When working from home it is convenient to have fast local access to Git repositories - both to avoid the potentially slow download of very large repositories multiple times and to cope in the case of connectivity failures. This image is intended to be run on a developer's local network (or local machine, for single-machine setups) and to proxy all read access to the workplace Git servers so that large downloads will be faster and operation can continue when connectivity to the workplace server is unavailable.
This does not attempt to do anything clever with write access to the server (or, indeed, anything non-clever) - it is a read-only proxy. This makes use of Git's ability to configure different URIs for fetching from and pushing to a remote such that you can fetch from the proxy, and push directly to the workplace server.
docker build -t git-wfh .
To use the docker-compose.yaml file copy environment.sample to environment, edit to configure for your deployment, and then
docker-compose up -d. You should, of course, read what it's doing
to understand it before running it.
Ensure that your ssh config allows agent forwarding to the proxy, e.g. in ~/.ssh/config
Host proxy.mynetwork
ForwardAgent yes
Then configure your local git so that when it tries to fetch from the workplace remote it'll fetch from the proxy, and when pushing it'll still push to the workplace, e.g.
git config --global url.ssh://git@proxy.mynetwork:9022/.insteadOf ssh://git@workplace:22/
git config --global url.ssh://git@workplace:22/.pushInsteadOf ssh://git@workplace:22/
If your process gets destroyed in the middle of a checkout and you end up with a broken repository, just delete the relevant half-baked repository manually and let it recover on next fetch.
Other Git mirroring solutions exist, although the ones I found didn't do quite what I wanted. One might also consider https://github.com/opensafely/git-server-proxy or https://github.com/guillon/git-mirror.