By default, circusd keeps its logging to stdout rather sparse. This lack of output can make things hard to troubleshoot when processes seem to be having trouble starting.
To increase the logging circusd provides, try increasing the log level. To see the available log levels just use the –help flag.
$ circus --log-level debug test.ini
One word of warning. If a process is flapping and the debug log level is turned on, you will see messages for each start attempt. It might be helpful to configure the app that is flapping to use a warmup_delay to slow down the messages to a manageable pace.
[watcher:webapp]
cmd = python -m myapp.wsgi
warmup_delay = 5
By default, stdout and stderr are captured by the circusd process. If you are testing your config and want to see the output in line with the circusd output, you can configure your watcher to use the StdoutStream class.
[watcher:webapp]
cmd = python -m myapp.wsgi
stdout_stream.class = StdoutStream
stderr_stream.class = StdoutStream
If your application is producing a traceback or error when it is trying to start up you should be able to see it in the output.