What are the available logging levels in Fabric? (no replies)

I had mysqlfabric crash today (having some connection problems) - I've been running it in a screen - and the log file did not show the shutdown, but the console output did:

[INFO] 1435267594.013612 - XML-RPC-Session-1 - Stopping failure detector.
[INFO] 1435267594.284559 - XML-RPC-Session-1 - Shutting down Executor.
[INFO] 1435267594.285836 - XML-RPC-Session-1 - Executor has stopped.
[INFO] 1435267594.286290 - XML-RPC-Session-1 - Fabric node stopped.

- so it seems log_level=INFO does not send this error info to the log. There's definitely a DEBUG mode, but that's a little wordy - and catting /opt/local/bin/mysqlfabric turned up nothing.

Where could I look up what the available loging levels are?