Adding new os_subnets_facts module

There can be instances during an Ansible play where the list of subnets
currently available from OpenStack is required.  This update provides
subnet list functionality as a new os_subnets_facts module.

lib/ansible/modules/cloud/openstack/os_subnets_facts.py

@@ -0,0 +1,152 @@
+#!/usr/bin/python
+
+# Copyright (c) 2015 Hewlett-Packard Development Company, L.P.
+#
+# This module 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.
+#
+# This software 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 software.  If not, see <http://www.gnu.org/licenses/>.
+
+try:
+    import shade
+    HAS_SHADE = True
+except ImportError:
+    HAS_SHADE = False
+
+DOCUMENTATION = '''
+---
+module: os_subnets_facts
+short_description: Retrieve facts about one or more OpenStack subnets.
+version_added: "2.0"
+author: "Davide Agnello (@dagnello)"
+description:
+    - Retrieve facts about one or more subnets from OpenStack.
+requirements:
+    - "python >= 2.6"
+    - "shade"
+options:
+   subnet:
+     description:
+        - Name or ID of the subnet
+     required: false
+   filters:
+     description:
+        - A dictionary of meta data to use for further filtering.  Elements of
+          this dictionary may be additional dictionaries.
+     required: false
+extends_documentation_fragment: openstack
+'''
+
+EXAMPLES = '''
+# Gather facts about previously created subnets
+- os_subnets_facts:
+    auth:
+      auth_url: https://your_api_url.com:9000/v2.0
+      username: user
+      password: password
+      project_name: someproject
+- debug: var=openstack_subnets
+
+# Gather facts about a previously created subnet by name
+- os_subnets_facts:
+    auth:
+      auth_url: https://your_api_url.com:9000/v2.0
+      username: user
+      password: password
+      project_name: someproject
+    name:  subnet1
+- debug: var=openstack_subnets
+
+# Gather facts about a previously created subnet with filter (note: name and
+  filters parameters are Not mutually exclusive)
+- os_subnets_facts:
+    auth:
+      auth_url: https://your_api_url.com:9000/v2.0
+      username: user
+      password: password
+      project_name: someproject
+    filters:
+      tenant_id: 55e2ce24b2a245b09f181bf025724cbe
+- debug: var=openstack_subnets
+'''
+
+RETURN = '''
+This module registers subnet details in facts named: openstack_subnets.  If a
+subnet name/id and or filter does not result in a subnet found, an empty list
+is set in openstack_subnets.
+id:
+    description: Unique UUID.
+    returned: success
+    type: string
+name:
+    description: Name given to the subnet.
+    returned: success
+    type: string
+network_id:
+    description: Network ID this subnet belongs in.
+    returned: success
+    type: string
+cidr:
+    description: Subnet's CIDR.
+    returned: success
+    type: string
+gateway_ip:
+    description: Subnet's gateway ip.
+    returned: success
+    type: string
+enable_dhcp:
+    description: DHCP enable flag for this subnet.
+    returned: success
+    type: bool
+ip_version:
+    description: IP version for this subnet.
+    returned: success
+    type: int
+tenant_id:
+    description: Tenant id associated with this subnet.
+    returned: success
+    type: string
+dns_nameservers:
+    description: DNS name servers for this subnet.
+    returned: success
+    type: list of strings
+allocation_pools:
+    description: Allocation pools associated with this subnet.
+    returned: success
+    type: list of dicts
+'''
+
+def main():
+
+    argument_spec = openstack_full_argument_spec(
+        name=dict(required=False, default=None),
+        filters=dict(required=False, default=None)
+    )
+    module = AnsibleModule(argument_spec)
+
+    if not HAS_SHADE:
+        module.fail_json(msg='shade is required for this module')
+
+    try:
+        cloud = shade.openstack_cloud(**module.params)
+        subnets = cloud.search_subnets(module.params['name'],
+                                         module.params['filters'])
+        module.exit_json(changed=False, ansible_facts=dict(
+            openstack_subnets=subnets))
+
+    except shade.OpenStackCloudException as e:
+        module.fail_json(msg=e.message)
+
+# this is magic, see lib/ansible/module_common.py
+from ansible.module_utils.basic import *
+from ansible.module_utils.openstack import *
+if __name__ == '__main__':
+    main()