Added module to handle rabbit policies [1]

Used quite a bit of the existing rabbit modules provied by @chrishoffman.

[1] https://www.rabbitmq.com/parameters.html

library/messaging/rabbitmq_policy

+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# (c) 2013, John Dewey <john@dewey.ws>
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+DOCUMENTATION = '''
+---
+module: rabbitmq_policy
+short_description: Manage the state of policies in RabbitMQ
+description:
+  - Manage the state of a virtual host in RabbitMQ
+version_added: "1.0"
+author: John Dewey
+options:
+  name:
+    description:
+      - The name of the policy to manage.
+    required: true
+    default: null
+  vhost:
+    description:
+      - The name of the vhost to apply to.
+    required: false
+    default: /
+  pattern:
+    description:
+      - A regex of queues to apply the policy to.
+    required: true
+    default: null
+  params:
+    description:
+      - A json dict describing the policy.
+    required: true
+    default: null
+  priority:
+    description:
+      - The priority of the policy.
+    required: false
+    default: 0
+  node:
+    description:
+      - Erlang node name of the rabbit we wish to configure.
+    required: false
+    default: rabbit
+  state:
+    description:
+      - The state of the policy.
+    default: present
+    choices: [present, absent]
+'''
+
+EXAMPLES = '''
+# Ensure that the /vhost contains the HA policy.
+- rabbitmq_policy: name=/ params='{"ha-mode":"all"}' policy=HA pattern='.*'
+'''
+class RabbitMqPolicy(object):
+    def __init__(self, module, name):
+        self._module = module
+        self._name = name
+        self._vhost = module.params['vhost']
+        self._pattern = module.params['pattern']
+        self._params = module.params['params']
+        self._priority = module.params['priority']
+        self._node = module.params['node']
+        self._rabbitmqctl = module.get_bin_path('rabbitmqctl', True)
+
+    def _exec(self, args, run_in_check_mode=False):
+        if not self._module.check_mode or (self._module.check_mode and run_in_check_mode):
+            cmd = [self._rabbitmqctl, '-q', '-n', self._node]
+            args.insert(1, '-p')
+            args.insert(2, self._vhost)
+            rc, out, err = self._module.run_command(cmd + args, check_rc=True)
+            return out.splitlines()
+        return list()
+
+    def list(self):
+        policies = self._exec(['list_policies'], True)
+
+        for policy in policies:
+            policy_name = policy.split('\t')[1]
+            if policy_name == self._name:
+                return True
+        return False
+
+    def set(self):
+        args = ['set_policy']
+        args.append(self._name)
+        args.append(self._pattern)
+        args.append(self._params)
+        args.append('--priority')
+        args.append(self._priority)
+        return self._exec(args)
+
+    def clear(self):
+        return self._exec(['clear_policy', self._name])
+
+
+def main():
+    arg_spec = dict(
+        name=dict(required=True),
+        vhost=dict(default='/'),
+        pattern=dict(required=True),
+        params=dict(required=True),
+        priority=dict(default='0'),
+        node=dict(default='rabbit'),
+        state=dict(default='present', choices=['present', 'absent']),
+    )
+
+    module = AnsibleModule(
+        argument_spec=arg_spec,
+        supports_check_mode=True
+    )
+
+    name = module.params['name']
+    state = module.params['state']
+    rabbitmq_policy = RabbitMqPolicy(module, name)
+
+    changed = False
+    if rabbitmq_policy.list():
+        if state == 'absent':
+            rabbitmq_policy.clear()
+            changed = True
+        else:
+            changed = False
+    elif state == 'present':
+        rabbitmq_policy.set()
+        changed = True
+
+    module.exit_json(changed=changed, name=name, state=state)
+
+# this is magic, see lib/ansible/module_common.py
+#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+main()