Boxlang Scheduled Tasks

BoxLang Scheduled Tasks

Overview

BoxLang offers two scheduling models:

1. Scheduler DSL (in-process code execution) using scheduler classes backed by BaseScheduler and ScheduledTask
2. bx:schedule component (HTTP-driven tasks) for create/update/delete/pause/resume/list/run task endpoints

Use the Scheduler DSL for rich in-process logic and task callbacks. Use bx:schedule for simple persistent URL triggers.

Application.bx Integration

You can register scheduler classes directly in Application.bx so they are auto-discovered for the app context.

For full descriptor behavior (app discovery, multi-app isolation, lifecycle), see application-descriptor.

class {

    this.name = "MyApp"

    // Auto-register scheduler classes for this application
    this.schedulers = [
        "schedulers.DailyMaintenance",
        "schedulers.HourlyReports"
    ]

}

Use this when scheduler lifecycle should be managed with application startup/shutdown rather than ad-hoc schedulerStart() calls.

Option 1: Scheduler DSL (Recommended for Code Workloads)

A scheduler class wraps BaseScheduler and registers tasks fluently in configure().

class {

    property name="scheduler"
    property name="logger"

    function configure() {
        scheduler
            .setSchedulerName( "reporting-scheduler" )
            .setTimezone( "America/Chicago" )

        scheduler.task( "daily-report", "reports" )
            .call( () => generateDailyReport() )
            .everyDayAt( "02:00" )
            .onFailure( ( task, exception ) => {
                logger.error( "Task #task.getName()# failed: #exception.message#" )
            } )
    }

}

Registering and Starting Scheduler Classes

// Start from class path (creates, configures, registers, and starts)
schedulerStart( className = "schedulers.ReportingScheduler", name = "reporting", force = true )

// Lookup / control
schedulerGet( "reporting" )
schedulerStats( "reporting" )
schedulerRestart( "reporting", force = false, timeout = 30 )
schedulerShutdown( "reporting", force = false, timeout = 30 )

Option 2: bx:schedule Component (HTTP-Driven)

bx:schedule persists task definitions (default: ${boxlang-home}/config/tasks.json) and executes scheduled HTTP GET requests.

bx:schedule action="create"
    task="nightlyCleanup"
    url="https://myapp.example/tasks/cleanup"
    cronTime="0 2 * * *";

bx:schedule action="pause" task="nightlyCleanup";
bx:schedule action="run" task="nightlyCleanup";
bx:schedule action="delete" task="nightlyCleanup";

Use this approach for webhooks, callback endpoints, and operational pings.

Scheduler BIFs

Core scheduler lifecycle BIFs:

• schedulerStart( className, name?, force=true )
• schedulerGet( name )
• schedulerGetAll()
• schedulerList()
• schedulerStats( name? )
• schedulerRestart( name, force=false, timeout=30 )
• schedulerShutdown( name, force=false, timeout=30 )

Notes:

• schedulerStart() instantiates the BoxLang class, wraps it in BoxScheduler, calls configure(), then registers/starts it.
• schedulerRestart() and schedulerShutdown() validate scheduler existence and throw if missing.

Task Registration Patterns

Use meaningful names and optional groups for operational clarity.

scheduler.task( "cleanup-expired-sessions", "maintenance" )
    .call( () => cleanupSessions() )
    .every( 15, "minutes" )

scheduler.task( "send-weekly-digest", "notifications" )
    .call( () => sendDigest() )
    .everyWeekOn( "Monday", "08:30" )

Disable-at-registration for debugging:

scheduler.xtask( "experimental-task", "debug" )
    .call( () => runExperiment() )
    .everyMinute()

Common Frequency APIs

• every( period, timeUnit )
• spacedDelay( delay, timeUnit ) (no overlap style)
• cron( expression )
• everySecond(), everyMinute(), everyHour(), everyHourAt( minute )
• everyDay(), everyDayAt( "HH:mm" )
• everyWeek(), everyWeekOn( day, time )
• everyMonth(), everyMonthOn( day, time )
• everyYear(), everyYearOn( month, day, time )
• onWeekdays( time ), onWeekends( time )

Time units supported in scheduler APIs include: days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds.

Cron Support

Supported formats:

• 5-field Unix: minute hour day-of-month month day-of-week
• 6-field Quartz: second minute hour day-of-month month day-of-week

Examples:

// Every day at 2:00 AM
scheduler.task( "nightly" )
    .call( () => nightlyJob() )
    .cron( "0 2 * * *" )

// Every weekday at 8:30:00 AM
scheduler.task( "weekday-digest" )
    .call( () => digestJob() )
    .cron( "0 30 8 * * MON-FRI" )

Best Practices

• Always set explicit scheduler name and timezone.
• Use descriptive task names and logical groups.
• Keep task bodies small; move heavy fan-out work to async executors.
• Prefer onFailure hooks and centralized logging for observability.
• Avoid overly fine-grained intervals without throughput checks.
• Use spacedDelay() or no-overlap patterns when tasks can run longer than their interval.

Troubleshooting

• Scheduler not found: confirm schedulerStart() was called and schedulerList() contains the name.
• Task never firing: verify timezone, cron expression, and start/end constraints.
• Duplicate/stacked runs: use spacing/no-overlap strategies instead of strict fixed-rate behavior.
• Silent failures: inspect scheduler logger output and schedulerStats() counters (totalFailures, lastResult).