THREESCALE-11061: Async mode: Add support for Redis logical DBs

[jlledom]

This comes from of #350.

Now the Async mode supports Redis logical databases, and honors URLs like redis://localhost:6379/6

The support has been also added for sentinels. A typical config would look like this:

CONFIG_REDIS_PROXY=redis://redis-master/6
CONFIG_REDIS_SENTINEL_HOSTS=redis://localhost:26379,redis://localhost:26380,redis://localhost:26381

Jira: https://issues.redhat.com/browse/THREESCALE-11061

[jlledom]

From #389 (comment):

@akostadinov

Instead of monkey patching upstream protocol class, it is a much better approach to use our own class and use the upstream protocol class with the composition pattern. Like I commented here: #350 (comment)

I don't understand what you mean. I'm not monkey patching the original protocol class, I added a new class ExtendedRESP2 which in fact is pretty similar to the example you mentioned:

https://github.com/socketry/async-redis/blob/feb67542dc27947fddbc647ad4b7289645975698/examples/auth/wrapper.rb#L52-L74

[akostadinov]

I added a new class ExtendedRESP2 which in fact is pretty similar to the example you mentioned

Because I saw you using the Async namespace, I thought this is monkey-patching the class. Could you use our own namespace for the class? It's clearer what comes from where.

[mayorova]

I'm thinking whether we need to report an error if the db is not an integer.
Or just let the client respond to select {invalid-value} with whatever it likes?

[akostadinov]

Yeah, I wouldn't bother reraising this.

[jlledom]

agree with @akostadinov

[jlledom]

I added a new class ExtendedRESP2 which in fact is pretty similar to the example you mentioned

Because I saw you using the Async namespace, I thought this is monkey-patching the class. Could you use our own namespace for the class? It's clearer what comes from where.

True. Fixed in 41a9925

[akostadinov]

Nice! It's a bummer that Redis is somehow conflicting though. I'm fine to keep it as is. One possible option is to call the module AsyncRedis for example. But I leave it to your preference.

[jlledom]

Nice! It's a bummer that Redis is somehow conflicting though. I'm fine to keep it as is. One possible option is to call the module AsyncRedis for example. But I leave it to your preference.

Yeah, I think I'm gonna rename it.

[jlledom]

Nice! It's a bummer that Redis is somehow conflicting though. I'm fine to keep it as is. One possible option is to call the module AsyncRedis for example. But I leave it to your preference.

Yeah, I think I'm gonna rename it.

@akostadinov done in 7a2da06