BzrSync - Bazaar repository/branch synchronization tool
=======================================================

BzrSync is a tool to help a developer using Bazaar on multiple machines.
It automatically keeps selected repositories and branches synchronized across
the machines. Bazaar itself is used for the synchronization (with "bzr pull"),
ensuring consistency at all times.

Features
--------

- any number of machines are supported

- consistency is guaranteed at all times

Installation
------------

To install the latest stable version of BzrSync, using pip_:

::

  pip install bzrsync

or using setuptools_:

::

  easy_install bzrsync

Otherwise, if neither pip_ nor setuptools_ are available, it is possible
to download (eg. from PyPI_) the `source`_ package, extract it and run the
usual ``setup.py`` commands:

::

  python setup.py install

.. _pip: http://pypi.python.org/pypi/pip
.. _setuptools: http://pypi.python.org/pypi/setuptools
.. _EasyInstall: http://peak.telecommunity.com/DevCenter/EasyInstall
.. _PyPI: http://pypi.python.org/pypi
.. _`source`: http://pypi.python.org/pypi/bzrsync


Usage
-----

Let's suppose you work from three different workstations, and their hostnames
are `alpha`, `beta` and `gamma`. You want to keep your Bazaar repositories and
branches synchronized between all three nodes using BzrSync.
BzrSync is meant to be used with shared repositories, so if you are not
using these, you should re-organize your branches to use shared repositories.
It's easier to keep all the repositories inside the same directory.
In our example our repositories will reside in ~/bzr and their names will
end in ".bzr".
In each shared repository, at the top level there should be a directory for
each node. In our case `alpha`, `beta` and `gamma`.
For example, let's imagine we have a repository named "project-foo.bzr".
We are working on `alpha`, and have created a `trunk` and a `feature-1` branch.
We'll have:

::

  ~/bzr/project-foo.bzr/
  ~/bzr/project-foo.bzr/alpha
  ~/bzr/project-foo.bzr/alpha/trunk
  ~/bzr/project-foo.bzr/alpha/feature-1
  ~/bzr/project-foo.bzr/beta
  ~/bzr/project-foo.bzr/gamma

Let's suppose we also have a `local.bzr` repository we don't want to
synchronize, in either direction.

BzrSync needs a YAML config file, by default `~/.bazaar/bzrsync.yaml`,
listing the repositories and the branches we.
In this example its contents will be:

::

  # remote nodes
  # (a host can be specified with an optional port as HOST:PORT)
  hosts:
  - alpha
  - beta
  - gamma

  # where repositories specified with a relative path/pattern are located
  root: ~/bzr

  # *all* repositories
  repositories: "*.bzr"

  # specific repositories to exclude from 'repositories'
  exclude:
  - local.bzr

  # repositories to export to remote nodes
  export: "*.bzr"

  # specific repositories excluded from export
  export_exclude:
  - local.bzr

  # repositories to sync from remotes
  sync: "*.bzr"

  # specific repositories excluded from sync
  sync_exclude:
  - local.bzr

We can use exactly this same configuration file on all three nodes.

BzrSync won't create the shared repositories for you, so before proceeding,
do so now on all the nodes, remembering to create also the node
subdirectories.

Then launch the BzrSync daemon on all the nodes:

::

  alpha$ bzrsync serve

  beta$ bzrsync serve

  gamma$ bzrsync serve

Now let's sync project-foo.bzr from alpha to beta:

  beta$ bzrsync sync ~/bzr/project-foo.bzr

This will pull to `beta` all the branches from `~/bzr/project-foo.bzr/alpha/`
on `alpha`, and all the branches from `~/bzr/project-foo.bzr/gamma/`
on `gamma`.
In our case, only alpha has branches right now, so in practice we'll
get the branches `alpha/trunk` and `alpha/feature-1` from `alpha` to
`beta`, keeping them as `alpha/trunk` and `alpha/feature-1`.

If you want to work on `beta`, now branch from the newly synchronized branches
to their counterparts inside the `beta/` subdirectory:

::

  beta$ bzr branch ~/bzr/project-foo.bzr/alpha/feature-1 ~/bzr/project-foo.bzr/beta/feature-1
  beta$ bzr co ~/bzr/project-foo.bzr/beta/feature-1 foo-feature-1
  beta$ cd foo-feature-1
  ...
  hack hack hack
  ...
  beta$ commit

Now on `beta` we'll have:

::

  ~/bzr/project-foo.bzr/
  ~/bzr/project-foo.bzr/alpha
  ~/bzr/project-foo.bzr/alpha/trunk
  ~/bzr/project-foo.bzr/alpha/feature-1
  ~/bzr/project-foo.bzr/beta
  ~/bzr/project-foo.bzr/beta/feature-1
  ~/bzr/project-foo.bzr/gamma

When you have finished working on beta, you can sync from alpha:

  alpha$ bzrsync sync ~/bzr/project-foo.bzr

and this will create `beta/feature-1` on `alpha` too, which you can
pull onto `alpha/feature-1` if not diverged, or merge it otherwise,
and start working from `alpha` again.

Please see the example `bzrsync.yaml` file for a more complete example, which
includes also branch sets.

Help and Development
--------------------

Alternatively, if you'd like to update the software occasionally to pick
up the latest bug fixes and enhancements before they make it into an
offical release, branch from the `Bazaar`_ repository hosted on `LaunchPad`_
instead.
Just follow the procedure outlined below:

1. Make sure that you have `Bazaar`_ installed, and that you can run its
   commands from a shell. (Enter ``bzr help`` at a shell prompt to test
   this.)

2. Create a local branch and working tree from the official one::

    bzr branch lp:bzrsync bzrsync

3. Then from the ``bzrsync`` directory you can run the ``setup.py develop``
   command to install the library in your Python `site-packages` directory
   using a link, which allows to continue developing inside the working tree
   without the need to re-install after every change. See the
   `setuptools development mode`_ documention for more information::

    $ sudo
    # python setup.py develop

.. _`development home page`: https://launchpad.net/bzrsync
.. _`bugs`: https://bugs.launchpad.net/bzrsync
.. _`LaunchPad`: http://launchpad.net
.. _`Bazaar`: http://bazaar-vcs.org/
.. _`changes`: http://bazaar.launchpad.net/~softwarefabrica/bzrsync/trunk/changes
.. _`PYTHONPATH`: http://docs.python.org/tut/node8.html#SECTION008110000000000000000
.. _`junction`: http://www.microsoft.com/technet/sysinternals/FileAndDisk/Junction.mspx
.. _`setuptools development mode`: http://peak.telecommunity.com/DevCenter/setuptools#development-mode


LICENSE
-------

This software is covered by the GNU General Public License version 2.
It is:

    Copyright (C) 2010-2011  Marco Pantaleoni. All rights reserved.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2 as
    published by the Free Software Foundation.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
