Are you tired of getting above message?

Micro's builtin debugger might annoy you sometimes with not traceback about what caused the Internal Server Error. Let's catch internal server error just by using a simple middleware. Note this will only work with Starlette & FastAPI. Let's say you have the following app:

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello World"}

For some reason this causes Internal Server Error but micros's debugger is unable to output any error log! Here comes the role of a middleware which can catch the exception and send response accordingly.

Caution

This method is not suitable for production as it might leak sensitive information with traceback. Thanks to a discord friend baller#0001 for pointing it out.

Creating Exception Handling Middleware

import traceback
from fastapi import FastAPI
from fastapi.requests import Request
from fastapi.responses import JSONResponse


async def catch_exceptions_middleware(request: Request, call_next):
    try:
        return await call_next(request)
    except Exception as e:
        err = traceback.format_exception(type(e), e, e.__traceback__)
        return JSONResponse(content={"traceback": err}, status_code=500)

Adding middleware to the app

import traceback
from fastapi import FastAPI
from fastapi.requests import Request
from fastapi.responses import JSONResponse


async def catch_exceptions_middleware(request: Request, call_next):
    try:
        return await call_next(request)
    except Exception as e:
        err = traceback.format_exception(type(e), e, e.__traceback__)
        return JSONResponse(content={"traceback": err}, status_code=500)

app = FastAPI()
app.middleware('http')(catch_exceptions_middleware)

@app.get("/")
async def root():
    return {"message": "Hello World"}

You are all set

Now you will be able to receive detailed tracebacks like the following: