Dynamic upstream generation

aromanov · 2018-09-28T00:57:52+00:00

I've been trying to identify the last HTTP request from a buffer of 10 requests sent on a TCP connection in nginx. I've tried to use the header_in field in t...

Dynamic upstream generation

aromanov

Hi,

Is there any way to use balancer_by_lua to set multiple upstreams to serve a request?

Maybe there are other modules that will allow me to do this? Or will it be necessary to implement it all in Lua?

The goal is to dynamically generate upstream with one or more servers so that these upstreams remain subject to proxy_next_upstream and similar settings?

Thanks.

piotrprz

Please read the documentation, it works exactly as you need it to: https://github.com/openresty/lua-resty-core/blob/master/lib/ngx/balancer.md. balancer_by_lua is a callback called when nginx needs an upstream address, and it's your responsibility to set next tried address and stop conditions. That way you can easily implement various complex balancing schemes, different for each request.

If your upstreams change frequently that is the way to go. If you rarely change them then it may be easier to dynamically generate nginx config - depending on the amount of Lua code you already have.

W dniu czwartek, 27 września 2018 18:57:52 UTC+2 użytkownik Anton Romanov napisał:

Hi,

Is there any way to use balancer_by_lua to set multiple upstreams to serve a request?

Maybe there are other modules that will allow me to do this? Or will it be necessary to implement it all in Lua?

The goal is to dynamically generate upstream with one or more servers so that these upstreams remain subject to proxy_next_upstream and similar settings?

Thanks.

aromanov

Yes. I misunderstood one of the examples. It seemed like you could pass
an array of servers and have the module handle the rest, but it
obviously has to be handled manually.

I guess, it asks for a PR.

Thanks for clarification.


On 30/09/2018 23:35, Piotr Przybylski wrote:
> Please read the documentation, it works exactly as you need it to:
> https://github.com/openresty/lua-resty-core/blob/master/lib/ngx/balancer.md.
> balancer_by_lua is a callback called when nginx needs an upstream
> address, and it's your responsibility to set next tried address and stop
> conditions. That way you can easily implement various complex balancing
> schemes, different for each request.
> 
> If your upstreams change frequently that is the way to go. If you rarely
> change them then it may be easier to dynamically generate nginx config -
> depending on the amount of Lua code you already have.