I've been trying to specify
actionsource => 'puppet:///modules/blah/blah/....'
but when I run puppet, I get this error:
'Error: Validation of File[custom-log.local] failed: You cannot specify more than one of content, source, target at /tmp/kitchen/modules/fail2ban/manifests/action.pp:149'
Looking over the filter.pp vs the action.pp, I directly copied over the $manage_file_content and edited it to reflect action instead of filter, and it appears to work fine now.