The fallback method would still work but it would get into a state where it would let the certificate expire for 10s before getting a new one. And the new one used the less secure RPC endpoint.
This is also a pretty large refactoring of the auto encrypt code. I was going to write some tests around the certificate monitoring but it was going to be impossible to get a TestAgent configured in such a way that I could write a test that ran in less than an hour or two to exercise the functionality.
Moving the certificate monitoring into its own package will allow for dependency injection and in particular mocking the cache types to control how it hands back certificates and how long those certificates should live. This will allow for exercising the main loop more than would be possible with it coupled so tightly with the Agent.
The initial auto encrypt CSR wasn’t containing the user supplied IP and DNS SANs. This fixes that. Also We were configuring a default :: IP SAN. This should be ::1 instead and was fixed.
AutoEncrypt needs the server-port because it wants to talk via RPC. Information from gossip might not be available at that point and thats why the server-port is being used.
Auto-encrypt meant to fallback to the default port when it wasn't provided, but it hadn't been because of an issue with the error handling. We were checking against an incomplete error value:
"missing port in address" vs "address $HOST: missing port in address"
Additionally, all RPCs to AutoEncrypt.Sign were using a.config.ServerPort, so those were updated to use ports resolved by resolveAddrs, if they are available.
