Merge pull request #2208 from rocheparadox/master

Email notification for low stock

InvenTree/InvenTree/tasks.py

@@ -52,7 +52,7 @@ def schedule_task(taskname, **kwargs):
         pass
 
 
-def offload_task(taskname, force_sync=False, *args, **kwargs):
+def offload_task(taskname, *args, force_sync=False, **kwargs):
     """
         Create an AsyncTask if workers are running.
         This is different to a 'scheduled' task,
@@ -108,7 +108,7 @@ def offload_task(taskname, force_sync=False, *args, **kwargs):
             return
         
         # Workers are not running: run it as synchronous task
-        _func()
+        _func(*args, **kwargs)
 
 
 def heartbeat():
@@ -290,7 +290,7 @@ def update_exchange_rates():
     Rate.objects.filter(backend="InvenTreeExchange").exclude(currency__in=currency_codes()).delete()
 
 
-def send_email(subject, body, recipients, from_email=None):
+def send_email(subject, body, recipients, from_email=None, html_message=None):
     """
     Send an email with the specified subject and body,
     to the specified recipients list.
@@ -306,4 +306,5 @@ def send_email(subject, body, recipients, from_email=None):
         from_email,
         recipients,
         fail_silently=False,
+        html_message=html_message
     )

InvenTree/InvenTree/test_api.py

@@ -102,9 +102,9 @@ class APITests(InvenTreeAPITestCase):
 
     fixtures = [
         'location',
-        'stock',
-        'part',
         'category',
+        'part',
+        'stock'
     ]
 
     token = None

InvenTree/part/models.py

@@ -1988,6 +1988,9 @@ class Part(MPTTModel):
     def related_count(self):
         return len(self.get_related_parts())
 
+    def is_part_low_on_stock(self):
+        return self.total_stock <= self.minimum_stock
+
 
 def attach_file(instance, filename):
     """ Function for storing a file for a PartAttachment

InvenTree/part/tasks.py

@@ -0,0 +1,52 @@
+# Author: Roche Christopher
+# Created at 10:26 AM on 31/10/21
+
+import logging
+
+from django.utils.translation import ugettext_lazy as _
+from django.template.loader import render_to_string
+
+from InvenTree import tasks as inventree_tasks
+from part.models import Part
+
+logger = logging.getLogger("inventree")
+
+
+def notify_low_stock(part: Part):
+    """
+    Notify users who have starred a part when its stock quantity falls below the minimum threshold
+    """
+
+    from allauth.account.models import EmailAddress
+    starred_users_email = EmailAddress.objects.filter(user__starred_parts__part=part)
+
+    if len(starred_users_email) > 0:
+        logger.info(f"Notify users regarding low stock of {part.name}")
+        context = {
+            'part_name': part.name,
+            # Part url can be used to open the page of part in application from the email.
+            # It can be facilitated when the application base url is accessible programmatically.
+            # 'part_url': f'{application_base_url}/part/{stock_item.part.id}',
+
+            # quantity is in decimal field datatype. Since the same datatype is used in models,
+            # it is not converted to number/integer,
+            'part_quantity': part.total_stock,
+            'minimum_quantity': part.minimum_stock
+        }
+        subject = _(f'Attention! {part.name} is low on stock')
+        html_message = render_to_string('stock/low_stock_notification.html', context)
+        recipients = starred_users_email.values_list('email', flat=True)
+        inventree_tasks.send_email(subject, '', recipients, html_message=html_message)
+
+
+def notify_low_stock_if_required(part: Part):
+    """
+    Check if the stock quantity has fallen below the minimum threshold of part. If yes, notify the users who have
+    starred the part
+    """
+
+    if part.is_part_low_on_stock():
+        inventree_tasks.offload_task(
+            'part.tasks.notify_low_stock',
+            part
+        )

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, post_delete
 from django.dispatch import receiver
 
 from markdownx.models import MarkdownxField
@@ -41,6 +41,7 @@ from users.models import Owner
 
 from company import models as CompanyModels
 from part import models as PartModels
+from part import tasks as part_tasks
 
 
 class StockLocation(InvenTreeTree):
@@ -1651,6 +1652,24 @@ def before_delete_stock_item(sender, instance, using, **kwargs):
         child.save()
 
 
+@receiver(post_delete, sender=StockItem, dispatch_uid='stock_item_post_delete_log')
+def after_delete_stock_item(sender, instance: StockItem, **kwargs):
+    """
+    Function to be executed after a StockItem object is deleted
+    """
+
+    part_tasks.notify_low_stock_if_required(instance.part)
+
+
+@receiver(post_save, sender=StockItem, dispatch_uid='stock_item_post_save_log')
+def after_save_stock_item(sender, instance: StockItem, **kwargs):
+    """
+   Hook function to be executed after StockItem object is saved/updated
+    """
+
+    part_tasks.notify_low_stock_if_required(instance.part)
+
+
 class StockItemAttachment(InvenTreeAttachment):
     """
     Model for storing file attachments against a StockItem object.

InvenTree/stock/templates/stock/low_stock_notification.html

@@ -0,0 +1,30 @@
+{% load i18n %}
+
+<p>{% trans "Hi, " %} {{ part_name }} {% trans "is low on stock. Kindly do the needful." %}</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)">{%  trans "Part low on stock" %}</th>
+    </tr>
+
+    <tr style="height: 3rem; border-bottom: 1px solid">
+        <th>{% trans "Part Name" %}</th>
+        <th>{% trans "Available Quantity" %}</th>
+        <th>{% trans "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">{% trans "You are receiving this mail because you have starred the part " %} {{ part_name }}
+            {% trans "Inventree application" %}
+            </td>
+    </tr>
+
+</table>
+