Add rax_network module

Based on the refactor work @sivel is doing, adding a rax_network module
to create/delete networks in the Rackspace Public Cloud.

See: https://github.com/ansible/ansible/issues/4577

library/cloud/rax_network

+#!/usr/bin/python -tt
+# 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: rax_network
+short_description: create / delete an isolated network in Rackspace Public Cloud
+description:
+     - creates / deletes a Rackspace Public Cloud isolated network.
+version_added: "1.4"
+options:
+  state:
+    description:
+     - Indicate desired state of the resource
+    choices: ['present', 'absent', 'deleted']
+    default: present
+  credentials:
+    description:
+     - File to find the Rackspace credentials in (ignored if C(api_key) and
+       C(username) are provided)
+    default: null
+    aliases: ['creds_file']
+  api_key:
+    description:
+     - Rackspace API key (overrides C(credentials))
+  username:
+    description:
+     - Rackspace username (overrides C(credentials))
+  label:
+    description:
+     - Label (name) to give the network
+    default: null
+  cidr:
+    description:
+     - cidr of the network being created
+    default: null
+  region:
+    description:
+     - Region to create the network in
+    default: DFW
+requirements: [ "pyrax" ]
+author: Christopher H. Laco, Jesse Keating
+notes:
+  - The following environment variables can be used, C(RAX_USERNAME),
+    C(RAX_API_KEY), C(RAX_CREDS), C(RAX_CREDENTIALS), C(RAX_REGION).
+  - C(RAX_CREDENTIALS) and C(RAX_CREDS) points to a credentials file
+    appropriate for pyrax
+  - C(RAX_USERNAME) and C(RAX_API_KEY) obviate the use of a credentials file
+  - C(RAX_REGION) defines a Rackspace Public Cloud region (DFW, ORD, LON, ...)
+'''
+
+EXAMPLES = '''
+- name: Build an Isolated Network
+  gather_facts: False
+
+  tasks:
+    - name: Network create request
+      local_action:
+        module: rax_network
+        credentials: ~/.raxpub
+        label: my-net
+        cidr: 192.168.3.0/24
+        state: present
+'''
+
+import sys
+import os
+
+try:
+    import pyrax
+    import pyrax.utils
+    from pyrax import exc
+except ImportError:
+    print("failed=True msg='pyrax required for this module'")
+    sys.exit(1)
+
+
+def cloud_network(module, state, label, cidr):
+    for arg in (state, label, cidr):
+        if not arg:
+            module.fail_json(msg='%s is required for cloud_networks' % arg)
+
+    instances = []
+    changed = False
+    network = None
+
+    if state == 'present':
+        try:
+            network = pyrax.cloud_networks.find_network_by_label(label)
+        except exc.NetworkNotFound:
+            try:
+                network = pyrax.cloud_networks.create(label, cidr=cidr)
+                changed = True
+            except Exception, e:
+                module.fail_json(msg='%s' % e.message)
+        except Exception:
+            module.fail_json(msg='%s' % e.message)
+
+    elif state in ('absent', 'deleted'):
+        try:
+            network = pyrax.cloud_networks.find_network_by_label(label)
+            network.delete()
+            changed = True
+        except exc.NetworkNotFound:
+            pass
+        except Exception, e:
+            module.fail_json(msg='%s' % e.message)
+
+    if network:
+        instance = {'id': network.id,
+                    'label': network.label,
+                    'cidr': network.cidr}
+        instances.append(instance)
+
+    module.exit_json(changed=changed, instances=instances)
+
+
+def main():
+    module = AnsibleModule(
+        argument_spec=dict(
+            state=dict(default='present',
+                       choices=['present', 'deleted', 'absent']),
+            credentials=dict(aliases=['creds_file']),
+            api_key=dict(),
+            username=dict(),
+            region=dict(),
+            label=dict(),
+            cidr=dict()
+        )
+    )
+
+    credentials = module.params.get('credentials')
+    api_key = module.params.get('api_key')
+    username = module.params.get('username')
+    region = module.params.get('region')
+    state = module.params.get('state')
+    label = module.params.get('label')
+    cidr = module.params.get('cidr')
+
+    try:
+        username = username or os.environ.get('RAX_USERNAME')
+        api_key = api_key or os.environ.get('RAX_API_KEY')
+        credentials = credentials or \
+            os.environ.get('RAX_CREDENTIALS') or \
+            os.environ.get('RAX_CREDS_FILE')
+        region = region or os.environ.get('RAX_REGION')
+
+    except KeyError, e:
+        module.fail_json(msg='Unable to load %s' % e.message)
+
+    try:
+        pyrax.set_setting("identity_type", "rackspace")
+        if api_key and username:
+            pyrax.set_credentials(username, api_key=api_key, region=region)
+        elif credentials:
+            credentials = os.path.expanduser(credentials)
+            pyrax.set_credential_file(credentials, region=region)
+        else:
+            raise Exception('No credentials supplied!')
+    except Exception, e:
+        module.fail_json(msg='%s' % e.message)
+
+    cloud_network(module, state, label, cidr)
+
+# this is magic, see lib/ansible/module_common.py
+#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+
+main()