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One way to customize Bazaar's behaviour is with *hooks*. Hooks allow you to
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perform actions before or after certain Bazaar operations. The operations
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include ``commit``, ``push``, ``pull``, and ``uncommit``.
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To use a hook, you should `write a plugin <#writing-a-plugin>`_. Instead of
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creating a new command, this plugin will define and install the hook. Here's
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from bzrlib import branch
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def post_push_hook(push_result):
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print "The new revno is %d" % push_result.new_revno
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branch.Branch.hooks.install_hook('post_push', post_push_hook)
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branch.Branch.hooks.name_hook(post_push_hook, 'My post_push hook')
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To use this example, create a file named ``push_hook.py``, and stick it in
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``plugins`` subdirectory of your configuration directory. (If you have never
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installed any plugins, you may need to create the ``plugins`` directory).
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First, we define a function that will be run after ``push`` completes. We
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could also use an instance method or a callable object. All push hooks take a
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single argument, the ``push_result``.
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Next, we install the hook. ``'post_push'`` identifies where we want to install
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the hook, and the second parameter is the hook itself.
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Finally, we name the hook. This is optional, but it means the hook name can
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be used in progress messages and error messages.
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That's it! The next time you push, it should show "The new revno is...".
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Of course, hooks can be much more elaborate than this, because you have the
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full power of Python at your disposal. Now that you know how to use hooks,
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what you do with them is up to you.
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For a complete list of hooks and their parameters, see `Hooks
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<../user-reference/bzr_man.html#hooks>`_ in the User Reference.