aiohttp single log record traceback

single_record_traceback.py

import logging
from traceback import TracebackException

from aiohttp import web
from aiohttp.abc import StreamResponse
from aiohttp.typedefs import Handler
from aiohttp.web_exceptions import HTTPException

logger = logging.getLogger(__name__)
routes = web.RouteTableDef()

CAPTURE_LOCALS = True  # get it from .env / settings


@web.middleware
async def error_middleware(request: web.Request, handler: Handler) -> StreamResponse:
    """Process all unhandled exceptions."""
    try:
        return await handler(request)

    # upstream http-based exceptions (e.g. raised 404)
    except HTTPException:
        raise

    # catch real exceptions
    except Exception as exc:
        tb = _prepare_traceback(exc)
        logger.error("Handled exception! %s", tb)
        return web.Response(text="Something went wrong (apology text)", status=500)


def _prepare_traceback(exc: Exception) -> str:
    """Prepare readable traceback."""
    tb_exc = TracebackException.from_exception(exc, capture_locals=CAPTURE_LOCALS)
    return "\n".join(tb_exc.format())


@routes.get("/")
async def bad_handler(request: web.Request):
    """Brake everything!"""
    foo = "foo"
    bar = {"some": "data"}
    return foo / bar


if __name__ == "__main__":
    app = web.Application(middlewares=[error_middleware])
    app.add_routes(routes)
    web.run_app(app)

1. Добавил возможность печатать переменные в debug-режиме

Handled exception! Traceback (most recent call last):

  File "/app/draft.py", line 19, in error_middleware
    return await handler(request)
           ^^^^^^^^^^^^^^^^^^^^^^
    exc = TypeError("unsupported operand type(s) for /: 'str' and 'dict'")
    handler = <function bad_handler at 0x103cdeb60>
    request = <Request GET / >

  File "/app/draft.py", line 44, in bad_handler
    return foo / bar
           ~~~~^~~~~
    bar = {'some': 'data'}
    foo = 'foo'
    request = <Request GET / >

TypeError: unsupported operand type(s) for /: 'str' and 'dict'

2. Добавил upstream для HTTP-ошибок, которые намеренно вызываем сами, например 404.
   При необходимости можно разместить в нём инструменты дебаг-логирования

try:
    ...
except HTTPException as exc:
    if logger.isEnabledFor(logging.DEBUG):
        ... # some heavy preparations
        logger.debug("Raised HTTP-exception %s: %s", type(exc).__name__, exc)
    raise