Docker Wait for Deps

A simple container that puts itself on hold until the other services declared in the docker-compose are accessible via TCP.

Available for linux/amd64 and linux/arm64 architectures.

Example usage:

Sample docker-compose.yml:

version: '2'
services:
  mongo:
    image: mongo:6
    container_name: mongo
    ports:
      - 27017:27017
    networks:
      - my-network

  redis:
    container_name: redis
    image: redis:6
    ports:
      - 6379:6379
    networks:
      - my-network

  server:
    container_name: server
    image: server
    ports:
      - 3000:3000
    networks:
      - my-network

  start_dependencies:
    image: ducktors/docker-wait-for-dependencies
    depends_on:
      - mongo
      - redis
    container_name: wait-for-dependencies
    command: mongo:27017 redis:6379
    networks:
      - my-network

Then, to guarantee that mongo and redis are ready before running server:

$ docker-compose run --rm start_dependencies
# Some output from docker compose
$ docker-compose up server

By default, there will be a 2 second sleep time between each check. You can modify this by setting the SLEEP_LENGTH environment variable:

  start_dependencies:
    image: ducktors/docker-wait-for-dependencies
    environment:
      - SLEEP_LENGTH: 0.5

By default, there will be a 300 seconds timeout before cancelling the wait_for. You can modify this by setting the TIMEOUT_LENGTH environment variable:

  start_dependencies:
    image: ducktors/docker-wait-for-dependencies
    environment:
      - SLEEP_LENGTH: 1
      - TIMEOUT_LENGTH: 60