What are your logging requirements? Do you just need to capture that it was launched/completed and the inputs? Or do you need to capture the workings of the action itself?
We log the majority of requests to Splunk by subscribing to the relevant event topics. So in this case, it would be subscribing to deployment.resource.action.pre/post topics. And then the workflow that is called enumerates the inputs, gets the status, etc. and sends it over to Splunk. And then we build dashborads to see which day-2's are being run, if they're succeeding, etc.
We also log our scripts there as well. So if we write any custom day-2 actions, the corresponding script we ultimately call to do the work will send its params/details/messages to Splunk as well. Although, that wouldn't be an option for oob day-2 actions of course.
