--
-- sfive
--
-- sfive - spreadspace streaming statistics suite is a generic
-- statistic collection tool for streaming server infrastuctures.
-- The system collects and stores meta data like number of views
-- and throughput from a number of streaming servers and stores
-- it in a global data store.
-- The data acquisition is designed to be generic and extensible in
-- order to support different streaming software.
-- sfive also contains tools and applications to filter and visualize
-- live and recorded data.
--
--
-- Copyright (C) 2014 Christian Pointner <equinox@spreadspace.org>
--                    Markus Grueneis <gimpf@gimpf.org>
--
-- This file is part of sfive.
--
-- sfive is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License version 3
-- as published by the Free Software Foundation.
--
-- sfive is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with sfive. If not, see <http://www.gnu.org/licenses/>.
--
--
-- Install this by adding the following to your nginx.conf
--
-- location /sfive {
--   allow localhost;
--   deny  all;
--
--   lua_check_client_abort on;
--   content_by_lua_file '/path/to/s5-nginx-fetch.lua';
-- }
--

local sfive = ngx.shared.sfive

local function fetch_cleanup()
   ngx.log(ngx.INFO, "SFive(fetch): cleanup fetch")
   sfive:delete("fetch:connected")
end

local ok, err, force = sfive:add("fetch:connected", 1)
-- TODO: race condition: when client disconnects here we won't free up the singleton...
if not ok then
   if err == "exists" then
      ngx.exit(ngx.HTTP_SERVICE_UNAVAILABLE)
   else
      ngx.log(ngx.ERR, "SFive(fetch): failed to set connected flag: " .. err)
      ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)
   end
else
   local ok, err = ngx.on_abort(fetch_cleanup)
   if not ok then
      ngx.log(ngx.ERR, "SFive(fetch): failed to register the on_abort callback: ", err)
      ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)
   end

   ngx.log(ngx.INFO, "SFive(fetch): client connected")

   local sfive_log = ngx.shared.sfive_log
   while true do
      logs = sfive_log:get_keys()
      for i, k in ipairs(logs) do
         local ok, err = ngx.say(sfive_log:get(k))
         if not ok then
            ngx.log(ngx.ERR, "SFive(fetch): failed to register the on_abort callback: ", err)
            break
         end
         sfive_log:delete(k)
      end
      ngx.flush()
      ngx.sleep(0.1)
   end
   fetch_cleenup()
end