Citadel: Implement warning threshold

Also add error message

citadel/indico_citadel/plugin.py

@@ -18,6 +18,7 @@
 from indico_citadel.backend import LiveSyncCitadelBackend
 from indico_citadel.cli import cli
 from indico_livesync import LiveSyncPluginBase
+from indico_citadel.util import check_event_categories
 
 
 class CitadelSettingsForm(IndicoForm):
@@ -51,6 +52,12 @@ class CitadelSettingsForm(IndicoForm):
                                                 'is used, the internal Indico search interface will be used. This may '
                                                 'be useful when you are still running a larger initial export and do '
                                                 'not want people to get incomplete search results during that time.'))
+    large_category_warning_threshold = IntegerField(_('Large Category Warning Threshold'),
+                                                    [NumberRange(min=0)],
+                                                    description=_('This shows a warning message to admins when '
+                                                                  'the number of events in a category surpasses '
+                                                                  'the threshold set here. You can set the '
+                                                                  'threshold to 0 to suppress this warning.'))
 
 
 class CitadelPlugin(LiveSyncPluginBase):
@@ -75,13 +82,15 @@ class CitadelPlugin(LiveSyncPluginBase):
         'num_threads_files': 5,
         'num_threads_files_initial': 25,
         'disable_search': False,
+        'large_category_warning_threshold': 0,
     }
     backend_classes = {'citadel': LiveSyncCitadelBackend}
 
     def init(self):
         super().init()
         self.connect(signals.core.get_search_providers, self.get_search_providers)
         self.connect(signals.plugin.cli, self._extend_indico_cli)
+        self.template_hook('category-protection-page', check_event_categories)
 
     def get_search_providers(self, sender, **kwargs):
         from indico_citadel.search import CitadelProvider

citadel/indico_citadel/templates/event_category_warning.html

@@ -0,0 +1,9 @@
+{% from 'message_box.html' import message_box %}
+
+{% call message_box('warning', large_icon=true, fixed_width=true) %}
+    {% trans category_title=category.title, max_events_threshold=threshold -%}
+        <b>The '{{ category_title }}' category contains over {{ max_events_threshold }} events - this may cause performance issues.</b>
+        <br/>
+        Please consider using groups instead of individual users to avoid having to re-send large amounts of changes to users individually.
+    {%- endtrans %}
+{% endcall %}

citadel/indico_citadel/util.py

@@ -13,6 +13,7 @@
 
 from flask import current_app
 from flask.globals import _cv_app
+from flask_pluginengine.plugin import render_plugin_template
 
 from indico.core.db import db
 from indico.core.db.sqlalchemy.principals import PrincipalMixin, PrincipalPermissionsMixin, PrincipalType
@@ -215,3 +216,12 @@ def get_user_access(user, admin_override_enabled=False):
                             for x in user.iter_all_multipass_groups()]
         access += _include_capitalized_groups(multipass_groups)
     return access
+
+def check_event_categories(category):
+        from indico_citadel.plugin import CitadelPlugin
+
+        threshold = CitadelPlugin.settings.get('large_category_warning_threshold')
+        num_events = category.deep_events_count
+
+        if threshold and num_events > threshold:
+            return render_plugin_template('event_category_warning.html', category=category, threshold=threshold)