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Cron Trigger (Scheduled Task)

The Cron Trigger enables automatic workflow execution at precise times based on cron expressions.

What does this integration do?​

The Cron Trigger starts workflows according to a scheduled timeline. It uses cron expressions to define complex schedules - from simple hourly executions to complex, condition-dependent schedules.

Typical Use Cases:

  • Report Generation: Create automatic daily, weekly, or monthly reports
  • Data Processing: Regular processing of large datasets
  • System Maintenance: Automated maintenance tasks and cleanup operations
  • Monitoring: Regular system checks and health monitoring
  • Backup Processes: Automated data backups at scheduled times

User Configuration​

Basic Configuration​

Cron Expression

  • Purpose: Defines the schedule for workflow execution
  • Format: Standard cron syntax with 5 or 6 fields
  • Examples: 
    0 9 * * *        # Daily at 9:00 AM
    0 */6 * * *      # Every 6 hours
    0 0 * * 1        # Every Monday at midnight
    30 14 1 * *      # 1st of every month at 2:30 PM
    0 8 * * 1-5      # Weekdays at 8:00 AM
    */15 * * * *     # Every 15 minutes

Timezone - Optional

  • Purpose: Determines the timezone for cron execution
  • Default: Server system timezone
  • Examples: 
    Europe/Berlin
    America/New_York
    Asia/Tokyo
    UTC

Result (Timestamp) - Variable for timestamp

  • Purpose: Name of the variable that stores the execution timestamp
  • Content: ISO timestamp of trigger execution
  • Usage: Can be used in subsequent workflow steps
  • Example: triggerTime → stores "2024-03-15T09:00:00.000Z"

Cron Expression Help​

Field Meanings:

* * * * * *
│ │ │ │ │ │
│ │ │ │ │ └─ Day of week (0-7, Sunday = 0 or 7)
│ │ │ │ └─── Month (1-12)
│ │ │ └───── Day of month (1-31)
│ │ └─────── Hour (0-23)
│ └───────── Minute (0-59)
└─────────── Second (0-59, optional)

Special Characters:

  • * - Any value (every minute, every hour, etc.)
  • */5 - Every 5 units (every 5 minutes, every 5 hours, etc.)
  • 1,3,5 - Specific values (minute 1, 3, and 5)
  • 1-5 - Range (Monday to Friday for weekdays)
  • 0 9-17 * * 1-5 - Weekdays from 9-17 every hour

Common Patterns:

0 0 * * *          # Daily at midnight
0 */1 * * *        # Hourly
*/30 * * * *       # Every 30 minutes
0 9,17 * * 1-5     # Weekdays at 9:00 and 17:00
0 2 * * 0          # Sundays at 2:00 AM
0 0 1 * *          # Monthly on 1st at midnight
0 0 1 1 *          # Yearly on January 1st at midnight

Workflow Integration​

Data Provision​

The Cron Trigger provides the following data for the workflow:

Timestamp Variable

  • Name: As defined in configuration
  • Format: ISO 8601 timestamp
  • Timezone: UTC or as configured
  • Example: "2024-03-15T09:00:00.000Z"

Usage in Subsequent Steps​

Example usage of timestamp variable:

Variable: triggerTime
Value: 2024-03-15T09:00:00.000Z

Using in LLM Action:
"Create a report for the period until {{triggerTime}}"

Using in HTTP Action:
URL: https://api.example.com/reports?date={{triggerTime}}

Practical Examples​

Daily Report at 9:00 AM​

Configuration:

  • Cron Expression: 0 9 * * *
  • Timezone: Europe/Berlin
  • Result: reportTime

Usage: Generates daily reports at 9:00 AM Central European Time

Weekday Reminder​

Configuration:

  • Cron Expression: 0 8 * * 1-5
  • Timezone: Europe/Berlin
  • Result: reminderTime

Usage: Sends reminders or starts check processes on weekdays at 8:00 AM

Weekly Backup​

Configuration:

  • Cron Expression: 0 2 * * 0
  • Timezone: UTC
  • Result: backupTime

Usage: Starts backup process on Sundays at 2:00 AM UTC

Monitoring Every 15 Minutes​

Configuration:

  • Cron Expression: */15 * * * *
  • Result: checkTime

Usage: Checks system status every 15 minutes

Technical Details​

Schema Configuration​

configSchema: {
  cronExpression: {
    name: 'Cron Expression',
    schema: z.string()
  },
  timezone: {
    name: 'Timezone',
    schema: z.string().optional()
  },
  outputName: {
    name: 'Result (Timestamp)',
    reference: 'memory-out',
    schema: z.string(),
  },
}

Internal Implementation​

Cron Engine:

  • Uses node-cron library for precise scheduling
  • Fallback to setInterval when node-cron is not available
  • Automatic timezone handling
  • Robust error handling for invalid expressions

Timestamp Generation:

  • Generates ISO 8601 formatted timestamps
  • Considers configured timezone
  • Makes timestamps available in workflow memory

Resource Management:

  • Minimal CPU usage between executions
  • Automatic cleanup on stop
  • Supports multiple parallel cron triggers

Validation and Error Handling​

Cron Expression Validation:

  • Syntax verification before activation
  • Helpful messages for invalid expressions
  • Support for 5 and 6 field formats

Timezone Handling:

  • Validation of timezone names
  • Fallback to system timezone for invalid values
  • Support for all IANA timezone designations

Error Scenarios:

  • Invalid cron expressions are rejected
  • Unknown timezones fall back to UTC
  • System errors are logged and reported

Best Practices​

Scheduling​

Resource Optimization:

  • Avoid too frequent executions (under 1 minute) unless necessary
  • Distribute regular jobs across different times
  • Consider system load when scheduling

Timezone Management:

  • Use explicit timezone specifications for production environments
  • Consider daylight saving time changes
  • Document timezone decisions for the team

Workflow Design​

Robustness:

  • Implement error handling in scheduled workflows
  • Consider that jobs might run multiple times simultaneously
  • Plan for different execution times (time zone changes)

Monitoring:

  • Monitor execution times of scheduled workflows
  • Set alerts for failed scheduled executions
  • Document expected execution frequencies

Maintenance​

Cron Expression Management:

  • Test complex cron expressions before production use
  • Document the meaning of each cron expression for the team
  • Use online tools to validate complex expressions

Performance Monitoring:

  • Monitor resource usage during frequent executions
  • Optimize workflows for fast execution with repeated jobs
  • Schedule resource-intensive jobs outside peak hours

The Cron Trigger is the foundation for time-based automation in Vectense Platform and enables precise, reliable scheduled workflow execution.