Most of the tests in this file require a Dulwich server, so let’s start one:

>>> from dulwich.repo import Repo
>>> from dulwich.server import DictBackend, TCPGitServer
>>> import threading
>>> repo = Repo.init(b"remote", mkdir=True)
>>> cid = repo.do_commit(b"message", committer=b"Jelmer <jelmer@samba.org>")
>>> backend = DictBackend({b'/': repo})
>>> dul_server = TCPGitServer(backend, b'localhost', 0)
>>> threading.Thread(target=dul_server.serve).start()
>>> server_address, server_port=dul_server.socket.getsockname()

Remote repositories

The interface for remote Git repositories is different from that for local repositories.

The Git smart server protocol provides three basic operations:

  • upload-pack - provides a pack with objects requested by the client
  • receive-pack - imports a pack with objects provided by the client
  • upload-archive - provides a tarball with the contents of a specific revision

The smart server protocol can be accessed over either plain TCP (git://), SSH (git+ssh://) or tunneled over HTTP (http://).

Dulwich provides support for accessing remote repositories in dulwich.client. To create a new client, you can either construct one manually:

>>> from dulwich.client import TCPGitClient
>>> client = TCPGitClient(server_address.encode('ascii'), server_port)

Retrieving raw pack files

The client object can then be used to retrieve a pack. The fetch_pack method takes a determine_wants callback argument, which allows the client to determine which objects it wants to end up with:

>>> def determine_wants(refs):
...    # retrieve all objects
...    return refs.values()

Another required object is a “graph walker”, which is used to determine which objects that the client already has should not be sent again by the server. Here in the tutorial we’ll just use a dummy graph walker which claims that the client doesn’t have any objects:

>>> class DummyGraphWalker(object):
...     def ack(self, sha): pass
...     def next(self): pass
...     def __next__(self): pass

With the determine_wants function in place, we can now fetch a pack, which we will write to a BytesIO object:

>>> from io import BytesIO
>>> f = BytesIO()
>>> remote_refs = client.fetch_pack(b"/", determine_wants,
...    DummyGraphWalker(), pack_data=f.write)

f will now contain a full pack file:

>>> print(f.getvalue()[:4].decode('ascii'))
PACK

Fetching objects into a local repository

It is also possible to fetch from a remote repository into a local repository, in which case Dulwich takes care of providing the right graph walker, and importing the received pack file into the local repository:

>>> from dulwich.repo import Repo
>>> local = Repo.init(b"local", mkdir=True)
>>> remote_refs = client.fetch(b"/", local)

Let’s shut down the server now that all tests have been run:

>>> dul_server.shutdown()