Transient SSL SYSCALL error: EOF detected

[steve-chavez]

Problem

Now that we no longer ignore errors on the LISTEN channel (#3533) sometimes there are transient errors that shouldn't affect end users since PostgREST will recover immediately.

One example is SSL SYSCALL error: EOF detected:

Failed listening for notifications on the "pgrst" channel. SSL SYSCALL error: EOF detected
Retrying listening for notifications in 1 seconds...
Listening for notifications on the "pgrst" channel

The LISTEN connection might be interrupted by a proxy. We got the same report on #3313 (reply in thread).

Solution

Detect this error and indicate it's transient on the logs.

[steve-chavez]

With that said, my own personal opinion is that a transient error with remaining retries does not warrant an error event. Maybe a warning.
dotnet/efcore#15269 (comment)

I agree with the above. We should log the SSL error only at the warning level.

If the retrying delay goes beyond 1 second only then log an error? Or maybe just detect the SSL syscall message?