Request middlware runs twice when exception is thrown

I can’t tell if this is intentional or not. I think I’ve brought it up before, but its affecting me again when maintaining some of my plugins.

Minimal reproduction:

from sanic import Sanic
from sanic.exceptions import SanicException
from sanic.response import html

app = Sanic(__name__)

@app.middleware("request")
def my_middleware1(request):
    print("Middleware 1 ran", flush=True)

@app.middleware("request")
def my_middleware2(request):
    print("Middleware 2 ran", flush=True)
    raise SanicException()

@app.get("/")
def index(request):
    return html("<p>hello world</p>")

if __name__ == "__main__":
    app.run(debug=True, auto_reload=False, access_log=False)

Output:

[2022-01-04 13:32:31 +1000] [45332] [INFO] Starting worker [45332]
Middleware 1 ran
Middleware 2 ran
[2022-01-04 13:32:39 +1000] [45332] [ERROR] Exception occurred while handling uri: 'http://localhost:8000/'
Traceback (most recent call last):
  File "handle_request", line 62, in handle_request
    ...
  File "_run_request_middleware", line 26, in _run_request_middleware
    ...
  File "/home/ash/CODE/sanic/sanicpluginsframework/this.py", line 17, in my_middleware2
    raise SanicException()
sanic.exceptions.SanicException: None
Middleware 1 ran   #<--- Ran again!
Middleware 2 ran   #<--- Ran again! 

This is because app handle_exception does executes _run_request_middleware again, after handle_request has already executed _run_request_middleware.

Offending code is here: https://github.com/sanic-org/sanic/blob/a7bc8b56bab01e066357e6dcc67c0dc9df864298/sanic/app.py#L786-L791

[ashleysommer]

Yep, this can be closed. There was a problem with my test setup. As you see, my example code runs without issue.

[ahopkins]

Phew 😌

I was worried this morning when I saw this issue in my inbox 😆