CronJobs in Kontroler

Creating CronJobs

Kontroler makes it easy to create scheduled workflows using cron syntax. These workflows can be configured with retry logic, conditional execution, and sophisticated error handling.

Basic CronJob Structure

Here’s a simple example that runs every minute and demonstrates retry logic:

apiVersion: kontroler.greedykomodo/v1alpha1
kind: DAG
metadata:
  name: cronjob
spec:
  schedule: "*/1 * * * *"
  task:
    - name: "job"
      command: ["sh", "-c"]
      args:
        [
          "if [ $((RANDOM%2)) -eq 0 ]; then echo $second; else exit 1; fi",
        ]
      image: "alpine:latest"
      backoff:
        limit: 3
      conditional:
        enabled: true
        retryCodes: [1]

Breaking Down the Components

Schedule Definition
```
schedule: "*/1 * * * *"
```
- Uses standard cron syntax
- This example runs every minute
- Supports all cron expressions
Task Configuration
```
task:
  - name: "job"
    image: "alpine:latest"
```
- Defines the task to be executed
- Specifies the container image
- Each task must have a unique name
Command and Arguments
```
command: ["sh", "-c"]
args:
  ["if [ $((RANDOM%2)) -eq 0 ]; then echo $second; else exit 1; fi"]
```
- Sets the command to run
- Arguments are passed as an array
- Supports shell commands and scripts
Retry Configuration
```
backoff:
  limit: 3
conditional:
  enabled: true
  retryCodes: [1]
```
- backoff.limit: Maximum number of retries
- conditional.enabled: Enables conditional retries
- retryCodes: Exit codes that trigger retries

Common Cron Patterns

# Every 5 minutes
schedule: "*/5 * * * *"

# Every hour
schedule: "0 * * * *"

# Every day at midnight
schedule: "0 0 * * *"

# Every Monday at 9am
schedule: "0 9 * * 1"

Best Practices

Error Handling
- Always define retry conditions
- Use appropriate backoff limits
- Consider retry codes carefully

Resource Management

task:
  - name: "job"
    resources:
      requests:
        cpu: "100m"
        memory: "128Mi"
      limits:
        cpu: "200m"
        memory: "256Mi"

Logging
- Use clear task names
- Output meaningful logs
- Consider log retention