VR: don't restart xl2tpd when the remote access VPN config is unchanged

systemvm/debian/opt/cloud/bin/configure.py

@@ -1274,7 +1274,7 @@ def configure_l2tpIpsec(self, left, obj):
         l2tp_changed = l2tpfile.commit()
 
         secret = CsFile(vpnsecretfilte)
-        secret.empty()
+        secret.repopulate()
         secret.addeq(": PSK \"%s\"" % (psk))
         secret_changed = secret.commit()
 

systemvm/test/TestCsRemoteAccessVpn.py

@@ -0,0 +1,70 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import os
+import secrets
+import shutil
+import tempfile
+import unittest
+from unittest import mock
+
+import configure
+from configure import CsRemoteAccessVpn
+
+# random per run, never a real key
+PSK1 = secrets.token_hex(8)
+PSK2 = secrets.token_hex(8)
+
+
+class TestCsRemoteAccessVpn(unittest.TestCase):
+
+    def setUp(self):
+        self.dir = tempfile.mkdtemp()
+        self.vpn = CsRemoteAccessVpn.__new__(CsRemoteAccessVpn)
+        self.vpn.VPNCONFDIR = self.dir
+        self.obj = {"local_ip": "10.1.2.1", "local_cidr": "198.51.100.0/24", "public_interface": "eth1",
+                    "ip_range": "10.1.2.2-10.1.2.8", "preshared_key": PSK1, "vpn_server_ip": "203.0.113.10"}
+        real = configure.CsFile
+        # keep every file configure_l2tpIpsec() writes inside the test directory
+        patcher = mock.patch("configure.CsFile", side_effect=lambda name: real(os.path.join(self.dir, os.path.basename(name))))
+        patcher.start()
+        self.addCleanup(patcher.stop)
+        self.addCleanup(shutil.rmtree, self.dir)
+
+    def configure(self):
+        return self.vpn.configure_l2tpIpsec("203.0.113.10", self.obj)
+
+    def secret(self):
+        with open(os.path.join(self.dir, "ipsec.any.secrets")) as f:
+            return f.read()
+
+    def test_unchanged_config_is_not_reported_as_changed(self):
+        # an unchanged pass must not restart xl2tpd, which drops every connected client
+        self.assertTrue(self.configure())
+        self.assertFalse(self.configure())
+        self.assertEqual(self.secret(), ': PSK "%s"\n' % PSK1)
+
+    def test_changed_psk_is_reported_as_changed(self):
+        self.configure()
+        self.obj["preshared_key"] = PSK2
+        self.assertTrue(self.configure())
+        self.assertEqual(self.secret(), ': PSK "%s"\n' % PSK2)
+        self.assertFalse(self.configure())
+
+
+if __name__ == '__main__':
+    unittest.main()