Append layer to container registry image

This utility script appends a tarball to an existing container image available in a container registry (without having to pull existing image data).

It supports any registry that implements the OCI Distribution Spec.

Installation

Use the script as-is or install using pip:

$ pip install appendlayer

This registers the entry-point "appendlayer" which typically lets you call it directly as an executable command.

Authentication

The script reads an OAuth2 refresh token from the REFRESH_TOKEN environment variable.

For example, for Azure Container Registry:

$ export REFRESH_TOKEN=$(az acr login -t --name <registry-name>.azurecr.io 2>/dev/null | \
      jq -r .accessToken)

(The snippet above requires jq to print out the access token.)

Usage

Pipe in the layer contents using a tarball and provide the repository (or image) name and the old and new tags:

$ echo "Hello world" > test.txt
$ tar cvf - test.txt | appendlayer <host> <repository> <old-tag> <new-tag>

For Azure Container Registry (ACR) for example, the host is typically <registry-name>.azurecr.io.

Changes

1.0 (2022-01-29)

• Initial release.