auth.lua

local count = 0
core.register_service("auth", "http", function (applet)
        count = count + 1
        -- Get X-Auth-Token --
        local token = applet.headers['x-auth-token'][0]

        local cmd = 'curl -H "X-Auth-Token:'..token..'"'
        cmd = cmd..' -sL -w "%{http_code}\\n"'
        cmd = cmd..' "https://staging.identity-internal.api.rackspacecloud.com/v2.0/tokens/'..token..'"'
        cmd = cmd..'  -o /dev/null'

        print(os.time())
        local output = io.popen(cmd)
        local result = output:read()
        output:close()
        print(os.time())
        print('----')
        print(count)
        if (result == 200) then
                applet:set_status(200)
        else
                applet:set_status(403)
        end

        local response = ""
        applet:add_header("content-length", string.len(response))
        applet:add_header("content-type", "text/plain")
        applet:start_response()
        applet:send(response)
end)

fetcher.lua

core.register_fetches("auth3", function(txn)
  core.Debug('FETCHER')
  local token = txn.f:hdr("x-auth-token")
  
  if token == nil then
    core.Debug('token is nil')
    return false
  end

  core.Debug('token exists')

  local identity_endpoint = 'https://staging.identity-internal.api.rackspacecloud.com/v2.0/tokens/'

  local t0 = socket.gettime()
  local body, code, headers = http.request(identity_endpoint .. token)
  local t1 = socket.gettime()
  local elapsed_time = t1 - t0 -- TODO set haproxy stat?
  core.Debug('call to identity took: ' .. elapsed_time .. 'ms')

  if body == nil then
    core.Debug('call to identity failed: ' .. code)
    return false
  end

  if code ~= 200 then
    core.Debug('token check failed: ' .. code)
    core.Debug('token check failed: ' .. body)
    pp(headers)

    local obj, pos, err = json.decode(body, 1, nil)
    print(obj['unauthorized']['message'])

    return false
  end

  -- TODO get json data from inside token response
  -- set
  txn:Debug('token ok: ' .. body)
  return true
end)

ha.conf

global
	lua-load auth.lua

listen http_in
	http-request use-service lua.auth
	bind *:8080
	mode http
	timeout connect 5000
	timeout client  50000
	timeout server  50000