Trying (but failing still) with yaml.

SciPost_v1/signalprocessors.py

@@ -12,7 +12,7 @@ from submissions.models import Submission
 class AutoSearchIndexingProcessor(signals.RealtimeSignalProcessor):
 
     @app.task(bind=True, name='signalprocessors.remove_object_indexes',
-              serializer='pickle')
+              serializer='yaml')
     def remove_objects_indexes(self, sender, objects):
         """
         Given a set of `objects` model instances, remove them from the index as preparation
@@ -34,7 +34,7 @@ class AutoSearchIndexingProcessor(signals.RealtimeSignalProcessor):
                     pass
 
     @app.task(bind=True, name='signalprocessors.update_instance_indexes',
-              serializer='pickle')
+              serializer='yaml')
     def update_instance_indexes(self, sender, instance):
         """
         Given an individual model instance, update its entire indexes.

requirements.txt

@@ -61,7 +61,7 @@ six==1.10.0
 snowballstemmer==1.2.1
 
 # Scheduled tasks
-celery==4.2.1
+celery[yaml]==4.2.1
 django-celery-results==1.0.1
 django-celery-beat==1.1.1
 flower==0.9.2