My team and I regularly use Docker for lightweight local environments that are pre-configured with things we need to develop that project. (It helps avoid things like "works on my machine".) If I need to work on a Terraform module, I can launch the Docker environment that has all the tools I need pre-installed and ready-to-go, and I can make my changes, run tests, and perform all sorts of general software development tasks. When I'm done, I press Ctrl+D.
We can easily read specific environment variables from the host environment and pass them into the Docker environment (e.g., AWS credentials, Terraform variables), and for Git, we can mount the local SSH directory into the container in read-only mode so that we can fetch and push (-v ~/.ssh:/root/.ssh:ro) to GitHub Enterprise.
Herein lies the problem with migrating the SSH keys into 1Password and not having them on-disk. There's nothing to mount, and 1Password only runs on the host. The low-fi solution is to keep my SSH keys on-disk for Docker, while copying them into 1P for use with that SSH agent, but then what's the point to using 1Password SSH?
A higher-fi solution (since this is desktop-use Docker; not for deployment) would be the ability to mount a unix socket from the host into the Docker container, and have some kind of tiny agent built for Linux (namely Alpine Linux) that can run and facilitate whatever signals need to be sent so that when I run
git pull inside the Docker container, this agent sends a signal to 1Password on the host asking for authentication.
1Password Version: 80600043 (beta channel)
Extension Version: N/A
OS Version: macOS 12.3β