zachbg/docker-cron

By zachbg

•Updated 6 months ago

Container-aware cron scheduler with supercronic for Docker environments

Image

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Overview Tags

zachbg/docker-cron repository overview

⁠docker-cron

Universal cron scheduler for Docker — run any command on a schedule.

⁠Why?

Docker doesn't have cron. Every deployment needs scheduled tasks. This image:

Just works — no config files needed, use environment variables
Docker-aware — includes docker CLI for container management tasks
Multiple jobs — via env vars, files, or arguments
Timezone support — set TZ and schedules follow local time
Proper logging — stdout/stderr, not syslog
Tiny — Alpine-based, ~15MB

⁠Quick Start

⁠One-liner

docker run -d \
  -e CRON_SCHEDULE="*/5 * * * *" \
  -e CRON_COMMAND="echo hello" \
  zachbg/docker-cron

⁠Multiple Jobs

docker run -d \
  -e CRON_JOB_1="*/5 * * * * curl -sf https://myapp.com/health" \
  -e CRON_JOB_2="0 3 * * * curl -X POST https://myapp.com/api/cleanup" \
  -e CRON_JOB_3="0 * * * * echo hourly task" \
  zachbg/docker-cron

⁠Docker Compose

services:
  cron:
    image: zachbg/docker-cron
    restart: unless-stopped
    environment:
      - TZ=America/New_York
      - CRON_JOB_BACKUP=0 3 * * * curl -sf http://backup:8080/run
      - CRON_JOB_CLEANUP=0 */6 * * * curl -X POST http://app:3000/api/cleanup
      - CRON_JOB_HEALTH=*/5 * * * * curl -sf https://hc.example.com/ping/xxx
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock  # Optional: for Docker commands

⁠Docker Container Management

services:
  cron:
    image: zachbg/docker-cron
    restart: unless-stopped
    environment:
      - CRON_JOB_RESTART=0 4 * * * docker restart myapp
      - CRON_JOB_PRUNE=0 2 * * 0 docker system prune -af
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

⁠Mounted Crontab File

services:
  cron:
    image: zachbg/docker-cron
    volumes:
      - ./crontab:/etc/cron.d/jobs

⁠Configuration Methods

Method	Example
Env vars	`CRON_JOB_1="* * * * * echo hi"`
Schedule + Command	`CRON_SCHEDULE="* * * * *"` + `CRON_COMMAND="echo hi"`
Mount file	`-v ./crontab:/etc/cron.d/jobs`
Arguments	`docker run zachbg/docker-cron "* * * * * echo hi"`

⁠Environment Variables

Variable	Default	Description
`CRON_JOB_*`		Cron jobs (name is for your reference)
`CRON_SCHEDULE`		Schedule for single-job mode
`CRON_COMMAND`		Command for single-job mode
`TZ`	`UTC`	Timezone for schedules

⁠License

MIT

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Image

Digest

sha256:20d7bf01d…

Size

20.7 MB

Last updated

6 months ago

docker pull zachbg/docker-cron