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# Copyright 2013 Canonical Ltd.
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# Charm Helpers Developers <juju@lists.ubuntu.com>
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"""Charm Helpers ansible - declare the state of your machines.
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This helper enables you to declare your machine state, rather than
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program it procedurally (and have to test each change to your procedures).
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Your install hook can be as simple as:
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import charmhelpers.contrib.ansible
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hooks = charmhelpers.contrib.ansible.AnsibleHooks(
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playbook_path="playbook.yaml")
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@hooks.hook('install', 'upgrade-charm')
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charmhelpers.contrib.ansible.install_ansible_support()
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and won't need to change (nor will its tests) when you change the machine
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All of your juju config and relation-data are available as template
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variables within your playbooks and templates.
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An install playbook looks
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- name: Install dependencies.
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group: name={{ item.name }} gid={{ item.gid }}
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- { name: 'deploy_user', gid: 1800 }
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- { name: 'service_user', gid: 1500 }
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Alternatively, you can apply individual playbooks with:
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charmhelpers.contrib.ansible.apply_playbook('playbooks/install.yaml')
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Read more online about playbooks[1] and standard ansible modules[2].
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[1] http://www.ansibleworks.com/docs/playbooks.html
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[2] http://www.ansibleworks.com/docs/modules.html
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import charmhelpers.contrib.templating.contexts
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import charmhelpers.core.host
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import charmhelpers.core.hookenv
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import charmhelpers.fetch
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charm_dir = os.environ.get('CHARM_DIR', '')
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ansible_hosts_path = '/etc/ansible/hosts'
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# Ansible will automatically include any vars in the following
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# file in its inventory when run locally.
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ansible_vars_path = '/etc/ansible/host_vars/localhost'
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available_tags = set([])
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def install_ansible_support(from_ppa=True, ppa_location='ppa:rquillo/ansible'):
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"""Installs the ansible package.
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By default it is installed from the PPA [1] linked from
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the ansible website [2] or from a ppa specified by a charm config.
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[1] https://launchpad.net/~rquillo/+archive/ansible
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[2] http://www.ansibleworks.com/docs/gettingstarted.html#ubuntu-and-debian
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If from_ppa is empty, you must ensure that the package is available
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from a configured repository.
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charmhelpers.fetch.add_source(ppa_location)
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charmhelpers.fetch.apt_update(fatal=True)
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charmhelpers.fetch.apt_install('ansible')
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with open(ansible_hosts_path, 'w+') as hosts_file:
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hosts_file.write('localhost ansible_connection=local')
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def apply_playbook(playbook, tags=None):
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tags = ",".join(tags)
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charmhelpers.contrib.templating.contexts.juju_state_to_yaml(
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ansible_vars_path, namespace_separator='__',
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allow_hyphens_in_keys=False)
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call.extend(['--tags', '{}'.format(tags)])
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subprocess.check_call(call)
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def get_tags_for_playbook(playbook_path):
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"""Return all tags within a playbook.
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The charmhelpers lib should not depend on ansible, hence the
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Discussion whether --list-tags should be a feature of ansible at
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import ansible.callbacks
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import ansible.playbook
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stats = ansible.callbacks.AggregateStats()
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callbacks = ansible.callbacks.PlaybookRunnerCallbacks(stats)
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runner_callbacks = ansible.callbacks.PlaybookRunnerCallbacks(stats)
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playbook = ansible.playbook.PlayBook(playbook=playbook_path,
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runner_callbacks=runner_callbacks,
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myplay = ansible.playbook.Play(playbook, ds=playbook.playbook[0],
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basedir=os.path.dirname(playbook_path))
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_, playbook_tags = myplay.compare_tags([])
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playbook_tags.remove('all')
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class AnsibleHooks(charmhelpers.core.hookenv.Hooks):
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"""Run a playbook with the hook-name as the tag.
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This helper builds on the standard hookenv.Hooks helper,
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but additionally runs the playbook with the hook-name specified
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using --tags (ie. running all the tasks tagged with the hook-name).
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hooks = AnsibleHooks(playbook_path='playbooks/my_machine_state.yaml')
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# All the tasks within my_machine_state.yaml tagged with 'install'
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# will be run automatically after do_custom_work()
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# For most of your hooks, you won't need to do anything other
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# than run the tagged tasks for the hook:
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@hooks.hook('config-changed', 'start', 'stop')
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def just_use_playbook():
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# As a convenience, you can avoid the above noop function by specifying
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# the hooks which are handled by ansible-only and they'll be registered
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# hooks = AnsibleHooks(
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# 'playbooks/my_machine_state.yaml',
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# default_hooks=['config-changed', 'start', 'stop'])
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if __name__ == "__main__":
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# execute a hook based on the name the program is called by
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hooks.execute(sys.argv)
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def __init__(self, playbook_path, default_hooks=None):
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"""Register any hooks handled by ansible.
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default_hooks is now deprecated, as we use ansible to
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determine the supported hooks from the playbook.
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super(AnsibleHooks, self).__init__()
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self.playbook_path = playbook_path
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# The hooks decorator is created at module load time, which on the
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# first run, will be before ansible is itself installed.
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available_tags.update(get_tags_for_playbook(playbook_path))
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available_tags.add('install')
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if default_hooks is not None:
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"The use of default_hooks is deprecated. Ansible is now "
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"used to query your playbook for available tags.",
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noop = lambda *args, **kwargs: None
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for hook in available_tags:
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self.register(hook, noop)
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def execute(self, args):
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"""Execute the hook followed by the playbook using the hook as tag."""
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super(AnsibleHooks, self).execute(args)
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hook_name = os.path.basename(args[0])
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if hook_name in available_tags:
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charmhelpers.contrib.ansible.apply_playbook(
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self.playbook_path, tags=[hook_name])
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hooks/charmhelpers/contrib/ansible/__init__.py
