[@sentry/nextjs] Errored API routes trigger "API resolved without sending a response"

[adarnon]

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Package + Version

• @sentry/nextjs

Version:

6.10.0

Description

Describe your issue in detail, ideally, you have a reproducible demo that you can show.

The withSentry() API route wrapper monkeypatches res.end() function to await for flush before closing a request. While this is certainly useful for serverless environments, it could cause a false positive warning on deployments with a custom server (e.g., Express).

Since normal Next API route code does not await for res.end() to finish, the handler's promise returns before the response has ended properly. This causes Next to detect the API route as having finished without a response, even though the response is sent a few moments later. Here is an example:

A workaround is to wrap all API routes with another callback that always performs await res.end() before returning.

[etrepum]

We're getting these false positives as well. I haven't put in the time to look at testing this but I think that the only way to workaround this issue is in the wrapper, since there are transitive calls to res.end in express (e.g. res.send or res.json). I think that attaching a promise to the context would be sufficient, like this: https://github.com/getsentry/sentry-javascript/compare/master...etrepum:resolve-with-response-gh-3852?expand=1&w=1

[jordymeow]

It does this for all my requests as well, even though I do this:

return res.status(200).json({ success: true });

I hope this will be fixed :)

[KieraDOG]

Any plan on this one? I'm currently doing something like this to get rid of the message

import * as Sentry from '@sentry/nextjs';

// ISSUE: https://github.com/getsentry/sentry-javascript/issues/3852
// API resolved without sending a response for *, this may result in stalled requests.
const withSentry = (fn) => async (req, res) => {
  await Sentry.withSentry(fn)(req, res);
  await res.end();
};

export default withSentry;

[adikari]

I am having the same issue in development. I have not deployed it to production to verify yet.

This gets logged in the server log:

API resolved without sending a response for /api/graphql, this may result in stalled requests.

And no error is logged in sentry.

If I have the barebone code from the example, it works fine. However, my actual code does a call to server and uses await to wait for the response. If there is error in server, then I don't get any report in sentry.

[kaykdm]

You can set externalResolver to true in api route config since it is handled by sentry (external)
https://nextjs.org/docs/api-routes/api-middlewares#custom-config

[benjamintd]

@kaykdm Thanks for this workaround! Is there a way to set a default config for all API routes ? From the docs it seems that there is no option to do this in next.config.js, which means this config has to be added to all API routes individually.

@KieraDOG the workaround in this comment did not work for me. This resulted in the response being ended before the actual content is sent, which means stalling requests (especially in a development environment).

[maccman]

Why are you guys monkey patching .end() ?

https://github.com/getsentry/sentry-javascript/blob/master/packages/nextjs/src/utils/withSentry.ts#L22

Can you not just return a promise to Next?

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀