added clear_extra for removing instances when config.count decreases

Yelp · Aug 2, 2013 · 8b9bc0a · 8b9bc0a
1 parent b9e88c3
commit 8b9bc0a
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Showing 4 changed files with 19 additions and 0 deletions.
diff --git a/tests/core/service_test.py b/tests/core/service_test.py
@@ -154,13 +154,15 @@ def test_update_node_pool_enabled(self):
         self.service.enabled = True
         self.service.update_node_pool()
         self.service.instances.update_node_pool.assert_called_once_with()
+        self.service.instances.clear_extra.assert_called_once_with()
         self.service.repair.assert_called_once_with()
 
     def test_update_node_pool_disabled(self):
         autospec_method(self.service.repair)
         self.service.enabled = False
         self.service.update_node_pool()
         self.service.instances.update_node_pool.assert_called_once_with()
+        self.service.instances.clear_extra.assert_called_once_with()
         assert not self.service.repair.called
 
 

diff --git a/tests/core/serviceinstance_test.py b/tests/core/serviceinstance_test.py
@@ -550,6 +550,16 @@ def test_update_node_pool_diff_everything(self):
             assert all([instance.stop.called for instance in self.collection.instances])
             assert_equal(self.collection.instances, [])
 
+    def test_clear_extra(self):
+        instance_a = mock.Mock()
+        instance_b = mock.Mock()
+        instance_c = mock.Mock()
+        self.collection.instances = [instance_a, instance_b, instance_c]
+        self.collection.config.count = 2
+        self.collection.clear_extra()
+        assert_equal(self.collection.instances, [instance_a, instance_b])
+        instance_c.stop.assert_called_once_with()
+
 
 if __name__ == "__main__":
     run()
diff --git a/tron/core/service.py b/tron/core/service.py
@@ -158,6 +158,7 @@ def restore_state(self, state_data):
 
     def update_node_pool(self):
         self.instances.update_node_pool()
+        self.instances.clear_extra()
         if self.enabled:
             self.repair()
 

diff --git a/tron/core/serviceinstance.py b/tron/core/serviceinstance.py
@@ -480,6 +480,12 @@ def update_node_pool(self):
             self.instances = [i for i in self.instances if
                               i not in needs_new_node]
 
+    def clear_extra(self):
+        """Clear out instances if too many exist."""
+        for i in range(0, self.missing, -1):
+            instance = self.instances.pop()
+            instance.stop()
+
     @property
     def missing(self):
         return self.config.count - len(self.instances)