Overview
The CronJob construct creates a Kubernetes CronJob for running scheduled tasks with configurable history limits and restart policies.
Class Definition
export class CronJob extends Construct {
constructor(scope: Construct, jobname: string, props: CronJobProps)
}
Constructor Parameters
Job name (will be prefixed with release name)
CronJob configuration properties
CronJobProps
Extends ContainerProps with cron-specific options.
Container Properties
Docker image name (without tag)
tag
string
default:"GIT_SHA env var"
Docker image tag. Defaults to GIT_SHA environment variable.
Name of Kubernetes secret to mount as environment variables
Container command to executecmd: ['python', 'manage.py', 'cleanup_old_data']
env
Array<{name: string, value: string}>
Additional environment variablesenv: [
{ name: 'CLEANUP_DAYS', value: '30' }
]
pullPolicy
'IfNotPresent' | 'Always' | 'Never'
default:"IfNotPresent"
Container image pull policy
CronJob-Specific Properties
Cron schedule expressionschedule: '0 2 * * *' // Every day at 2 AM
schedule: '*/15 * * * *' // Every 15 minutes
schedule: '0 0 * * 0' // Every Sunday at midnight
restartPolicy
'Always' | 'OnFailure' | 'Never'
default:"Never"
Restart policy for the job container
Never: Don’t restart on failure (default)OnFailure: Restart only if the container failsAlways: Always restart the container
Number of successful finished jobs to retain in history
Number of failed jobs to retain in history
secretMounts
Array<{name: string, mountPath: string, subPath: string}>
Secret volume mounts for the cronjob containersecretMounts: [
{
name: 'backup-credentials',
mountPath: '/etc/secrets',
subPath: 'credentials.json'
}
]
Creates and attaches a service account to job pods. Service account name is set to the release name.
Naming Convention
CronJob names are automatically prefixed with the release name:
${RELEASE_NAME}-${jobname}
RELEASE_NAME=myapp and jobname=cleanup, the final name is myapp-cleanup.
Labels
Each cronjob automatically applies the label:
app.kubernetes.io/name: <RELEASE_NAME>-<jobname>
Container Ports
CronJobs are created with noContainerPorts: true, meaning no container ports are exposed (see src/cronjob.ts:65).
Usage Examples
Daily Backup Job
import { CronJob } from './cronjob';
new CronJob(chart, 'backup', {
image: 'pennlabs/backup-tool',
schedule: '0 2 * * *', // 2 AM daily
cmd: ['./backup.sh'],
secret: 'backup-secrets',
restartPolicy: 'OnFailure',
successLimit: 7, // Keep last 7 successful runs
failureLimit: 3 // Keep last 3 failed runs
});
Database Cleanup
new CronJob(chart, 'cleanup', {
image: 'pennlabs/backend',
schedule: '0 0 * * 0', // Weekly on Sunday
cmd: ['python', 'manage.py', 'cleanup_old_records'],
secret: 'db-secrets',
env: [
{ name: 'DJANGO_SETTINGS_MODULE', value: 'app.settings.production' },
{ name: 'CLEANUP_DAYS', value: '90' }
]
});
Data Sync Job
new CronJob(chart, 'sync', {
image: 'pennlabs/sync-service',
schedule: '*/30 * * * *', // Every 30 minutes
cmd: ['./sync.sh'],
secretMounts: [
{
name: 'api-credentials',
mountPath: '/etc/credentials',
subPath: 'api-key.json'
}
],
restartPolicy: 'Never',
successLimit: 10,
failureLimit: 5
});
Report Generation with Service Account
new CronJob(chart, 'reports', {
image: 'pennlabs/reporting',
schedule: '0 9 1 * *', // 9 AM on first day of month
cmd: ['python', 'generate_reports.py'],
secret: 'report-secrets',
createServiceAccount: true, // Needs K8s API access
restartPolicy: 'OnFailure',
env: [
{ name: 'REPORT_TYPE', value: 'monthly' },
{ name: 'OUTPUT_FORMAT', value: 'pdf' }
]
});
Cache Warming
new CronJob(chart, 'cache-warmer', {
image: 'pennlabs/cache-tool',
schedule: '0 */4 * * *', // Every 4 hours
cmd: ['./warm-cache.sh'],
secret: 'cache-secrets',
restartPolicy: 'Never',
successLimit: 3,
failureLimit: 2,
pullPolicy: 'Always'
});
┌───────────── minute (0 - 59)
│ ┌───────────── hour (0 - 23)
│ │ ┌───────────── day of month (1 - 31)
│ │ │ ┌───────────── month (1 - 12)
│ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday)
│ │ │ │ │
│ │ │ │ │
* * * * *
Common Examples:
0 0 * * * - Daily at midnight0 */6 * * * - Every 6 hours*/15 * * * * - Every 15 minutes0 9 * * 1-5 - 9 AM on weekdays0 0 1 * * - First day of every month
Environment Variables
Required environment variables:
Git commit SHA. Automatically injected into container and used as default image tag.
RELEASE_NAME
string
default:"undefined_release"
Release name used for prefixing cronjob names and service account names.
Source Reference
Defined in src/cronjob.ts:55