Question 239635 in Docker Question posted in
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Docker – Conditional "depends_on" in compose.yml

I have a compose file where I have a php and db service. In the development environment the application is dependent on the local db service, but in production there’s already a (non-dockerized) database running. I gave the db service a profile called "development", but now when I run it in production with docker compose up without the profile, I get the following:

service db is required by php but is disabled. Can be enabled by profiles [development]

Is there a way to have this depends_on option only applicable based on a condition? For example if APP_ENV=development, or something like that? And if not, what would be the most elegant alternative?

version: "3.9"

services:
  php:
    context: "./docker/php"
    target: "${APP_ENV:?}"
    depends_on:
      db:
        condition: "service_started"
  db:
    build:
      context: "./docker/db"
      profiles:
        - development
Tags:

2

Answers


  1. 0

    The best way is to write startup sh script.
    The code I provide bellow is not tested, I wrote as a pseudo code
    And I assumed the database you use is Postgres

    #!/bin/bash

if [ "$APP_ENV" = "development" ]; then
    # Start the DB container
    docker-compose up -d db

    # Wait until the DB container is up and running
    until docker-compose exec db pg_isready -h localhost -U postgres > /dev/null 2>&1; do
        sleep 1
    done
fi

# Start the PHP container
docker-compose up -d php
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  2. 0

    You can have multiple Compose files. These files are merged together, and override files can have extra settings or entire extra containers.

    In the setup you describe, your base Compose file would have the main application, but not the database

    # docker-compose.yml
version: '3.8'
services:
  php:
    image: registry.example.com/php:${PHP_TAG:-latest}

    You could augment this with settings for production only

    # docker-compose.prod.yaml
version: '3.8'
services:
  php:
    environment:
      PGHOST: database.example.com

    or have a separate Compose file with developer-oriented settings. These would include the instructions on how to build the image, and in your setup it would also include the dedicated database container.

    # docker-compose.dev.yaml
version: '3.8'
services:
  php:
    build: ./docker/php
    depends_on:
      db:
        condition: service_started
    environment:
      PGHOST: db
  db:
    build: ./docker/db

    Probably the easiest way to use these is to use a symbolic link to make one of the files named docker-compose.override.yaml

    ln -s docker-compose.dev.yaml docker-compose.override.yaml

    but you can also use a docker-compose -f option; note that you need to list every Compose file if you do, and you need to include it on every Compose invocation.

    docker-compose 
  -f docker-compose.yaml 
  -f docker-compose.dev.yaml 
  up -d
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