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:
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 tuples with four elements, the author name and email, the unix time and time offset in minutes:
>>> commit.author
('J. David Ibáñez', 'jdavid.ibp@gmail.com', 1315005198, 120)
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
- J. David Ibáñez jdavid@itaapy.com
GPLv2 with linking exception. See COPYING for more details.