit__(*args))
async def __aexit__(self, *args):
return await self.rqst_ctx.__aexit__(*args)
[docs]class WebSocketResponse:
'''
A high-level wrapper of :class:`aiohttp.ClientWebSocketResponse`.
'''
__slots__ = ('_session', '_raw_ws', )
def __init__(self, session: BaseSession,
underlying_ws: aiohttp.ClientWebSocketResponse):
self._session = session
self._raw_ws = underlying_ws
@property
def session(self) -> BaseSession:
return self._session
@property
def raw_weboscket(self) -> aiohttp.ClientWebSocketResponse:
return self._raw_ws
@property
def closed(self):
return self._raw_ws.closed
async def close(self):
await self._raw_ws.close()
def __aiter__(self):
return self._raw_ws.__aiter__()
async def __anext__(self):
return await self._raw_ws.__anext__()
def exception(self):
return self._raw_ws.exception()
async def send_str(self, raw_str: str):
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
await self._raw_ws.send_str(raw_str)
async def send_json(self, obj: Any):
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
await self._raw_ws.send_json(obj)
async def send_bytes(self, data: bytes):
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
await self._raw_ws.send_bytes(data)
async def receive_str(self) -> str:
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
return await self._raw_ws.receive_str()
async def receive_json(self) -> Any:
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
return await self._raw_ws.receive_json()
async def receive_bytes(self) -> bytes:
if self._raw_ws.closed:
raise aiohttp.ServerDisconnectedError('server disconnected')
return await self._raw_ws.receive_bytes()
[docs]class WebSocketContextManager:
'''
The context manager returned by :func:`Request.connect_websocket`.
'''
__slots__ = (
'session', 'ws_ctx', 'response_cls',
'on_enter',
)
def __init__(self, session, ws_ctx, *,
on_enter: Callable = None,
response_cls: WebSocketResponse = WebSocketResponse):
self.session = session
self.ws_ctx = ws_ctx
self.response_cls = WebSocketResponse
self.on_enter = on_enter
async def __aenter__(self):
try:
raw_ws = await self.ws_ctx.__aenter__()
except aiohttp.ClientError as e:
msg = 'Request to the API endpoint has failed.\n' \
'Check your network connection and/or the server status.\n' \
'Error detail: {!r}'.format(e)
raise BackendClientError(msg) from e
wrapped_ws = self.response_cls(self.session, raw_ws)
if self.on_enter is not None:
await self.on_enter(wrapped_ws)
return wrapped_ws
async def __aexit__(self, *args):
return await self.ws_ctx.__aexit__(*args)