[FR] Slack notifications & notification method updates (#4114)

* [FR] Slack notification
Add slack sending method
Fixes #3843

* Add global panel with notification methods

* add plugin information

* fix plugin lookup and link

* Add settings content mixin

* Add instructions for Slack setup

* fix rendering of custom settings content

InvenTree/plugin/builtin/integration/core_notifications.py

@@ -3,13 +3,15 @@
 from django.template.loader import render_to_string
 from django.utils.translation import gettext_lazy as _
 
+import requests
 from allauth.account.models import EmailAddress
 
 import common.models
 import InvenTree.helpers
 import InvenTree.tasks
-from plugin import InvenTreePlugin
-from plugin.mixins import BulkNotificationMethod, SettingsMixin
+from plugin import InvenTreePlugin, registry
+from plugin.mixins import (BulkNotificationMethod, SettingsContentMixin,
+                           SettingsMixin)
 
 
 class PlgMixin:
@@ -23,7 +25,7 @@ class PlgMixin:
         return CoreNotificationsPlugin
 
 
-class CoreNotificationsPlugin(SettingsMixin, InvenTreePlugin):
+class CoreNotificationsPlugin(SettingsContentMixin, SettingsMixin, InvenTreePlugin):
     """Core notification methods for InvenTree."""
 
     NAME = "CoreNotificationsPlugin"
@@ -39,8 +41,30 @@ class CoreNotificationsPlugin(SettingsMixin, InvenTreePlugin):
             'default': False,
             'validator': bool,
         },
+        'ENABLE_NOTIFICATION_SLACK': {
+            'name': _('Enable slack notifications'),
+            'description': _('Allow sending of slack channel messages for event notifications'),
+            'default': False,
+            'validator': bool,
+        },
+        'NOTIFICATION_SLACK_URL': {
+            'name': _('Slack incoming webhook url'),
+            'description': _('URL that is used to send messages to a slack channel'),
+            'protected': True,
+        },
     }
 
+    def get_settings_content(self, request):
+        """Custom settings content for the plugin."""
+        return """
+        <p>Setup for Slack:</p>
+        <ol>
+            <li>Create a new Slack app on <a href="https://api.slack.com/apps/new" target="_blank">this page</a></li>
+            <li>Enable <i>Incoming Webhooks</i> for the channel you want the notifications posted to</li>
+            <li>Set the webhook URL in the settings above</li>
+        <li>Enable the plugin</li>
+        """
+
     class EmailNotification(PlgMixin, BulkNotificationMethod):
         """Notificationmethod for delivery via Email."""
 
@@ -94,3 +118,53 @@ class CoreNotificationsPlugin(SettingsMixin, InvenTreePlugin):
             InvenTree.tasks.send_email(subject, '', targets, html_message=html_message)
 
             return True
+
+    class SlackNotification(PlgMixin, BulkNotificationMethod):
+        """Notificationmethod for delivery via Slack channel messages."""
+
+        METHOD_NAME = 'slack'
+        METHOD_ICON = 'fa-envelope'
+        GLOBAL_SETTING = 'ENABLE_NOTIFICATION_SLACK'
+
+        def get_targets(self):
+            """Not used by this method."""
+            return self.targets
+
+        def send_bulk(self):
+            """Send the notifications out via slack."""
+
+            instance = registry.plugins.get(self.get_plugin().NAME.lower())
+            url = instance.get_setting('NOTIFICATION_SLACK_URL')
+
+            if not url:
+                return False
+
+            ret = requests.post(url, json={
+                'text': str(self.context['message']),
+                'blocks': [
+                    {
+                        "type": "section",
+                        "text": {
+                            "type": "plain_text",
+                            "text": str(self.context['name'])
+                        }
+                    },
+                    {
+                        "type": "section",
+                        "text": {
+                            "type": "mrkdwn",
+                            "text": str(self.context['message'])
+                        },
+                        "accessory": {
+                            "type": "button",
+                            "text": {
+                                "type": "plain_text",
+                                "text": str(_("Open link")), "emoji": True
+                            },
+                            "value": f'{self.category}_{self.obj.pk}',
+                            "url": self.context['link'],
+                            "action_id": "button-action"
+                        }
+                    }]
+            })
+            return ret.ok