Use Celery for index updating if available

Otherwise, use real-time updating (AlekSIS, by contract, is guaranteed
to be slow without Celery ;)).

aleksis/core/settings.py

@@ -561,6 +561,7 @@ LOGGING = {
 }
 
 HAYSTACK_BACKEND_SHORT = _settings.get("search.backend", "simple")
+
 if HAYSTACK_BACKEND_SHORT == "simple":
     HAYSTACK_CONNECTIONS = {
         'default': {
@@ -581,3 +582,9 @@ elif HAYSTACK_BACKEND_SHORT == "whoosh":
             'PATH': _settings.get("search.index", os.path.join(BASE_DIR, "whoosh_index")),
         },
     }
+
+if _settings.get("celery.enabled", False) and _settings.get("search.celery", True):
+    INSTALLED_APPS.append("celery_haystack")
+    HAYSTACK_SIGNAL_PROCESSOR = 'celery_haystack.signals.CelerySignalProcessor'
+else:
+    HAYSTACK_SIGNAL_PROCESSOR = 'haystack.signals.RealtimeSignalProcessor'

aleksis/core/util/search.py

+from django.conf import settings
+
 from haystack import indexes
 
 # Not used here, but simplifies imports for apps
 Indexable = indexes.Indexable  # noqa
 
+if settings.HAYSTACK_SIGNAL_PROCESSOR == 'celery_haystack.signals.CelerySignalProcessor':
+    from haystack.indexes import SearchIndex as BaseSearchIndex
+else:
+    from celery_haystack.indexes import CelerySearchIndex as BaseSearchIndex
 
-class SearchIndex(indexes.SearchIndex):
+class SearchIndex(BaseSearchIndex):
     """ Base class for search indexes on AlekSIS models
 
     It provides a default document field caleld text and exects

pyproject.toml

@@ -69,10 +69,11 @@ django-colorfield = "^0.2.1"
 django-bleach = "^0.6.1"
 django-memoize = "^2.2.1"
 django-haystack = "^3.0"
+celery-haystack = {version="^0.3.1", optional=true}
 
 [tool.poetry.extras]
 ldap = ["django-auth-ldap"]
-celery = ["Celery", "django-celery-results", "django-celery-beat", "django-celery-email"]
+celery = ["Celery", "django-celery-results", "django-celery-beat", "django-celery-email", "celery-haystack"]
 
 [tool.poetry.dev-dependencies]
 sphinx = "^2.1"