diff --git a/shoebox/handlers.py b/shoebox/handlers.py
index a6b4cca..c796615 100644
--- a/shoebox/handlers.py
+++ b/shoebox/handlers.py
@@ -37,11 +37,11 @@ class CallbackList(ArchiveCallback):
     def __init__(self, **kwargs):
         super(CallbackList, self).__init__(**kwargs)
         self.callbacks = []
-        self.config = kwargs.get('config', {})
-        callback_list_str = self.config.get('callback_list', "")
-        callback_list = [x.strip() for x in callback_list_str.split(",")]
-        self.callback_list = [simport.load(c) for c in callback_list]
-
+        self.config = kwargs
+        callback_str = self.config.get('callback_list', "")
+        callback_str_list = [x.strip() for x in callback_str.split(",")]
+        self.callbacks = [simport.load(c)(**self.config)
+                            for c in callback_str_list]
     # TODO(Sandy): Need some exception handling around these.
     # The failure of one shouldn't stop processing.
     def on_open(self, filename):
@@ -53,7 +53,7 @@ class CallbackList(ArchiveCallback):
             c.on_close(filename)
 
 
-class ChangeExtensionCallback(object):
+class ChangeExtensionCallback(ArchiveCallback):
     """filename.dat becomes filename.dat.done"""
     def __init__(self, **kwargs):
         super(ChangeExtensionCallback, self).__init__(**kwargs)
@@ -63,7 +63,7 @@ class ChangeExtensionCallback(object):
         os.rename(filename, "%s.%s" % (filename, self.new_extension))
 
 
-class MoveFileCallback(object):
+class MoveFileCallback(ArchiveCallback):
     def __init__(self, **kwargs):
         super(MoveFileCallback, self).__init__(**kwargs)
         self.destination_folder = kwargs.get('destination_folder', '.')
diff --git a/shoebox/roll_checker.py b/shoebox/roll_checker.py
index a59cf79..4cd922c 100644
--- a/shoebox/roll_checker.py
+++ b/shoebox/roll_checker.py
@@ -13,10 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
+
 import notification_utils
 
 
 class RollChecker(object):
+    def __init__(self, **kwargs):
+        pass
+
     def start(self, archive):
         """Called when a new archive is selected."""
         pass
@@ -32,8 +37,10 @@ class NeverRollChecker(RollChecker):
 
 
 class TimeRollChecker(RollChecker):
-    def __init__(self, timedelta):
-        self.timedelta = timedelta
+    def __init__(self, **kwargs):
+        super(TimeRollChecker, self).__init__()
+        minutes = int(kwargs.get('roll_minutes', 60))
+        self.timedelta = datetime.timedelta(minutes=minutes)
 
     def start(self, archive):
         self.start_time = notification_utils.now()
@@ -44,9 +51,10 @@ class TimeRollChecker(RollChecker):
 
 
 class SizeRollChecker(RollChecker):
-    def __init__(self, size_in_mb):
-        self.size_in_mb = size_in_mb
+    def __init__(self, **kwargs):
+        super(SizeRollChecker, self).__init__()
+        self.roll_size_mb = int(kwargs.get('roll_size_mb', 1))
 
     def check(self, archive):
         size = archive.get_file_handle().tell()
-        return (size / 1048576) >= self.size_in_mb
+        return (size / 1048576) >= self.roll_size_mb
diff --git a/test/integration/test_rolling.py b/test/integration/test_rolling.py
index 3bdd629..fcd25b7 100644
--- a/test/integration/test_rolling.py
+++ b/test/integration/test_rolling.py
@@ -51,7 +51,7 @@ class TestSizeRolling(unittest.TestCase):
     def test_size_rolling(self):
         callback = ArchiveCallback()
 
-        checker = roll_checker.SizeRollChecker(1)
+        checker = roll_checker.SizeRollChecker(roll_size_mb=1)
         manager = roll_manager.WritingRollManager("test_%Y_%m_%d_%X_%f.events",
                                                   checker,
                                                   TEMPDIR,
diff --git a/test/test_roll_checker.py b/test/test_roll_checker.py
index ce57e9f..15cbb31 100644
--- a/test/test_roll_checker.py
+++ b/test/test_roll_checker.py
@@ -9,18 +9,18 @@ from shoebox import roll_checker
 
 class TestRollChecker(unittest.TestCase):
     def test_time_roll_checker_start(self):
-        one_hour = datetime.timedelta(hours=1)
-        x = roll_checker.TimeRollChecker(one_hour)
+        x = roll_checker.TimeRollChecker(roll_minutes=60)
         now = datetime.datetime.utcnow()
         with mock.patch.object(notification_utils, 'now') as dt:
             dt.return_value = now
             x.start(None)
         self.assertEqual(x.start_time, now)
+        one_hour = datetime.timedelta(hours=1)
         self.assertEqual(x.end_time, now + one_hour)
 
     def test_time_roll_checker_end(self):
         one_hour = datetime.timedelta(hours=1)
-        x = roll_checker.TimeRollChecker(one_hour)
+        x = roll_checker.TimeRollChecker(roll_minutes=60)
         now = datetime.datetime.utcnow()
         x.start_time = now
         x.end_time = now + one_hour
@@ -37,10 +37,9 @@ class TestRollChecker(unittest.TestCase):
             self.assertFalse(x.check(None))
 
     def test_size_roll_checker_end(self):
-        one_mb = 1048576
-        x = roll_checker.SizeRollChecker(10)
-
+        x = roll_checker.SizeRollChecker(roll_size_mb=10)
         archive = mock.Mock()
+        one_mb = 1048576
         archive.get_file_handle.return_value.tell.return_value = one_mb * 5
         self.assertFalse(x.check(archive))