Support different redis db inside the same instance.

[mastrolinux]

Since python redis does not support select: https://github.com/andymccurdy/redis-py#thread-safety

And some users uses different db in the same redis instance-port pair, could be good to support the syntax:

redis_urls: password@host:9002:2 in the redis.conf file

to access for example:

redis.StrictRedis(host='host', port=9002, db=2, password='password')

now is only supported:

``redis.StrictRedis(host='host', port=9002, password='password')`

You should change the _get_conn methond from
def _get_conn(self, host, port, password):

to def _get_conn(self, host, port, password, db):

[clutchski]

Correct me if I'm wrong, but I think the redis INFO command returns the same data regardless of what DB it's connected to. Is there something particular you're looking to get by querying each database?

[mastrolinux]

Custom queries are almost impossible with the current api interface. To add the needed queries we do not have to just add our queries but to change your connection method and make our agent not fully compatible with your. Could be good to have an abstract interface supporting all connections parameters currently supported by python-redis.

[clutchski]

Oh I see, you want to collect metrics from specific queries. Out of curiosity, what kind of data are you collecting? I'm wondering if it belongs in the generic redis check or a custom check? Or are you just looking to extend the current redis check to make a custom check?

[mastrolinux]

I am just looking to extend the current redis check to make customs checks using the same interface and methods you alredy use instead of writing again them from scratch breaking compatibility.
I am collecting the number of value for a key (like a count) they are bloking queries running on the slave only. We use the slave for all the monitoring queries.

[alq666]

Slotting this for 3.7. The configuration format has changed, which will make our work easier as a matter of fact.

[remh]

Will be done for 3.7.1 or 3.8.0

[mastrolinux]

Very cool, thanks.