SB-23 Add network interface option

examples/cameraServiceExample.py

@@ -3,7 +3,7 @@
 from context_logger import get_logger, setup_logging
 
 from examples import setup_shutdown
-from hello import ServiceInfo, Hello, Group
+from hello import ServiceInfo, Hello, Group, GroupUrl
 
 setup_logging('hello')
 
@@ -13,8 +13,11 @@
 def main() -> None:
     shutdown_event = setup_shutdown()
 
+    # Define the group URL optionally specifying the network interface
+    url = GroupUrl(address='239.0.1.1', port=5555, interface='wlan0')
+
     # Define the group to advertise the camera service on
-    group = Group(name='effective-range/sniper', url='udp://239.0.1.1:5555')
+    group = Group.create(name='effective-range/sniper', url=url)
 
     # Define the service information for the camera
     hostname = 'er-sniper-camera-1'

hello/group.py

@@ -5,6 +5,25 @@
 from dataclasses import dataclass
 from enum import Enum
 
+import netifaces
+
+
+@dataclass
+class GroupUrl:
+    address: str
+    port: int
+    protocol: str = 'udp'
+    interface: str | None = None
+
+    def resolve(self) -> str:
+        if self.interface and self.interface in netifaces.interfaces():
+            inet_address = netifaces.ifaddresses(self.interface).get(netifaces.AF_INET)
+            if inet_address and len(inet_address) > 0:
+                address = inet_address[0].get('addr')
+                return f'{self.protocol}://{address};{self.address}:{self.port}'
+
+        return f'{self.protocol}://{self.address}:{self.port}'
+
 
 class GroupPrefix(Enum):
     HELLO = 'hello'
@@ -22,6 +41,10 @@ def hello(self) -> 'PrefixedGroup':
     def query(self) -> 'PrefixedGroup':
         return PrefixedGroup(GroupPrefix.QUERY, self)
 
+    @staticmethod
+    def create(name: str, url: GroupUrl) -> 'Group':
+        return Group(name, url.resolve())
+
 
 @dataclass
 class PrefixedGroup:

pyproject.toml

@@ -8,6 +8,7 @@ maintainers = [
     { name = "Ferenc Nandor Janky & Attila Gombos", email = "info@effective-range.com" }
 ]
 dependencies = [
+    "netifaces",
     "pyzmq @ git+https://github.com/EffectiveRange/pyzmq.git@v27.1.0+drafts1",
     "python-context-logger @ git+https://github.com/EffectiveRange/python-context-logger.git@latest",
     "python-common-utility @ git+https://github.com/EffectiveRange/python-common-utility.git@latest"

tests/groupTest.py

@@ -0,0 +1,82 @@
+import unittest
+from unittest import TestCase
+
+from context_logger import setup_logging
+
+from hello import GroupUrl, Group
+
+
+class GroupTest(TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        setup_logging('hello', 'DEBUG', warn_on_overwrite=False)
+
+    def setUp(self):
+        print()
+
+    def test_url_resolves_when_interface_is_not_provided(self):
+        # Given
+        group_url = GroupUrl(protocol='udp', address='239.0.1.1', port=5555)
+
+        # When
+        url = group_url.resolve()
+
+        # Then
+        self.assertEqual('udp://239.0.1.1:5555', url)
+
+    def test_url_resolves_when_interface_is_provided(self):
+        # Given
+        group_url = GroupUrl(protocol='udp', address='239.0.1.1', port=5555, interface='lo')
+
+        # When
+        url = group_url.resolve()
+
+        # Then
+        self.assertEqual('udp://127.0.0.1;239.0.1.1:5555', url)
+
+    def test_url_resolves_when_interface_is_provided_but_not_exists(self):
+        # Given
+        group_url = GroupUrl(protocol='udp', address='239.0.1.1', port=5555, interface='nonexistent0')
+
+        # When
+        url = group_url.resolve()
+
+        # Then
+        self.assertEqual('udp://239.0.1.1:5555', url)
+
+    def test_group_created_with_resolved_url(self):
+        # Given
+        group_url = GroupUrl(address='239.0.1.1', port=5555, interface='lo')
+
+        # When
+        group = Group.create('test-group', group_url)
+
+        # Then
+        self.assertEqual(Group(name='test-group', url='udp://127.0.0.1;239.0.1.1:5555'), group)
+
+    def test_prefixed_group_created_with_hello_prefix(self):
+        # Given
+        group = Group('test-group', 'udp://239.0.1.1:5555')
+
+        # When
+        prefixed_group = group.hello()
+
+        # Then
+        self.assertEqual('hello:test-group', prefixed_group.name)
+        self.assertEqual(group.url, prefixed_group.url)
+
+    def test_prefixed_group_created_with_query_prefix(self):
+        # Given
+        group = Group('test-group', 'udp://239.0.1.1:5555')
+
+        # When
+        prefixed_group = group.query()
+
+        # Then
+        self.assertEqual('query:test-group', prefixed_group.name)
+        self.assertEqual(group.url, prefixed_group.url)
+
+
+if __name__ == '__main__':
+    unittest.main()