pygit2 is a set of Python bindings to the libgit2 linkable C Git library. The supported versions of Python are 2.6, 2.7, 3.1 and 3.2
Through this text Python 3 is used for the inline examples. Also, the Python 3 terminology is used (for instance we say text strings instead of unicode strings).
First you need to install the latest version of libgit2. You can find platform-specific instructions to build the library in the libgit2 website:
http://libgit2.github.com
Next, make sure you have the required library dependencies for pygit2: OpenSSL and ZLib. For instance, in Debian-based systems run:
$ sudo apt-get install zlib1g-dev libssl-dev
Also, make sure you have Python 2.6+ installed together with the Python development headers.
When those are installed, you can install pygit2:
$ git clone git://github.com/libgit2/pygit2.git $ cd pygit2 $ python setup.py install $ python setup.py test
Everything starts by opening an existing repository:
>>> from pygit2 import Repository
>>> repo = Repository('pygit2/.git')
Or by creating a new one:
>>> from pygit2 import init_repository
>>> bare = False
>>> repo = init_repository('test', bare)
These are the basic attributes of a repository:
Repository.path -- path to the Git repository
Repository.workdir -- path to the working directory, None in the case of
a bare repo
In the first place Git is a key-value storage system. The values stored are called objects, there are four types (commits, trees, blobs and tags), for each type pygit2 has a Python class:
# Get the last commit
>>> head = repo.lookup_reference('HEAD')
>>> head = head.resolve()
>>> commit = repo[head.oid]
# Show commits and trees
>>> commit
<pygit2.Commit object at 0x7f9d2f3000b0>
>>> commit.tree
<pygit2.Tree object at 0x7f9d2f3000f0>
These four classes (Commit, Tree, Blob and Tag) inherit from
the Object base class, which provides shared behaviour. A Git object is
identified by a unique object id, which is a binary byte string; this is
often represented as an hexadecimal text string:
>>> commit.oid b'x\xde\xb5W\x8d\x01<\xdb\xdf\x08o\xa1\xd1\xa3\xe7\xd9\x82\xe8\x88\x8f' >>> commit.hex '78deb5578d013cdbdf086fa1d1a3e7d982e8888f'
The API of pygit2 accepts both the raw object id and its hexadecimal representation, the difference is done based on its type (a byte or a text string).
This is the common interface for all Git objects:
Object.type -- one of the GIT_OBJ_COMMIT, GIT_OBJ_TREE,
GIT_OBJ_BLOB or GIT_OBJ_TAG constants
Object.oid -- the object id, a byte string 20 bytes long
Object.hex -- hexadecimal representation of the object id, a text
string 40 chars long
Object.read_raw() -- returns the byte string with the raw contents of the
of the object
Objects can not be modified once they have been created.
Commit.author -- the author of the commit Commit.committer -- the committer of the commit Commit.message -- the message, a text string Commit.tree -- the tree object attached to the commit Commit.parents -- the list of parent commits
The author and committer attributes of commit objects are Signature
objects:
>>> commit.author <pygit2.Signature object at 0x7f75e9b1f5f8>
This is their interface:
Signature.name -- person's name Signature.email -- person's email address Signature.time -- unix time Signature.offset -- offset from utc in minutes
A tree is a sorted collection of tree entries. It is similar to a folder or directory in a file system. Each entry points to another tree or a blob. A tree can be iterated, and partially implements the sequence and mapping interfaces:
# Number of entries >>> tree = commit.tree >>> len(tree) 6 # Iteration >>> for entry in tree: ... print(entry.hex, entry.name) ... 7151ca7cd3e59f3eab19c485cfbf3cb30928d7fa .gitignore c36f4cf1e38ec1bb9d9ad146ed572b89ecfc9f18 COPYING 32b30b90b062f66957d6790c3c155c289c34424e README.md c87dae4094b3a6d10e08bc6c5ef1f55a7e448659 pygit2.c 85a67270a49ef16cdd3d328f06a3e4b459f09b27 setup.py 3d8985bbec338eb4d47c5b01b863ee89d044bd53 test # Get an entry by name >>> entry = tree['pygit2.c'] >>> entry <pygit2.TreeEntry object at 0xcc10f0> # Get the object the entry points to >>> blob = repo[entry.oid] >>> blob <pygit2.Blob object at 0xcc12d0>
This is the interface of a tree entry:
TreeEntry.name -- name of the tree entry TreeEntry.oid -- the id of the git object TreeEntry.hex -- hexadecimal representation of the oid TreeEntry.attributes -- the Unix file attributes TreeEntry.to_object() -- returns the git object (equivalent to repo[entry.oid])
A blob is equivalent to a file in a file system:
Blob.data -- the contents of the blob, a byte string
XXX
Reference lookup:
>>> master_ref = repo.lookup_reference("refs/heads/master")
>>> commit = repo[master_ref.oid]
>>> from pygit2 import GIT_SORT_TIME >>> for commit in repo.walk(oid, GIT_SORT_TIME): ... print commit.hex
Index read:
>>> index = repo.index >>> index.read() >>> oid = index['path/to/file'].oid # from path to object id >>> blob = repo[oid] # from object id to object
Iterate over all entries of the index:
>>> for entry in index: ... print entry.path, entry.hex
Index write:
>>> index.add('path/to/file') # git add
>>> del index['path/to/file'] # git rm
>>> index.write() # don't forget to save the changes
Inspect the status of the repository:
>>> from pygit2 import GIT_STATUS_CURRENT >>> status = repo.status() >>> for filepath, flags in status.items(): ... if flags != GIT_STATUS_CURRENT: ... print "Filepath %s isn't clean" % filepath
Fork libgit2/pygit2 on GitHub, make it awesomer (preferably in a branch named for the topic), send a pull request.
XXX
- David Borowitz <dborowitz@google.com>
- David Ibáñez <jdavid@itaapy.com>
GPLv2 with linking exception. See COPYING for more details.