helm-cron

Helm chart for a minimal pod that triggers Drupal cron on a schedule by wget-ing a site's public /cron/<token> URL from a crontab entry. Used by favish Drupal projects as a lightweight cron trigger.

Published to https://favish.github.io/helm-cron and consumed as a chart dependency.

Superseded for high-traffic projects. Triggering cron over the public URL routes the request to the serving php fleet. Projects where cron is heavy (search indexing, feed imports, purges) should instead use the dedicated cron-worker in helm-drupal, which runs drush cron on its own pod with no impact on the serving HPA. This chart remains valid for lightweight cron needs.

Contents

• What it deploys
• Layout
• Usage
• Key values
• Releasing
• Local checks
• Conventions (agents & contributors)
• Pending improvements

What it deploys

A single-replica Deployment running the favish/cron-drupal image, with a ConfigMap that renders one crontab line:

<period> date -R && echo 'Running Drupal cron via wget...' && wget -O - -q -t 1 <url>

url is required when the chart is enabled (a missing url now fails the render fast instead of shipping a silently-broken crontab).

Layout

cron/                            # the chart
├── Chart.yaml                   # metadata (version injected at release time)
├── values.yaml                  # defaults
└── templates/
    ├── deployment.yaml
    └── configmap.yaml           # the crontab line
.github/workflows/release.yml    # tag -> publish chart
CHANGELOG.md

Usage

Declare the dependency in the consuming umbrella chart:

dependencies:
  - name: cron
    repository: https://favish.github.io/helm-cron
    version: 1.0.2
    condition: cron.enabled

Values:

cron:
  enabled: true
  period: "*/10 * * * *"                       # crontab schedule
  url: "https://cms.example.com/cron/<token>"  # required when enabled

Key values

Value	Default	Meaning
url	— (required)	Drupal cron URL to hit. Render fails if unset while enabled.
period	*/10 * * * *	Crontab schedule.
resources	requests only	Container resources.

Releasing

GitHub Actions (.github/workflows/release.yml). Merge to master, update CHANGELOG.md, then tag:

git tag 1.0.3 && git push origin 1.0.3

The workflow packages the chart and publishes to the gh-pages Helm repo. workflow_dispatch runs a dry-run. Migrated from CircleCI; actions/checkout uses the built-in GITHUB_TOKEN, no deploy key.

Local checks

helm lint ./cron --set url=https://example.com/cron

cp cron/Chart.yaml /tmp/c.bak
printf '\nversion: 0.0.0-test\n' >> cron/Chart.yaml
helm template t ./cron --set url=https://example.com/cron
helm template t ./cron            # expect: error, url required
cp /tmp/c.bak cron/Chart.yaml

Conventions (agents & contributors)

• Chart version is injected from the git tag at release; not in Chart.yaml.
• Release = push a git tag. No manual gh-pages step.
• For heavy cron workloads, prefer the helm-drupal cron-worker over this chart.

Pending improvements

• No resource limits (only requests) and no liveness/readiness probe — a cron target that is failing leaves a Running-but-useless pod with no signal.
• The image tag (favish/cron-drupal:1.0.0-alpha.1) is a hardcoded pre-release pin in the template; move repo/tag to values and pin a stable release.
• wget -q -t 1 swallows failures; drop -q so failures surface in pod logs for log-based alerting.
• No securityContext; the pod runs as the image default.