How do I proxy requests to different upstreams based on the incoming port number in Kong?
Kong doesn’t route requests based on the incoming port by default. Configure multiple ports with proxy_listen, then use a pre-function plugin whose Lua script checks kong.request.get_port() and calls kong.service.set_target() to send each port’s traffic to a different upstream. This requires setting untrusted_lua to on or lax (not the default strict), since set_target() is otherwise blocked.
I would like to proxy requests to different upstreams regarding different incoming ports like below
e.g
http://<kong>:7000/test will be proxied to upstream1(https://<upstream1>:443/xxx)
http://<kong>:8000/test will be proxied to upstream2(https://<upstream2>:443/xxx)
http://<kong>:9000/test will be proxied to upstream3(https://<upstream3>:443/xxx)How to realize it?
As Kong does not support routing requests based on ports, we have to use the pre-function plugin to realize it.
Please refer bellow procedure to send requests based on different ports
(Please modify Lua script/service object/route object depend on your requirements)
Prerequisite: The pre-function plugin’s kong.service.set_target() call requires the untrusted_lua Kong configuration property to be set to on or lax (the default is now strict, which excludes this call). Set KONG_UNTRUSTED_LUA=on and restart Kong before proceeding, otherwise the plugin will fail with a 500 error: attempt to call field 'set_target' (a nil value).
Enable multiple proxy ports for Kong and restart Kong.
Modify below parameter in kong configuration
KONG_PROXY_LISTEN/proxy_listen=0.0.0.0:7000, 0.0.0.0:8000, 0.0.0.0:9000, 0.0.0.0:8443 sslRestart Kong
kong restartCreate below service object and route object
service:
name: test
url: https://<upstream1>:443/xxx
route:
name: test
path: /testWrite a Lua script like below, let’s name it as redirect.lua
local port = kong.request.get_port()
if port == 8000 then
kong.service.set_target("<upstream2>", 443)
kong.service.request.set_scheme("https")
kong.service.request.set_path("/xxx")
elseif port == 9000 then
kong.service.set_target("<upstream3>", 443)
kong.service.request.set_scheme("https")
kong.service.request.set_path("/xxx")
endEnable the pre-function plugin on the route object we created in step 2
curl -X POST http://<kong>:8001/routes/test/plugins \
-F "name=pre-function" \
-F "config.access[1]=@/path/to/redirect.lua"Testing
curl -i http://<kong>:7000/test
> response from upstream1
curl -i http://<kong>:8000/test
> response from upstream2
curl -i http://<kong>:9000/test
> response from upstream3As we could see,
request from 7000 port has been proxied to upstream1,
request from 8000 port has been proxied to upstream2,
request from 9000 port has been proxied to upstream3.