dhet / scan-docker-tags-action

A GitHub action for scanning Docker repositories for recently-updated tags.

Scan Docker Tags Action

Scan a Docker repository for recently-updated tags. This allows you to trigger builds whenever a given Docker image is updated.

Example

This example workflow scans a Docker repository every 15 minutes and prints all tags that were updated since the last run.

name: Scan Docker Repo
on:
  schedule:
    - cron: '*/15 * * * *'

jobs:
  scan:
    name: List Recent Updates
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Scan Docker Repository
        uses: dhet/scan-docker-tags-action@v1.0.1
        with:
          image: mhart/alpine-node
          max-age-minutes: 15
          username: ${{ secrets.DOCKER_HUB_USER }}
          password: ${{ secrets.DOCKER_HUB_PASSWORD }}
        id: scan
      - name: Print
        run: "echo 'Recent updates: ${{ steps.scan.outputs.tags }}'"

Output:

Recent updates: slim-14.4,slim-14,slim,latest

Required Inputs

Parameter	Description
image	The image repository to scan (sans tag), e.g. "mhart/alpine-node"
max-age-minutes	The maximum age of tags to consider. Older tags are discarded. E.g. 30 for 30 minutes
username	The username used to authenticate against the Docker repository
password	The password used to authenticate against the Docker repository

Optional Inputs

Parameter	Description	Default
tag-regex	A regular expression for filtering tags. Backslashes need to be escaped. E.g. \\d+\\.\\d+$ matches 0.10, 1.2, 1.12.123, etc.; latest matches only the "latest" tag.	.*
repo-url	The URL of the Docker registry. Defaults to Dockerhub.	https://hub.docker.com

Outputs

The only output this action exposes is the tags output. tags is a comma-separated list of all image tags that have changed in the specified time frame. The list is sorted by date in ascending order. E.g. v1.0.7,v1.0.8,latest.