Jobs

Introduction

The jobs section allows defining scheduled or event-driven tasks that execute commands or make HTTP requests. Jobs can be useful for running periodic maintenance tasks, executing background processes, or ensuring essential workflows are automated.

Job Structure

Each job consists of the following fields:

• name (str, required) – A unique name for the job.
• trigger (str, required) – Defines when the job should run.
  • This can be a cron expression (e.g., '*/15 * * * *' for every 15 minutes).
  • It can also be 'post-deployment' to run after deployment.
  • 'pre-deployment' is currently not supported.
• action (required) – Specifies the task to run. More details in the next section. A job can:
  • Run a command using execute.
  • Make an HTTP request using fetch.
• retries (int, Optional) – The maximum number of times the job should retry upon failure.
• timeout (duration, Optional) – The maximum time a job is allowed to run before timing out (e.g., '10m' for 10 minutes).
• max_schedule_drift (duration, Optional) – The maximum allowed delay before the job is considered late. (e.g., '10m' for 10 minutes)

Fully working examples configuration can be found here.

Job Actions

This section defines the action field in a job definition. There are two types of actions for a job:

1. Executing a command (execute)

   Runs a CLI command with Optional environment variables.

   action:
     execute:
       command: install-wp
       cli_args:
         - "--version"
         - "--help"
       env:
         LOG_LEVEL: DEBUG
         EXTRA_FLAGS: "--enable-feature-1 --enable-feature-2"
   • command (str, Optional) – The command to execute.
   • cli_args (List[str], Optional) – Arguments for the command.
   • env (map, Optional) – Environment variables.

2. Making an HTTP request (fetch)

   Sends an HTTP request to a specific endpoint.

   action:
     fetch:
       path: /wp-cron.php
       timeout: '10m'
       headers:
         - name: Accept
           value: application/json
         - name: User-Agent
           value: Wasmer-CronJob
    
   • path (str, required) – The request URL path.
   • method (str, Optional) – HTTP method (defaults to GET).
   • headers (list[object[name, value]], Optional) – HTTP headers as yaml objects. The objects have two fields, name which is the header name, and value which is the value of header field.
   • body (str, Optional) – Request body.
   • timeout (duration, Optional) – Maximum time to wait for a response.

Example Jobs Configuration

Below are examples of various job types based on their trigger and action.

Fetch job

This job fetches the / path on it's app every 15 minutes.

kind: wasmer.io/App.v0
package: wasmer/hello
jobs:
  - name: ping-server-every-15-minutes
    trigger: '*/15 * * * *'
    action:
      fetch:
        path: /
        timeout: 30s

Execute job

This job runs php --version every minute.

kind: wasmer.io/App.v0
package: wasmer/wordpress
jobs:
  - name: check-php-version
    trigger: '*/1 * * * *'
    action:
      execute:
        command: php
        cli_args: ["--version"]

Post deployment job

This job fetches the /warm-up-caches path on it's app after each deployment.

kind: wasmer.io/App.v0
package: wasmer/hello
jobs:
  - name: ping-server-every-15-minutes
    trigger: post-deployment
    action:
      fetch:
        path: /warm-up-caches
        timeout: 30s

Use Cases

• Post-deployment setup: The installation job ensures necessary setup commands run after deployment.
• Scheduled background tasks: The wp-cron job triggers WordPress’s cron system every 15 minutes.