[1028] removed self reference in XfrinConnection, which apparently caused

reference leak.  To test this case, introduced a framework for testing
process_xfrin().  This setup will be used for subseuent related fixes.

src/bin/xfrin/tests/xfrin_test.py

@@ -16,6 +16,7 @@
 import unittest
 import shutil
 import socket
+import sys
 import io
 from isc.testutils.tsigctx_mock import MockTSIGContext
 from xfrin import *
@@ -216,8 +217,8 @@ class MockXfrin(Xfrin):
                                  request_type, check_soa)
 
 class MockXfrinConnection(XfrinConnection):
-    def __init__(self, sock_map, zone_name, rrclass, shutdown_event,
-                 master_addr):
+    def __init__(self, sock_map, zone_name, rrclass, datasrc_client,
+                 shutdown_event, master_addr, tsig_key=None):
         super().__init__(sock_map, zone_name, rrclass, MockDataSourceClient(),
                          shutdown_event, master_addr)
         self.query_data = b''
@@ -300,7 +301,7 @@ class TestXfrinState(unittest.TestCase):
     def setUp(self):
         self.sock_map = {}
         self.conn = MockXfrinConnection(self.sock_map, TEST_ZONE_NAME,
-                                        TEST_RRCLASS, threading.Event(),
+                                        TEST_RRCLASS, None, threading.Event(),
                                         TEST_MASTER_IPV4_ADDRINFO)
         self.begin_soa = RRset(TEST_ZONE_NAME, TEST_RRCLASS, RRType.SOA(),
                                RRTTL(3600))
@@ -585,7 +586,7 @@ class TestXfrinConnection(unittest.TestCase):
             os.remove(TEST_DB_FILE)
         self.sock_map = {}
         self.conn = MockXfrinConnection(self.sock_map, TEST_ZONE_NAME,
-                                        TEST_RRCLASS, threading.Event(),
+                                        TEST_RRCLASS, None, threading.Event(),
                                         TEST_MASTER_IPV4_ADDRINFO)
         self.soa_response_params = {
             'questions': [example_soa_question],
@@ -720,13 +721,13 @@ class TestAXFR(TestXfrinConnection):
         # to confirm an AF_INET6 socket has been created.  A naive application
         # tends to assume it's IPv4 only and hardcode AF_INET.  This test
         # uncovers such a bug.
-        c = MockXfrinConnection({}, TEST_ZONE_NAME, TEST_RRCLASS,
+        c = MockXfrinConnection({}, TEST_ZONE_NAME, TEST_RRCLASS, None,
                                 threading.Event(), TEST_MASTER_IPV6_ADDRINFO)
         c.bind(('::', 0))
         c.close()
 
     def test_init_chclass(self):
-        c = MockXfrinConnection({}, TEST_ZONE_NAME, RRClass.CH(),
+        c = MockXfrinConnection({}, TEST_ZONE_NAME, RRClass.CH(), None,
                                 threading.Event(), TEST_MASTER_IPV4_ADDRINFO)
         axfrmsg = c._create_query(RRType.AXFR())
         self.assertEqual(axfrmsg.get_question()[0].get_class(),
@@ -1679,6 +1680,52 @@ class TestXfrinRecorder(unittest.TestCase):
         self.recorder.decrement(TEST_ZONE_NAME)
         self.assertEqual(self.recorder.xfrin_in_progress(TEST_ZONE_NAME), False)
 
+class TestXfrinProcess(unittest.TestCase):
+    def setUp(self):
+        self.unlocked = False
+
+    def tearDown(self):
+        self.assertTrue(self.unlocked)
+
+    def increment(self, zone_name):
+        '''Fake method of xfrin_recorder.increment.
+
+        '''
+        pass
+
+    def decrement(self, zone_name):
+        '''Fake method of xfrin_recorder.decrement.
+
+        '''
+        self.unlocked = True
+
+    def publish_xfrin_news(self, zone_name, rrclass, ret):
+        '''Fake method of serve.publish_xfrin_news
+
+        '''
+        pass
+
+    def create_xfrinconn(self, sock_map, zone_name, rrclass, datasrc_client,
+                         shutdown_event, master_addrinfo, tsig_key):
+        conn = MockXfrinConnection(sock_map, zone_name, rrclass,
+                                   datasrc_client, shutdown_event,
+                                   master_addrinfo, tsig_key)
+
+        # An awkward check that would specifically identify an old bug
+        # where initialziation of XfrinConnection._tsig_ctx_creator caused
+        # self reference and subsequently led to reference leak.
+        orig_ref = sys.getrefcount(conn)
+        conn._tsig_ctx_creator = None
+        self.assertEqual(orig_ref, sys.getrefcount(conn))
+
+        return conn
+
+    def test_process_xfrin_normal(self):
+        process_xfrin(self, self, TEST_ZONE_NAME, TEST_RRCLASS, None, None,
+                      (socket.AF_INET, socket.SOCK_STREAM,
+                       TEST_MASTER_IPV4_ADDRESS), False, None, RRType.AXFR(),
+                      self.create_xfrinconn)
+
 class TestXfrin(unittest.TestCase):
     def setUp(self):
         # redirect output

src/bin/xfrin/xfrin.py.in

@@ -323,6 +323,7 @@ class XfrinFirstData(XfrinState):
                  conn.zone_str())
             # We are now going to add RRs to the new zone.  We need create
             # a Diff object.  It will be used throughtout the XFR session.
+            # DISABLE FOR DEBUG
             conn._diff = Diff(conn._datasrc_client, conn._zone_name, True)
             self.set_xfrstate(conn, XfrinAXFR())
         return False
@@ -479,10 +480,7 @@ class XfrinConnection(asyncore.dispatcher):
         self._tsig_ctx = None
         # tsig_ctx_creator is introduced to allow tests to use a mock class for
         # easier tests (in normal case we always use the default)
-        self._tsig_ctx_creator = self.__create_tsig_ctx
-
-    def __create_tsig_ctx(self, key):
-        return TSIGContext(key)
+        self._tsig_ctx_creator = lambda key : TSIGContext(key)
 
     def __set_xfrstate(self, new_state):
         self.__state = new_state
@@ -800,7 +798,7 @@ class XfrinConnection(asyncore.dispatcher):
 
 def process_xfrin(server, xfrin_recorder, zone_name, rrclass, db_file,
                   shutdown_event, master_addrinfo, check_soa, tsig_key,
-                  request_type):
+                  request_type, conn_class=XfrinConnection):
     xfrin_recorder.increment(zone_name)
 
     # Create a data source client used in this XFR session.  Right now we
@@ -820,8 +818,8 @@ def process_xfrin(server, xfrin_recorder, zone_name, rrclass, db_file,
 
     # Create a TCP connection for the XFR session and perform the operation.
     sock_map = {}
-    conn = XfrinConnection(sock_map, zone_name, rrclass, datasrc_client,
-                           shutdown_event, master_addrinfo, tsig_key)
+    conn = conn_class(sock_map, zone_name, rrclass, datasrc_client,
+                      shutdown_event, master_addrinfo, tsig_key)
     # XXX: We still need _db_file for temporary workaround in _create_query().
     # This should be removed when we eliminate the need for the workaround.
     conn._db_file = db_file
@@ -835,7 +833,6 @@ def process_xfrin(server, xfrin_recorder, zone_name, rrclass, db_file,
     server.publish_xfrin_news(zone_name, rrclass, ret)
     xfrin_recorder.decrement(zone_name)
 
-
 class XfrinRecorder:
     def __init__(self):
         self._lock = threading.Lock()