Logging

Logger hierarchy

zmqtt uses the standard logging module with the following logger names:

zmqtt
  ├── zmqtt.transport
  ├── zmqtt.protocol
  └── zmqtt.client

Configure any of these with the standard logging API.

Enabling logging

The simplest way to see all library output:

import logging
logging.basicConfig(level=logging.DEBUG)

For production, configure only the loggers you care about:

import logging
logging.getLogger("zmqtt.client").setLevel(logging.WARNING)
logging.getLogger("zmqtt.protocol").setLevel(logging.DEBUG)

What DEBUG output looks like

At DEBUG level, the protocol layer logs every packet sent and received:

DEBUG zmqtt.protocol  → CONNECT client_id='' clean_session=True keepalive=60
DEBUG zmqtt.protocol  ← CONNACK session_present=False return_code=0
DEBUG zmqtt.protocol  → SUBSCRIBE filters=['sensors/#']
DEBUG zmqtt.protocol  ← SUBACK return_codes=[0]
DEBUG zmqtt.protocol  ← PUBLISH topic='sensors/temp' qos=0 retain=False
DEBUG zmqtt.protocol  → PINGREQ
DEBUG zmqtt.protocol  ← PINGRESP
DEBUG zmqtt.protocol  → DISCONNECT

At INFO level the client layer logs reconnection events:

WARNING zmqtt.client  Connection lost, reconnecting in 1.0s
INFO    zmqtt.client  Successfully reconnected

Duplicate-filter warnings come from zmqtt.protocol (see Subscribing — Duplicate-filter guard):

WARNING zmqtt.protocol  Filter 'data/temp' already registered; skipping duplicate

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See also: Reconnection · Error Handling