robomagus/docker-dependency-delay repository overview

⁠Docker Depencency Delay

A hacky Docker image that hijacks dockers healthcheck and depends_on mechanism to delay startup of other containers. This enables injection of dependencies on non-container related requirements, such as system uptime or file presence.

⁠Features

This image implements a HealthCheck that will remain in startup / unhealthy until a selection of requirements is satisfied. These can be configured using environment variables listed below. These requirements are skipped when no value is provided, and processed in the order listed.

• MIN_SYSTEM_UPTIME: System uptime (in seconds) must be greater than the value provided.
• REQUIRED_FILES: A list of Files or Directories that must exist, separated by |.
  • Useful for e.g. detecting the presence of removable media.
• REQUIRED_CONTAINER_NAMES: A list of Container names that must be up and Healthy, separated by |.
  • Enables implicit dependency on docker containers without the addional behavior of the depends_on option, such as the restart of the services listed under depends_on when a service is force-recreated.

⁠Example docker-compose config:

The following docker compose config causes the startup of jellyfin to be delayed until the system has been up at least 5 minutes, The external HDD is mounted (containing the media library), And Authentik⁠ authentication system is up and running.

services:
  media_stack_delay:
    image: robomagus/docker-dependency-delay:latest
    container_name: media_stack_delay
    restart: unless-stopped
    environment:
      - MIN_SYSTEM_UPTIME=300
      - REQUIRED_FILES=/ext-storage/lost+found
      - REQUIRED_CONTAINER_NAMES=authentik_worker|authentik_server
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /ext-storage:/ext-storage:ro

  jellyfin:
    image: linuxserver/jellyfin:latest
    container_name: jellyfin
    restart: unless-stopped
    depends_on:
      media_stack_delay:
        condition: service_healthy
    volumes:
      - /ext-storage/data/media:/data