multi-server ("clustered") event scheduler

events are stored in MySQL so they survive a shutdown, reboot, crash, alien abduction and more!
events are any api command


git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk/contrib@15204 d0543943-73ff-0310-b7d9-9358b9ac24b2

trixter/README

@@ -23,6 +23,13 @@ with the programs whether commercial or FOSS.
 
 == FILE LIST ==
 
+scheduled_event.lua
+	LUA script that adds scheduler ability via a MySQL store.
+	Allows for many systems to process events to scale to enterprise capability
+	Events survive switch shutdown, restart, reboot, crash, etc
+	Simple DB schema which allows you to easily integrate into webapps
+
+
 apiexec.pl
 	Execute api commands from the console/cron/windows scheduler/etc
 

trixter/scheduled_event.lua

+-- Version: MPL 1.1
+--
+-- The contents of this file are subject to the Mozilla Public License Version
+-- 1.1 (the "License"); you may not use this file except in compliance with
+-- the License. You may obtain a copy of the License at
+-- http://www.mozilla.org/MPL
+--
+-- Software distributed under the License is distributed on an "AS IS" basis
+-- WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+-- for the specific language governing rights and limitations under the
+-- License
+--
+-- The Original Code is FreeSWITCH[tm] LUA event scheduler
+--
+-- The Initial Developer of the Original Code is
+-- Bret McDanel <bret AT 0xdecafbad dot com>
+--
+-- Portions created by the Initial Developer are Copyright (C) 2007
+-- the Initial Developer. All Rights Reserved
+--
+-- Contributor(s)
+--
+-- Why use this?
+--  No reason in particular, however if you use sched_api and shut down you lose your scheduled events, by
+--  placing them in a database you get the advantage of them being able to survive a shutdown/crash/reboot/etc
+--  Additionally this script is written in a way to allow for multiple switch boxes to access the same database
+--  and look  for events to process, in this way you can scale this to a very large amount of actions
+--
+--
+-- Usage: in FreeSWITCH console or fs_cli,
+-- luarun scheduled_event.lua
+--        starts the script - this is not needed if its auto loaded
+-- luarun scheduled_event.lua <dbuser username> <dbhost hostname> <dbpass password> <dbname database_name>
+--        changes the DB info allowing you to do load management, maintenence, or other things
+-- luarun scheduled_event.lua stop
+--        stops the running script
+--   
+--      in lua.conf.xml:
+-- 	 <param name="startup-script" value="scheduled_event.lua"/>
+--	 
+--
+-- You need to get "mysql.so" for lua and install it in <freeswitch install>/luasql/mysql.so 
+--   (or some other place that is in the search path)
+--
+-- Minimal DB schema **AUTOMAGICALLY CREATED IF IT DOES NOT EXIST** (at script start)
+-- CREATE TABLE scheduler (
+--    acctid int(11) NOT NULL auto_increment,
+--    action varchar(1024) NOT NULL,
+--    timestamp timestamp NOT NULL,
+--    primary key (acctid)
+-- );
+--
+-- "actions" in the scheduler table should be api commands eg:
+-- insert into scheduler (action,timestamp) values ("pa call 1234",NOW())
+-- 
+--
+-- Every "heartbeat" events are pulled 1 at a time using write locks on mysql
+-- if your MySQL supports those locks, then only one process can access the DB at a time
+-- events are immediately deleted, and then processed to keep the lock time low
+-- failed events are NOT rescheduled
+-- many boxes can pull events and process them, however I did not attempt to process more
+-- events than time allows for in a given heartbeat interval, some backlog may exist which
+-- may cause this script to totally freak
+
+
+   require "luasql.mysql"
+   
+   -- Database setup
+   DATABASE = "database"
+   USERNAME = "dbuser"
+   PASSWORD = "het is geheim"
+   DBHOST   = "localhost"
+   TABLENAME = "scheduler"
+
+   -- LOGGING
+   LOGLEVEL = "info"
+   
+   -- PROGNAME
+   PROGNAME = "scheduled_event.lua"
+   
+   function logger(message)
+      freeswitch.console_log(LOGLEVEL,"["..PROGNAME.."] "..message.."\n")
+   end
+   
+   
+   if argv[1] then
+      i=1
+      while argv[i] do
+	 if argv[i] == "stop" then
+	    local event = freeswitch.Event("custom", "lua::scheduled_event")
+	    event:addHeader("Action", "stop")
+	    event:fire()
+	    logger("Sent stop message to lua script")
+	    return
+	 elseif (argv[i] == "dbuser") then
+	    i=i+1
+	    if argv[i] then
+	       logger("Setting DB Username to "..argv[i])
+	       USERNAME = argv[i]
+	    else
+	       logger("You must specify a username!")
+	    end
+	 elseif (argv[i] == "dbhost") then
+	    i=i+1
+	    if argv[i] then
+	       logger("Setting DB Hostname to "..argv[i])
+	       DBHOST = argv[i]
+	    else
+	       logger("You must specify a hostname!")
+	    end
+	 elseif (argv[i] == "dbpass") then
+	    i=i+1
+	    if argv[i] then
+	       logger("Setting DB Password to "..argv[i])
+	       PASSWORD = argv[i]
+	    else
+	       logger("You must specify a password!")
+	    end
+	 elseif (argv[i] == "dbname") then
+	    i=i+1
+	    if argv[i] then
+	       logger("Setting DB to "..argv[i])
+	       DATABASE = argv[i]
+	    else
+	       logger("You must specify a database name!")
+	    end
+	 end
+	 i=i+1
+      end
+      return
+   end
+   
+   --Main function starts here
+   logger("Starting")
+
+   -- ensure DB works, create table if it doesnt exist
+   env = assert (luasql.mysql())
+   dbcon = assert (env:connect(DATABASE,USERNAME,PASSWORD,DBHOST))
+   blah = assert(dbcon:execute("CREATE TABLE if not exists "..TABLENAME.." ("..
+			"acctid int(11) NOT NULL auto_increment,"..
+			"action varchar(1024) NOT NULL,"..
+			"timestamp timestamp NOT NULL,"..
+			"primary key (acctid)"..
+			       ")"))
+   dbcon:close()
+   env:close()
+
+   local event_name
+   local event_subclass
+
+   con = freeswitch.EventConsumer("all") -- too lazy to figure out why "heartbeat CUSTOM lua::scheduled_event"
+                                         -- does not work properly, that is really all we need
+   api = freeswitch.API()
+
+
+   if blah ~= 0 then
+      logger("Unable to connect to DB or create the table, something is broken.")
+   else
+      for e in (function() return con:pop(1) end) do
+	 event_name = e:getHeader("Event-Name") or ""
+	 event_subclass = e:getHeader("Event-Subclass") or ""
+	 
+	 if(event_name == "HEARTBEAT") then
+	    env = assert (luasql.mysql())
+	    dbcon = assert (env:connect(DATABASE,USERNAME,PASSWORD,DBHOST))
+	    while true do
+	       assert (dbcon:execute("LOCK TABLE "..TABLENAME.." WRITE"))
+	       cur = assert (dbcon:execute("select * from "..TABLENAME.." where timestamp < NOW() order by timestamp desc limit 1"))
+	       row = cur:fetch({},"a")
+	       if not row then
+		  break
+	       end
+	       assert(dbcon:execute("delete from "..TABLENAME.." where acctid = "..row.acctid));
+	       assert (dbcon:execute("UNLOCK TABLES"))
+	       apicmd,apiarg = string.match(row.action,"(%w+) (.*)")
+	       api:execute(apicmd,apiarg)
+	    end
+	    dbcon:close()
+	    env:close()
+	 else if (event_name == "CUSTOM" and event_subclass == "lua::scheduled_event") then
+	       action = e:getHeader("Action") or ""
+	       if (action == "stop") then
+		  logger("got stop message, Exiting")
+		  break
+	       end
+	    end
+	 end
+      end
+   end
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