pygit2 - libgit2 bindings in Python

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).

INSTALLING AND RUNNING

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

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

The repository

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

Git objects

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.head

# 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.

Commits

A commit is a snapshot of the working dir with meta informations like author, committer and others.:

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

Signatures

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

Trees

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])

Diff

A diff shows the changes between trees, an index or the working dir:

# Diff two trees
>>> t0 = repo.head.tree
>>> t1 = repo.head.parents[0]
>>> diff = t0.diff(t1)
>>> diff

# Diff a tree with the index
>>> tree = repo.head.tree
>>> diff = tree.diff(repo.index)

# Diff a tree with the current working dir
>>> tree = repo.head.tree
>>> diff = tree.diff()

The interface for a diff:

Diff.changes          -- Dict of 'files' and 'hunks' for every change
Diff.patch            -- a patch for every changeset
Diff.merge            -- Merge two Diffs

Blobs

A blob is equivalent to a file in a file system.:

# create a blob out of memory
>>> oid  = repo.create_blob('foo bar')
>>> blob = repo[oid]

Blob.data -- the contents of the blob, a byte string

Tags

A tag is a static label for a commit. See references for more information.

References

Reference lookup:

>>> all_refs = repo.listall_references()
>>> master_ref = repo.lookup_reference("refs/heads/master")
>>> commit = repo[master_ref.oid]

Reference log:

>>> head = repo.lookup_reference('refs/heads/master')
>>> for entry in head.log():
...     print(entry.message)

The interface for RefLogEntry:

RefLogEntry.committer -- Signature of Committer
RefLogEntry.message   -- the message of the RefLogEntry
RefLogEntry.oid_old   -- oid of old reference
RefLogEntry.oid_new   -- oid of new reference

Revision walking

You can iterate through the revision history with repo.walk:

>>> from pygit2 import GIT_SORT_TIME
>>> for commit in repo.walk(oid, GIT_SORT_TIME):
...     print(commit.hex)

The index file

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

Status

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

CONTRIBUTING

Fork libgit2/pygit2 on GitHub, make it awesomer (preferably in a branch named for the topic), send a pull request.

TODO

See issues

AUTHORS

• David Borowitz <dborowitz@google.com>
• J David Ibáñez <jdavid@itaapy.com>

LICENSE

GPLv2 with linking exception. See COPYING for more details.