help request: how to mannually routing to another service base on some condition

[darkSheep404]

Description

Dear apisix team, i want to base on some condition to routing to different service
when i use ctx.upstream_id = conf.upstream_id it will routing to new upstream
but when i use ctx.service_id = conf.service_id , it still routing to old version
Cause we have plugins on service level , routing to new service will be better than routing to a new upstream
May I know how can we mannually change service to annother service in plugin code ?

local core       = require("apisix.core")
local upstream   = require("apisix.upstream")
local schema_def = require("apisix.schema_def")
local expr       = require("resty.expr.v1")

local plugin_name = "custom-traffic-split"
local schema = {
    type = "object",
    properties = {
        upstream_id = schema_def.id_schema,
        service_id = schema_def.id_schema
    }
}

local _M = {
    version = 0.1,
    priority = 966,
    name = plugin_name,
    schema = schema
}

function _M.check_schema(conf)
    return core.schema.check(schema, conf)
end

function _M.access(conf, ctx)
    if not conf then
        return
    end

    --  
    local gary_release = core.request.header(ctx, "gary_version")
    if not gary_release then
        return
    end

    -- 
    if conf.upstream_id then
        ctx.upstream_id = conf.upstream_id
        return
    end


    if conf.service_id then
        ctx.service_id = conf.service_id 
        return
    end


   
end

return _M

Environment

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

[Baoyuantop]

Route matching and service merging are performed before the access phase. Once matching and merging are completed, simply changing ctx.service_id during subsequent plugin processing will not result in re-obtaining service configuration and re-merging route configuration.

In contrast, the processing logic of upstream_id is different. It is mainly used to directly select upstream services in the request phase and does not involve configuration merging. Therefore, it can be changed dynamically in the access phase of the plugin.

If you really need to route traffic to different services based on conditions, you should continue to use ctx.upstream_id = conf.upstream_id, which is a valid approach. Consider configuring plugins at the route level, rather than relying on the service level.

[Baoyuantop]

If there is still a problem, please open it again.