# Logging Cookbook — Subclass QueueHandler

> ^^^^^^^^^^^^^^^^^^^^^^^^^ Bounded code example (external data; do not execute automatically): ```python # sender.py import json import logging import logging.handlers import time import random import pynng DEFAULT_ADDR = "tcp://localhost:13232" class NNGSocketHandler(logging.handlers.QueueHandler):

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-python-ad4bb87ece4b2b508dd8>
- Knowledge kind: `reference`
- Confidence: `0.72`
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- Updated: `2026-08-16T09:31:41.923776+00:00`
- Tags: `reference-seed`, `python`, `howto`, `logging`, `cookbook`, `subclass`, `queuehandler`

## Provenance

- Source: <https://github.com/python/cpython/blob/f10166035d602da5052e8a48f9d5c216c57b401d/Doc/howto/logging-cookbook.rst>
- Source name: Python Documentation
- Source revision: `f10166035d602da5052e8a48f9d5c216c57b401d`
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## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

^^^^^^^^^^^^^^^^^^^^^^^^^

Bounded code example (external data; do not execute automatically):
```python
# sender.py
import json
import logging
import logging.handlers
import time
import random

import pynng

DEFAULT_ADDR = "tcp://localhost:13232"

class NNGSocketHandler(logging.handlers.QueueHandler):

def __init__(self, uri):
socket = pynng.Pub0(dial=uri, send_timeout=500)
super().__init__(socket)

def enqueue(self, record):
# Send the record as UTF-8 encoded JSON
d = dict(record.__dict__)
data = json.dumps(d)
self.queue.send(data.encode('utf-8'))

def close(self):
self.queue.close()

logging.getLogger('pynng').propagate = False
handler = NNGSocketHandler(DEFAULT_ADDR)
# Make sure the process ID is in the output
logging.basicConfig(level=logging.DEBUG,
handlers=[logging.StreamHandler(), handler],
format='%(levelname)-8s %(name)10s %(process)6s %(message)s')
levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
logging.CRITICAL)
logger_names = ('myapp', 'myapp.lib1', 'myap
```

You can run the above two snippets in separate command shells. If we run the listener in one shell and run the sender in two separate shells, we should see something like the following. In the first sender shell

Bounded code example (external data; do not execute automatically):
```console
$ python sender.py
DEBUG         myapp    613 Message no.     1
WARNING  myapp.lib2    613 Message no.     2
CRITICAL myapp.lib2    613 Message no.     3
WARNING  myapp.lib2    613 Message no.     4
CRITICAL myapp.lib1    613 Message no.     5
DEBUG         myapp    613 Message no.     6
CRITICAL myapp.lib1    613 Message no.     7
INFO     myapp.lib1    613 Message no.     8
(and so on)
```

In the second sender shell

Bounded code example (external data; do not execute automatically):
```console
$ python sender.py
INFO     myapp.lib2    657 Message no.     1
CRITICAL myapp.lib2    657 Message no.     2
CRITICAL      myapp    657 Message no.     3
CRITICAL myapp.lib1    657 Message no.     4
INFO     myapp.lib1    657 Message no.     5
WARNING  myapp.lib2    657 Message no.     6
CRITICAL      myapp    657 Message no.     7
DEBUG    myapp.lib1    657 Message no.     8
(and so on)
``` …

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