Git remote helper for rclone-supported services

TL;DR: Turn most cloud storage services (eg: Dropbox) into remote git services, with optional encryption.

This is a Git remote helper for backends supported by rclone.

This enables using git pull or git push with a remote git repository stored on popular cloud services with no native Git support. Optionally, it enables using zero-knowledge encryption via rclone's crypt.

Installation and Usage

• Visit the rclone website and follow the instructions for installation of rclone, and configuration of access to the desired service(s).

• Install this package:

   pip3 install git-remote-rclone-reds
  

  or place the git-remote-rclone executable provided here into the system path, such that Git can find it.

Now it is possible to use URLs like rclone://<remote>/<path-on-remote> as push and pull URLs for Git.

For example, if access to a DropBox account has been configured as an rclone-remote named mydropbox, the URL rclone://mydropbox/myrepository identifies a remote in a directory myrepository/ under this DropBox account.

Configuration

git-remote-rclone can be configured to get git to prune the repo aggressively before uploading via rclone. This comes in handy to minimize the uploaded file size, at the cost of the time taken to prune. This can be a good tradeoff for low-bandwidth situations. To configure it, run this in your git repo:

git config --add git-remote-rclone.pruneaggressively "true"

git-gc is run only on the repo that is uploaded. The local repo is left untouched.

Example

mkdir testrepo; cd testrepo
git init .
echo "Hello world." > xyz
git add xyz
git commit -m "Initial commit."
rclone mkdir mydropbox:test  # Assuming 'mydropbox' has been configured
git remote add rclone://mydropbox/test
git remote add origin rclone://mydropbox/test
git push origin -u main

Technical details

At the remote end, git-remote-rclone maintains a directory with two files:

• refs: a small text file listing the refs provided by the remote
• repo-<SHA>.tar.gz: an archive of a bare Git repository

When interacting with a remote, git-remote-rclone obtains and extracts a copy of the remote repository archive (placed at .git/rclone/<remote-name> in the local Git repository). All Git operations are performed locally. Whenever the state of the mirror repository has changed, it is compacted to minimize transfer size and uploaded to the remote storage service. Likewise, the remote storage service is checked for updates before the local mirror repository is updated.

git-remote-rclone aims to minimize API usage of remote storage services. Per invocation, it only queries for the filenames in the remote repository archive, downloads two files (if needed), and uploads two files (if needed, and on push only).

Tested with

• rclone 1.63.1
• Google Drive
• Onedrive
• DropBox
• Rclone crypt

Repo migration

git-remote-rclone-reds is not backward compatible with (cannot directly read/write) existing remotes created by datalad/git-remote-rclone. Migrating a repo is required.

However, migrating a repo back and forth between git-remote-rclone and git-remote-rclone-reds is very easy. A small one-time change is required. Instead of repo.7z, git-remote-rclone-reds uses repo-SHA.tar.gz. So in theory, you could unpack, repack, and rename, using the compute_sha.py that ships with git-remote-rclone-reds, and that works fine.

But there's a much easier way, which is to get git to do all the work:

# Upgrade to git-remote-rclone-reds
pip3 uninstall git-remote-rclone
pip3 install git-remote-rclone-reds

# Upgrade the repo.
git remote -v
origin  rclone://cloud/old (fetch)
origin  rclone://cloud/old (push)

git remote add new rclone://cloud/new
git push -u new main

# You can now verify rclone://cloud/new looks right, and then rename it to `origin`

This works for migrations in the opposite direction too.

Acknowledgements

This work is based on datalad/git-remote-rclone. This work changes the design for compatibility with rclone backends like crypt that do not support file hashes.