ERR_STREAM_WRITE_AFTER_END

[jessehansen]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which package are you using?

@sentry/nextjs

SDK Version

7.17.2

Framework Version

NextJS 12.3.1

Link to Sentry event

No response

Steps to Reproduce

We're using Sentry with Next.JS on Vercel. Last week we updated from @sentry/nextjs version 7.13.0 to 7.16.0, and we started seeing some requests to API endpoints returning 500 errors without any corresponding events in Sentry. We have since updated to @sentry/nextjs@7.17.2 and are getting the same errors. The Function logs on Vercel show up with an error message for ERR_STREAM_WRITE_AFTER_END.

Additional Info:

• Node Version: 16.16.0
• Webpack version: 5.73.0

We tried removing all of the wrapping withSentry calls from our API routes, but it didn't stop these errors.

Expected Result

No internal stream errors output to Vercel's function logs.

Actual Result

(Line Breaks added for readability)

2022-10-31T19:44:11.763Z	44cbcf3d-c3f9-48cf-8aa2-659e324a5ed5	ERROR	Uncaught Exception 	
{"errorType":"Error",
"errorMessage":"write after end",
"trace":
["Error [ERR_STREAM_WRITE_AFTER_END]: write after end",
"    at new NodeError (node:internal/errors:372:5)",
"    at ServerResponse.end (node:_http_outgoing:846:15)",
"    at ServerResponse.apiRes.end (/var/task/node_modules/next/dist/server/api-utils/node.js:346:25)",
"    at ServerResponse.sentryWrappedEnd [as end] (/var/task/node_modules/@sentry/nextjs/cjs/config/wrappers/utils/responseEnd.js:29:22)",
"    at processTicksAndRejections (node:internal/process/task_queues:96:5)"]}
Unknown application error occurred

I believe this to be related to #4151

[tlenex]

Locking @sentry/nextjs at exact 7.14.0 seems to walk around the issue. Hopefully this will get fixed soon

[jessehansen]

We have been doing some more testing with this, and it looks like the issue is due to our apollo-server graphql endpoint being automatically instrumented with @sentry/nextjs > 7.14.0. When we add withSentry to the same endpoint, even in version 7.13.0, we start seeing this error. Perhaps the real issue is that sentry and Apollo Server don't play nice together in next API routes?

[jessehansen]

Today we received this error in production, on 7.13.0. It happened on a simple status-check endpoint, which simply sends a 200 response with json data. I think this should be reproducible in a minimal next's environment on vercel with these 2 files and a cron job or something similar hitting the endpoint:

Here is the full source of the api route it happened on pages/api/status-check.ts:

import type { NextApiRequest, NextApiResponse } from "next";
import { withSentry } from "@sentry/nextjs";
import { logger } from "@:server/logger";

const statusCheck = async (
  _req: NextApiRequest,
  res: NextApiResponse
): Promise<any> => {
  try {
    res.json({ data: { up: true } });
    return res.status(200).end();
  } catch (err) {
    logger.warn("Error occurred during diag api check", err);
    return res
      .status(500)
      .send(
        "Error occurred while checking dependencies. Failed to connect to DB."
      );
  }
};

export default withSentry(statusCheck);

I can attach the source for the logger package as well, it's a simple Bunyan logger with a stream forwarding errors to Sentry:

import { createLogger } from "bunyan";
import type { LogLevel, Stream } from "bunyan";
import * as Sentry from "@sentry/nextjs";

const name =
  process?.env?.LOGGER_NAME ??
  process?.env?.npm_package_name ??
  "unknown logger";

const level: LogLevel =
  (process?.env?.LOGGER_LEVEL?.toLocaleLowerCase() as LogLevel) ?? "info";

const streams: Stream[] = [
  {
    level,
    stream: process.stdout,
  },
];

if (
  process.env.NODE_ENV === "production" &&
  process.env.DISABLE_SENTRY !== "1"
) {
  const sentryError = (err: any): Error => {
    if (err instanceof Error) return err;
    const error = new Error(err.message);
    error.name = err.name;
    error.stack = err.stack;
    // @ts-ignore sentry needs these props if they are present
    error.code = err.code;
    // @ts-ignore sentry needs these props if they are present
    error.signal = err.signal;
    return error;
  };

  streams.push({
    level: "error",
    type: "raw",
    stream: {
      // @ts-ignore bunyan WriteFn is not typed well
      write: ({ err, msg, tags, level: _level, ...extra }: object) => {
        if (err) {
          Sentry.captureException(sentryError(err), {
            extra,
            level: "error",
            tags,
          });
        } else {
          Sentry.captureMessage(msg, { extra, level: "error", tags });
        }
      },
    },
  });
}

export const logger = createLogger({
  name,
  streams,
});

logger.info({ message: `Logging with level '${level}'` });

[timfish]

Why are you calling .end()?

To return an ok JSON response the nextjs docs suggest:

res.status(200).json({ data: { up: true } })

[311chaos]

Why are you calling .end()?

To return an ok JSON response the nextjs docs suggest:

res.status(200).json({ data: { up: true } })

You are correct in that you could write this differently, but are you suggesting that we should never use .end()?

Another example might be for when you need to respond with a 204.

res.status(204).end()

[timfish]

Yes, if res.status(204).end() causes this issue, this would be considered a bug.

Why are you returning a value from the API route handler? None of the nextjs examples return anything. I think this may be causing an issue since Sentrys end wrapping is async.

try {
    res.json({ data: { up: true } });
    return res.status(200).end();
  } catch (err) {
    logger.warn("Error occurred during diag api check", err);
    return res
      .status(500)
      .send(
        "Error occurred while checking dependencies. Failed to connect to DB."
      );
  }

Should this not work without return?

[311chaos]

Yes, if res.status(204).end() causes this issue, this would be considered a bug.

Why are you returning a value from the API route handler? None of the nextjs examples return anything. I think this may be causing an issue since Sentrys end wrapping is async.

try {
    res.json({ data: { up: true } });
    return res.status(200).end();
  } catch (err) {
    logger.warn("Error occurred during diag api check", err);
    return res
      .status(500)
      .send(
        "Error occurred while checking dependencies. Failed to connect to DB."
      );
  }

Should this not work without return?

I am not certain on this (I will have to double check with the team after holiday), but I think this was in an attempt to fix the warning messages that get created after adding Sentry to our API routes: API resolved without sending a response for /api/xxx, this may result in stalled requests. Eventually we figured out that we had to set an env var for SENTRY_IGNORE_API_RESOLUTION_ERROR to make those stop barking.

[timfish]

At this point return is only mildly suspicious to me because it differs from the examples. I'll not get a chance to try this myself until after the US vacation weekend.

Can you confirm that you only get the error in production? And is this only in production with Vercel? I haven't managed to reproduce this error yet but I haven't tried Vercel yet since it'll be much more painful to debug!

[jessehansen]

Hi all - sorry for the delay, I was out for the holidays. I realize that calling .end() and returning were probably not the best, but I thought it was still interesting to have code for reproducing this issue that didn't include the rest of our stack. To answer your questions - I have only seen this error happen in production, but it doesn't happen every time - only occasionally. Our production is in Vercel, I don't have a different production environment to see if it happens.