Add support for managing network segments

Adds a module to manage Neutron network segments where the
segmentation plugin is enabled.

Segments are relatively simple and do not support modification
beyond the name/description, so most attributes are used for
initial segment creation, or filtering results in order to
perform updates.

Depends-On: https://review.opendev.org/c/openstack/ansible-collections-openstack/+/955752
Change-Id: I4647fd96aaa15460d82765365f98a18ddf2693db

plugins/modules/network_segment.py

@@ -0,0 +1,183 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2025 British Broadcasting Corporation
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+DOCUMENTATION = '''
+---
+module: network_segment
+short_description: Creates/removes network segments from OpenStack
+author: OpenStack Ansible SIG
+description:
+   - Add, update or remove network segments from OpenStack.
+options:
+   name:
+     description:
+        - Name to be assigned to the segment. Although Neutron allows for
+          non-unique segment names, this module enforces segment name
+          uniqueness.
+     required: true
+     type: str
+   description:
+     description:
+        - Description of the segment
+     type: str
+   network:
+     description:
+        - Name or id of the network to which the segment should be attached
+     type: str
+   network_type:
+     description:
+        - The type of physical network that maps to this segment resource.
+     type: str
+   physical_network:
+     description:
+        - The physical network where this segment object is implemented.
+     type: str
+   segmentation_id:
+     description:
+        - An isolated segment on the physical network. The I(network_type)
+          attribute defines the segmentation model. For example, if the
+          I(network_type) value is vlan, this ID is a vlan identifier. If
+          the I(network_type) value is gre, this ID is a gre key.
+     type: int
+   state:
+     description:
+        - Indicate desired state of the resource.
+     choices: ['present', 'absent']
+     default: present
+     type: str
+extends_documentation_fragment:
+- openstack.cloud.openstack
+'''
+
+EXAMPLES = '''
+# Create a VLAN type network segment named 'segment1'.
+- openstack.cloud.network_segment:
+    cloud: mycloud
+    name: segment1
+    network: my_network
+    network_type: vlan
+    segmentation_id: 2000
+    physical_network: my_physnet
+    state: present
+'''
+
+RETURN = '''
+id:
+    description: Id of segment
+    returned: On success when segment exists.
+    type: str
+network_segment:
+    description: Dictionary describing the network segment.
+    returned: On success when network segment exists.
+    type: dict
+    contains:
+        description:
+            description: Description
+            type: str
+        id:
+            description: Id
+            type: str
+        name:
+            description: Name
+            type: str
+        network_id:
+            description: Network Id
+            type: str
+        network_type:
+            description: Network type
+            type: str
+        physical_network:
+            description: Physical network
+            type: str
+        segmentation_id:
+            description: Segmentation Id
+            type: int
+'''
+
+from ansible_collections.openstack.cloud.plugins.module_utils.openstack import OpenStackModule
+
+
+class NetworkSegmentModule(OpenStackModule):
+
+    argument_spec = dict(
+        name=dict(required=True),
+        description=dict(),
+        network=dict(),
+        network_type=dict(),
+        physical_network=dict(),
+        segmentation_id=dict(type='int'),
+        state=dict(default='present', choices=['absent', 'present'])
+    )
+
+    def run(self):
+
+        state = self.params['state']
+        name = self.params['name']
+        network_name_or_id = self.params['network']
+
+        kwargs = {}
+        filters = {}
+        for arg in ('description', 'network_type', 'physical_network', 'segmentation_id'):
+            if self.params[arg] is not None:
+                kwargs[arg] = self.params[arg]
+
+        for arg in ('network_type', 'physical_network'):
+            if self.params[arg] is not None:
+                filters[arg] = self.params[arg]
+
+        if network_name_or_id:
+            network = self.conn.network.find_network(network_name_or_id,
+                                                     ignore_missing=False,
+                                                     **filters)
+            kwargs['network_id'] = network.id
+            filters['network_id'] = network.id
+
+        segment = self.conn.network.find_segment(name, **filters)
+
+        if state == 'present':
+            if not segment:
+                segment = self.conn.network.create_segment(name=name, **kwargs)
+                changed = True
+            else:
+                changed = False
+                update_kwargs = {}
+
+                # As the name is required and all other attributes cannot be
+                # changed (and appear in filters above), we only need to handle
+                # updates to the description here.
+                for arg in ["description"]:
+                    if (
+                        arg in kwargs
+                        # ensure user wants something specific
+                        and kwargs[arg] is not None
+                        # and this is not what we have right now
+                        and kwargs[arg] != segment[arg]
+                    ):
+                        update_kwargs[arg] = kwargs[arg]
+
+                if update_kwargs:
+                    segment = self.conn.network.update_segment(
+                        segment.id, **update_kwargs
+                    )
+                    changed = True
+
+            segment = segment.to_dict(computed=False)
+            self.exit(changed=changed, network_segment=segment, id=segment['id'])
+        elif state == 'absent':
+            if not segment:
+                self.exit(changed=False)
+            else:
+                self.conn.network.delete_segment(segment['id'])
+                self.exit(changed=True)
+
+
+def main():
+    module = NetworkSegmentModule()
+    module()
+
+
+if __name__ == '__main__':
+    main()