Fix problems connecting to redis sentinel with SSL

[amanda11]

When connecting to redis SSL via sentinel then 2 problems are encountered:

1. redis 3.5.3 did not support ssl parameters for sentinel, see sentinel: Add SentinelManagedSSLConnection redis/redis-py#1419. So upping the version of redis library
2. When using eventlet and redis SSL then there are connection problems, due to the fact the redis library has expected timeouts, but monkey patched SSL library is throwing different exception. See Eventlet raises a different exception on SSL timeouts vs standard Python eventlet/eventlet#692. This causes problems on connecting to redis SSL via sentinel. It also is likely to be the cause of error: SSL Error with st2 sensor connection redis #5337 as the stack trace encountered is the same.
   Therefore when monkey patching SSL library, keep the exception raised on timeout to be socket.timeout.

[raviorch]

Amanda, Please let us know which version of Redis you used to fix the Redis and Sentinel issues for TLS. Redis officially supports TLS from their 6.0 version onwards. Text from redis.io : "SSL/TLS is supported by Redis starting with version 6 as an optional feature that needs to be enabled at compile time." Are you using the latest Redis version 7.0 or 6.2.2?

[amanda11]

I used 6.2.7 and compiled at run-time to enable SSL for my testing (which is latest on the 6.2 stream). But the changes here are compatible with non-SSL and SSL redis versions, so work fine with the versions that the bash installer uses (though in those cases the package manager will pull down non-SSL version of redis), therefore if using the package manager redis you won't have SSL support.
I have no reason to believe this won't work with redis 7, but I have not verified that.
This Pr is to resolve problems found with users that install redis separately with TLS enabled.

[raviorch]

Amanda, Thanks for the update, I was wondering if the ssl fix that you have put in also has the fix for providing an username password for Redis. Please let us know.

[amanda11]

As far as I know there is no issue with username/password with non-ssl redis. I've used StackStorm connected to redis secured by username/password before quite happily, on many StackStorm versions including 3.7.0

[cognifloyd]

Eventlet strikes again. 🙄