This is a sample project that will open in a devcontainer, use the Docker socket from the host (not DinD), and be configured with a Docker config.json file to access private registries.
Before making a request to the Docker engine, the Docker CLI fetches and attachs the appropriate credentials to the request.
When using Docker Desktop, those credentials are stored in the Mac OSX keychain. When using the CLI on the host, it can access those credentials. But, when attempting to access those credentials from inside a container, no luck.
This project is configured to use the .devcontainer/cred-setup.sh file as an initializeCommand lifecycle hook, which runs on the host before the devcontainer starts. This script extracts the credentials and creates a config.json file, from which the CLI inside the container can use.