Scheduled Tasks

The ColdBox Scheduled Tasks offers a fresh, programmatic and human approach to scheduling tasks on your server and multi-server application

Introduction

Scheduled tasks have always been a point of soreness for many developers in ANY language. Especially choosing where to place them for execution: should it be cron? windows task scheduler? ColdFusion engine? Jenkins, Gitlab? and the list goes on and on.

ColdBox Scheduled Tasks

The ColdBox Scheduled Tasks offers a fresh, programmatic and human approach to scheduling tasks on your server and multi-server application. It allows you to define your tasks in a portable Scheduler we lovingly call the Scheduler.cfc which not only can be used to define your tasks, but also monitor all of their life-cycles and metrics of tasks. Since ColdBox is also hierarchical, it allows for every single ColdBox Module to also define a Scheduler and register their own tasks as well. This is a revolutionary approach to scheduling tasks in an HMVC application.

The ColdBox Scheduler is built on top of the core async package Scheduler.

Global App Scheduler

Every ColdBox application has a global scheduler created for you by convention and registered with a WireBox ID of [email protected]. However, you can have complete control of the scheduler by creating the following file: config/Scheduler.cfc. This is a simple CFC with a configure() method where you will define your tasks and several life-cycle methods.

config/Scheduler.cfc
component {
/**
* Configure the ColdBox Scheduler
*/
function configure() {
/**
* --------------------------------------------------------------------------
* Configuration Methods
* --------------------------------------------------------------------------
* From here you can set global configurations for the scheduler
* - setTimezone( ) : change the timezone for ALL tasks
* - setExecutor( executorObject ) : change the executor if needed
*/
/**
* --------------------------------------------------------------------------
* Register Scheduled Tasks
* --------------------------------------------------------------------------
* You register tasks with the task() method and get back a ColdBoxScheduledTask object
* that you can use to register your tasks configurations.
*/
task( "Clear Unregistered Users" )
.call( () => getInstance( "UserService" ).clearRecentUsers() )
.everyDayAt( "09:00" );
task( "Hearbeat" )
.call( () => runEvent( "main.heartbeat" ) )
.every( 5, "minutes" )
.onFailure( ( task, exception ) => {
getInstance( "System" ).sendBadHeartbeat( exception );
} );
}
/**
* Called before the scheduler is going to be shutdown
*/
function onShutdown(){
}
/**
* Called after the scheduler has registered all schedules
*/
function onStartup(){
}
/**
* Called whenever ANY task fails
*
* @task The task that got executed
* @exception The ColdFusion exception object
*/
function onAnyTaskError( required task, required exception ){
}
/**
* Called whenever ANY task succeeds
*
* @task The task that got executed
* @result The result (if any) that the task produced
*/
function onAnyTaskSuccess( required task, result ){
}
/**
* Called before ANY task runs
*
* @task The task about to be executed
*/
function beforeAnyTask( required task ){
}
/**
* Called after ANY task runs
*
* @task The task that got executed
* @result The result (if any) that the task produced
*/
function afterAnyTask( required task, result ){
}
}

Life-Cycle Methods

Every Scheduler can create life-cycle methods and monitor the scheduled tasks:

Method

Description

onStartup()

Called after the scheduler has registered all schedules

onShutdown()

Called before the scheduler is going to be shutdown

onAnyTaskError(task,exception)

Called whenever ANY task fails

onAnyTaskSuccess(task,result)

Called whenever ANY task succeeds

beforeAnyTask(task)

Called before ANY task runs

afterAnyTask(task,result)

Called after ANY task runs

Configuration Methods

Method

Description

setTimezone( timezone )

Set the timezone to use for all registered tasks

setExecutor( executor )

Override the executor generated for the scheduler

Timezone For All Tasks

By default, all tasks run under the system default timezone which usually is UTC. However, if you would like to change to a different execution timezone, then you can use the setTimeZone() method and pass in a valid timezone string:

setTimezone( "America/Chicago" )

Remember that some timezones utilize daylight savings time. When daylight saving time changes occur, your scheduled task may run twice or even not run at all. For this reason, we recommend avoiding timezone scheduling when possible.

Custom Executor

By default the scheduler will register a scheduled executor with a default of 20 threads for you with a name of [email protected] If you want to add in your own executor as per your configurations, then just call the setExecutor() method.

setExecutor(
getAsyncManager().newScheduledExecutor( "mymymy", 50 )
);

You can find how to work with executors in our executors section.

Scheduler Properties

Every scheduler has the following injections available to you in the variables scope

Object

Description

asyncManager

Async manager reference

cachebox

CacheBox reference

controller

ColdBox controller reference

executor

Scheduled executor

log

A pre-configured log object

started

A boolean flag indicating if the scheduler has started or not

tasks

The collection of registered tasks

timezone

Java based timezone object

util

ColdBox utility

wirebox

WireBox reference

Scheduler ColdBox Methods

Every scheduler has several useful ColdBox interaction methods you can use when registering your tasks callable methods.

Method

Description

announce()

Announce an interception

externalView()

Render an external view

getCache()

Get a cache from CacheBox

getColdBoxSetting()

Get a ColdBox setting

getEnv()

Retrieve a environment variable only

getInstance()

Get a instance object from WireBox

getModuleConfig()

Get a module config

getModuleSettings()

Get a module setting

getRenderer()

Get the ColdBox Renderer

getSetting()

Get an app Setting

getSystemSetting()

Retrieve a Java System property or env value by name. It looks at properties first then environment variables

getSystemProperty()

Retrieve a Java System property only

layout()

Render a layout

locateDirectoryPath()

Resolve a directory to be either relative or absolute in your application

locateFilePath()

Resolve a file to be either relative or absolute in your application

runEvent()

Run a ColdBox Event

runRoute()

Run a ColdBox Route

settingExists()

Check if a setting exists

setSetting()

Set a setting

view()

Render a view

Scheduler Utility Methods

Every scheduler has several utility methods:

Method

Description

getRegisteredTasks()

Get an ordered array of all the tasks registered in the scheduler

getTaskRecord( name )

Get the task record structure by name:

{

name,

task,

future,

scheduledAt,

registeredAt,

error,

errorMessage,

stacktrace

}

getTaskStats()

Builds out a struct report for all the registered tasks in this scheduler

hasTask( name )

Check if a scheduler has a task registered by name

hasStarted()

Has the scheduler started already

removeTask( name )

Cancel a task and remove it from the scheduler

startup()

Startup the scheduler. This is called by ColdBox for you. No need to call it.

shutdown()

Shutdown the scheduler

task( name )

Register a new task and return back to you the task so you can build it out.

Scheduling Tasks

Ok, now that we have seen all the capabilities of the scheduler, let's dive deep into scheduling tasks with the task( name ) method.

Registering Tasks

Once you call on this method, the scheduler will create a ColdBoxScheduledTask object for you, configure it, wire it, register it and return it to you.

task( "my-task" )

You can find the API Docs for this object here: https://s3.amazonaws.com/apidocs.ortussolutions.com/coldbox/6.4.0/coldbox/system/web/tasks/ColdBoxScheduledTask.html

Task Closure/Lambda/Object

You register the callable event via the call() method on the task object. You can register a closure/lambda or a invokable CFC. If you register an object, then we will call on the object's run() method by default, but you can change it using the method argument and call any public/remote method.

// Lambda Syntax
task( "my-task" )
.call( () => getInstance( "myService" ).runcleanup() )
.everyHour();
// Closure Syntax
task( "my-task" )
.call( function(){
// task here
} )
.everyHourAt( 45 );
// Object with run() method
task( "my-task" )
.call( getInstance( "MyTask" ) )
.everyDay()
// Object with a custom method
task( "my-task" )
.call( getInstance( "CacheService" ), "reapCache" )
.everydayAt( "13:00" )

Frequencies

There are many many frequency methods in ColdBox scheduled tasks that will enable the tasks in specific intervals. Every time you see that an argument receives a timeUnit the available options are:

  • days

  • hours

  • minutes

  • seconds

  • milliseconds (default)

  • microseconds

  • nanoseconds

Ok, let's go over the frequency methods:

Frequency Method

Description

every( period, timeunit )

Run the task every custom period of execution

spacedDelay( spacedDelay, timeunit )

Run the task every custom period of execution but with NO overlaps

everyMinute()

Run the task every minute from the time it get's scheduled

everyHour()

Run the task every hour from the time it get's scheduled

everyHourAt( minutes )

Set the period to be hourly at a specific minute mark and 00 seconds

everyDay()

Run the task every day at midnight

everyDayAt( time )

Run the task daily with a specific time in 24 hour format: HH:mm

everyWeek()

Run the task every Sunday at midnight

everyWeekOn( day, time )

Run the task weekly on the given day of the week and time

everyMonth()

Run the task on the first day of every month at midnight

everyMonthOn( day, time )

Run the task every month on a specific day and time

onFirstBusinessDayOfTheMonth( time )

Run the task on the first Monday of every month

onLastBusinessDayOfTheMonth( time )

Run the task on the last business day of the month

everyYear()

Run the task on the first day of the year at midnight

everyYearOn( month, day, time )

Set the period to be weekly at a specific time at a specific day of the week

onWeekends( time )

Run the task on Saturday and Sunday

onWeekdays( time )

Run the task only on weekdays at a specific time.

onMondays( time )

Only on Mondays

onTuesdays( time )

Only on Tuesdays

onWednesdays( time )

Only on Wednesdays

onThursdays( time )

Only on Thursdays

onFridays( time )

Only on Fridays

onSaturdays( time )

Only on Saturdays

onSundays( time )

Only on Sundays

All time arguments are defaulted to midnight (00:00)

Preventing Overlaps

Tasks with a fixed frequency vs delayed frequency

By default all tasks that have interval rates/periods that will execute on that interval schedule. However, what happens if a task takes longer to execute than the period? Well, by default the task will execute even if the previous one has not executed. If you want to prevent this behavior, then you can use the withNoOverlaps() method and ColdBox will register the tasks with a fixed delay. Meaning the intervals do not start counting until the last task has finished executing.

Task With Fixed Delay
task( "test" )
.call( () => getInstance( "CacheService" ).reap() )
.everyMinute()
.withNoOverlaps();

Spaced delays are a feature of the Scheduled Executors. There is even a spacedDelay( delay, timeUnit ) method in the Task object.

Delaying First Execution

Every task can also have an initial delay of first execution by using the delay() method.

/**
* Set a delay in the running of the task that will be registered with this schedule
*
* @delay The delay that will be used before executing the task
* @timeUnit The time unit to use, available units are: days, hours, microseconds, milliseconds, minutes, nanoseconds, and seconds. The default is milliseconds
*/
ScheduledTask function delay( numeric delay, timeUnit = "milliseconds" )

The delay is numeric and the timeUnit can be:

  • days

  • hours

  • minutes

  • seconds

  • milliseconds (default)

  • microseconds

  • nanoseconds

// Lambda Syntax
task( "my-task" )
.call( () => getInstance( "myService" ).runcleanup() )
.delay( "5000" )
.everyHour();

Please note that the delay pushes the execution of the task into the future only for the first execution.

One Off Tasks

A part from registering tasks that have specific intervals/frequencies you can also register tasks that can be executed ONCE ONLY. These are great for warming up caches, registering yourself with control planes, setting up initial data collections and so much more.

Basically, you don't register a frequency just the callable event. Usually, you can also combine them with a delay of execution, if you need them to fire off after certain amount of time has passed.

task( "build-up-cache" )
.call( () => getInstance( "DataServices" ).buildCache() )
.delay( 1, "minutes" );
task( "notify-admin-server-is-up" )
.call( () => getInstance( "SettingService" ).notifyAppIsUp( getUtil().getServerIp() ) )
.delay( 30, "seconds" );
task( "register-container" )
.call( () => runEvent( "tasks.registerContainer" ) )
.delay( 30, "seconds" );

Life-Cycle Methods

We already saw that a scheduler has life-cycle methods, but a task can also have several useful life-cycle methods:

Method

Description

after( target )

Store the closure to execute after the task executes

function( task, results )

before( target )

Store the closure to execute before the task executes

function( task )

onFailure( target )

Store the closure to execute if there is a failure running the task

function( task, exception )

onSuccess( target )

Store the closure to execute if the task completes successfully

function( task, results )

task( "testharness-Heartbeat" )
.call( function() {
if ( randRange(1, 5) eq 1 ){
throw( message = "I am throwing up randomly!", type="RandomThrowup" );
}
writeDump( var='====> I am in a test harness test schedule!', output="console" );
} )
.every( "5", "seconds" )
.before( function( task ) {
writeDump( var='====> Running before the task!', output="console" );
} )
.after( function( task, results ){
writeDump( var='====> Running after the task!', output="console" );
} )
.onFailure( function( task, exception ){
writeDump( var='====> test schedule just failed!! #exception.message#', output="console" );
} )
.onSuccess( function( task, results ){
writeDump( var="====> Test scheduler success : Stats: #task.getStats().toString()#", output="console" );
} );

Timezone

By default, all tasks will ask the scheduler for the timezone to run in. However, you can override it on a task-by-task basis using the setTimezone( timezone ) method:

setTimezone( "America/Chicago" )

Remember that some timezones utilize daylight savings time. When daylight saving time changes occur, your scheduled task may run twice or even not run at all. For this reason, we recommend avoiding timezone scheduling when possible.

Truth Test Constraints

There are many ways to constrain the execution of a task. However, you can register a when() closure that will be executed at runtime and boolean evaluated. If true, then the task can run, else it is disabled.

task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.when( function(){
// Can we run this task?
return true;
);

Server Fixation

If you are running a cluster of your application and you register tasks they will run at their schedule in EVERY server/container the application has been deployed to. This might not be a great idea if you want only ONE task to run no matter how many servers/containers you have deployed your application on. For this situation you can use the onOneServer() method which tells ColdBox to ONLY run the task once on the first server that wins the race condition.

task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.onOneServer();

This feature ONLY works when you are using a distributed cache like redis, mongo, elastic, couchbase or a JDBC CacheBox provider in CacheBox.

Changing the Cache Provider

By default this feature leverages the template cache provider in CacheBox. However, you can change which cache provider will be used for storing the locking and tracking entries.

task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.setCacheName( "redis" )
.onOneServer();

Environment Constraints

All ColdBox applications have a runnable environment stored in the environment setting. You can use that to register a task with constraints of environment using the onEnvironment( environment ) method. This means that the task will ONLY run on those environments. The environment argument can be a single string, a list of environments or an array of environments.

task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.onEnvironments( "staging" );
task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.onEnvironments( [ "staging", "production" ] );
task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.onEnvironments( "staging,production" );

Disabling/Pausing Tasks

Every task is runnable from registration according to the frequency you set. However, you can manually disable a task using the disable() method:

task( "my-task" )
.call( () => getInstance( "securityService" ).cleanOldUsers() )
.daily()
.disable();

Once you are ready to enable the task, you can use the enable() method:

myTask.enable()

Task Stats

All tasks keep track of themselves and have lovely metrics. You can use the getStats() method to get a a snapshot structure of the stats in time. Here is what you get in the stats structure:

Metric

Description

created

The timestamp of when the task was created in memory

inetHost

The hostname of the machine this task is registered with

lastRun

The last time the task ran

lastResult

The last result the task callable produced

localIp

The ip address of the server this task is registered with

neverRun

A boolean flag indicating if the task has NEVER been ran

nextRun

When the task will run next

totalFailures

How many times the task has failed execution

totalRuns

How many times the task has run

totalSuccess

How many times the task has run and succeeded

/**
* Called after ANY task runs
*
* @task The task that got executed
* @result The result (if any) that the task produced
*/
function afterAnyTask( required task, result ){
log.info( "task #task.getName()# just ran. Metrics: #task.getStats().toString()# ");
}

Task Helpers

We have created some useful methods that you can use when working with asynchronous tasks:

Method

Description

err( var )

Send output to the error stream

getCache()

Get the CacheBox provider assigned for server fixation

getCacheName()

Get the name of the cache region to use for server fixation

getEnvironments()

Get the assigned running environments for the task

getServerFixation()

Get the boolean flag that indicates that this task runs on all or one server

hasScheduler()

Verifies if the task is assigned a scheduler or not

isDisabled()

Verifies if the task has been disabled by bit

isConstrained()

Verifies if the task has been constrained to run by server fixation, environments, weekends, weekdays, dayOfWeek, or dayOfMonth

out( var )

Send output to the output stream

setCacheName()

Set the cache name to use for server fixation

start()

This kicks off the task into the scheduled executor manually. This method is called for you by the scheduler upon application startup or module loading.

Schedulers For Modules

Every module in ColdBox also has a convention of config/Scheduler.cfc that if detected will register that scheduler for you with a WireBox ID of [email protected]{moduleName}. ColdBox will register the scheduler for you and also store it in the module's configuration struct with a key of scheduler. ColdBox will also manage it's lifecycle and destroy it if the module is unloaded. All the rules for schedulers apply, happy scheduling!

+ MyModule
+ config
- Router.cfc
- Scheduler.cfc