Trinidad Scheduler Extension
Trinidad Scheduler uses Quartz to schedule processes for execution. It can be run as a server extension to Trinidad and/or a Web Application extension for Trinidad. If run as a server extension all schedulers will get the server configuration options each option that is defined at the Web Application level will override the server option.
Trinidad Scheduler creates a unique scheduler for each web application. Most processes we schedule are scheduled using the Cron Trigger and run_later.
Along with Trinidad in your application's Gemfile :
group :server do platform :jruby do gem 'trinidad', require: false gem 'trinidad_scheduler_extension', require: false end end
Or install it yourself as a plain old gem :
$ gem install trinidad_scheduler_extension
Like all extensions set it up in the configuration file (e.g. trinidad.yml). In either the extensions block or under web app's extentions add "scheduler" :
--- port: 4242 # ... extensions: scheduler: # #some shortcuts are provided : # thread_count: 3 # thread_priority: 5 # interrupt_on_shutdown: false # #any quartz config might be specified : # org.quartz.jobStore.misfireThreshold: 1000 # #short format (without org.quartz prefix) : # rmi.export: true
It is valid to use the top level scheduling methods and
run_later together :
class ScheduledLog < TrinidadScheduler.Cron "0/5 * * * * ?" def run _logger.info "Executed every 5 seconds" TrinidadScheduler.run_later do _logger.info "Executed after a 3 second delay" end end end
Trinidad Scheduler is very lazy. Schedulers will only be instantiated when they are needed to execute a job or to setup a schedule for execution.
This laziness extends to even runtime definition of classes and use of
in conditional statements. When a
run_later block is encountered or a class is
defined at runtime that inherits from a
TrinidadScheduler base method the
scheduler will be created and started (if it does not exist).
If schedules are defined during application initialization then the scheduler will not be started until after the application is started by Tomcat.
NOTE: The lazy nature of
TrinidadScheduler also gives the user time to define
a logger outstide of the default configured log4j StdOut logger that is included
The extension defines several methods that return classes based on the configuration options provided. These methods map to the scheduler trigger type that Quartz provides. The implemented triggers are CronTrigger, SimpleTrigger, and DateIntervalTrigger.
To define a process to be run based on a cron expression :
class ScheduledClass < TrinidadScheduler.Cron "0/5 * * * * ?" def run _logger.info "I am printed every 5 seconds" end end
TrinidadScheduler.Cron takes a cron expression as it's only argument
and returns a class. This anonymous class is the parent of
does the work to wrap
ScheduledClass for use as a
CronTrigger in Quartz.
The instance method
run must be defined because it is called when the scheduled
process is triggered. _logger is an instance variable available in
which gives the class access to the Quartz logger that is configured.
Schedule an INFO log message every 5 seconds starting now, setting the end is not necessary in this context, but is done :
class TestJob < TrinidadScheduler.Simple :start => Time.now, :end => Time.now + 240, :repeat 3, :interval => 5000 def run _logger.info "I am inside this block" #=> prints "I am inside this block" every 5 seconds end end
The simple trigger will execute based on options passed to TrinidadScheduler.Simple, the options available are outlined above in the example, none of them are necessary if you only want to trigger the process once. You can define a start and end time as well as how many times to fire the trigger along with an interval to be observed between trigger execution.
Schedule an INFO log message every 5 seconds starting now and ending after 4 minutes
class TestJob < TrinidadScheduler.DateInterval :start => Time.now, :end => Time.now + 240, :unit => :second, :interval => 5 def run _logger.info "I am inside this block" #=> prints "I am inside this block" every 5 seconds end end
DateInterval Trigger will execute a triggered process based on the
configuration options passed.
For more information on using the
DateInterval trigger consult the source.
Schedules a block of code to run in another Thread after execution proceeds in the current Thread after the job runs it removes itself from the job scheduler.
run_later with default 3 second delay :
TrinidadScheduler.run_later do _logger.info "I am inside this block" #=> prints "I am inside this block" end
Using run_later with a 20 second delay :
TrinidadScheduler.run_later(:delay => 20) do _logger.info "I am inside this block" #=> prints "I am inside this block" end
Behind the scenes run_later is actually implemented using an anonymous class
that inherits from
TrinidadScheduler.Simple to schedule the run.
Open Source software is a community effort - thanks to all, but the following were instrumental in the inspiration for Trinidad's scheduler :
techwhizbang for handling of Quartz JobFactory
why_metaid for metaid extension
TERRACOTTA for continued support of Quartz Scheduler
@calavera for Trinidad server