Determining how the Docker Free Tier sunset affects you

How news of the Docker Free Tier being sunset in March 2023 led to organisations wanting to understand their dependence on different namespaces or images on the public Docker Hub.

(Note: adapted from the blog post Working out which Docker namespaces and images you most depend on)

Context

When Docker announced that Free Team organisations would be sunset in March 2023, there was a good deal of concern from the Software Engineering community, many of whom were unclear how much of an impact this would have on them.

This change had an impact to not only teams running their own Docker hub organisations (also known as "namespaces"), but pulling from other peoples' namespaces, or if anyone outside of their organisation was pulling from their namespace.

For instance, if a well-used namespace, such as goreleaser, did not either apply for a Docker-Sponsored Open Source Project, or pay up, then any downstream users would be impacted by more frequent rate limits or even being unable to pull the images until the next billing cycle.

This introduced considerable risk to companies that didn't a straightforward means to easily query this data, and Docker Inc didn't provide any tooling to work this out for yourself.

Although Docker have since cancelled this change, understanding the usage of Docker images across your organisation can be super helpful, which is expanded upon in Case study: Determining the Docker registries, namespaces and images you most depend on.

Problem

Which namespaces do we depend on?

Data

Let's say that we have the following data in the renovate table:

platform	organisation	repo	package_name	version	current_version	package_manager	package_file_path	datasource	dep_types
gitlab	technottingham	Hack24-API	mongo	3.4.3	3.4.3	docker-compose	docker-compose.yml	docker	[]
gitlab	jamietanna	annadodson	monachus/hugo			gitlabci	.gitlab-ci.yml	docker	["image"]
github	co-cddo	api-catalogue	ruby	3.3.0-alpine	3.3.0-alpine	dockerfile	Dockerfile	docker	["final"]
github	elastic	beats	busybox			docker-compose	.ci/jobs/docker-compose.yml	docker	[]
github	incident-io	catalog-importer	alpine	20230329	20230329	dockerfile	Dockerfile	docker	["final"]
github	thechangelog	changelog.com	ghcr.io/thechangelog/changelog-runtime	elixir-v1.14.5-erlang-v26.2-nodejs-v20.10.0		docker-compose	.devcontainer/docker-compose.yml	docker	[]
github	cloud-custodian	cloud-custodian	cloudcustodian/c7n	latest		helm-values	tools/ops/azure/container-host/chart/values.yaml	docker	[]
github	hashicorp	consul	docker.mirror.hashicorp.services/alpine	3.18	3.18	dockerfile	Dockerfile	docker	["stage"]
gitlab	jamietanna	content-negotiation	openjdk	11	11	gitlabci	.gitlab-ci.yml	docker	["image"]
gitlab	jamietanna	content-negotiation-go	golang	1.18	1.18	gitlabci	.gitlab-ci.yml	docker	["image"]
gitlab	jamietanna	cucumber-reporting-plugin	openjdk	11	11	gitlabci	.gitlab-ci.yml	docker	["image"]
github	wiremock	wiremock-graphql-extension	maven	3.6.3-jdk-11-slim	3.6.3-jdk-11-slim	dockerfile	wiremock-graphql-extension/Dockerfile	docker	["stage"]

(Note: this is a subset of the available data)

Query

The dmd CLI has an inbuilt query that produced the following output:

$ dmd report mostPopularDockerImages --db dmd.db
Renovate

(ommitted output for brevity)

+----------------------------------+-----+
| NAMESPACE                        |   # |
+----------------------------------+-----+
| library                          | 499 |
| ghcr.io/gravitational            |  18 |
| dockersamples                    |  12 |
| gcr.io/distroless                |  11 |
| public.ecr.aws/gravitational     |  10 |
| registry1.dsop.io/redhat/ubi     |  10 |
| docker.mirror.hashicorp.services |  10 |
| wiremock                         |   8 |
| docker                           |   8 |
| docker.elastic.co/elasticsearch  |   7 |
| cimg                             |   6 |
| hashicorpdev                     |   6 |
+----------------------------------+-----+

(ommitted output for brevity)

Note that this isn't straightforward to do with an SQL statement on its own.