buildx/docs/guides/bake/compose-file.md

Building from Compose file

Specification

Bake uses the compose-spec to parse a compose file and translate each service to a target.

# docker-compose.yml
services:
  webapp-dev: 
    build: &build-dev
      dockerfile: Dockerfile.webapp
      tags:
        - docker.io/username/webapp:latest
      cache_from:
        - docker.io/username/webapp:cache
      cache_to:
        - docker.io/username/webapp:cache

  webapp-release:
    build:
      <<: *build-dev
      x-bake:
        platforms:
          - linux/amd64
          - linux/arm64

  db:
    image: docker.io/username/db
    build:
      dockerfile: Dockerfile.db

$ docker buildx bake --print

{
  "group": {
    "default": {
      "targets": [
        "db",
        "webapp-dev",
        "webapp-release"
      ]
    }
  },
  "target": {
    "db": {
      "context": ".",
      "dockerfile": "Dockerfile.db",
      "tags": [
        "docker.io/username/db"
      ]
    },
    "webapp-dev": {
      "context": ".",
      "dockerfile": "Dockerfile.webapp",
      "tags": [
        "docker.io/username/webapp:latest"
      ],
      "cache-from": [
        "docker.io/username/webapp:cache"
      ],
      "cache-to": [
        "docker.io/username/webapp:cache"
      ]
    },
    "webapp-release": {
      "context": ".",
      "dockerfile": "Dockerfile.webapp",
      "tags": [
        "docker.io/username/webapp:latest"
      ],
      "cache-from": [
        "docker.io/username/webapp:cache"
      ],
      "cache-to": [
        "docker.io/username/webapp:cache"
      ],
      "platforms": [
        "linux/amd64",
        "linux/arm64"
      ]
    }
  }
}

Unlike the HCL format, there are some limitations with the compose format:

• Specifying variables or global scope attributes is not yet supported
• inherits service field is not supported, but you can use YAML anchors to reference other services like the example above

Extension field with x-bake

Even if some fields are not (yet) available in the compose specification, you can use the special extension field x-bake in your compose file to evaluate extra fields:

# docker-compose.yml
services:
  addon:
    image: ct-addon:bar
    build:
      context: .
      dockerfile: ./Dockerfile
      args:
        CT_ECR: foo
        CT_TAG: bar
      x-bake:
        tags:
          - ct-addon:foo
          - ct-addon:alp
        platforms:
          - linux/amd64
          - linux/arm64
        cache-from:
          - user/app:cache
          - type=local,src=path/to/cache
        cache-to:
          - type=local,dest=path/to/cache
        pull: true

  aws:
    image: ct-fake-aws:bar
    build:
      dockerfile: ./aws.Dockerfile
      args:
        CT_ECR: foo
        CT_TAG: bar
      x-bake:
        secret:
          - id=mysecret,src=./secret
          - id=mysecret2,src=./secret2
        platforms: linux/arm64
        output: type=docker
        no-cache: true

$ docker buildx bake --print

{
  "group": {
    "default": {
      "targets": [
        "aws",
        "addon"
      ]
    }
  },
  "target": {
    "addon": {
      "context": ".",
      "dockerfile": "./Dockerfile",
      "args": {
        "CT_ECR": "foo",
        "CT_TAG": "bar"
      },
      "tags": [
        "ct-addon:foo",
        "ct-addon:alp"
      ],
      "cache-from": [
        "user/app:cache",
        "type=local,src=path/to/cache"
      ],
      "cache-to": [
        "type=local,dest=path/to/cache"
      ],
      "platforms": [
        "linux/amd64",
        "linux/arm64"
      ],
      "pull": true
    },
    "aws": {
      "context": ".",
      "dockerfile": "./aws.Dockerfile",
      "args": {
        "CT_ECR": "foo",
        "CT_TAG": "bar"
      },
      "tags": [
        "ct-fake-aws:bar"
      ],
      "secret": [
        "id=mysecret,src=./secret",
        "id=mysecret2,src=./secret2"
      ],
      "platforms": [
        "linux/arm64"
      ],
      "output": [
        "type=docker"
      ],
      "no-cache": true
    }
  }
}

Complete list of valid fields for x-bake:

• cache-from
• cache-to
• no-cache
• no-cache-filter
• output
• platforms
• pull
• secret
• ssh
• tags