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After several iterations, Docker Registry was upgraded from version 1 to version 2. Especially being new, some commands needed to be included or adequately documented on its official documentation website.

An example is getting a list of images in a Docker Registry.

This article will discuss getting the image list in Docker Registry V2.

Get the full list of images on Docker Registry V2

Before we begin, pull the latest version of Docker Registry in DockerHub by running the following command.

$ docker pull distribution/registry:master

In Docker Registry version 1, we could get a list of all images by performing an API GET call to the base URL of http://myregistry:5000/v1/search? Although not implied in the documentation, we can also perform a similar approach to update and different base URL by calling a GET request.

List all repositories and mirrors

When Docker updated the Docker Registry to version 2, they also updated all the API base URLs. So now, instead of calling the v1 base URL, we can use the following URL.

$ curl -X GET https://myregistry:5000/v2/_catalog

The default results only show one hundred (100) mirror records, but if you need to show more, you can paginate the results by appending query parameters.

$ curl -X GET https://myregistry:5000/v2/_catalog?n=<count>

List all tags for a repository

If we need to list all the tags of a repository, we can use the following different endpoints.

$ curl -X GET https://myregistry:5000/v2/<name>/tags/list

We can replace the name value with the name of the repository we want to query tags from.

Querying the API using credentials

If the registry requires authentication, we must specify our credentials in the curl command by adding the -u flag.

$ curl -X GET -u <username>:<password> https://myregistry:5000/v2/_catalog
$ curl -X GET -u <username>:<password> https://myregistry:5000/v2/<name>/tags/list

If our registry used a self-signed certificate instead of credentials, we could make an insecure request by adding the -k and --insecure flags. However, this is considered a security risk, so use it at your own risk.

The Docker Registry v2 API provides more endpoints to satisfy more requests. We can find the complete endpoints in this link.