Skip ready functions if not in main thread or plugins are not loaded yet (#5005)

* Skip ready functions if not in main thread or plugins are not loaded yet

* Debug integration tests

* Update ready.py

* Update ready.py

* Fix isInMainThread and isPluginRegistryLoaded ready functions

* Preload gunicorn app to only invoke the appconfig ready functions once

* debug: test prints for statistics

* Remove debug print

* Test without

* Revert "Test without"

This reverts commit 1bc1872893.

* Second test

* Add checks back to part, label, user model

* Add checks back to inventree, plugin apps

* log server output for debugging

* hopefully I can get the log this time+

* Next test

* Test with --noreload

* Next test

* trigger: ci, because session expired

* block the second ready execution instead of the first

* fix: load order

* Fix test and revert gh actions workflow change

* Added all_apps method to reload machanism

* Changed detect reload mechanism

* Also trigger ready on reload

* Add skipping second reload back for testing mode

* Added doc string back

* Update InvenTree/plugin/base/integration/AppMixin.py

InvenTree/InvenTree/apps.py

@@ -14,7 +14,8 @@ from django.db.utils import IntegrityError
 import InvenTree.conversion
 import InvenTree.tasks
 from InvenTree.config import get_setting
-from InvenTree.ready import canAppAccessDatabase, isInTestMode
+from InvenTree.ready import (canAppAccessDatabase, isInMainThread,
+                             isInTestMode, isPluginRegistryLoaded)
 
 logger = logging.getLogger("inventree")
 
@@ -34,6 +35,10 @@ class InvenTreeConfig(AppConfig):
         - Collecting notification methods
         - Adding users set in the current environment
         """
+        # skip loading if plugin registry is not loaded or we run in a background thread
+        if not isPluginRegistryLoaded() or not isInMainThread():
+            return
+
         if canAppAccessDatabase() or settings.TESTING_ENV:
             InvenTree.tasks.check_for_migrations(worker=False)
 

InvenTree/InvenTree/ready.py

@@ -1,5 +1,6 @@
 """Functions to check if certain parts of InvenTree are ready."""
 
+import os
 import sys
 
 
@@ -18,6 +19,18 @@ def isRunningMigrations():
     return 'migrate' in sys.argv or 'makemigrations' in sys.argv
 
 
+def isInMainThread():
+    """Django runserver starts two processes, one for the actual dev server and the other to reload the application.
+
+    - The RUN_MAIN env is set in that case. However if --noreload is applied, this variable
+    is not set because there are no different threads.
+    """
+    if "runserver" in sys.argv and "--noreload" not in sys.argv:
+        return os.environ.get('RUN_MAIN', None) == "true"
+
+    return True
+
+
 def canAppAccessDatabase(allow_test: bool = False, allow_plugins: bool = False, allow_shell: bool = False):
     """Returns True if the apps.py file can access database records.
 
@@ -65,3 +78,19 @@ def canAppAccessDatabase(allow_test: bool = False, allow_plugins: bool = False,
             return False
 
     return True
+
+
+def isPluginRegistryLoaded():
+    """Ensures that the plugin registry is already loaded.
+
+    The plugin registry reloads all apps onetime after starting if there are AppMixin plugins,
+    so that the discovered AppConfigs are added to Django. This triggers the ready function of
+    AppConfig to execute twice. Add this check to prevent from running two times.
+
+    Note: All apps using this check need to be registered after the plugins app in settings.py
+
+    Returns: 'False' if the registry has not fully loaded the plugins yet.
+    """
+    from plugin import registry
+
+    return registry.plugins_loaded

InvenTree/InvenTree/settings.py

@@ -199,13 +199,13 @@ INSTALLED_APPS = [
     'build.apps.BuildConfig',
     'common.apps.CommonConfig',
     'company.apps.CompanyConfig',
+    'plugin.apps.PluginAppConfig',          # Plugin app runs before all apps that depend on the isPluginRegistryLoaded function
     'label.apps.LabelConfig',
     'order.apps.OrderConfig',
     'part.apps.PartConfig',
     'report.apps.ReportConfig',
     'stock.apps.StockConfig',
     'users.apps.UsersConfig',
-    'plugin.apps.PluginAppConfig',
     'web',
     'generic',
     'InvenTree.apps.InvenTreeConfig',       # InvenTree app runs last

InvenTree/common/tests.py

@@ -879,7 +879,7 @@ class CommonTest(InvenTreeAPITestCase):
         from plugin import registry
 
         # set flag true
-        common.models.InvenTreeSetting.set_setting('SERVER_RESTART_REQUIRED', False, None)
+        common.models.InvenTreeSetting.set_setting('SERVER_RESTART_REQUIRED', True, None)
 
         # reload the app
         registry.reload_plugins()

InvenTree/gunicorn.conf.py

@@ -8,3 +8,6 @@ workers = multiprocessing.cpu_count() * 2 + 1
 
 max_requests = 1000
 max_requests_jitter = 50
+
+# preload app so that the ready functions are only executed once
+preload_app = True

InvenTree/label/apps.py

@@ -12,7 +12,8 @@ from django.conf import settings
 from django.core.exceptions import AppRegistryNotReady
 from django.db.utils import OperationalError
 
-from InvenTree.ready import canAppAccessDatabase
+from InvenTree.ready import (canAppAccessDatabase, isInMainThread,
+                             isPluginRegistryLoaded)
 
 logger = logging.getLogger("inventree")
 
@@ -35,6 +36,10 @@ class LabelConfig(AppConfig):
 
     def ready(self):
         """This function is called whenever the label app is loaded."""
+        # skip loading if plugin registry is not loaded or we run in a background thread
+        if not isPluginRegistryLoaded() or not isInMainThread():
+            return
+
         if canAppAccessDatabase(allow_test=False):
 
             try:

InvenTree/part/apps.py

@@ -5,7 +5,8 @@ import logging
 from django.apps import AppConfig
 from django.db.utils import OperationalError, ProgrammingError
 
-from InvenTree.ready import canAppAccessDatabase, isImportingData
+from InvenTree.ready import (canAppAccessDatabase, isImportingData,
+                             isInMainThread, isPluginRegistryLoaded)
 
 logger = logging.getLogger("inventree")
 
@@ -16,6 +17,10 @@ class PartConfig(AppConfig):
 
     def ready(self):
         """This function is called whenever the Part app is loaded."""
+        # skip loading if plugin registry is not loaded or we run in a background thread
+        if not isPluginRegistryLoaded() or not isInMainThread():
+            return
+
         if canAppAccessDatabase():
             self.update_trackable_status()
             self.reset_part_pricing_flags()

InvenTree/plugin/apps.py

@@ -10,7 +10,7 @@ from django.apps import AppConfig
 
 from maintenance_mode.core import set_maintenance_mode
 
-from InvenTree.ready import canAppAccessDatabase
+from InvenTree.ready import canAppAccessDatabase, isInMainThread
 from plugin import registry
 
 logger = logging.getLogger('inventree')
@@ -23,6 +23,10 @@ class PluginAppConfig(AppConfig):
 
     def ready(self):
         """The ready method is extended to initialize plugins."""
+        # skip loading if we run in a background thread
+        if not isInMainThread():
+            return
+
         if not canAppAccessDatabase(allow_test=True, allow_plugins=True):
             logger.info("Skipping plugin loading sequence")  # pragma: no cover
         else:

InvenTree/plugin/base/integration/AppMixin.py

@@ -46,8 +46,12 @@ class AppMixin:
                         settings.INSTALLED_APPS += [plugin_path]
                         registry.installed_apps += [plugin_path]
                         apps_changed = True
+
             # if apps were changed or force loading base apps -> reload
-            if apps_changed or force_reload:
+            # Ignore reloading if we are in testing mode and apps are unchanged so that tests run faster
+            # registry.reload_plugins(...) first unloads and then loads the plugins
+            # always reload if we are not in testing mode so we can expect the second reload
+            if not settings.TESTING or apps_changed or force_reload:
                 # first startup or force loading of base apps -> registry is prob false
                 if registry.apps_loading or force_reload:
                     registry.apps_loading = False

InvenTree/plugin/registry.py

@@ -11,7 +11,7 @@ import os
 import subprocess
 import time
 from pathlib import Path
-from typing import Dict, List, OrderedDict
+from typing import Any, Dict, List, OrderedDict
 
 from django.apps import apps
 from django.conf import settings
@@ -54,13 +54,14 @@ class PluginsRegistry:
         self.plugins_inactive: Dict[str, InvenTreePlugin] = {}  # List of inactive instances
         self.plugins_full: Dict[str, InvenTreePlugin] = {}      # List of all plugin instances
 
-        self.plugin_modules: List(InvenTreePlugin) = []         # Holds all discovered plugins
-        self.mixin_modules: Dict[str, any] = {}                 # Holds all discovered mixins
+        self.plugin_modules: List[InvenTreePlugin] = []         # Holds all discovered plugins
+        self.mixin_modules: Dict[str, Any] = {}                 # Holds all discovered mixins
 
         self.errors = {}                                        # Holds discovering errors
 
         # flags
         self.is_loading = False                                 # Are plugins being loaded right now
+        self.plugins_loaded = False                             # Marks if the registry fully loaded and all django apps are reloaded
         self.apps_loading = True                                # Marks if apps were reloaded yet
 
         self.installed_apps = []                                # Holds all added plugin_paths
@@ -161,6 +162,9 @@ class PluginsRegistry:
             if full_reload:
                 full_reload = False
 
+        # ensure plugins_loaded is True
+        self.plugins_loaded = True
+
         # Remove maintenance mode
         if not _maintenance:
             set_maintenance_mode(False)
@@ -212,7 +216,9 @@ class PluginsRegistry:
         logger.info('Start reloading plugins')
 
         with maintenance_mode_on():
+            self.plugins_loaded = False
             self.unload_plugins(force_reload=force_reload)
+            self.plugins_loaded = True
             self.load_plugins(full_reload=full_reload)
 
         logger.info('Finished reloading plugins')

InvenTree/report/apps.py

@@ -18,7 +18,12 @@ class ReportConfig(AppConfig):
     def ready(self):
         """This function is called whenever the report app is loaded."""
 
-        from InvenTree.ready import canAppAccessDatabase
+        from InvenTree.ready import (canAppAccessDatabase, isInMainThread,
+                                     isPluginRegistryLoaded)
+
+        # skip loading if plugin registry is not loaded or we run in a background thread
+        if not isPluginRegistryLoaded() or not isInMainThread():
+            return
 
         # Configure logging for PDF generation (disable "info" messages)
         logging.getLogger('fontTools').setLevel(logging.WARNING)

InvenTree/users/apps.py

@@ -5,7 +5,8 @@ import logging
 from django.apps import AppConfig
 from django.db.utils import OperationalError, ProgrammingError
 
-from InvenTree.ready import canAppAccessDatabase
+from InvenTree.ready import (canAppAccessDatabase, isInMainThread,
+                             isPluginRegistryLoaded)
 
 logger = logging.getLogger('inventree')
 
@@ -17,6 +18,11 @@ class UsersConfig(AppConfig):
 
     def ready(self):
         """Called when the 'users' app is loaded at runtime"""
+
+        # skip loading if plugin registry is not loaded or we run in a background thread
+        if not isPluginRegistryLoaded() or not isInMainThread():
+            return
+
         if canAppAccessDatabase(allow_test=True):
 
             try:

docker/gunicorn.conf.py

@@ -37,3 +37,6 @@ logger.info(f"Starting gunicorn server with {workers} workers")
 
 max_requests = 1000
 max_requests_jitter = 50
+
+# preload app so that the ready functions are only executed once
+preload_app = True