Remove docker images

Remove obsolete docker images.

Prerequisite

Install Docker.

Supported tag syntax

The tags following this regex are supported:

^[vV]?(\d{1,5})(\.\d{1,5})?(\.\d{1,5})?(-.*)?$

ex) Supported tags:

1.0
1.0-SNAPSHOT
v2.10.1
2.0-BR291-SNAPSHOT
8-jdk

ex) Non supported tag:

123456.1 (major version has more than 5 digits)
ver1.2

Canonical version

If the tag matches the following regex, it is recognized as a canonical (non snapshot) version.

^[vV]?(\d{1,5})(\.\d{1,5})?(\.\d{1,5})?

Snapshot version

If the tag ends with "-SNAPSHOT", it is recognized as a snapshot version.

Branch

If non "-SNAPSHOT" string follows, it is recognized as a branch.

ex) Branch: BR102(canonical version)

1.4-BR102

ex) Branch: BR102(snapshot version)

1.4-BR102-SNAPSHOT

How it works

1. Invoke "docker images" to obtain the list of docker image.

| Image name | tag | -|- | foo/myapp | 1.0 | | foo/myapp | 1.0-SNAPSHOT | | bar/app | 1.2 | | foo/myapp | 1.1 | | foo/myapp | 1.1-SNAPSHOT | | foo/myapp | 1.2 | | bar/app | 2.2 | | foo/myapp | 1.3 |

1. Grouping the list by image name.

| Image name | tag | -|- | foo/myapp | 1.0 | | foo/myapp | 1.0-SNAPSHOT | | foo/myapp | 1.3 | | foo/myapp | 1.1 | | foo/myapp | 1.1-SNAPSHOT | | foo/myapp | 1.2 | | bar/app | 2.2 | | bar/app | 1.2 |

1. Grouping the list by canonical/snapshot version.

| Image name | tag | -|- | foo/myapp | 1.0-SNAPSHOT | | foo/myapp | 1.1-SNAPSHOT | | foo/myapp | 1.0 | | foo/myapp | 1.3 | | foo/myapp | 1.1 | | foo/myapp | 1.2 | | bar/app | 2.2 | | bar/app | 1.2 |

1. Sort by version number.

| Image name | tag | -|- | foo/myapp | 1.0-SNAPSHOT | | foo/myapp | 1.1-SNAPSHOT | | foo/myapp | 1.0 | | foo/myapp | 1.1 | | foo/myapp | 1.2 | | foo/myapp | 1.3 | | bar/app | 1.2 | | bar/app | 2.2 |

1. Apply the following rule.
   For snapshot version, keep the latest version. For canonical version, keep the three newest versions. You can modify the keep count by argument.

| Image name | tag | delete | -|-|- | foo/myapp | 1.0-SNAPSHOT | delete | | foo/myapp | 1.1-SNAPSHOT | keep | | foo/myapp | 1.0 | delete | | foo/myapp | 1.1 | keep | | foo/myapp | 1.2 | keep | | foo/myapp | 1.3 | keep | | bar/app | 1.2 | keep | | bar/app | 2.2 | keep |

1. Invoke "docker rmi" to remove image

Argument

• --version
  Show tool version.

• --dry-run
  Do not invoke "docker rmi" instead, just show the images that will be deleted.

• --keep [count]
  Specify keep count for canonical versions. Default to 3.

• --keep-snapshot [count]
  Specify keep count for snapshot versions. Default to 1.

• --repository-type [type]
  Specify docker image repository type. Can use 'docker' and 'ibmcr'. The 'docker' means docker image repository. The 'ibmcr' means IBM Cloud Registry. Default to 'docker'.

IBM Cloud Registry

If you want to use IBM Cloud Registry, specify '--repository-type ibmcr'. In this case, you need to login IBM Cloud Registry in advance.

$ ibmcloud login
$ ibmcloud cr login
$ remove_docker_images --repository-type ibmcr

If you want to execute it in non-interactive environment such as in CI server, you can use API key.

$ export IBMCLOUD_API_KEY=YOUR_CONTAINER_REGISTRY_APIKEY
$ ibmcloud login
$ ibmcloud cr login
$ remove_docker_images --repository-type ibmcr

You can create API key at web console:

• Manage => IAM => Service IDs => Create
• Input name and click Create.
• Click Access Policies.
• Click Assign access.
• Select IAM services.
• Click drop down 'No access' and select Container Registry.
• In 'Service access', check Reader and Writer.
• Click Add.
• Click Assign.
• Click API keys.
• Click Create.
• Input Name and click Create.
• Now, you can copy the API Key.

Binary

Linux(x86_64): 0.1.0-SNAPSHOT