Docker Image Resource

Tracks and builds Docker images.

Note: docker registry must be v2.

Maintainer Note

The Concourse project does not recommend using this resource-type. You should use the registry-image for downloading/uploading container images.

For building, we recommend using the oci-build task, which uses Docker's buildx to build images.

Together, these tools have proven to be more robust than this resource-type. We would like to eventually deprecate this resource-type but have no timeline for whan that will happen.

Source Configuration

• repository: Required. The name of the repository, e.g. concourse/docker-image-resource.

Note: When configuring a private registry which requires a login, the registry's address must contain at least one '.' e.g. registry.local or contain the port (e.g. registry:443 or registry:5000). Otherwise docker hub will be used.

Note: When configuring a private registry using a non-root CA, you must include the port (e.g. :443 or :5000) even though the docker CLI does not require it.

• tag: Optional. The tag to track. Defaults to latest.

• username: Optional. The username to authenticate with when pushing.

• password: Optional. The password to use when authenticating.

• additional_private_registries: Optional. An array of objects with the following format:

yaml additional_private_registries: - registry: example.com/my-private-docker-registry username: my-username password: ((my-secret:my-secret)) - registry: example.com/another-private-docker-registry username: another-username password: ((another-secret:another-secret))

Each entry specifies a private docker registry and credentials to be passed to docker login. This is used when a Dockerfile contains a FROM instruction referring to an image hosted in a docker registry that requires a login.

• aws_access_key_id: Optional. AWS access key to use for acquiring ECR credentials.

• aws_secret_access_key: Optional. AWS secret key to use for acquiring ECR credentials.

• aws_session_token: Optional. AWS session token (assumed role) to use for acquiring ECR credentials.

• insecure_registries: Optional. An array of CIDRs or host:port addresses to whitelist for insecure access (either http or unverified https). This option overrides any entries in ca_certs with the same address.

• registry_mirror: Optional. A URL pointing to a docker registry mirror service.

Note: registry_mirror is ignored if repository contains an explicitly-declared registry-hostname-prefixed value, such as my-registry.com/foo/bar, in which case the registry cited in the repository value is used instead of the registry_mirror.

• ca_certs: Optional. An array of objects with the following format:

yaml ca_certs: - domain: example.com:443 cert: | -----BEGIN CERTIFICATE----- ... -----END CERTIFICATE----- - domain: 10.244.6.2:443 cert: | -----BEGIN CERTIFICATE----- ... -----END CERTIFICATE-----

Each entry specifies the x509 CA certificate for the trusted docker registry residing at the specified domain. This is used to validate the certificate of the docker registry when the registry's certificate is signed by a custom authority (or itself).

The domain should match the first component of repository, including the port. If the registry specified in repository does not use a custom cert, adding ca_certs will break the check script. This option is overridden by entries in insecure_registries with the same address or a matching CIDR.

• client_certs: Optional. An array of objects with the following format:

yaml client_certs: - domain: example.com cert: | -----BEGIN CERTIFICATE----- ... -----END CERTIFICATE----- key: | -----BEGIN RSA PRIVATE KEY----- ... -----END RSA PRIVATE KEY----- - domain: 10.244.6.2 cert: | -----BEGIN CERTIFICATE----- ... -----END CERTIFICATE----- key: | -----BEGIN RSA PRIVATE KEY----- ... -----END RSA PRIVATE KEY-----

Each entry specifies the x509 certificate and key to use for authenticating against the docker registry residing at the specified domain. The domain should match the first component of repository.

• max_concurrent_downloads: Optional. Maximum concurrent downloads.

Limits the number of concurrent download threads.

• max_concurrent_uploads: Optional. Maximum concurrent uploads.

Limits the number of concurrent upload threads.

• startup_timeout: Optional. Default 120. The timeout in seconds to wait for the Docker daemon to start. Increase this value if you're experiencing timeouts during Docker daemon startup on slower systems.

Behavior

check: Check for new images.

The current image digest is fetched from the registry for the given tag of the repository.

in: Fetch the image from the registry.

Pulls down the repository image by the requested digest.

The following files will be placed in the destination:

• /image: If save is true, the docker saved image will be provided here.
• /repository: The name of the repository that was fetched.
• /tag: The tag of the repository that was fetched.
• /image-id: The fetched image ID.
• /digest: The fetched image digest.
• /rootfs.tar: If rootfs is true, the contents of the image will be provided here.
• /metadata.json: Collects custom metadata. Contains the container env variables and running user.
• /docker_inspect.json: Output of the docker inspect on image_id. Useful if collecting LABEL metadata from your image.

Parameters

• save: Optional. Place a docker saved image in the destination.
• rootfs: Optional. Place a .tar file of the image in the destination.
• skip_download: Optional. Skip docker pull of image. Artifacts based on the image will not be present.

As with all concourse resources, to modify params of the implicit get step after each put step you may also set these parameters under a put get_params. For example:

put: foo
params: {...}
get_params: {skip_download: true}

out: Push an image, or build and push a Dockerfile.

Push a Docker image to the source's repository and tag. The resulting version is the image's digest.

Parameters

• additional_tags: Optional. Path to a file containing a whitespace-separated list of tags. The Docker build will additionally be pushed with those tags.

• build: Optional. The path of a directory containing a Dockerfile to build.

• build_args: Optional. A map of Docker build-time variables. These will be available as environment variables during the Docker build.

While not stored in the image layers, they are stored in image metadata and so it is recommend to avoid using these to pass secrets into the build context. In multi-stage builds ARGs in earlier stages will not be copied to the later stages, or in the metadata of the final stage.

The build metadata environment variables provided by Concourse will be expanded in the values (the syntax is $SOME_ENVVAR or ${SOME_ENVVAR}).

Example:

yaml build_args: DO_THING: true HOW_MANY_THINGS: 2 EMAIL: me@yopmail.com CI_BUILD_ID: concourse-$BUILD_ID

• build_args_file: Optional. Path to a JSON file containing Docker build-time variables.

Example file contents:

yaml { "EMAIL": "me@yopmail.com", "HOW_MANY_THINGS": 1, "DO_THING": false }

• secrets: Optional. A map of Docker build-time secrets. These will be available as mounted paths only during the docker build phase.

Secrets are not stored in any metadata or layers, so they are safe to use for access tokens and the like during the build.

Example:

yaml secrets: secret1: env: BUILD_ID secret2: source: /a/secret/file.txt

• cache: Optional. Default false. When the build parameter is set, first pull image:tag from the Docker registry (so as to use cached intermediate images when building). This will cause the resource to fail if it is set to true and the image does not exist yet.

• cache_from: Optional. An array of images to consider as cache, in order to reuse build steps from a previous build. The array elements are paths to directories generated by a get step with save: true. This has a similar aim of cache, but it loads the images from disk instead of pulling them from the network, so that Concourse resource caching can be used. It also allows more than one image to be specified, which is useful for multi-stage Dockerfiles. If you want to cache an image used in a FROM step, you should put it in load_bases instead.

• cache_tag: Optional. Default tag. The specific tag to pull before building when cache parameter is set. Instead of pulling the same tag that's going to be built, this allows picking a different tag like latest or the previous version. This will cause the resource to fail if it is set to a tag that does not exist yet.

• dockerfile: Optional. The path of the Dockerfile in the directory if it's not at the root of the directory.

• docker_buildkit: Optional. This enables a Docker BuildKit build. The value should be set to 1 if applicable.

• import_file: Optional. A path to a file to docker import and then push.

• labels: Optional. A map of labels that will be added to the image.

Example:

yaml labels: commit: b4d4823 version: 1.0.3

• labels_file: Optional. Path to a JSON file containing the image labels.

Example file contents:

json { "commit": "b4d4823", "version": "1.0.3" }

• load: Optional. The path of a directory containing an image that was fetched using this same resource type with save: true.

• load_base: Optional. A path to a directory containing an image to docker load before running docker build. The directory must have image, image-id, repository, and tag present, i.e. the tree produced by /in.

• load_bases: Optional. Same as load_base, but takes an array to load multiple images.

• load_file: Optional. A path to a file to docker load and then push. Requires load_repository.

• load_repository: Optional. The repository of the image loaded from load_file.

• load_tag: Optional. Default latest. The tag of image loaded from load_file

• pull_repository: Optional. DEPRECATED. Use get and load instead. A path to a repository to pull down, and then push to this resource.

• pull_tag: Optional. DEPRECATED. Use get and load instead. Default latest. The tag of the repository to pull down via pull_repository.

• tag: DEPRECATED - Use tag_file instead

• tag_file: Optional. The value should be a path to a file containing the name of the tag. When not set, the Docker build will be pushed with tag value set by tag in source configuration.

• tag_as_latest: Optional. Default false. If true, the pushed image will be tagged as latest in addition to whatever other tag was specified.

• tag_prefix: Optional. If specified, the tag read from the file will be prepended with this string. This is useful for adding v in front of version numbers.

• target_name: Optional. Specify the name of the target build stage. Only supported for multi-stage Docker builds

Example

resources:
- name: git-resource
  type: git
  source: # ...

- name: git-resource-image
  type: docker-image
  source:
    repository: concourse/git-resource
    username: username
    password: password

- name: git-resource-rootfs
  type: s3
  source: # ...

jobs:
- name: build-rootfs
  plan:
  - get: git-resource
  - put: git-resource-image
    params: {build: git-resource}
    get_params: {rootfs: true}
  - put: git-resource-rootfs
    params: {file: git-resource-image/rootfs.tar}

Development

Prerequisites

• golang is required - version 1.9.x is tested; earlier versions may also work.
• docker is required - version 23.x is tested; earlier versions may also work.

Running the tests

The tests have been embedded with the Dockerfile; ensuring that the testing environment is consistent across any docker enabled platform. When the docker image builds, the test are run inside the docker container, on failure they will stop the build.

Run the tests with the following command:

docker build -t docker-image-resource --target tests .

To use the newly built image, push it to a docker registry that's accessible to Concourse and configure your pipeline to use it:

resource_types:
- name: docker-image-resource
  type: docker-image
  privileged: true
  source:
    repository: example.com:5000/docker-image-resource
    tag: latest

resources:
- name: some-image
  type: docker-image-resource
  ...

Contributing

Please make all pull requests to the master branch and ensure tests pass locally.