mirror-git-to-s3

Python functions and CLI to mirror git repositories available on HTTP(S) to S3. Essentially converts smart protocol git repositories to the so-called dumb protocol. Does not use temporary disk space, and uses streaming under the hood. This should allow the mirroring to be run on systems that don't have much disk or available memory, even on large repositories.

Work in progress. This README serves as a rough design spec.

Usage

To mirror one or more repositories from Python, use the mirror_repos function, passing it an iterable of (source, target) mappings.

from mirror_git_to_s3 import mirror_repos

mirror_repos((
	('https://example.test/my-first-repo', 's3://my-bucket/my-first-repo'),
	('https://example.test/my-second-repo', 's3://my-bucket/my-second-repo'),
))

In the previous example the iterable is itself a tuple. However in general any iterable is supported, Under the hood repositories are processed in parallel, and transfers can start before the entire list is known.

from mirror_git_to_s3 import mirror_repos

def mappings():
	yield ('https://example.test/my-first-repo', 's3://my-bucket/my-first-repo')
	yield ('https://example.test/my-second-repo', 's3://my-bucket/my-second-repo')

mirror_repos(mappings())

Under the hood, boto3 is used to communicate with S3. The boto3 client is constructed automatically, but you can override the default by using the get_s3_client argument.

import boto3
from mirror_git_to_s3 import mirror_repos

mirror_repos(mappings(), get_s3_client=lambda: boto3.client('s3'))

This can be used to mirror to S3-compatible storage.

import boto3
from mirror_git_to_s3 import mirror_repos

mirror_repos(mappings(), get_s3_client=lambda: boto3.client('s3', endpoint_url='http://my-host.com/'))

To mirror repositories from the the command line pairs of --source --target options can be passed to mirror-git-to-s3.

mirror-git-to-s3 \
	--source 'https://example.test/my-first-repo' --target 's3://my-bucket/my-first-repo' \
	--source 'https://example.test/my-second-repo' --target 's3://my-bucket/my-second-repo'

At the time of writing, there is no known standard way of discovering a set of associated git repositories, hence to remain general, this project must be told the source and target addresses of each repository explicitly.