Adds sample plugin which responds to triggered events

- Adds some example trigger events for the "Part" model

InvenTree/part/models.py

@@ -60,6 +60,8 @@ import common.models
 
 import part.settings as part_settings
 
+from plugin.events import trigger_event
+
 
 logger = logging.getLogger("inventree")
 
@@ -1980,10 +1982,10 @@ class Part(MPTTModel):
 
     @property
     def attachment_count(self):
-        """ Count the number of attachments for this part.
+        """
+        Count the number of attachments for this part.
         If the part is a variant of a template part,
         include the number of attachments for the template part.
-
         """
 
         return self.part_attachments.count()
@@ -2181,7 +2183,11 @@ def after_save_part(sender, instance: Part, created, **kwargs):
     Function to be executed after a Part is saved
     """
 
-    if not created:
+    trigger_event('part.saved', part_id=instance.pk)
+
+    if created:
+        trigger_event('part.created', part_id=instance.pk)
+    else:
         # Check part stock only if we are *updating* the part (not creating it)
 
         # Run this check in the background

InvenTree/plugin/builtin/integration/mixins.py

@@ -189,10 +189,10 @@ class EventMixin:
     which provide pairs of 'event':'function'
 
     Notes:
-    
+
     Events are called by name, and based on the django signal nomenclature,
     e.g. 'part.pre_save'
-    
+
     Receiving functions must be prototyped to match the 'event' they receive.
 
     Example:

InvenTree/plugin/events.py

@@ -8,11 +8,14 @@ from __future__ import unicode_literals
 import logging
 
 from django.conf import settings
+from django.db import transaction
 
 from common.models import InvenTreeSetting
 
 from InvenTree.tasks import offload_task
 
+from plugin.registry import plugin_registry
+
 
 logger = logging.getLogger('inventree')
 
@@ -38,12 +41,30 @@ def trigger_event(event, *args, **kwargs):
 def process_event(event, *args, **kwargs):
     """
     Respond to a triggered event.
-    
+
     This function is run by the background worker process.
+
+    This function may queue multiple functions to be handled by the background worker.
     """
 
     logger.info(f"Processing event '{event}'")
 
     # Determine if there are any plugins which are interested in responding
     if settings.PLUGIN_TESTING or InvenTreeSetting.get_setting('ENABLE_PLUGINS_EVENTS'):
-        pass
+
+        # Run atomically, to ensure that either *all* tasks are registered, or *none*
+        with transaction.atomic():
+            for slug, callbacks in plugin_registry.mixins_events.items():
+                # slug = plugin slug
+                # callbacks = list of (event, function) tuples
+
+                for _event, _func in callbacks:
+                    if _event == event:
+
+                        logger.info(f"Running task '{_func}' for plugin '{slug}'")
+
+                        offload_task(
+                            _func,
+                            *args,
+                            **kwargs
+                        )

InvenTree/plugin/plugin.py

@@ -63,3 +63,15 @@ class InvenTreePlugin():
                 raise error
 
         return cfg
+
+    def is_active(self):
+        """
+        Return True if this plugin is currently active
+        """
+
+        cfg = self.plugin_config()
+
+        if cfg:
+            return cfg.active
+        else:
+            return False

InvenTree/plugin/registry.py

@@ -56,8 +56,10 @@ class PluginsRegistry:
 
         # integration specific
         self.installed_apps = []         # Holds all added plugin_paths
+
         # mixins
         self.mixins_settings = {}
+        self.mixins_events = {}
 
     # region public plugin functions
     def load_plugins(self):
@@ -265,6 +267,7 @@ class PluginsRegistry:
         logger.info(f'Found {len(plugins)} active plugins')
 
         self.activate_integration_settings(plugins)
+        self.activate_integration_events(plugins)
         self.activate_integration_schedule(plugins)
         self.activate_integration_app(plugins, force_reload=force_reload)
 
@@ -275,6 +278,7 @@ class PluginsRegistry:
 
         self.deactivate_integration_app()
         self.deactivate_integration_schedule()
+        self.deactivate_integration_events()
         self.deactivate_integration_settings()
 
     def activate_integration_settings(self, plugins):
@@ -299,6 +303,41 @@ class PluginsRegistry:
         # clear cache
         self.mixins_settings = {}
 
+    def activate_integration_events(self, plugins):
+        """
+        Activate triggered events mixin for applicable plugins
+        """
+
+        logger.info('Activating plugin events')
+
+        from common.models import InvenTreeSetting
+
+        self.mixins_events = {}
+
+        event_count = 0
+
+        if settings.PLUGIN_TESTING or InvenTreeSetting.get_setting('ENABLE_PLUGINS_EVENTS'):
+
+            for slug, plugin in plugins:
+
+                if plugin.mixin_enabled('events'):
+                    config = plugin.plugin_config()
+
+                    # Only activate events for plugins which are enabled
+                    if config and config.active:
+                        self.mixins_events[slug] = plugin.events
+
+                        event_count += len(plugin.events)
+
+        if event_count > 0:
+            logger.info(f"Registered callbacks for {event_count} events")
+
+    def deactivate_integration_events(self):
+        """
+        Deactivate events for all plugins
+        """
+        self.mixins_events = {}
+
     def activate_integration_schedule(self, plugins):
 
         logger.info('Activating plugin tasks')

InvenTree/plugin/samples/integration/event_sample.py

@@ -0,0 +1,29 @@
+"""
+Sample plugin which responds to events
+"""
+
+from plugin import IntegrationPluginBase
+from plugin.mixins import EventMixin
+
+
+def on_part_saved(*args, **kwargs):
+    """
+    Simple function which responds to a triggered event
+    """
+
+    part_id = kwargs['part_id']
+    print(f"func on_part_saved() - part: {part_id}")
+
+
+class EventPlugin(EventMixin, IntegrationPluginBase):
+    """
+    A sample plugin which provides supports for triggered events
+    """
+
+    PLUGIN_NAME = "EventPlugin"
+    PLUGIN_SLUG = "event"
+    PLUGIN_TITLE = "Triggered Events"
+
+    EVENTS = [
+        ('part.saved', 'plugin.samples.integration.event_sample.on_part_saved'),
+    ]

InvenTree/plugin/samples/integration/scheduled_task.py

@@ -32,7 +32,7 @@ class ScheduledTaskPlugin(ScheduleMixin, IntegrationPluginBase):
         'hello': {
             'func': 'plugin.samples.integration.scheduled_task.print_hello',
             'schedule': 'I',
-            'minutes': 5,
+            'minutes': 45,
         },
         'world': {
             'func': 'plugin.samples.integration.scheduled_task.print_hello',

InvenTree/templates/InvenTree/settings/plugin_settings.html

@@ -90,7 +90,7 @@
                 </td>
             </tr>
             <tr>
-                <td></td>
+                <td><span class='fas fa-sitemap'></span></td>
                 <td>{% trans "Installation path" %}</td>
                 <td>{{ plugin.package_path }}</td>
             </tr>