Notify users who have starred a part when that part's stock quantity falls below the minimum quanitity/threshold through email.

InvenTree/stock/models.py

@@ -17,7 +17,7 @@ from django.db.models import Sum, Q
 from django.db.models.functions import Coalesce
 from django.core.validators import MinValueValidator
 from django.contrib.auth.models import User
-from django.db.models.signals import pre_delete
+from django.db.models.signals import pre_delete, post_save
 from django.dispatch import receiver
 
 from markdownx.models import MarkdownxField
@@ -36,6 +36,7 @@ import label.models
 from InvenTree.status_codes import StockStatus, StockHistoryCode
 from InvenTree.models import InvenTreeTree, InvenTreeAttachment
 from InvenTree.fields import InvenTreeModelMoneyField, InvenTreeURLField
+from InvenTree import tasks as inventree_tasks
 
 from users.models import Owner
 
@@ -1651,6 +1652,17 @@ def before_delete_stock_item(sender, instance, using, **kwargs):
         child.save()
 
 
+@receiver(post_save, sender=StockItem)
+def after_save_stock_item(sender, instance: StockItem, **kwargs):
+    """
+    Check if the stock quantity has fallen below the minimum threshold of part. If yes, notify the users who have
+    starred the part
+    """
+
+    if instance.quantity <= instance.part.minimum_stock:
+        inventree_tasks.notify_low_stock(instance)
+
+
 class StockItemAttachment(InvenTreeAttachment):
     """
     Model for storing file attachments against a StockItem object.

InvenTree/stock/templates/stock/low_stock_notification.html

@@ -0,0 +1,27 @@
+<p>{{ message }}</p>
+
+<table style="border-collapse:collapse; width: 80%;margin-left: 10%; font-size: 1rem">
+
+    <tr style="background: aliceblue; height: 4rem;">
+        <th colspan="3" style="padding-bottom: 1rem; font-size: 1.5rem; color:rgb(210,0, 0)">Part low on stock</th>
+    </tr>
+
+    <tr style="height: 3rem; border-bottom: 1px solid">
+        <th>Part Name</th>
+        <th>Available Quantity</th>
+        <th>Minimum Quantity</th>
+    </tr>
+
+    <tr style="height: 3rem">
+        <td style="text-align: center">{{ part_name }}</td>
+        <td style="text-align: center">{{ part_quantity }}</td>
+        <td style="text-align: center">{{ minimum_quantity }}</td>
+    </tr>
+
+    <tr style="background-color: aliceblue;height: 4rem;">
+        <td colspan="3" style="padding-top:1rem; text-align: center">You are receiving this mail because you have starred the part {{ part_name }} in
+            Inventree application</td>
+    </tr>
+
+</table>
+