Proposal: allow to list tags/IDs of remote image

[miminar]

As a Docker user, I'd like to be able to list tags and Image IDs of remote images without downloading binary blobs.

Possible interface

Add -l flag to docker tag denoting list tags. If given name matches local image, its tags will be listed. Otherwise a remote registry will be listed.

Example:

docker tag -l docker.io/fedora
REPOSITORY          TAG                 IMAGE ID
fedora              20                  d7f0e75cf11fd6fe9fc3e676bb423f1504ea20da110d4d480f74cda8cb94f574
fedora              21                  e26efd418c4841f7299832fe7689de3e820d91a16bb4cff5b72eb9b09d712753
fedora              22                  ded7cd95e059788f2586a51c275a4f151653779d6a7f4dad77c2bd34601d94e4
fedora              heisenbug           d7f0e75cf11fd6fe9fc3e676bb423f1504ea20da110d4d480f74cda8cb94f574
fedora              latest              ded7cd95e059788f2586a51c275a4f151653779d6a7f4dad77c2bd34601d94e4
fedora              rawhide             f62b946038358811c82b9ce50601674a7e1b52ee742557429f244415064251b6

[steelbrain]

A friendly bump, this would be nice to see implemented in docker soon

[andyxning]

@steelbrain Any updates on this?

[steelbrain]

@andyxning Not that I am aware of :(

[olalonde]

Does anyone know a work around? As part of a CI/CD script, I'm trying to avoid building an image if it's already in my AWS ECR repository. I'm using the git short version to tag images.

[Hossrod]

Would really like to see this as well. Work around for us has been to use the Docker Hub API. For example, doing a GET on https://index.docker.io/v1/repositories/<namespace>/<repo_name>/tags returns json array with list of tags.

[olalonde]

I ended up writing this script (for AWS ECR) as a work around: https://gist.github.com/36a7e8b70769fb87c0d037ff01fb4e91

[outofcoffee]

Here's a variant of the script that checks ECR using the AWS CLI: https://gist.github.com/outofcoffee/8f40732aefacfded14cce8a45f6e5eb1

[miminar]

There's also skopeo: https://github.com/projectatomic/skopeo#inspecting-a-repository

[demofly]

Oneliner for CI/CD in my GCP/GCR env:

gcloud container images list-tags --filter="tags=(master)" --format="table[no-heading](digest)" "eu.gcr.io/ci-test-env/system-nginx-ci-lb"

It returns digest or empty data to stdout for image "eu.gcr.io/ci-test-env/system-nginx-ci-lb:master"

Or, we can return count of images with tag. 0 will mean not found:

function docker_image_exists()
{
  TAG=$(echo "$1" | sed -r 's#^.*:([^:]+)$#\1#')
  URL=$(echo "$1" | sed -r 's#^[^:/]*://##' | sed -r 's#:([^:]+)$##')
  gcloud container images list-tags --filter="tags=(${TAG})" --format="table[no-heading](digest)" "${URL}" | wc -l
}

docker_image_exists "https://eu.gcr.io/ci-test-env/system-nginx-ci-lb:master"

[paologallinaharbur]

any update?

[Miserlou]

Please update this. There is so much copypasta garbage out there about checking the URL response from the API using bash. Make this is a native feature!

[irfanbaigse]

still waiting

[thaJeztah]

related docker/roadmap#117