Docker Images¶

GoReleaser can build and push Docker images. Let's see how it works.

How it works¶

You can declare multiple Docker images. They will be matched against the binaries generated by your builds section and packages generated by your nfpms section.

If you have only one build setup, the configuration is as easy as adding the name of your image to your .goreleaser.yaml file:

dockers:
  - image_templates:
      - user/repo

Tip

The image_templates attribute supports templating. Learn more about the name template engine.

You also need to create a Dockerfile in your project's root folder:

FROM scratch
ENTRYPOINT ["/mybin"]
COPY mybin /

This configuration will build and push a Docker image named user/repo:tagname.

Warning

Note that we are not building any go files in the Docker build phase, we are merely copying the binary to a scratch image and setting up the entrypoint.

Customization¶

Of course, you can customize a lot of things:

# .goreleaser.yaml
dockers:
  # You can have multiple Docker images.
  - #
    # ID of the image, needed if you want to filter by it later on (e.g. on custom publishers).
    id: myimg

    # GOOS of the built binaries/packages that should be used.
    # Default: 'linux'
    goos: linux

    # GOARCH of the built binaries/packages that should be used.
    # Default: 'amd64'
    goarch: amd64

    # GOARM of the built binaries/packages that should be used.
    # Default: '6'
    goarm: ""

    # GOAMD64 of the built binaries/packages that should be used.
    # Default: 'v1'
    goamd64: "v2"

    # IDs to filter the binaries/packages.
    ids:
      - mybuild
      - mynfpm

    # Templates of the Docker image names.
    #
    # Templates: allowed
    image_templates:
      - "myuser/myimage:latest"
      - "myuser/myimage:{{ .Tag }}"
      - "myuser/myimage:{{ .Tag }}-{{ .Env.FOOBAR }}"
      - "myuser/myimage:v{{ .Major }}"
      - "gcr.io/myuser/myimage:latest"

    # Skips the docker build.
    # Could be useful if you want to skip building the windows docker image on
    # linux, for example.
    #
    # Templates: allowed
    # Since: v1.14 (pro)
    # This option is only available on GoReleaser Pro.
    skip_build: false

    # Skips the docker push.
    # Could be useful if you also do draft releases.
    #
    # If set to auto, the release will not be pushed to the Docker repository
    #  in case there is an indicator of a prerelease in the tag, e.g. v1.0.0-rc1.
    #
    # Templates: allowed (since v1.19)
    skip_push: false

    # Path to the Dockerfile (from the project root).
    #
    # Default: 'Dockerfile'
    # Templates: allowed.
    dockerfile: "{{ .Env.DOCKERFILE }}"

    # Use this instead of `dockerfile` if the contents of your Dockerfile are
    # supposed to go through the template engine as well.
    #
    # `dockerfile` is ignored when this is set.
    #
    # Since: v1.20 (pro)
    # This feature is only available in GoReleaser Pro.
    # Templates: allowed
    templated_dockerfile: "{{.Env.DOCKERFILE }}"

    # Set the "backend" for the Docker pipe.
    #
    # Valid options are: docker, buildx, podman.
    #
    # Podman is a GoReleaser Pro feature and is only available on Linux.
    #
    # Default: 'docker'
    use: docker

    # Docker build flags.
    #
    # Templates: allowed
    build_flag_templates:
      - "--pull"
      - "--label=org.opencontainers.image.created={{.Date}}"
      - "--label=org.opencontainers.image.title={{.ProjectName}}"
      - "--label=org.opencontainers.image.revision={{.FullCommit}}"
      - "--label=org.opencontainers.image.version={{.Version}}"
      - "--build-arg=FOO={{.Env.Bar}}"
      - "--platform=linux/arm64"

    # Extra flags to be passed down to the push command.
    push_flags:
      - --tls-verify=false

    # If your Dockerfile copies files other than binaries and packages,
    # you should list them here as well.
    # Note that GoReleaser will create the same structure inside a temporary
    # folder, so if you add `foo/bar.json` here, on your Dockerfile you can
    # `COPY foo/bar.json /whatever.json`.
    # Also note that the paths here are relative to the folder in which
    # GoReleaser is being run (usually the repository root folder).
    # This field does not support wildcards, you can add an entire folder here
    # and use wildcards when you `COPY`/`ADD` in your Dockerfile.
    extra_files:
      - config.yml

    # Additional templated extra files to add to the Docker image.
    # Those files will have their contents pass through the template engine,
    # and its results will be added to the build context the same way as the
    # extra_files field above.
    #
    # Since: v1.17 (pro)
    # This feature is only available in GoReleaser Pro.
    # Templates: allowed
    templated_extra_files:
      - src: LICENSE.tpl
        dst: LICENSE.txt
        mode: 0644

Warning

Note that you will have to manually login into the Docker registries you want to push to — GoReleaser does not login by itself.

Tip

Learn more about the name template engine.

Tip

You can also create multi-platform images using the docker_manifests config.

These settings should allow you to generate multiple Docker images, for example, using multiple FROM statements, as well as generate one image for each binary in your project or one image with multiple binaries, as well as install the generated packages instead of copying the binary and configs manually.

Generic Image Names¶

Some users might want to keep their image name as generic as possible. That can be accomplished simply by adding template language in the definition:

# .goreleaser.yaml
project_name: foo
dockers:
  - image_templates:
      - "myuser/{{.ProjectName}}"

This will build and publish the following images:

myuser/foo

Tip

Learn more about the name template engine.

Keeping docker images updated for current major¶

Some users might want to push docker tags :v1, :v1.6, :v1.6.4 and :latest when v1.6.4 (for example) is built. That can be accomplished by using multiple image_templates:

# .goreleaser.yaml
dockers:
  - image_templates:
      - "myuser/myimage:{{ .Tag }}"
      - "myuser/myimage:v{{ .Major }}"
      - "myuser/myimage:v{{ .Major }}.{{ .Minor }}"
      - "myuser/myimage:latest"

This will build and publish the following images:

myuser/myimage:v1.6.4
myuser/myimage:v1
myuser/myimage:v1.6
myuser/myimage:latest

With these settings you can hopefully push several Docker images with multiple tags.

Tip

Learn more about the name template engine.

Publishing to multiple docker registries¶

Some users might want to push images to multiple docker registries. That can be accomplished by using multiple image_templates:

# .goreleaser.yaml
dockers:
  - image_templates:
      - "docker.io/myuser/myimage:{{ .Tag }}"
      - "docker.io/myuser/myimage:latest"
      - "gcr.io/myuser/myimage:{{ .Tag }}"
      - "gcr.io/myuser/myimage:latest"

This will build and publish the following images to docker.io and gcr.io:

myuser/myimage:v1.6.4
myuser/myimage:latest
gcr.io/myuser/myimage:v1.6.4
gcr.io/myuser/myimage:latest

Applying Docker build flags¶

Build flags can be applied using build_flag_templates. The flags must be valid Docker build flags.

# .goreleaser.yaml
dockers:
  - image_templates:
      - "myuser/myimage"
    build_flag_templates:
      - "--pull"
      - "--label=org.opencontainers.image.created={{.Date}}"
      - "--label=org.opencontainers.image.title={{.ProjectName}}"
      - "--label=org.opencontainers.image.revision={{.FullCommit}}"
      - "--label=org.opencontainers.image.version={{.Version}}"

This will execute the following command:

docker build -t myuser/myimage . \
  --pull \
  --label=org.opencontainers.image.created=2020-01-19T15:58:07Z \
  --label=org.opencontainers.image.title=mybinary \
  --label=org.opencontainers.image.revision=da39a3ee5e6b4b0d3255bfef95601890afd80709 \
  --label=org.opencontainers.image.version=1.6.4

Tip

Learn more about the name template engine.

Use a specific builder with Docker buildx¶

If buildx is enabled, the default context builder will be used when building the image. This builder is always available and backed by BuildKit in the Docker engine. If you want to use a different builder, you can specify it using the build_flag_templates field:

# .goreleaser.yaml
dockers:
  - image_templates:
      - "myuser/myimage"
    use: buildx
    build_flag_templates:
      - "--builder=mybuilder"

Tip

Learn more about the buildx builder instances.

Podman¶

GoReleaser Pro

The podman backend is a GoReleaser Pro feature.

You can use podman instead of docker by setting use to podman on your config:

# .goreleaser.yaml
dockers:
  - image_templates:
      - "myuser/myimage"
    use: podman

Note that GoReleaser will not install Podman for you, nor change any of its configuration.

If you want to use it rootless, make sure to follow this guide.