Plugin sequence fix (#10057)

* Fix error message

* Add registry ready flag

* Add is_ready func

* Cleaner init code

* Protect against plugin access until ready

* Add decorator for registry entrypoint funcs

* Tweak return value

* Only add plugin URLs if registry is ready

* Fix load logic

* Refactor @registry_entrypoint decorator

* Tweak

* Typing

* Reimplement is_ready property

src/backend/InvenTree/InvenTree/apps.py

@@ -9,7 +9,7 @@ from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.core.exceptions import AppRegistryNotReady
 from django.db import transaction
-from django.db.utils import IntegrityError, OperationalError
+from django.db.utils import IntegrityError
 
 import structlog
 from allauth.socialaccount.signals import social_account_updated
@@ -65,7 +65,8 @@ class InvenTreeConfig(AppConfig):
             self.start_background_tasks()
 
             if not InvenTree.ready.isInTestMode():  # pragma: no cover
-                self.update_exchange_rates()
+                # Update exchange rates
+                InvenTree.tasks.offload_task(InvenTree.tasks.update_exchange_rates)
                 # Let the background worker check for migrations
                 InvenTree.tasks.offload_task(InvenTree.tasks.check_for_migrations)
 
@@ -179,6 +180,8 @@ class InvenTreeConfig(AppConfig):
                 InvenTree.tasks.offload_task(
                     InvenTree.tasks.heartbeat, force_async=True, group='heartbeat'
                 )
+        except AppRegistryNotReady:  # pragma: no cover
+            pass
         except Exception:
             pass
 
@@ -194,63 +197,6 @@ class InvenTreeConfig(AppConfig):
                 except Exception as e:  # pragma: no cover
                     logger.exception('Error loading tasks for %s: %s', app_name, e)
 
-    def update_exchange_rates(self):  # pragma: no cover
-        """Update exchange rates each time the server is started.
-
-        Only runs *if*:
-        a) Have not been updated recently (one day or less)
-        b) The base exchange rate has been altered
-        """
-        try:
-            from djmoney.contrib.exchange.models import ExchangeBackend
-
-            from common.currency import currency_code_default
-            from InvenTree.tasks import update_exchange_rates
-        except AppRegistryNotReady:  # pragma: no cover
-            pass
-
-        base_currency = currency_code_default()
-
-        update = False
-
-        try:
-            backend = ExchangeBackend.objects.filter(name='InvenTreeExchange')
-
-            if backend.exists():
-                backend = backend.first()
-
-                last_update = backend.last_update
-
-                if last_update is None:
-                    # Never been updated
-                    logger.info('Exchange backend has never been updated')
-                    update = True
-
-                # Backend currency has changed?
-                if base_currency != backend.base_currency:
-                    logger.info(
-                        'Base currency changed from %s to %s',
-                        backend.base_currency,
-                        base_currency,
-                    )
-                    update = True
-
-        except ExchangeBackend.DoesNotExist:
-            logger.info('Exchange backend not found - updating')
-            update = True
-
-        except Exception:
-            # Some other error - potentially the tables are not ready yet
-            return
-
-        if update:
-            try:
-                update_exchange_rates()
-            except OperationalError:
-                logger.warning('Could not update exchange rates - database not ready')
-            except Exception as e:
-                logger.exception('Error updating exchange rates: %s (%s)', e, type(e))
-
     def update_site_url(self):
         """Update the site URL setting.
 

src/backend/InvenTree/common/currency.py

@@ -15,12 +15,14 @@ import InvenTree.helpers
 logger = structlog.get_logger('inventree')
 
 
-def currency_code_default():
+def currency_code_default(create: bool = True):
     """Returns the default currency code (or USD if not specified)."""
     from common.settings import get_global_setting
 
     try:
-        code = get_global_setting('INVENTREE_DEFAULT_CURRENCY', create=True, cache=True)
+        code = get_global_setting(
+            'INVENTREE_DEFAULT_CURRENCY', create=create, cache=True
+        )
     except Exception:  # pragma: no cover
         # Database may not yet be ready, no need to throw an error here
         code = ''

src/backend/InvenTree/plugin/apps.py

@@ -32,23 +32,11 @@ class PluginAppConfig(AppConfig):
         else:
             logger.info('Loading InvenTree plugins')
 
-            if not registry.is_loading:
+            if not registry.is_ready:
-                # this is the first startup
+                # Mark the registry as ready
-                try:
+                # This ensures that other apps cannot access the registry before it is fully initialized
-                    from common.models import InvenTreeSetting
+                logger.info('Plugin registry is ready - performing initial load')
-
+                registry.set_ready()
-                    if InvenTreeSetting.get_setting(
-                        'PLUGIN_ON_STARTUP', create=False, cache=False
-                    ):
-                        # make sure all plugins are installed
-                        registry.install_plugin_file()
-                except Exception:  # pragma: no cover
-                    pass
-
-                # Perform a full reload of the plugin registry
-                registry.reload_plugins(
-                    full_reload=True, force_reload=True, collect=True
-                )
 
                 # drop out of maintenance
                 # makes sure we did not have an error in reloading and maintenance is still active

src/backend/InvenTree/plugin/registry.py

@@ -4,6 +4,7 @@
 - Manages setup and teardown of plugin class instances
 """
 
+import functools
 import importlib
 import importlib.util
 import os
@@ -43,6 +44,37 @@ from .plugin import InvenTreePlugin
 logger = structlog.get_logger('inventree')
 
 
+def registry_entrypoint(check_reload: bool = True, default_value: Any = None) -> Any:
+    """Function decorator for registry entrypoints methods.
+
+    - Ensure that the registry is ready before calling the method.
+    - Check if the registry needs to be reloaded.
+    """
+
+    def decorator(method):
+        """Decorator to ensure registry is ready before calling the method."""
+
+        @functools.wraps(method)
+        def wrapper(self, *args, **kwargs):
+            """Wrapper function to ensure registry is ready."""
+            if not self.ready:
+                logger.warning(
+                    "Plugin registry is not ready - cannot call method '%s'",
+                    method.__name__,
+                )
+                return default_value
+
+            # Check if the registry needs to be reloaded
+            if check_reload:
+                self.check_reload()
+
+            return method(self, *args, **kwargs)
+
+        return wrapper
+
+    return decorator
+
+
 class PluginsRegistry:
     """The PluginsRegistry class."""
 
@@ -68,6 +100,8 @@ class PluginsRegistry:
         'parameter-exporter',
     ]
 
+    ready: bool
+
     def __init__(self) -> None:
         """Initialize registry.
 
@@ -82,6 +116,8 @@ class PluginsRegistry:
             str, InvenTreePlugin
         ] = {}  # List of all plugin instances
 
+        self.ready = False  # Marks if the registry is ready to be used
+
         # Keep an internal hash of the plugin registry state
         self.registry_hash = None
 
@@ -100,11 +136,35 @@ class PluginsRegistry:
 
         self.installed_apps = []  # Holds all added plugin_paths
 
+    def set_ready(self):
+        """Set the registry as ready to be used.
+
+        This method should only be called once per application start,
+        after all apps have been loaded and the registry is fully initialized.
+        """
+        from common.models import InvenTreeSetting
+
+        self.ready = True
+
+        # Install plugins from file (if required)
+        if InvenTreeSetting.get_setting('PLUGIN_ON_STARTUP', create=False, cache=False):
+            # make sure all plugins are installed
+            registry.install_plugin_file()
+
+        # Perform initial plugin discovery
+        self.reload_plugins(full_reload=True, force_reload=True, collect=True)
+
+    @property
+    def is_ready(self) -> bool:
+        """Return True if the plugin registry is ready to be used."""
+        return self.ready
+
     @property
     def is_loading(self) -> bool:
         """Return True if the plugin registry is currently loading."""
         return self.loading_lock.locked()
 
+    @registry_entrypoint()
     def get_plugin(
         self, slug: str, active: bool = True, with_mixin: Optional[str] = None
     ) -> InvenTreePlugin:
@@ -118,9 +178,6 @@ class PluginsRegistry:
         Returns:
             InvenTreePlugin or None: The plugin instance if found, otherwise None.
         """
-        # Check if the registry needs to be reloaded
-        self.check_reload()
-
         if slug not in self.plugins:
             logger.warning("Plugin registry has no record of plugin '%s'", slug)
             return None
@@ -169,6 +226,7 @@ class PluginsRegistry:
 
         return cfg
 
+    @registry_entrypoint()
     def set_plugin_state(self, slug: str, state: bool):
         """Set the state(active/inactive) of a plugin.
 
@@ -176,9 +234,6 @@ class PluginsRegistry:
             slug (str): Plugin slug
             state (bool): Plugin state - true = active, false = inactive
         """
-        # Check if the registry needs to be reloaded
-        self.check_reload()
-
         if slug not in self.plugins_full:
             logger.warning("Plugin registry has no record of plugin '%s'", slug)
             return
@@ -190,6 +245,7 @@ class PluginsRegistry:
         # Update the registry hash value
         self.update_plugin_hash()
 
+    @registry_entrypoint()
     def call_plugin_function(self, slug: str, func: str, *args, **kwargs):
         """Call a member function (named by 'func') of the plugin named by 'slug'.
 
@@ -198,9 +254,6 @@ class PluginsRegistry:
 
         Instead, any error messages are returned to the worker.
         """
-        # Check if the registry needs to be reloaded
-        self.check_reload()
-
         raise_error = kwargs.pop('raise_error', True)
 
         plugin = self.get_plugin(slug)
@@ -220,6 +273,8 @@ class PluginsRegistry:
         return plugin_func(*args, **kwargs)
 
     # region registry functions
+
+    @registry_entrypoint(default_value=[])
     def with_mixin(
         self, mixin: str, active: bool = True, builtin: Optional[bool] = None
     ) -> list[InvenTreePlugin]:
@@ -230,9 +285,6 @@ class PluginsRegistry:
             active (bool, optional): Filter by 'active' status of plugin. Defaults to True.
             builtin (bool, optional): Filter by 'builtin' status of plugin. Defaults to None.
         """
-        # Check if the registry needs to be loaded
-        self.check_reload()
-
         mixin = str(mixin).lower().strip()
 
         result = []
@@ -304,6 +356,7 @@ class PluginsRegistry:
 
         logger.info('Finished unloading plugins')
 
+    @registry_entrypoint(check_reload=False)
     def reload_plugins(
         self,
         full_reload: bool = False,
@@ -369,7 +422,7 @@ class PluginsRegistry:
             logger.info('Plugin Registry: Loaded %s plugins', len(self.plugins))
 
         except Exception as e:
-            logger.exception('Expected error during plugin reload: %s', e)
+            logger.exception('Unexpected error during plugin reload: %s', e)
             log_error('reload_plugins', scope='plugins')
 
         finally:
@@ -900,6 +953,7 @@ class PluginsRegistry:
 
         return str(data.hexdigest())
 
+    @registry_entrypoint(default_value=False, check_reload=False)
     def check_reload(self):
         """Determine if the registry needs to be reloaded.
 

src/backend/InvenTree/plugin/urls.py

@@ -18,28 +18,32 @@ def get_plugin_urls():
 
     urls = []
 
-    if get_global_setting('ENABLE_PLUGINS_URL', False) or settings.PLUGIN_TESTING_SETUP:
+    if registry.is_ready:
-        for plugin in registry.with_mixin(PluginMixinEnum.URLS):
+        if (
-            try:
+            get_global_setting('ENABLE_PLUGINS_URL', False)
-                if plugin_urls := plugin.urlpatterns:
+            or settings.PLUGIN_TESTING_SETUP
-                    # Check if the plugin has a custom URL pattern
+        ):
-                    for url in plugin_urls:
+            for plugin in registry.with_mixin(PluginMixinEnum.URLS):
-                        # Attempt to resolve against the URL pattern as a validation check
+                try:
-                        try:
+                    if plugin_urls := plugin.urlpatterns:
-                            url.resolve('')
+                        # Check if the plugin has a custom URL pattern
-                        except Resolver404:
+                        for url in plugin_urls:
-                            pass
+                            # Attempt to resolve against the URL pattern as a validation check
+                            try:
+                                url.resolve('')
+                            except Resolver404:
+                                pass
 
-                    urls.append(
+                        urls.append(
-                        re_path(
+                            re_path(
-                            f'^{plugin.slug}/',
+                                f'^{plugin.slug}/',
-                            include((plugin_urls, plugin.slug)),
+                                include((plugin_urls, plugin.slug)),
-                            name=plugin.slug,
+                                name=plugin.slug,
+                            )
                         )
-                    )
+                except Exception:
-            except Exception:
+                    log_error('get_plugin_urls', plugin=plugin.slug)
-                log_error('get_plugin_urls', plugin=plugin.slug)
+                    continue
-                continue
 
     # Redirect anything else to the root index
     urls.append(