**********************************************************************
Installation
**********************************************************************

.. |lq| unicode:: U+00AB
.. |rq| unicode:: U+00BB


.. contents:: Contents
   :local:


Requirements
============

- Python 2.7, 3.2+ or pypy (including the development headers)
- Libgit2 v0.23.x
- cffi 0.8.1+
- Libssh2, optional, used for SSH network operations.
- pkg-config, optional, used for SSH network operations.

.. warning::

   One common mistake users do is to choose incompatible versions of libgit2
   and pygit2. See below for a reference table of compatible versions.  Double
   check the versions do match before filing a bug report.

Version numbers
---------------

The version number of pygit2 is composed of three numbers separated by dots
|lq| *major.minor.micro* |rq|, where the first two numbers
|lq| *major.minor* |rq| match the first two numbers of the libgit2 version,
while the last number |lq| *.micro* |rq| auto-increments independently.

As illustration see this table of compatible releases:

+-----------+--------+----------------+----------------------------------------+
|**libgit2**| 0.23.0 | 0.22.0, 0.22.1 | 0.21.1, 0.21.2                         |
+-----------+--------+----------------+----------------------------------------+
|**pygit2** | 0.23.0 | 0.22.0         | 0.21.0, 0.21.1, 0.21.2, 0.21.3, 0.21.4 |
+-----------+--------+----------------+----------------------------------------+

.. warning::

   Backwards compatibility is not guaranteed even between micro releases.
   Please check the release notes for incompatible changes before upgrading to
   a new release.


Quick install
=============

To install the latest version of libgit2 system wide, in the ``/usr/local``
directory, do:

.. code-block:: sh

   $ wget https://github.com/libgit2/libgit2/archive/v0.23.0.tar.gz
   $ tar xzf v0.23.0.tar.gz
   $ cd libgit2-0.23.0/
   $ cmake .
   $ make
   $ sudo make install

.. seealso::

   For detailed instructions on building libgit2 check
   https://libgit2.github.com/docs/guides/build-and-link/

Now install pygit2, and then verify it is correctly installed:

.. code-block:: sh

   $ pip install pygit2
   ...
   $ python -c 'import pygit2'


Troubleshooting
---------------

The verification step may fail if the dynamic linker does not find the libgit2
library:

.. code-block:: sh

   $ python -c 'import pygit2'
   Traceback (most recent call last):
     File "<string>", line 1, in <module>
     File "pygit2/__init__.py", line 29, in <module>
       from _pygit2 import *
   ImportError: libgit2.so.0: cannot open shared object file: No such file or directory

This happens for instance in Ubuntu, the libgit2 library is installed within
the ``/usr/local/lib`` directory, but the linker does not look for it there. To
fix this call ``ldconfig``:

.. code-block:: sh

   $ sudo ldconfig
   $ python -c 'import pygit2'

If it still does not work, please open an issue at
https://github.com/libgit2/pygit2/issues, I would like to know about it.


Build options
=============

``LIBGIT2`` -- If you install libgit2 in an unusual place, you will need to set
the ``LIBGIT2`` environment variable before installing pygit2.  This variable
tells pygit2 where libgit2 is installed.  We will see a concrete example later,
when explaining how to install libgit2 within a virtual environment.

``LIBGIT2_LIB`` -- This is a more rarely used build option, it allows to
override the library directory where libgit2 is installed, useful if different
from from ``$LIBGIT2/lib``.


libgit2 within a virtual environment
====================================

This is how to install both libgit2 and pygit2 within a virtual environment.

This is useful if you don't have root acces to install libgit2 system wide.
Or if you wish to have different versions of libgit2/pygit2 installed in
different virtual environments, isolated from each other.

Create the virtualenv, activate it, and set the ``LIBGIT2`` environment
variable:

.. code-block:: sh

   $ virtualenv venv
   $ source venv/bin/activate
   $ export LIBGIT2=$VIRTUAL_ENV

Install libgit2 (see we define the installation prefix):

.. code-block:: sh

   $ wget https://github.com/libgit2/libgit2/archive/v0.23.0.tar.gz
   $ tar xzf v0.23.0.tar.gz
   $ cd libgit2-0.23.0/
   $ cmake . -DCMAKE_INSTALL_PREFIX=$LIBGIT2
   $ make
   $ make install

Install pygit2:

.. code-block:: sh

   $ export LDFLAGS="-Wl,-rpath='$LIBGIT2/lib',--enable-new-dtags $LDFLAGS"
   $ pip install pygit2
   $ python -c 'import pygit2'


The run-path
------------------------------------------

Did you notice we set the `rpath <http://en.wikipedia.org/wiki/Rpath>`_ before
installing pygit2?  Since libgit2 is installed in a non standard location, the
dynamic linker will not find it at run-time, and ``lddconfig`` will not help
this time.

So you need to either set ``LD_LIBRARY_PATH`` before using pygit2, like:

.. code-block:: sh

   $ export LD_LIBRARY_PATH=$LIBGIT2/lib
   $ python -c 'import pygit2'

Or, like we have done in the instructions above, use the `rpath
<http://en.wikipedia.org/wiki/Rpath>`_, it hard-codes extra search paths within
the pygit2 extension modules, so you don't need to set ``LD_LIBRARY_PATH``
everytime. Verify yourself if curious:

.. code-block:: sh

   $ readelf --dynamic lib/python2.7/site-packages/pygit2-0.23.0-py2.7-linux-x86_64.egg/_pygit2.so | grep PATH
    0x000000000000001d (RUNPATH)            Library runpath: [/tmp/venv/lib]


Installing on Windows
===================================

pygit2 expects to find the libgit2 installed files in the directory specified
in the ``LIBGIT2`` environment variable.

In addition, make sure that libgit2 is build in "__cdecl" mode.
The following recipe shows you how to do it, assuming you're working
from a bash shell:

.. code-block:: sh

   $ export LIBGIT2=C:/Dev/libgit2
   $ wget https://github.com/libgit2/libgit2/archive/v0.23.0.tar.gz
   $ tar xzf v0.23.0.tar.gz
   $ cd libgit2-0.23.0/
   $ cmake . -DSTDCALL=OFF -DCMAKE_INSTALL_PREFIX=$LIBGIT2 -G "Visual Studio 9 2008"
   $ cmake --build . --config release --target install
   $ ctest -v

At this point, you're ready to execute the generic pygit2 installation
steps described above.


Installing on OS X
===================================

.. note::

   You will need the `XCode <https://developer.apple.com/xcode/>`_ Developer
   Tools from Apple. This free download from the Mac App Store will provide the
   clang compiler needed for the installation of pygit2.

   This section was tested on OS X 10.9 Mavericks and OS X 10.10 Yosemite with
   Python 3.3 in a virtual environment.

The easiest way is to first install libgit2 with the `Homebrew <http://brew.sh>`_
package manager and then use pip3 for pygit2. The following example assumes that
XCode and Hombrew are already installed.

.. code-block:: sh

   $ brew update
   $ brew install libgit2
   $ pip3 install pygit2
