indico-plugin-category-reminder

An Indico 3.3 plugin that sends automatic reminder emails for events in configured categories.

Table of Contents

• Features
• Installation
• Usage
• Template Variables
• How Reminders Are Dispatched
• Database Schema
• Development & Testing
• Troubleshooting
• Contribution Guide
• License

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Features

• 📧 Per-category rules – configure one or more reminder rules per category
• 👥 Custom recipient lists – any list of email addresses, not just event participants
• 🕐 Flexible timing – advance reminder N days before (default: 7) + day-of morning reminder
• ✏️ Jinja2 email templates – full access to event title, date, speakers, abstract, URL, etc.
• 👁️ Live preview – preview the rendered email against a real upcoming event before saving
• 🔒 Duplicate prevention – sent reminders are tracked so emails are never resent
• ⚙️ Category management UI – integrated into Indico's native category management sidebar

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Installation

pip install indico-plugin-category-reminder

Then run the database migration:

indico db upgrade --plugin category_reminder

Enable the plugin in your Indico admin panel under Admin → Plugins.

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Usage

1. Navigate to a category and open Category Management.
2. Click Event Reminders in the left sidebar.
3. Click Add reminder rule.
4. Fill in:
   • Rule name – human-readable label
   • Recipients – one email address per line
   • Subject template – Jinja2 template string
   • Body template – HTML Jinja2 template
   • Days before – how many days in advance to send (0 = disabled)
   • Day-of reminder – whether to also send on the event morning
   • Send hours – UTC hour for each reminder type
5. Click Preview to verify the rendered output against a real event.
6. Save and you're done — Celery handles the rest automatically.

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Template Variables

The following variables are available in both subject and body templates:

Variable	Description
event	The Indico Event object
event.title	Event title
event.start_dt	Start datetime (use `
event.end_dt	End datetime
event.room_name	Room name
event.venue_name	Venue/building name
event.description	Event description
event.external_url	Public URL of the event
speakers	List of speaker PersonLink objects
speaker.full_name	Speaker's full name
speaker.affiliation	Speaker's affiliation
abstract	Abstract text (first contribution or event description)
config	The CategoryReminderConfig object

Filters

Filter	Example
format_date	`{{ event.start_dt
format_datetime	`{{ event.start_dt

Example subject template

Reminder: {{ event.title }} – {{ event.start_dt | format_date }}

Example body snippet

<p>Speaker: 
{% for s in speakers %}{{ s.full_name }}{% if not loop.last %}, {% endif %}{% endfor %}
</p>
{% if abstract %}<p>{{ abstract }}</p>{% endif %}

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How Reminders Are Dispatched

A Celery periodic task (send_category_reminders) runs every hour. For each active rule it:

1. Queries all upcoming events in the linked category (within the next 30 days).
2. For each event, checks whether:
   • The advance reminder should fire today (event is exactly days_before days away) at the configured UTC hour.
   • The day-of reminder should fire today (event starts today) at the configured UTC hour.
3. Skips events for which a reminder of that type has already been sent.
4. Renders the Jinja2 templates and dispatches the email via Indico's standard email system.
5. Records the send in the sent_reminders table.

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Database Schema

Two tables are created in the plugin_category_reminder PostgreSQL schema:

• category_reminder_configs – one row per reminder rule
• sent_reminders – one row per (config, event, type) combination; prevents duplicates

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Development & Testing

git clone https://git.aquila-consortium.org/guilhem_lavaux/indico-plugin-reminder
cd indico-plugin-category-reminder
pip install -e ".[dev]"
pytest

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Troubleshooting

Issue	Symptom	Fix
No emails are sent	Celery worker not running	Start the worker: celery -A indico.app.celery worker --loglevel=info
Templates render incorrectly	Jinja2 syntax errors	Validate templates in the preview pane before saving
Duplicate emails	sent_reminders table not updated	Ensure the migration has run and the table exists
Plugin not visible	Plugin not listed in Admin → Plugins	Verify indico-plugin-category-reminder is installed in the same environment as Indico

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Contribution Guide

1. Fork the repository and create a feature branch: git checkout -b my-feature.
2. Make your changes and run tests: pytest.
3. Ensure code style passes: flake8 ..
4. Commit with a clear message and push: git push origin my-feature.
5. Open a pull request against the main branch and reference any relevant issue.

We welcome all contributions! For major changes, please open an issue first to discuss the approach.

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License

MIT