featrue: implement Aggregate request function

[soulsoul]

Assemble the data of two or more backend interfaces and return it as one interface.
The first parameter mapping requirement, the development of plugins should be no problem, but want to know whether there are ready-made plugins can support it?

将两个或者两个以上上游接口的数据组装起来，作为一个聚合请求接口的数据返回。

[moonming]

APISIX not have this kind of plugin yet, I think it's useful, welcome PR.

[Beckjiang]

Assemble the data of two or more backend interfaces and return it as one interface.
The first parameter mapping requirement, the development of plugins should be no problem, but want to know whether there are ready-made plugins can support it?

将两个或者两个以上上游接口的数据组装起来，作为一个聚合请求接口的数据返回。

I have the same demand. How is your project progress now?

[membphis]

we can use cosocket + resty-http to implement this.

[Beckjiang]

About the request, it could be in two modes "pipeline" or "parallel".

The "pipeline" mode is easy to implement by httpc:request_pipeline. But what about the "parallel" mode? ngx.thread.spawn + resty-http?

[moonming]

why we need parallel mode? cosocket will not block request.

[Beckjiang]

I think It is a way to reduce the total response time.

A similar question.
https://groups.google.com/forum/#!msg/openresty/ro8DmOdvXe8/66S-W0yGCAAJ

[membphis]

httpc:request_pipeline is good enough.

[Beckjiang]

well. I will try it. thx.

[membphis]

fixed #1388