help request: Can't APISIX routing request thru a middle-proxy between upstream?

[AmerDwight]

Description

In my case, the upstream server is hosted in other net, which is separated from net of APISIX The way to connect is probably go thru with middle-proxy, like:

+-----------------+         +---------+         +-----------------+
|    Network A    |         |         |         |    Network B    |
|                 |         |  Proxy  |         |                 |
|    [APISIX]-----|-------->|         |-------->|---[Server]      |
|        ^        |         |         |         |                 |
|        |        |         |         |         |                 |
|    [Request]    |         |         |         |                 |
+-----------------+         +---------+         +-----------------+

So, I set middle-proxy info in environment, ( Docker image: apisix:3.2.2-centos ) and testify the middle-proxy by curl command, which is doing fine.

But if I build in route of APISIX, it goes 503 response. I don't know why APISIX did not sent requests follow the middle-proxy setting in environment

upstream:

{
  "nodes": [
    {
      "host": "outersite", # this is a address that APISIX shall access with middle-proxy 
      "port": 80,
      "weight": 1
    }
  ],
  "timeout": {
    "connect": 6,
    "send": 6,
    "read": 6
  },
  "type": "roundrobin",
  "scheme": "http"
}

routes:

{
  "uri": "/proxy",
  "name": "proxy-t1-route",
  "upstream_id": "491273801099641868",
  "status": 1
}

CentOS proxy-set: /etc/bashrc

export http_proxy=http://squid:3128
export https_proxy=https://squid:3128

Environment

• APISIX version (run apisix version): apisix:3.2.2-centos
• Operating system (run uname -a): Docker - centos
• OpenResty / Nginx version (run openresty -V or nginx -V):
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info): bitnami/etcd:3.5
• APISIX Dashboard version, if relevant: apache/apisix-dashboard:latest
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[markokocic]

This is a common use case, but unfortunately, APISIX doesn't have an answer here. The reason is APISIX being based on nginx and nginx doesn't support proxies for upstreams, and also doesn't have plans to support it. Unlike curl, wget and some other tools.

There are tricks that can be done on the network level, like setting up a transparent proxy, or using some third-party utility like redsocks2 or similar, but it's definitively more involved.

I would definitively like to see an official doc how to set up a Linux or Docker VM with proxy support, or even a packed docker compose which works out of the box. I think this use case is pretty common for an API Gateway, and every commercial API Gateway that I can think of has an easy way to configure http_proxy or https_proxy on a gateway or endpoint level.

[AmerDwight]

@markokocic Yeah, I found that the mechanism was to find the address of upstreams while initializing, in order to achieve a static reference. Thanks for your reply and hints provided.