So I'm writing a function that use fastAPI cache to avoid making a bunch of post calls, then I'm wondering if is possible to write a test to validate that the functions is just called once and then reuse the cached value.
from fastapi_cache.decorator import cache
#cache(expire=60)
async def get_auth_token() -> str:
## just to exemplify
return "token"
class TestAuth(IsolatedAsyncioTestCase):
async def test_get_token_success(self):
"""Test get token"""
# success
_token = await get_auth_token()
assert _token is not None
assert _token == "token"
# here is the trick
# calling again should not call post again
_token = await get_auth_token()
mock_post.assert_called_once()
but I'm getting this error
AssertionError: Expected 'post' to have been called once. Called 2 times.
Another idea: return token with timestamp, that you can check timestamp to verify whether it is get from function or cache.
For example:
import time
from fastapi_cache.decorator import cache
#cache(expire=60)
async def get_auth_token() -> str:
## just to exemplify
return str(time.time())
class TestAuth(IsolatedAsyncioTestCase):
async def test_get_token_success(self):
"""Test get token"""
timestamp = str(time.time())
# success
token1 = await get_auth_token()
assert token1 is not None
assert timestamp <= token1 <= str(time.time())
# here is the trick
# calling again should not call post again
token2 = await get_auth_token()
assert token1 == token2
# check expire
time.sleep(60)
token3 = await get_auth_token()
assert token3 != token1
I have a piece of code which uses asyncio.gather to make simultaneous requests:
estimated_income, judicial_records = await asyncio.gather(
*(client.get_estimated_income(), client.get_judicial_records()), return_exceptions=True
)
# `client.get_estimated_income()` calls `CREDIT_BUREAU_URL`
# `client.get_judicial_records()` calls `NATIONAL_ARCHIVES_URL`
In my tests I'm trying to simulate some scenarios by mocking the requests status:
mock_aioresponse.get(NATIONAL_ARCHIVES_URL, status=200)
mock_aioresponse.get(CREDIT_BUREAU_URL, status=400)
If I run a single test, it works as expected but if I run more than one (and the others don't even have to use mock_aioresponse) I reach that piece of code twice and start to get some Connection refused errors in the second time (the first one works just fine) - which propagates to the tests making they fail.
The weirdest thing to me is reaching that function twice if I run more than one test.
How can I use aioresponses to accomplish my test cases?
CODE:
# main.py
#app.get(
"/leads/{lead_id}/sales_pipeline",
response_model=LeadRead,
responses={status.HTTP_404_NOT_FOUND: {"model": NotFoundResponse}},
)
def sales_pipeline(lead_id: int, db: Session = Depends(get_db)):
lead = db.get(Lead, lead_id)
if not lead:
raise HTTPException(status_code=404, detail="Lead not found")
pipeline_history = PipelineHistory(lead_id=lead.id)
db.add(pipeline_history)
db.commit()
db.refresh(pipeline_history)
# dispatch an event to handlers.py
dispatch(event_name=SALES_PIPELINE_ENTRYPOINT_EVENT_NAME, payload={"id": pipeline_history.id})
return lead
# handlers.py
async def _check_if_lead_is_able_to_become_prospect(
client: LeadExternalSystemsClient,
) -> Tuple[Optional[bool], Optional[str]]:
error_messages: List[str] = []
estimated_income, judicial_records = await asyncio.gather(
*(client.get_estimated_income(), client.get_judicial_records()), return_exceptions=True
)
if isinstance(estimated_income, LeadExternalSystemsClient.LeadExternalSystemsException):
error_messages.append("Credit Bureau network error")
if isinstance(judicial_records, LeadExternalSystemsClient.LeadExternalSystemsException):
error_messages.append("National Archives network error")
# more code
# `LeadExternalSystemsClient` class at client.py
class LeadExternalSystemsClient:
class LeadExternalSystemsException(Exception):
pass
def __init__(self, lead: Lead, timeout: int = 30):
self.lead = lead
self._session = ClientSession(
timeout=ClientTimeout(total=timeout),
connector=TCPConnector(limit=30, ssl=False),
raise_for_status=True,
)
async def __aenter__(self) -> "LeadExternalSystemsClient":
return self
async def __aexit__(self, *_, **__) -> None:
await self._session.close()
async def _request(self, method: str, url: str) -> Any:
try:
response = self._session.request(method=method, url=url)
return await response.json()
except ClientError as exception:
raise self.LeadExternalSystemsException(str(exception))
async def get_estimated_income(self) -> Dict[str, float]:
result = await self._request(method="GET", url=CREDIT_BUREAU_URL)
# more code
async def get_judicial_records(self) -> List[Dict[str, str]]:
result = await self._request(method="GET", url=NATIONAL_ARCHIVES_URL)
# more code
# tests
#pytest.mark.usefixtures("mock_engine_for_test")
def test_estimated_income_network_error(client, lead, mocker, mock_aioresponse):
# GIVEN
mocker.patch(
"app.consumers.handlers.LeadExternalSystemsClient.personal_information_is_valid",
return_value=True,
)
mock_aioresponse.get(NATIONAL_ARCHIVES_URL, status=200)
mock_aioresponse.get(CREDIT_BUREAU_URL, status=400)
# WHEN
response = client.get(f"/leads/{lead.id}/sales_pipeline")
result = client.get(f"/leads/{lead.id}").json()
# THEN
assert response.status_code == status.HTTP_200_OK
assert result["is_prospect"] is False
assert len(result["pipeline_histories"]) == 1
assert result["pipeline_histories"][0]["started_at"] is not None
assert result["pipeline_histories"][0]["finished_at"] is not None
assert result["pipeline_histories"][0]["extra_infos"] == "Credit Bureau network error"
assert result["pipeline_histories"][0]["status"] == PipelineStatus.NETWORK_ERROR.name
Looks like the solution is to pass repeat=True to aioresponses().get()
https://bytemeta.vip/repo/pnuckowski/aioresponses/issues/205
I have a class called database.py with a function called generate_token().
I would like to mock it and return a fixed value 321. So that I can see that the method was called and the return value returned.
How do I mock that? This is what I have tried.
#pytest.mark.asyncio
async def test_successful_register_returns_device_token(monkeypatch):
async def mock_generate_token():
return "321"
m = AsyncMock(mock_generate_token)
m.return_value = "321"
async with AsyncClient(app=app, base_url="http://127.0.0.1") as ac:
monkeypatch.setattr(database, "generate_token", m)
response = await ac.post(
"/register/",
headers={},
json={},
)
assert response.status_code == 201
assert "device_token" in response.json()
assert response.json()["device_token"] == "321"
It's actually much simpler than I thought, a normal #patch from from unittest.mock import patch is sufficient. It recognises the async methods and injects an AsyncMock automatically.
#pytest.mark.asyncio
#patch("service.auth_service.AuthService.generate_token")
async def test_successful_register_returns_device_token(self, mock_token):
mock_token.return_value = "321"
async with AsyncClient(app=app, base_url="http://testserver") as ac:
response = await ac.post(
"/register/",
headers={},
json={},
)
assert response.status_code == 201
assert "device_token" in response.json()
assert response.json()["device_token"] == "321"
I have such middleware
class RequestContext(BaseHTTPMiddleware):
async def dispatch(self, request: Request, call_next: RequestResponseEndpoint):
request_id = request_ctx.set(str(uuid4())) # generate uuid to request
body = await request.body()
if body:
logger.info(...) # log request with body
else:
logger.info(...) # log request without body
response = await call_next(request)
response.headers['X-Request-ID'] = request_ctx.get()
logger.info("%s" % (response.status_code))
request_ctx.reset(request_id)
return response
So the line body = await request.body() freezes all requests that have body and I have 504 from all of them. How can I safely read the request body in this context? I just want to log request parameters.
I would not create a Middleware that inherits from BaseHTTPMiddleware since it has some issues, FastAPI gives you a opportunity to create your own routers, in my experience this approach is way better.
from fastapi import APIRouter, FastAPI, Request, Response, Body
from fastapi.routing import APIRoute
from typing import Callable, List
from uuid import uuid4
class ContextIncludedRoute(APIRoute):
def get_route_handler(self) -> Callable:
original_route_handler = super().get_route_handler()
async def custom_route_handler(request: Request) -> Response:
request_id = str(uuid4())
response: Response = await original_route_handler(request)
if await request.body():
print(await request.body())
response.headers["Request-ID"] = request_id
return response
return custom_route_handler
app = FastAPI()
router = APIRouter(route_class=ContextIncludedRoute)
#router.post("/context")
async def non_default_router(bod: List[str] = Body(...)):
return bod
app.include_router(router)
Works as expected.
b'["string"]'
INFO: 127.0.0.1:49784 - "POST /context HTTP/1.1" 200 OK
In case you still wanted to use BaseHTTP, I recently ran into this problem and came up with a solution:
Middleware Code
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
import json
from .async_iterator_wrapper import async_iterator_wrapper as aiwrap
class some_middleware(BaseHTTPMiddleware):
async def dispatch(self, request:Request, call_next:RequestResponseEndpoint):
# --------------------------
# DO WHATEVER YOU TO DO HERE
#---------------------------
response = await call_next(request)
# Consuming FastAPI response and grabbing body here
resp_body = [section async for section in response.__dict__['body_iterator']]
# Repairing FastAPI response
response.__setattr__('body_iterator', aiwrap(resp_body)
# Formatting response body for logging
try:
resp_body = json.loads(resp_body[0].decode())
except:
resp_body = str(resp_body)
async_iterator_wrapper Code from
TypeError from Python 3 async for loop
class async_iterator_wrapper:
def __init__(self, obj):
self._it = iter(obj)
def __aiter__(self):
return self
async def __anext__(self):
try:
value = next(self._it)
except StopIteration:
raise StopAsyncIteration
return value
I really hope this can help someone! I found this very helpful for logging.
Big thanks to #Eddified for the aiwrap class
You can do this safely with a generic ASGI middleware:
from typing import Iterable, List, Protocol, Generator
import pytest
from starlette.responses import Response
from starlette.testclient import TestClient
from starlette.types import ASGIApp, Scope, Send, Receive, Message
class Logger(Protocol):
def info(self, message: str) -> None:
...
class BodyLoggingMiddleware:
def __init__(
self,
app: ASGIApp,
logger: Logger,
) -> None:
self.app = app
self.logger = logger
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
if scope["type"] != "http":
await self.app(scope, receive, send)
return
done = False
chunks: "List[bytes]" = []
async def wrapped_receive() -> Message:
nonlocal done
message = await receive()
if message["type"] == "http.disconnect":
done = True
return message
body = message.get("body", b"")
more_body = message.get("more_body", False)
if not more_body:
done = True
chunks.append(body)
return message
try:
await self.app(scope, wrapped_receive, send)
finally:
while not done:
await wrapped_receive()
self.logger.info(b"".join(chunks).decode()) # or somethin
async def consume_body_app(scope: Scope, receive: Receive, send: Send) -> None:
done = False
while not done:
msg = await receive()
done = "more_body" not in msg
await Response()(scope, receive, send)
async def consume_partial_body_app(scope: Scope, receive: Receive, send: Send) -> None:
await receive()
await Response()(scope, receive, send)
class TestException(Exception):
pass
async def consume_body_and_error_app(scope: Scope, receive: Receive, send: Send) -> None:
done = False
while not done:
msg = await receive()
done = "more_body" not in msg
raise TestException
async def consume_partial_body_and_error_app(scope: Scope, receive: Receive, send: Send) -> None:
await receive()
raise TestException
class TestLogger:
def __init__(self, recorder: List[str]) -> None:
self.recorder = recorder
def info(self, message: str) -> None:
self.recorder.append(message)
#pytest.mark.parametrize(
"chunks, expected_logs", [
([b"foo", b" ", b"bar", b" ", "baz"], ["foo bar baz"]),
]
)
#pytest.mark.parametrize(
"app",
[consume_body_app, consume_partial_body_app]
)
def test_body_logging_middleware_no_errors(chunks: Iterable[bytes], expected_logs: Iterable[str], app: ASGIApp) -> None:
logs: List[str] = []
client = TestClient(BodyLoggingMiddleware(app, TestLogger(logs)))
def chunk_gen() -> Generator[bytes, None, None]:
yield from iter(chunks)
resp = client.get("/", data=chunk_gen())
assert resp.status_code == 200
assert logs == expected_logs
#pytest.mark.parametrize(
"chunks, expected_logs", [
([b"foo", b" ", b"bar", b" ", "baz"], ["foo bar baz"]),
]
)
#pytest.mark.parametrize(
"app",
[consume_body_and_error_app, consume_partial_body_and_error_app]
)
def test_body_logging_middleware_with_errors(chunks: Iterable[bytes], expected_logs: Iterable[str], app: ASGIApp) -> None:
logs: List[str] = []
client = TestClient(BodyLoggingMiddleware(app, TestLogger(logs)))
def chunk_gen() -> Generator[bytes, None, None]:
yield from iter(chunks)
with pytest.raises(TestException):
client.get("/", data=chunk_gen())
assert logs == expected_logs
if __name__ == "__main__":
import os
pytest.main(args=[os.path.abspath(__file__)])
Turns out await request.json() can only be called once per the request cycle. So if you need to access the request body in multiple middlewares for filtering or authentication etc then there's a work around which is to create a custom middleware that copies the contents of request body in request.state. The middleware should be loaded as early as necessary. Each middleware next in chain or controller can then access the request body from request.state instead of calling await request.json() again. Here's a example:
class CopyRequestMiddleware(BaseHTTPMiddleware):
async def dispatch(self, request: Request, call_next):
request_body = await request.json()
request.state.body = request_body
response = await call_next(request)
return response
class LogRequestMiddleware(BaseHTTPMiddleware):
async def dispatch(self, request: Request, call_next):
# Since it'll be loaded after CopyRequestMiddleware it can access request.state.body.
request_body = request.state.body
print(request_body)
response = await call_next(request)
return response
The controller will access request body from request.state as well
request_body = request.state.body
Just because such solution not stated yet, but it's worked for me:
from typing import Callable, Awaitable
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
from starlette.responses import StreamingResponse
from starlette.concurrency import iterate_in_threadpool
class LogStatsMiddleware(BaseHTTPMiddleware):
async def dispatch( # type: ignore
self, request: Request, call_next: Callable[[Request], Awaitable[StreamingResponse]],
) -> Response:
response = await call_next(request)
response_body = [section async for section in response.body_iterator]
response.body_iterator = iterate_in_threadpool(iter(response_body))
logging.info(f"response_body={response_body[0].decode()}")
return response
def init_app(app):
app.add_middleware(LogStatsMiddleware)
iterate_in_threadpool actually making from iterator object async Iterator
If you look on implementation of starlette.responses.StreamingResponse you'll see, that this function used exactly for this
If you only want to read request parameters, best solution i found was to implement a "route_class" and add it as arg when creating the fastapi.APIRouter, this is because parsing the request within the middleware is considered problematic
The intention behind the route handler from what i understand is to attach exceptions handling logic to specific routers, but since it's being invoked before every route call, you can use it to access the Request arg
Fastapi documentation
You could do something as follows:
class MyRequestLoggingRoute(APIRoute):
def get_route_handler(self) -> Callable:
original_route_handler = super().get_route_handler()
async def custom_route_handler(request: Request) -> Response:
body = await request.body()
if body:
logger.info(...) # log request with body
else:
logger.info(...) # log request without body
try:
return await original_route_handler(request)
except RequestValidationError as exc:
detail = {"errors": exc.errors(), "body": body.decode()}
raise HTTPException(status_code=422, detail=detail)
return custom_route_handler
The issue is in Uvicorn. The FastAPI/Starlette::Request class does cache the body, but the Uvicorn function RequestResponseCycle::request() does not, so if you instantiate two or more Request classes and ask for the body(), only the instance that asks for the body first will have a valid body.
I solved creating a mock function that returns a cached copy of the request():
class LogRequestsMiddleware:
def __init__(self, app:ASGIApp) -> None:
self.app = app
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
receive_cached_ = await receive()
async def receive_cached():
return receive_cached_
request = Request(scope, receive = receive_cached)
# do what you need here
await self.app(scope, receive_cached, send)
app.add_middleware(LogRequestsMiddleware)
I'm writing "unittests" for my flask api. Using Flask.test_client() is easy locally. eg:
app = Flask(__name__)
client = app.test_client()
However, I want to still be able to do things such as
self.client.post('{0}/account/password'.format(self.base_path),
data=json.dumps(passwordu), headers=self.get_headers(),
content_type=self.content_type)
But I want the client to talk to a remote host.
I've seen I can use environ_override as a parameter to the client.post(...) method. To me there must be a simpler way to get a simple client that does the necessary sending of requests and decoding of responses in the same way test_client() does. However, subclassing client, still requires me to use a Flask instance.
Ok, firstly, thanks for the suggestion Anarci. Here's what I came up with.
I wouldn't call it nice OO design, but it works and is lazy.
class RemoteApiTest(AppTest, ApiTestMixin):
#classmethod
def setUpClass(cls):
super(RemoteApiTest, cls).setUpClass()
cls.kwargs = config.FLASK_CLIENT_CONFIG
cls.base_url = cls.kwargs.get('base_url')
cls.content_type = cls.kwargs.get('content_type')
cls.client = requests
cls.db = db
cls.db.create_all()
#classmethod
def tearDownClass(cls):
super(RemoteApiTest, cls).tearDownClass()
cls.db.session.remove()
cls.db.drop_all()
#cls.db.get_engine(cls.app).dispose()
#property
def base_url(self):
return self.__class__.base_url
#property
def content_type(self):
return self.__class__.content_type
def get_json(self, r):
return r.json()
#property
def headers(self):
headers = {'content-type': self.content_type}
if self.api_key:
headers.update({'X-consumer-apiKey': self.api_key})
return headers
def basic_checks(self, rv):
eq_(rv.status_code, 200)
r = rv.json()
assert rv is not None
assert r is not None
assert r.get('correlationID') is not None
return r
def setUp(self):
super(RemoteApiTest, self).setUp()
self.api_key = None
r = self.client.post('{0}/account/register'.format(self.base_url), data=json.dumps(account_register),
headers=self.headers)
j = r.json()
self.api_key = j['apiKey']
def tearDown(self):
rv = self.client.delete('{0}/account'.format(self.base_url), headers=self.headers)
super(RemoteApiTest, self).tearDown()
With that I can config the remote server etc in my same config, and I can reuse code like this:
class ApiTestMixin:
def test_account_get(self):
rv = self.client.get(self.base_url + '/account', headers=self.headers)
r = self.basic_checks(rv)
account = r.get('account')
eq_(account.get('fullName'), account_register.get('fullName'))
assert r.get('correlationID') is not None
Definitely open to criticism, but that's how I made it work,