Closed alexted closed 1 year ago
We have the same problem with both the fastapi versions 0.91.0 and 0.92.0 being effected. It seems like adding a middleware after startup is not valid anymore, though they also fixed the fact that middlewares are initialized multiple times. Is there an alternative way to integrate the instrumentator?
We're encountering the same issue. Here's where this was introduced in Starlette. https://github.com/encode/starlette/commit/51c1de1839ee187bb20de5748fca23baa37369c6#diff-3eb07c0eea72d98f1b844e07844c2a68b7c11c63956b67d5afdd9c7f79ab946fR135
I have the same problem. Maybe we can use https://github.com/stephenhillier/starlette_exporter instead? Does anybody have experience with that library, is it a drop-in replacement?
Yes, I too am thinking of switching to another library.
Is there any reason to implement the instrumentator on the "startup" event? Just moving the instrumentator outside of the event makes things work
This works until you run unit tests.
Is there any reason to implement the instrumentator on the "startup" event? Just moving the instrumentator outside of the event makes things work
Prometheus expects a fully initialized ASGI client, where uvicorn now delays execution in newer versions. Closing.
sorry I should have been more clear, what I'm currently doing is creating the instrumentator and "instrument" the app outside of the startup event, but actually "exposing" it on the startup event and seems to be working fine
sorry I should have been more clear, what I'm currently doing is creating the instrumentator and "instrument" the app outside of the startup event, but actually "exposing" it on the startup event and seems to be working fine
Can you share a bit of code here please?
Sure,, just a quick note, I'm using start_http_server
because I run my prometheus server on a diferent port, but I asume you could save the Instrumentator variable and just call .expose
on the startup_event function
from fastapi import FastAPI
from prometheus_client import start_http_server
from prometheus_fastapi_instrumentator import Instrumentator
async def startup_event():
start_http_server(8080)
app = FastAPI(
on_startup=[startup_event]
)
Instrumentator(
excluded_handlers=["/metrics"],
).instrument(app)
can confirm, this works with the new Fastapi
instrumentator = Instrumentator().instrument(app)
@app.on_event("startup")
async def _startup():
instrumentator.expose(app, endpoint='/metrics', tags=['metrics'])
Is there any reason to implement the instrumentator on the "startup" event? Just moving the instrumentator outside of the event makes things work
The README was updated to use startup
around 6 months ago due to #80. It is probably best to update the README again with the next release. Just tried it (while testing other things) and for me it works without startup
fine.
Here are relevant dependencies:
❯ pip list
Package Version Editable project location
--------------------------------- ------- ----------------------------
fastapi 0.92.0
prometheus-client 0.16.0
prometheus-fastapi-instrumentator 100.0.0
starlette 0.25.0
uvicorn 0.20.0
The code:
from fastapi import FastAPI
from prometheus_fastapi_instrumentator import Instrumentator
app = FastAPI()
@app.get("/app")
def read_main():
return {"message": "Hello World from main app"}
Instrumentator().instrument(app).expose(app)
Reproducible examples would be great as I am not using the package actively anymore.
it breaks all my unit tests:
@alexted does this also happen if you use https://github.com/stephenhillier/starlette_exporter? I think it is related to how the prometheus client library works. In the unit tests of this package here I call the following function at the beginning of every relevant unit test: https://github.com/trallnag/prometheus-fastapi-instrumentator/blob/master/tests/helpers/utils.py#L4
Another solution seems to be to use a new registry for every unit test: https://github.com/rycus86/prometheus_flask_exporter/issues/17
Current version of prometheus-fastapi-instrumentator does not support passing custom registry, but this feature has already been merged as part of clean up and I will release it today
Is there anything pointing against the solution by @alfaro28 / @harochau?
For me, it is working with all circumstances (unit tests + the app itself) and is much simpler than adding a new registry for every unit test etc.
@saschnet, I don't know 😆 I will update the README and switch to the example provided by @harochau
@alexted does this also happen if you use https://github.com/stephenhillier/starlette_exporter?
No, everything works fine when using this library. The application runs and the unit tests pass.
@trallnag thanks for the release. with the new version I started to get another error when running unit tests:
tests/v1_1/advertisers/test_get_expenses.py:107:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1757: in get
return await self.request(
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1533: in request
return await self.send(request, auth=auth, follow_redirects=follow_redirects)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1620: in send
response = await self._send_handling_auth(
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1648: in _send_handling_auth
response = await self._send_handling_redirects(
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1685: in _send_handling_redirects
response = await self._send_single_request(request)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_client.py:1722: in _send_single_request
response = await transport.handle_async_request(request)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/httpx/_transports/asgi.py:162: in handle_async_request
await self.app(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/fastapi/applications.py:271: in __call__
await super().__call__(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/applications.py:118: in __call__
await self.middleware_stack(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py:184: in __call__
raise exc
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/errors.py:162: in __call__
await self.app(scope, receive, _send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/cors.py:84: in __call__
await self.app(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:108: in __call__
response = await self.dispatch_func(request, call_next)
src/utils/middlewares/log_requests.py:19: in log_requests
response_body = [chunk async for chunk in response.body_iterator]
src/utils/middlewares/log_requests.py:19: in <listcomp>
response_body = [chunk async for chunk in response.body_iterator]
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:98: in body_stream
raise app_exc
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:70: in coro
await self.app(scope, receive_or_disconnect, send_no_error)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:109: in __call__
await response(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:270: in __call__
async with anyio.create_task_group() as task_group:
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/anyio/_backends/_asyncio.py:662: in __aexit__
raise exceptions[0]
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:273: in wrap
await func()
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:134: in stream_response
return await super().stream_response(send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:262: in stream_response
async for chunk in self.body_iterator:
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:98: in body_stream
raise app_exc
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:70: in coro
await self.app(scope, receive_or_disconnect, send_no_error)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:109: in __call__
await response(scope, receive, send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:270: in __call__
async with anyio.create_task_group() as task_group:
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/anyio/_backends/_asyncio.py:662: in __aexit__
raise exceptions[0]
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:273: in wrap
await func()
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:134: in stream_response
return await super().stream_response(send)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/responses.py:262: in stream_response
async for chunk in self.body_iterator:
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:98: in body_stream
raise app_exc
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/starlette/middleware/base.py:70: in coro
await self.app(scope, receive_or_disconnect, send_no_error)
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/prometheus_fastapi_instrumentator/middleware.py:181: in __call__
instrumentation(info)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
info = <prometheus_fastapi_instrumentator.metrics.Info object at 0x7feb23667fd0>
def instrumentation(info: Info) -> None:
> TOTAL.labels(info.method, info.modified_status, info.modified_handler).inc()
E NameError: free variable 'TOTAL' referenced before assignment in enclosing scope
../../.cache/pypoetry/virtualenvs/my-app-PzElRY_T-py3.10/lib/python3.10/site-packages/prometheus_fastapi_instrumentator/metrics.py:625: NameError
For now, I'm excluding 'prometheus_fastapi_instrumentator' when running tests. I'm using 'pytest' so incase anyone having the same problem:
instrumentor = None
if "pytest" not in sys.modules:
instrumentor = PrometheusFastApiInstrumentator(
should_group_status_codes=False
).instrument(
app,
)
and:
@app.on_event("startup")
async def _startup() -> None:
...
if "pytest" not in sys.modules:
setup_prometheus(app, instrumentor)
...
note: this would only work if you haven't imported 'pytest' outside your tests. there may be cleaner ways to check this.
@alexted, probably related to #219
The NameError
thing should be fixed now with the latest release https://github.com/trallnag/prometheus-fastapi-instrumentator/releases/tag/v5.11.0
The
NameError
thing should be fixed now with the latest release https://github.com/trallnag/prometheus-fastapi-instrumentator/releases/tag/v5.11.0
Thanks. NameError
is gone.
ty @trallnag
Hi! Since FastAPI version 0.91.0, I started getting the following error when trying to run the application:
I initiate the application this way: