(docker plugin) Additional tag alias support

[ejhayes]

What Changed

Thanks for creating this plugin! This PR does not change any existing behavior but does add some new functionality:

• All plugin configuration can now be passed in via environment variables
  • IMAGE, REGISTRY, TAG_LATEST, TAG_PRERELEASE_ALIASES, TAG_PULL_REQUEST_ALIASES
• README updates
• Added support for the following tag aliases
  • prereleases: pushes to any prerelease branch creates a branch tag in both git and docker (e.g. myimage:<branchName> docker tag and <branchName> git tag). Branch/Tag mapping can be configured via new prereleaseAliasMappings option
  • canary: creates pr-<prNumber> docker tag and pr-<prNumber> git tag
  • release: also creates a latest git tag (not just a latest docker tag)

Why

This provides the following benefits:

• Alias tags (e.g. pr-<prNumber>, latest, next, etc) are only created AFTER docker image is pushed
• Simplifies cases where you want to reference the shortcut version rather than the explicit version (for example if you are publishing new docker images of your service to DockerHub but your customers only care about latest, next, etc)

This functionality may not be desired for all use cases and hence is disabled by default.

Todo:

• Add tests
• Add docs

Change Type

Indicate the type of change your pull request is:

• documentation
• patch
• minor
• major

[ejhayes]

Hey @hipstersmoothie it looks like there might be an issue with the circleci builds.

Error: GitHub token not found!\n' +
    at Auto.loadConfig (/home/circleci/auto/packages/core/src/auto.ts:642:13)\n' +
    at processTicksAndRejections (internal/process/task_queues.js:97:5)\n' +
    at execute (/home/circleci/auto/packages/cli/src/run.ts:36:5)\n' +
    at Object.runCli (/home/circleci/auto/packages/cli/src/run.ts:144:3)\n',

Tests run fine locally for me.

[hipstersmoothie]

Updated the key

[hipstersmoothie]

Tag me again when ready to merge

[ejhayes]

Looks to be failing with the same error @hipstersmoothie

[hipstersmoothie]

Verified this all works locally. don't know what's up with CI

[hipstersmoothie]

🚀 PR was released in v10.37.3 🚀

[ejhayes]

Thanks @hipstersmoothie!