Connect to redis using upstream about lua-resty-redis

[agentzh]

@eoranged The lua-resty-redis library is based on ngx_lua's cosocket API, which is a parallel implementation to the ngx_http_upstream thing in the nginx core. You can do everything you did with ngx_redis2 + upstream {...} in Lua with lua-resty-redis but you cannot mix these two like accessing upstream {...} entries from within lua-resty-redis.

[eoranged]

It is sad, but I got It.

[agentzh]

@eoranged why do you still want to keep using your upstream {...} blocks?

[eoranged]

@agentzh As I have already mentioned in the question, http_upstream_module provides load-balancing and handles backend fails.

[agentzh]

@eoranged You can easily implement failover and load balancing yourself with a little bit of Lua if you're using lua-resty-redis. Also you have much more flexibility here.

See also https://github.com/agentzh/lua-resty-redis#load-balancing-and-failover

[wonderbeyond]

Any existing code for reference? whether lua or not.

[wonderbeyond]

I've done a very basic redis load balancer module: https://gist.github.com/wonderbeyond/11a20570bb5b1b1bf818bf03e527faf6

I just select the next server from a given list circularly.

[marius-c]

hmm is the above example correct ? is that counter shared across all workers / sessions ?

[wonderbeyond]

I have used it in production until now.

The counter is shared in one single worker.

[marius-c]

yep makes sense. just read the docs. thanks for sharing.

[wonderbeyond]

However, I think we need a more powerful balancer module.
e.g. We can report failure of one redis node to the balancer, the balancer will not select it for a period of time.

Are you interesting?