Troubleshooting Internal Server Error for Mailgun to Heroku Django Integration

Other Questions Mailgun
1

I’m stuck with a frustrating issue. My Django app on Heroku is supposed to handle incoming emails from Mailgun but it’s throwing a 500 error. The weird part is the view works fine when I test it manually or with a tool like Poster.

Here’s a simplified version of my view:

@csrf_exempt
def process_incoming_email(request):
    sender = request.POST.get('from')
    recipient = request.POST.get('to')
    message = request.POST.get('body-plain', '')

    try:
        # Do something with the email data
        pass
    except Exception as e:
        print(f'Error: {e}')

    return HttpResponse('Success')

Mailgun logs show a 500 error but don’t give any details. Heroku logs aren’t much help either.

I’m at a loss for how to debug this. Any ideas on what might be causing the issue? Also, is there a better way to test this locally without constantly deploying to Heroku? It’s really slowing down my development process.

Any tips would be greatly appreciated!

2

hey, have u tried a logging middleware to capture all requests? heroku may be hiding error details. also, check ur mailgun key config. ngrok works well for local webhook testing.

3

Have you considered using a try-except block to catch and log specific exceptions? This could provide more insight into what’s causing the 500 error. Additionally, ensure your Heroku config vars are set correctly for Mailgun.

For local testing, I’ve found that using a tool like Postman to simulate Mailgun’s POST requests can be quite effective. You can set up a local environment that mimics your Heroku setup, allowing for quicker iterations.

Another approach is to implement a custom error handler for 500 errors in Django. This can help you capture and log errors that might otherwise be swallowed by Heroku’s error handling.

Lastly, double-check that your view is properly decorated with @csrf_exempt. Sometimes, CSRF issues can cause unexpected 500 errors in production environments.

4

I’ve dealt with similar issues before, and it can be quite frustrating. One thing that helped me was setting up Sentry for error tracking. It gives you detailed error reports, even for 500 errors that Heroku might not show.

For local testing, I’d recommend using ngrok as CreativeArtist88 mentioned. It creates a secure tunnel to your localhost, allowing you to receive webhooks without deploying.

Also, double-check your Mailgun configuration on Heroku. Sometimes environment variables don’t sync properly, causing unexpected behavior in production.

Lastly, try adding more granular exception handling in your view. Log specific exceptions to narrow down where the issue might be occurring. This approach has saved me countless hours of debugging in the past.