SEBA-405 Convert synchronizer framework to library

Change-Id: If8562f23dc15c7d18d7a8b040b33756708b3c5ec
diff --git a/lib/xos-synchronizer/xossynchronizer/pull_steps/pullstep.py b/lib/xos-synchronizer/xossynchronizer/pull_steps/pullstep.py
new file mode 100644
index 0000000..adbc0b1
--- /dev/null
+++ b/lib/xos-synchronizer/xossynchronizer/pull_steps/pullstep.py
@@ -0,0 +1,33 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class PullStep(object):
+    """
+    All the pull steps defined in each synchronizer needs to inherit from this class in order to be loaded
+    """
+
+    def __init__(self, **kwargs):
+        """
+        Initialize a pull step
+        :param kwargs:
+        -- observed_model: name of the model that is being polled
+        """
+        self.observed_model = kwargs.get("observed_model")
+
+    def pull_records(self):
+        self.log.debug(
+            "There is no default pull_records, please provide a pull_records method for %s"
+            % self.observed_model
+        )