--
-- 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 /path/to/hls {
--   log_by_lua_file '/path/to/s5-nginx-log.lua';
-- }
--

local cleanup_delay = 1200
local log_exptime = 600

local log_cleanup = function(premature)
   local sfive = ngx.shared.sfive
   sfive:flush_expired()
   if premature then
      return
   end
   local ok, err = ngx.timer.at(cleanup_delay, log_cleanup)
   if not ok then
      ngx.log(ngx.ERR, "SFive(log): failed to reenqueue log_cleanup: ", err)
      sfive:delete("log:cleanup_running")
      return
   end
end

local start_cleanup_thread = function(sfive)
   local ok, err, force = sfive:add("log:cleanup_running", 1)
   if not ok then
      if err ~= "exists" then
         ngx.log(ngx.ERR, "SFive(log): failed to set cleanup_running flag: " .. err)
      end
      return
   end
   ok, err = ngx.timer.at(cleanup_delay, log_cleanup)
   if not ok then
      ngx.log(ngx.ERR, "SFive(log): failed to enqueue log_cleanup: ", err)
      sfive:delete("log:cleanup_running")
      return
   end
end

local status = ngx.var.status

if status == '200' or status == '206' then
   local sfive = ngx.shared.sfive
   local idx, err = sfive:incr("log:idx", 1)
   if not idx then
      ngx.log(ngx.ERR, "SFive(log): incrementing log index failed: " .. err)
   else
      local json = '{'
      json = json .. '"time": "' .. string.gsub(ngx.utctime(), " ", "T", 1) .. 'Z",'
      json = json .. '"client": "' .. ngx.var.remote_addr .. '",'
      json = json .. '"port": ' .. ngx.var.remote_port .. ','
      json = json .. '"ua": "' .. ngx.var.http_user_agent .. '",'
      json = json .. '"uri": "' .. ngx.var.uri .. '",'
      json = json .. '"status": ' .. status .. ','
      json = json .. '"bytes_sent": ' .. ngx.var.bytes_sent
      json = json .. '}'

      local sfive_log = ngx.shared.sfive_log
      local ok, err, force = sfive_log:add(idx, json, log_exptime)
      if not ok then
         ngx.log(ngx.ERR, "SFive(log): adding log line (".. idx .. ") to log store failed: " .. err)
      elseif force then
         ngx.log(ngx.WARN, "SFive(log): adding log line has overwritten other log lines - consider increasing the log store!")
      end
      start_cleanup_thread(sfive)
   end
end