The Qpidd broker and C++ clients can both use environment variables to enable logging. Use QPID_LOG_ENABLE to set the level of logging you are interested in (trace, debug, info, notice, warning, error, or critical):

$ export QPID_LOG_ENABLE="warning+"

The Qpidd broker and C++ clients use QPID_LOG_OUTPUT to determine where logging output should be sent. This is either a file name or the special values stderr, stdout, or syslog:

export QPID_LOG_TO_FILE="/tmp/myclient.out"

The Python client library supports logging using the standard Python logging module. The easiest way to do logging is to use the basicConfig(), which reports all warnings and errors:

from logging import basicConfig
basicConfig()

Qpidd also provides a convenience method that makes it easy to specify the level of logging desired. For instance, the following code enables logging at the DEBUG level:

from qpid.log import enable, DEBUG
enable("qpid.messaging.io", DEBUG)

For more information on Python logging, see http://docs.python.org/lib/node425.html. For more information on Qpid logging, use $ pydoc qpid.log.