Add Watcher.setup() method for datasync

rattail/datasync/daemon.py

@@ -92,6 +92,9 @@ def watch_for_changes(config, watcher):
     """
     from rattail.db import Session, model
 
+    # Let watcher do any setup it needs.
+    watcher.setup()
+
     # The 'last run' value is maintained as a naive UTC datetime.
     timefmt = '%Y-%m-%d %H:%M:%S'
     lastrun_setting = 'rattail.datasync.{0}.watcher.lastrun'.format(watcher.key)

rattail/datasync/watchers.py

@@ -37,6 +37,11 @@ class DataSyncWatcher(object):
         self.key = key
         self.delay = 1 # seconds
 
+    def setup(self):
+        """
+        This method is called when the watcher thread is first started.
+        """
+
     def get_changes(self, lastrun):
         """
         This must be implemented by the subclass.  It should check the source