[docs] Add Batch Notifications page

docs/user/batch-email-notifications.rst

@@ -0,0 +1,64 @@
+Batch Email Notifications
+=========================
+
+.. contents:: **Table of Contents**:
+    :depth: 2
+    :local:
+
+.. _notifications_batch_email_notifications:
+
+Batch Email Notifications
+-------------------------
+
+Batch email notifications help manage the volume of emails sent to users, particularly during periods of high alert activity. By batching emails, the system reduces the risk of emails being flagged as spam and prevents email inboxes from rejecting alerts due to overuse. The following features and configurations make up the batch email notification system:
+
+Batch Email Feature
+~~~~~~~~~~~~~~~~~~~
+
+The batch email notification feature ensures that:
+
+- If more than one email is sent to a specific user within a 30-minute window, subsequent emails are batched into a summary.
+- The sending of individual emails is paused for 30 minutes when batching is active.
+- **Note**: If new alerts arrive while a batch is pending, they are added to the existing summary. However, the timer does not reset. The batch email will be sent out when the initial 30-minute interval expires.
+
+Batch Email Example
+~~~~~~~~~~~~~~~~~~~
+
+Here is an example scenario where batch email notifications can be helpful:
+
+1. Multiple infrastructure issues cause numerous alerts within a short period.
+2. Without batching, each alert triggers an individual email, overwhelming the recipient's inbox.
+3. With batch email notifications enabled, the alerts are summarized into a single email, sent after the issues subside or the batch timer expires.
+
+Batch Email Summary
+~~~~~~~~~~~~~~~~~~~
+
+.. figure:: https://raw.githubusercontent.com/openwisp/openwisp-notifications/docs/docs/images/batch-email-summary.png
+    :target: https://raw.githubusercontent.com/openwisp/openwisp-notifications/docs/docs/images/batch-email-summary.png
+    :align: center
+
+The batch email system provides a summary that includes:
+
+- A list of the most recent notifications, limited by the display limit.
+- A call-to-action to view all notifications if the number exceeds the display limit.
+- The time the batch started, helping users understand the context of the alerts.
+
+Configuration Options
+~~~~~~~~~~~~~~~~~~~~~
+
+The following default configurations can be adjusted according to the needs:
+
+- **Email Batch Interval**: The time period for which individual email sending is paused when a batch is active. The default is set to 30 minutes.
+- **Email Batch Display Limit**: The maximum number of notifications displayed in a single batch email. The default is 15.
+
+These configurations are set in the `settings.py` file:
+
+.. code-block:: python
+
+    EMAIL_BATCH_INTERVAL = getattr(
+        settings, 'OPENWISP_NOTIFICATIONS_EMAIL_BATCH_INTERVAL', 30 * 60  # 30 minutes
+    )
+
+    EMAIL_BATCH_DISPLAY_LIMIT = getattr(
+        settings, 'OPENWISP_NOTIFICATIONS_EMAIL_BATCH_DISPLAY_LIMIT', 15
+    )

docs/user/intro.rst

@@ -8,6 +8,7 @@ include:
 - :doc:`sending-notifications`
 - :ref:`notifications_web_notifications`
 - :ref:`notifications_email_notifications`
+- :ref:`notifications_batch_email_notifications`
 - :doc:`notification-types`
 - :doc:`User notification preferences <notification-preferences>`
 - :ref:`Silencing notifications for specific objects temporarily or