BrokenPipeError: [Errno 32] Broken pipe

Python · updated 2026-11-04

Raised by a write or flush when the reader has closed its end. In a web app it usually means the browser or a proxy disconnected while the response was still streaming. In a script it means stdout was piped into a program such as head that stopped reading.

Traceback (most recent call last):
  File "/app/export/stream.py", line 44, in stream_rows
    out.write(line)
BrokenPipeError: [Errno 32] Broken pipe

Quick fix

In a server, a client disconnect is normal: catch BrokenPipeError around the write, stop producing output and don't report it as an error. In a CLI whose output may be piped into head, follow the Python docs: catch BrokenPipeError at the entry point, point stdout at /dev/null and exit. If it appears on calls to another service, that service closed the connection: treat it like a reset and retry idempotent calls.

1. Find what the write was going to: a client response, stdout, a subprocess pipe or another service.
2. Client response: catch it, stop the work for that request and log at debug level, not as an error.
3. CLI piped into head: catch BrokenPipeError in main, os.dup2 a devnull descriptor onto stdout, then sys.exit(1).
4. Subprocess: check whether the child exited early (its exit code and stderr).
5. Calls to another service: retry idempotent requests, and make sure a timeout is set.

import os
import sys

def main():
    try:
        for row in rows():
            print(row)
        sys.stdout.flush()
    except BrokenPipeError:
        # The reader (e.g. head) closed early. Silence stdout so the
        # interpreter's final flush doesn't raise again, then exit.
        devnull = os.open(os.devnull, os.O_WRONLY)
        os.dup2(devnull, sys.stdout.fileno())
        sys.exit(1)

if __name__ == "__main__":
    main()

Why it happens

Other fixes

• The Python docs advise against setting SIGPIPE to SIG_DFL to hide this: it makes the program exit without warning whenever any socket closes.
• Group client-disconnect errors separately in your error tracker so real failures stay visible.

Same error, other wording

• BrokenPipeError: [Errno 32] Broken pipe (Exception ignored in flush of stdout)
• ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine
• OSError: [Errno 32] Broken pipe

Related errors

• ConnectionResetError: [Errno 104] Connection reset by peer
• RuntimeError: Event loop is closed
• OSError: [Errno 98] Address already in use

More in Network and HTTP

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• Error: connect ECONNREFUSED 127.0.0.1:5432Node.js
• Error: connect ETIMEDOUT 10.0.4.12:5432Node.js
• TypeError: fetch failedNode.js
• Error: self-signed certificate in certificate chainNode.js
• Error: getaddrinfo ENOTFOUND api.example.comNode.js
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• httpx.ReadTimeout: The read operation timed outPython
• [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer...Python
• Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the clientNode.js
• 422 Unprocessable Entity: {"detail":[{"type":"missing","loc":["body","email"],"msg":"Field...Python

References: Python docs: Note on SIGPIPE, Python docs: built-in exceptions (BrokenPipeError)