Merge pull request #109 from juliantaylor/fix-watch-reset

fix watching with a specified resource version

watch/watch.py

@@ -124,6 +124,8 @@ class Watch(object):
         return_type = self.get_return_type(func)
         kwargs['watch'] = True
         kwargs['_preload_content'] = False
+        if 'resource_version' in kwargs:
+            self.resource_version = kwargs['resource_version']
 
         timeouts = ('timeout_seconds' in kwargs)
         while True:

watch/watch_test.py

@@ -16,12 +16,15 @@
 
 import unittest
 
-from mock import Mock
+from mock import Mock, call
 
 from .watch import Watch
 
 
 class WatchTests(unittest.TestCase):
+    def setUp(self):
+        # counter for a test that needs test global state
+        self.callcount = 0
 
     def test_watch_with_decode(self):
         fake_resp = Mock()
@@ -64,6 +67,74 @@ class WatchTests(unittest.TestCase):
         fake_resp.close.assert_called_once()
         fake_resp.release_conn.assert_called_once()
 
+    def test_watch_resource_version_set(self):
+        # https://github.com/kubernetes-client/python/issues/700
+        # ensure watching from a resource version does reset to resource
+        # version 0 after k8s resets the watch connection
+        fake_resp = Mock()
+        fake_resp.close = Mock()
+        fake_resp.release_conn = Mock()
+        values = [
+            '{"type": "ADDED", "object": {"metadata": {"name": "test1",'
+            '"resourceVersion": "1"}, "spec": {}, "status": {}}}\n',
+            '{"type": "ADDED", "object": {"metadata": {"name": "test2",'
+            '"resourceVersion": "2"}, "spec": {}, "sta',
+            'tus": {}}}\n'
+            '{"type": "ADDED", "object": {"metadata": {"name": "test3",'
+            '"resourceVersion": "3"}, "spec": {}, "status": {}}}\n'
+        ]
+        # return nothing on the first call and values on the second
+        # this emulates a watch from a rv that returns nothing in the first k8s
+        # watch reset and values later
+
+        def get_values(*args, **kwargs):
+            self.callcount += 1
+            if self.callcount == 1:
+                return []
+            else:
+                return values
+
+        fake_resp.read_chunked = Mock(
+            side_effect=get_values)
+
+        fake_api = Mock()
+        fake_api.get_namespaces = Mock(return_value=fake_resp)
+        fake_api.get_namespaces.__doc__ = ':return: V1NamespaceList'
+
+        w = Watch()
+        # ensure we keep our requested resource version or the version latest
+        # returned version when the existing versions are older than the
+        # requested version
+        # needed for the list existing objects, then watch from there use case
+        calls = []
+
+        iterations = 2
+        # first two calls must use the passed rv, the first call is a
+        # "reset" and does not actually return anything
+        # the second call must use the same rv but will return values
+        # (with a wrong rv but a real cluster would behave correctly)
+        # calls following that will use the rv from those returned values
+        calls.append(call(_preload_content=False, watch=True,
+                          resource_version="5"))
+        calls.append(call(_preload_content=False, watch=True,
+                          resource_version="5"))
+        for i in range(iterations):
+            # ideally we want 5 here but as rv must be treated as an
+            # opaque value we cannot interpret it and order it so rely
+            # on k8s returning the events completely and in order
+            calls.append(call(_preload_content=False, watch=True,
+                              resource_version="3"))
+
+        for c, e in enumerate(w.stream(fake_api.get_namespaces,
+                                       resource_version="5")):
+            if c == len(values) * iterations:
+                w.stop()
+
+        # check calls are in the list, gives good error output
+        fake_api.get_namespaces.assert_has_calls(calls)
+        # more strict test with worse error message
+        self.assertEqual(fake_api.get_namespaces.mock_calls, calls)
+
     def test_watch_stream_twice(self):
         w = Watch(float)
         for step in ['first', 'second']: