Customizing repository prefixes for ECR to ECR pull through cache

Pull through cache rules support both the ecr repository prefix and the upstream repository prefix. The ecr repository prefix is the repository namespace prefix in Amazon ECR cache registry that's associated with the rule. All repositories using this prefix become pull through cache-enabled repositories for the upstream registry defined in the rule. For example, a prefix of prod applies to all repositories beginning with prod/. To apply a template to all repositories in your registry that don't have an associated pull through cache rule, use ROOT as the prefix.

Important

There is always an assumed / applied to the end of the prefix. If you specify ecr-public as the prefix, Amazon ECR treats that as ecr-public/.

The upstream repository prefix matches the upstream repository name. By default, it's set to ROOT, which allows matching with any upstream repository. You can set the upstream repository prefix only when the Amazon ECR repository prefix has a non-ROOT value.

The following table shows the mapping between cache repository names and upstream repository names based on their prefix configurations in pull through cache rules.

Cache namespace	Upstream namespace	Mapping relationship (cache repository → upstream repository)
ecr-public	ROOT (default)	ecr-public/my-app/image1 → my-app/image1 ecr-public/my-app/image2 → my-app/image2
ROOT	ROOT	my-app/image1 → my-app/image1
team-a	team-a	team-a/myapp/image1 → team-a/myapp/image1
my-app	upstream-app	my-app/image1 → upstream-app/image1