Multiple Compose files to Add & Override attribute

Hai semuanya di materi kali ini kita akan membahas lebih detail tentang multiple compose files untuk Add & Override attribute

Using multiple Compose files enables you to customize a Compose application for different environments or different workflows. By default, Compose reads two files, a docker-compose.yml and an optional docker-compose.override.yml file. By convention, the docker-compose.yml contains your base configuration. The override file, as its name implies, can contain configuration overrides for existing services or entirely new services.

When you use multiple configuration files, you must make sure all paths in the files are relative to the base Compose file (the first Compose file specified with -f). This is required because override files need not be valid Compose files. Override files can contain small fragments of configuration. Tracking which fragment of a service is relative to which path is difficult and confusing, so to keep paths easier to understand, all paths must be defined relative to the base file.

Compose copies configurations from the original service over to the local one. If a configuration option is defined in both the original service and the local service, the local value replaces or extends the original value.

For single-value options like image, command or mem_limit, the new value replaces the old value.

berikut adalah docker-compose.yaml file:

services:
    myservice:
        # ...
        command: python app.py

berikut adalah docker-compose.override.yaml file:

services:
    myservice:
        # ...
        command: python otherapp.py

Ketika dijalankan dengan perintah docker-compose config maka hasilnya seperti berikut:

services:
    myservice:
        # ...
        command: python otherapp.py

For the multi-value options ports, expose, external_links, dns, dns_search, and tmpfs, Compose concatenates both sets of values:

berikut adalah docker-compose.yaml file:

services:
  myservice:
    # ...
    ports:
      - "80:80"

berikut adalah docker-compose.override.yaml file:

services:
  myservice:
    # ...
    ports:
      - "8000:8000"

Ketika dijalankan dengan perintah docker-compose config maka hasilnya seperti berikut:

services:
  myservice:
    # ...
    ports:
      - "8000:8000"
      - "80:80"

In the case of environment, labels, volumes, and devices, Compose “merges” entries together with locally-defined values taking precedence.

For environment and labels, the environment variable or label name determines which value is used:

berikut adalah docker-compose.yaml file:

services:
  myservice:
    # ...
    environment:
      - FOO=original
      - BAR=original

berikut adalah docker-compose.override.yaml file:

services:
  myservice:
    # ...
    environment:
      - BAR=local
      - BAZ=local

Ketika dijalankan dengan perintah docker-compose config maka hasilnya seperti berikut:

services:
  myservice:
    # ...
    environment:
      - FOO=original
      - BAR=local
      - BAZ=local

Entries for volumes and devices are merged using the mount path in the container:

berikut adalah docker-compose.yaml file:

services:
  myservice:
    # ...
    volumes:
      - ./original:/foo
      - ./original:/bar

berikut adalah docker-compose.override.yaml file:

services:
  myservice:
    # ...
    volumes:
      - ./local:/bar
      - ./local:/baz

Ketika dijalankan dengan perintah docker-compose config maka hasilnya seperti berikut:

services:
  myservice:
    # ...
    volumes:
      - ./original:/foo
      - ./local:/bar
      - ./local:/baz

Berikut contohnya, file docker-compose.yaml:

Serta berikut file docker-compose.override.yaml:

Jika dijalankan maka hasilnya seperti berikut:

➜ docker  cd .\09-docker-compose\extends\diff-envs\
➜ diff-envs  docker-compose config
networks:
  frontend: {}
services:
  webapp:
    build:
      args:
        NGINX_VERSION: mainline
      context: C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs
      dockerfile: Dockerfile
    environment:
      NGINX_DOMAIN_NAME: dev01.dimas-maryanto.com
      NGINX_PORT: '80'
      NGINX_ROOT_DOCUMENT: /var/www/html
    image: dimmaryanto93/nginx:latest
    networks:
      frontend: {}
    ports:
    - published: 8080
      target: 80
    volumes:
    - C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs\html:/usr/share/nginx/html:rw
version: '3.9'

## changed directory to root directory
## override using --project-directory option
➜ diff-envs  cd ../..
➜ docker  docker-compose --project-directory .\09-docker-compose\extends\diff-envs config
networks:
  frontend: {}
services:
  webapp:
    build:
      args:
        NGINX_VERSION: mainline
      context: C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs
      dockerfile: Dockerfile
    environment:
      NGINX_DOMAIN_NAME: dev01.dimas-maryanto.com
      NGINX_PORT: '80'
      NGINX_ROOT_DOCUMENT: /var/www/html
    image: dimmaryanto93/nginx:latest
    networks:
      frontend: {}
    ports:
    - published: 8080
      target: 80
    volumes:
    - C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs\html:/usr/share/nginx/html:rw
version: '3.9'

## override using specify file compose
➜ docker  docker-compose -f .\09-docker-compose\extends\diff-envs\docker-compose.yaml `
>> -f .\09-docker-compose\extends\diff-envs\docker-compose.override.yaml `
>> config
networks:
  frontend: {}
services:
  webapp:
    build:
      args:
        NGINX_VERSION: mainline
      context: C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs
      dockerfile: Dockerfile
    environment:
      NGINX_DOMAIN_NAME: dev01.dimas-maryanto.com
      NGINX_PORT: '80'
      NGINX_ROOT_DOCUMENT: /var/www/html
    image: dimmaryanto93/nginx:latest
    networks:
      frontend: {}
    ports:
    - published: 8080
      target: 80
    volumes:
    - C:\Users\dimasm93\Workspaces\youtube\docker\09-docker-compose\extends\diff-envs\html:/usr/share/nginx/html:rw
version: '3.9'