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.
- Use a duration such as 15m, 1h, or 24h for simple interval schedules.
- Use a cron expression for uniform schedules, such as '*/15 * * * *' for every 15 minutes.
- Use pre-deployment to run before a new app version is created.
- Use post-deployment to run after a new app version is created.
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.

Fully working examples configuration can be found here.

Schedules and Deployment Triggers

Scheduled jobs can use either a duration or a cron expression. Cron expressions must produce a uniform interval. For example, */15 * * * * is valid because it runs every 15 minutes, while a schedule such as 0 9 * * MON-FRI is not uniform because the interval between Friday and Monday is different.

Scheduled jobs are subject to the platform minimum interval, which defaults to 5 minutes. Deployment jobs use the special pre-deployment and post-deployment triggers and run once during deployment instead of being installed as recurring cron jobs.

Job Actions

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

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. If omitted, the app workload command is used.
- package (str, Optional) – Package source override for this job.
- cli_args (List[str], Optional) – Arguments for the command.
- env (map[str, str], Optional) – Environment variables.
- retries (int, Optional) – Maximum retry count.
- timeout (duration, Optional) – Maximum runtime. Defaults to 180s.
- max_schedule_drift (duration, Optional) – Maximum allowed delay before a scheduled job is considered late. Defaults to 180s.
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
    expect:
      status_codes: [200, 204]
```
- path (str, Optional) – The request URL path. Defaults to /.
- method (str, Optional) – HTTP method. Defaults to GET.
- headers (List[Header], Optional) – HTTP headers passed as a list of name/value pairs.
- body (str, Optional) – Request body.
- expect.status_codes (List[int], Optional) – Expected HTTP status codes.
- expect.body_includes (str, Optional) – Text that must be present in the response body.
- expect.body_regex (str, Optional) – Regular expression that must match the response body.
- retries (int, Optional) – Maximum retry count.
- timeout (duration, Optional) – Maximum time to wait for a response. Defaults to 180s.
- max_schedule_drift (duration, Optional) – Maximum allowed delay before a scheduled job is considered late. Defaults to 180s.

Example Jobs Configuration

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

Fetch job

This job fetches the / path on its app every 15 minutes.


kind: wasmer.io/App.v0
package: wasmer/static-web-server
jobs:
  - name: ping-server-every-15-minutes
    trigger: '*/15 * * * *'
    action:
      fetch:
        path: /
        timeout: 30s
        headers:
          - name: User-Agent
            value: Wasmer-CronJob

Interval job

This job runs on a simple duration schedule.


kind: wasmer.io/App.v0
package: wasmer/static-web-server
jobs:
  - name: ping-server-every-hour
    trigger: 1h
    action:
      fetch:
        path: /
        timeout: 30s

Execute job

This job runs a shell command every 15 minutes and writes the output to the job logs. Use execute when a cron job should run a package command instead of making an HTTP request.


kind: wasmer.io/App.v0
package: wasmer/bash
jobs:
  - name: write-heartbeat
    trigger: '*/15 * * * *'
    action:
      execute:
        command: bash
        cli_args: ["-lc", "date -u && echo cron heartbeat"]

Pre deployment job

This job runs a setup command before a new app version is created.


kind: wasmer.io/App.v0
package: wasmer/static-web-server
jobs:
  - name: prepare-release
    trigger: pre-deployment
    action:
      execute:
        package: wasmer/bash
        command: bash
        cli_args: ["-lc", "echo preparing release"]
        timeout: 5m

Post deployment job

This job fetches the / path on its app after each deployment.


kind: wasmer.io/App.v0
package: wasmer/static-web-server
jobs:
  - name: warm-up-app
    trigger: post-deployment
    action:
      fetch:
        path: /
        timeout: 30s

Use Cases

Pre-deployment migrations: Run setup or migration commands before publishing the new version.
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.