Starting on a visibility handler

pipeline/handlers/activation.py

@@ -0,0 +1,32 @@
+from .handler import Handler
+from ..exceptions import ValidationException
+
+
+@Handler.register
+class VisibilityHandler(Handler):
+    """
+    This class handles visibility settings for streams.
+    """
+    @classmethod
+    def wants(cls, jobspec, existing_package):
+        """
+        Return True if this handler wants to process this jobspec.
+        Raises an exception if the job is wanted but doesn't pass validation.
+
+        In order for a job to be wanted, the field 'sources' must exist and
+        at least one of the source items must contain a 'enabled' field.
+
+        """
+        pass
+
+    @classmethod
+    def _validate(cls, jobspec, existing_package):
+        """
+        Return True if the job is valid for this handler.
+
+        A job is valid as long as at least one of the package's source items
+        """
+        pass
+
+    def _handle(self, jobspec, existing_package, tempdir):
+        pass