wireguard: Remove NM connections when app is uninstalled

Tests:

- Install WireGuard and start the server. Uninstall the app and re-install.
Without the patch, the connection remain after uninstall. With the patch, the
connections are removed after uninstall and return to pristine state after
re-install.

- Functional tests succeed.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/wireguard/__init__.py

@@ -96,3 +96,8 @@ class WireguardApp(app_module.App):
         super().setup(old_version)
         if not old_version:
             self.enable()
+
+    def uninstall(self):
+        """De-configure and uninstall the app."""
+        utils.delete_connections()
+        super().uninstall()

plinth/modules/wireguard/utils.py

@@ -127,6 +127,17 @@ def enable_connections(enable):
                 pass  # Connection is already inactive
 
 
+def delete_connections():
+    """Remove all WireGuard connections."""
+    setting_name = nm.SETTING_WIREGUARD_SETTING_NAME
+    client = network.get_nm_client()
+    for connection in client.get_connections():
+        if connection.get_connection_type() != setting_name:
+            continue
+
+        connection.delete()
+
+
 def _get_public_key_from_private_key(private_key):
     process = subprocess.run(['wg', 'pubkey'], check=True, capture_output=True,
                              input=private_key.encode())