Currently, only private DockerHub registries are supported. This application is distributed as a Docker image.

Docker Hub | Changelog

Getting Started

The quickest way to get started is opening the sample-configuration directory and running Hubcycle via Docker Compose or Kubernetes. You can also pull and run this image standalone:

docker pull strongeleeroy/hubcycle

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Configuration -- Environment variables

Authentication

• dockerhub.username: DockerHub username.
• dockerhub.password: DockerHub password.

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Configuration -- Flags

The following flags can be passed as part of the docker composecommand or Kubernetes container args options of the container:

• --debug, -d: Enable debug level logging.
• --dry-run: Enable dry run mode (no tags will be deleted).
• --yaml: Use YAML configuration instead of JSON.

Docker compose example:

services:
  hubcycle:
    image: hubcycle:latest
    command: --dry-run --debug

Kubernetes example:

spec:
  containers:
    - name: hubcycle
      image: hubcycle:latest
      args: ["--dry-run", "--debug"]

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Configuration -- Lifecycle Rules (JSON configuration)

Image match and purging configuration is read from a single file located under /config/images.json, if none is given, tthe application defaults to legacy configuration (via environment variables and documented at the end of this README file).

This file can be shared to the container via a volume or configuration map.

The configuration file images.json must contain an array of images with their own configuration parameters.

Example A: Basic configuration

This configuration handles two images, a single tag matcher for image-a, and two tag matchers for image-b.

{
  "images": [
    {
      "name": "user/image-a",
      "match": [
        {
          "expression": "develop-.*",
          "keep": 3
        }
      ]
    }, {
      "name": "user/image-b",
      "match": [
        {
          "expression": "develop-.*",
          "keep": 3
        }, {
          "expression": "master-.*",
          "keep": 10
        }
      ]
    }
  ]
}

Example B: Setting defaults

We can set the default value of keep by setting a keep key on the image object instead of a matcher. If no keep value is given to a matcher or image, the system will default to 5.

In this example, image-a will use a keep value of 5 in the first matcher, image-b will use a keep value of 3 for the first matcher and default to 10 for the second.

{
  "images": [
    {
      "name": "user/image-a",
      "match": [
        {
          "expression": "develop-.*"
        }
      ]
    }, {
      "name": "user/image-b",
      "keep": 10,
      "match": [
        {
          "expression": "develop-.*",
          "keep": 3
        }, {
          "expression": "master-.*"
        }
      ]
    }
  ]
}

Example C: Shortcut syntax

We can use a slightly more compact syntax when we only need to handle a single matcher per image by using a string instead of a matcher array. Defaults behave in the same manner, image-a below will use a keep value of 5 (default) while image-b will use 10 (user set).

{
  "images": [
    {
      "name": "user/image-a",
      "match": "develop-.*"
    }, {
      "name": "user/image-b",
      "keep": 10,
      "match": "master-.*"
    }
  ]
}

Configuration -- Lifecycle Rules (YAML)

YAML configuration is the preferred alternative to JSON (which will eventually be deprecated). Image match and purging configuration can be read from a single file located under /config/images.yaml, if none is given, tthe application defaults to legacy configuration (via environment variables and documented at the end of this README file).

This file can be shared to the container via a volume or configuration map.

Using YAML configuration requires that the --yaml flag is passed as an argument to the Node application or container.

Example A: Basic configuration

This configuration handles two images, a single tag matcher for image-a, and two tag matchers for image-b.

images:
  - name: user/image-a
    match:
    - expression: develop-.*
      keep: 3
  - name: user/image-b
    match:
    - expression: develop-.*
      keep: 3
    - expression: master-.*
      keep: 10

Example B: Setting defaults

We can set the default value of keep by setting a keep key on the image object instead of a matcher. If no keep value is given to a matcher or image, the system will default to 5.

In this example, image-a will use a keep value of 5 in the first matcher, image-b will use a keep value of 3 for the first matcher and default to 10 for the second.

images:
  - name: user/image-a
    match:
    - expression: develop-.*
  - name: user/image-b
    keep: 10
    match:
    - expression: develop-.*
      keep: 3
    - expression: master-.*

Example C: Shortcut syntax

We can use a slightly more compact syntax when we only need to handle a single matcher per image by using a string instead of a matcher array. Defaults behave in the same manner, image-a below will use a keep value of 5 (default) while image-b will use 10 (user set).

images:
  - name: user/image-a
    match: develop-.*
  - name: user/image-b
    keep: 10
    match: master-.*

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Legacy Configuration -- Environment variables (DEPRECATED)

• dockerhub.organization: DockerHub organization.
• dockerhub.images: List of comma separated image repository names. (e.g.: image1,image2)
• match.expression:: RegExp expression that will be used to detect matching tags [default: develop-.*].
• keep: Number of old builds to keep (from those matching the expression above).

The complete image registry path is generated by merging the dockerhub.organization and dockerhub.images variables, and then matched to a tag using match.expression. For example, given the following values:

• dockerhub.organization: mycompany
• dockerhub.images: my-image,my-other-image,my-third-image
• match.expression: develop-.*

These would be a few matching tags:

mycompany/my-image:develop-001
mycompany/my-image:develop-002
mycompany/my-image:develop-123abc
mycompany/my-other-image:develop-001
mycompany/my-other-image:develop-002
mycompany/my-other-image:develop-123abc
mycompany/my-third-image:develop-001
mycompany/my-third-image:develop-002
mycompany/my-third-image:develop-123abc