Change security worker to use data interface

workers/securityworker/models_interface.py

@@ -0,0 +1,28 @@
+from abc import ABCMeta, abstractmethod
+from collections import namedtuple
+
+from six import add_metaclass
+
+class ScanToken(namedtuple('NextScanToken', ['min_id'])):
+  """
+  ScanToken represents an opaque token that can be passed between runs of the security worker
+  to continue scanning whereever the previous run left off. Note that the data of the token is
+  *opaque* to the security worker, and the security worker should *not* pull any data out or modify
+  the token in any way.
+  """
+
+@add_metaclass(ABCMeta)
+class SecurityWorkerDataInterface(object):
+  """
+  Interface that represents all data store interactions required by the security worker.
+  """
+
+  @abstractmethod
+  def candidates_to_scan(self, target_version, start_token=None):
+    """
+    Returns a tuple consisting of an iterator of all the candidates to scan and a NextScanToken.
+    The iterator returns a tuple for each iteration consisting of the candidate Image, the abort
+    signal, and the number of remaining candidates. If the iterator returned is None, there are
+    no candidates to process.
+    """
+    pass