Docker Image Checker

With this tool (called dic) you can check a given Docker image vs a base image. This, in go lang written tool, compares the latest build timestamps on any Docker repository.

Use Case

Normally you have an application Docker build on top of a base image like Alpine. I use very often the latest tag for my apps, because I do not have any critical dependencies on the underlying OS. So I will get to everytime the latest patched base image for my application. The Docker Image Checker supports me to detect in my CI/CD pipeline a newer base image and can trigger a new release or a rebuild of an existent image.

Usage

You can use a prepared Docker image on Docker Hub https://hub.docker.com/r/secanis/docker-image-checker:

    docker pull secanis/docker-image-checker:latest
    docker run --rm secanis/docker-image-checker:latest \
        ./dic -base "hub.docker.com/library/alpine:latest" -image "hub.docker.com/secanis/stjorna:2.1.3"

Or when you want to use it in a CI/CD pipeline, you can do something like this:

    if docker run --rm secanis/docker-image-checker:latest \
            ./dic -base "hub.docker.com/library/alpine:latest" \
            -image "hub.docker.com/secanis/stjorna:2.1.3"; then
        # do something in your pipeline
        echo "Command succeeded"
    else
        # do something in your pipeline
        echo "Command failed"
    fi

Download the binary from Github https://github.com/secanis/docker-image-checker/releases and unpack it.

    ./dic -base "hub.docker.com/library/alpine:latest" -image "hub.docker.com/secanis/stjorna:2.1.3"