How to get consumer tags in upstreams?

[99hops]

Hello, I am looking for a way to get consumer tags as header values in upstreams. What is the way to do this? I have request-transform plugin but I can't find the right values to put, please advice! 🙏

Maybe something like this? (:

- name: request-transformer
  enabled: true
  config:
    add:
      headers:
        - "x-consumer-tag1: ${kong.client.tag1}"

[StarlightIbuki]

It can be achieved by a custom plugin. Please refer to https://docs.konghq.com/gateway/latest/plugin-development/custom-logic/

[99hops]

Thanks @StarlightIbuki I was able to achieve it with post-function plugin like

local function getTag(tagsArray, targetTag)
    if not tagsArray or type(tagsArray) ~= "table" then
        return nil
    end

    for _, value in ipairs(tagsArray) do
        local tag, tagValue = string.match(value, "(.-)=(.+)")
        if tag == targetTag then
            return tagValue
        end
    end

    return nil  -- Tag not found
end

local function hasTag(tagsArray, targetTag)
    if not tagsArray or type(tagsArray) ~= "table" then
        return false
    end

    for _, value in ipairs(tagsArray) do
        local tag = string.match(value, "(.-)=(.+)")
        if tag == targetTag or value == targetTag then
            return true
        end
    end

    return false
end

return function()
   local consumer = kong.client.get_consumer()
   
   if consumer then
      local consumerTag1 = getTag(consumer.tags, "tag1")

      if consumerTag1 then
        kong.service.request.set_header("x-consumer-tag1", consumerTag1)
      end

      --if not hasTag(consumer.tags, "na") then
      --  kong.service.request.set_header("x-missing-tag", 'tag')
      --end
   else
     -- request not authenticated yet, or a credential
     -- without a consumer (external auth)
     kong.service.request.set_header("x-unauthorized", 'unauthorized')
   end
end