refactor(follower): use normal feed for one-off changes

Author: eiri

ibmcloudant/features/changes_follower.py

@@ -293,7 +293,7 @@ def __init__(
     ) -> None:
         self.options = kwargs
         self.limit = self.options.get('limit')
-        self._set_defaults()
+        self._set_defaults(_Mode.FINITE)
         self.service = service
         self.error_tolerance = error_tolerance
         self._iter = None
@@ -358,11 +358,16 @@ def options(self, value: Dict):
             raise ValueError(error_fmt.format(invalid_opts_list, class_name))
         self._options = value
 
-    def _set_defaults(self, limit: int = None):
-        defaults = {
-            'feed': PostChangesEnums.Feed.LONGPOLL,
-            'timeout': _LONGPOLL_TIMEOUT,
-        }
+    def _set_defaults(self, mode: _Mode, limit: int = None):
+        if mode == _Mode.FINITE:
+            defaults = {
+                'feed': PostChangesEnums.Feed.NORMAL
+            }
+        elif mode == _Mode.LISTEN:
+            defaults = {
+                'feed': PostChangesEnums.Feed.LONGPOLL,
+                'timeout': _LONGPOLL_TIMEOUT,
+            }
         if limit is not None:
             self.logger.debug(f'Applying changes limit {limit}')
             defaults['limit'] = limit
@@ -445,7 +450,7 @@ def _run(self, mode: _Mode):
         if self.limit is not None:
             batch_size = self.limit if self.limit < batch_size else batch_size
 
-        self._set_defaults(batch_size)
+        self._set_defaults(mode, batch_size)
         changes_caller = functools.partial(
             self.service.post_changes, **self.options
         )

test/unit/features/test_changes_follower.py

@@ -112,6 +112,16 @@ def test_validate_options_multiple_invalid_cases(self):
 
     def test_set_defaults(self):
         follower = ChangesFollower(self.client, db="db", **self.kwarg_valid)
+        expected = {
+            "feed": PostChangesEnums.Feed.NORMAL,
+            "timeout": None,
+        }
+        for opt, val in expected.items():
+            self.assertEqual(follower.options.get(opt), val)
+
+    def test_set_defaults_listen(self):
+        follower = ChangesFollower(self.client, db="db", **self.kwarg_valid)
+        follower._set_defaults(_Mode.LISTEN)
         expected = {
             "feed": PostChangesEnums.Feed.LONGPOLL,
             "timeout": _LONGPOLL_TIMEOUT,
@@ -121,7 +131,18 @@ def test_set_defaults(self):
 
     def test_set_defaults_with_limit(self):
         follower = ChangesFollower(self.client, db="db", **self.kwarg_valid)
-        follower._set_defaults(limit=12)
+        follower._set_defaults(_Mode.FINITE, limit=12)
+        expected = {
+            "feed": PostChangesEnums.Feed.NORMAL,
+            "timeout": None,
+            "limit": 12,
+        }
+        for opt, val in expected.items():
+            self.assertEqual(follower.options.get(opt), val)
+
+    def test_set_defaults_listen_with_limit(self):
+        follower = ChangesFollower(self.client, db="db", **self.kwarg_valid)
+        follower._set_defaults(_Mode.LISTEN, limit=12)
         expected = {
             "feed": PostChangesEnums.Feed.LONGPOLL,
             "timeout": _LONGPOLL_TIMEOUT,
@@ -133,7 +154,7 @@ def test_set_defaults_with_limit(self):
     def test_set_defaults_with_kwarg_limit(self):
         kwarg = {**self.kwarg_valid, **{"limit": 24}}
         follower = ChangesFollower(self.client, db="db", **kwarg)
-        follower._set_defaults(limit=12)
+        follower._set_defaults(_Mode.LISTEN, limit=12)
         self.assertEqual(follower.options.get("limit"), 12)