git-caching-proxy

Speed up repeated git clones / fetches and reduce network traffic

What is this?

The name is very straightforward: this is a caching proxy server for Git.

Once set up, the proxy server will maintain an up-to-date copy of any remote repositories you clone / fetch through it. This means cloning the same repository repeatedly will use much less network traffic, and as a result be much faster. A lot of time will be saved if, for example, you have a RUN git clone ... command in your Dockerfile.

Advantages

• Uses the original git commands: just git clone as usual, no need to remember a different command
• Can git config to use for all or some remotes automatically
• Very few dependencies: Python, Git, that's it
• Works via the simple Git daemon protocol

Limitations

• No authentication options available, just like the original Git daemon. Don't expose this to the Internet!
• Has no locking mechanisms to avoid concurrent operations on the cached git repositories, apart from what Git may already have. It's best to avoid cloning / fetching from the same remote repository from multiple clients at the same time.
• Does not support pushing. Git allows a remote to have different fetch and push URLs, so it may be possible to set up a remote to fetch from git-caching-proxy, and push to the remote repository directly, but I have not tested this personally.

Projects with similar goals

• https://github.com/google/goblet
• https://kooltux.github.io/git-cache/
• https://www.npmjs.com/package/git-cache

How to use

Requirements

• Python 3.9 or above
• Git
• Some disk space to store the cache repositories
• The example setup uses systemd, but any inetd-like super daemon will work

Setting up the server

This setup uses systemd. If using another inetd-like implementation, adjust as required.

1. Choose a server. It can be localhost, or a dedicated server.

2. The server is configured with environment variables. In the example setup, the variables are defined in git-caching-daemon.conf. Read the comments and edit accordingly. The provided systemd service file will use this file to provide environment variables.

3. Put git_caching_proxy.py and git-caching-daemon.conf somewhere convenient. The example setup have them in /opt/gitcache/. Make sure git_caching_proxy.py is executable.

4. Edit git-caching-daemon@.service. Specify the correct paths for the files you placed in the previous step. Also create a dedicated user / group for the service for best practice. The unit file specifies gitcache:gitcache.

5. Place git-caching-daemon@.service and git-caching-daemon@.service in /etc/systemd/system, and enable the socket with systemctl enable git-caching-daemon.socket. Open Port 9418 on the firewall if access from other hosts is desired.

Using git

TLDR:

Using manually: just add git://server-hostname/ in front of the real repository address. For example: git clone git://server-hostname/https://github.com/twisteroidambassador/git-caching-proxy.git

Using automatically: something like git config --global url."git://server-hostname/https://".insteadOf "https://"

Detailed instructions: work in progress