[req] Purge synced services on exit

[dekimsey]

Currently, consul-aws publishes the consul services and nodes. But does not clean-up after itself on exit. When we stopped the services and removed the container daemon we found all services were still listed.

I found this out when I decided to remove the discovery zone (via Terraform). AWS Cloud Map will not let one delete the zone until all services are deleted, and one cannot remove a service until all instances are deleted. There was much ... clicking that day.

Thank you

[hanshasselberg]

This is intentional, because I think in case consul-aws crashes, it is better if everything stays the way it was.
But I think we maybe could add a helper to delete everything consul-aws created?!

[dekimsey]

I feel that if consul-esm (as a daemon) terminates, then it should remove its synced services. I don't have any reason to expect them to survive. It's been awhile but does consul-aws gracefully lock on who is syncing to AWS? That might be an easy way to address crashing issues of a single instance.

Honestly, it wouldn't be so painful if the AWS interface for removing dead entries was better.

edit: A helper would be great regardless!