feat(backend): add signal for currency change (#13207)

* feat(backend): add signal for currency change

* fix receiver

src/backend/InvenTree/InvenTree/tasks.py

@@ -19,6 +19,7 @@ from django.core.management import call_command
 from django.db import DEFAULT_DB_ALIAS, connections, transaction
 from django.db.migrations.executor import MigrationExecutor
 from django.db.utils import NotSupportedError, OperationalError, ProgrammingError
+from django.dispatch import receiver
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 
@@ -32,6 +33,7 @@ from maintenance_mode.core import (
 from opentelemetry import trace
 
 from common.settings import get_global_setting, set_global_setting
+from common.signals import post_currency_change
 from plugin import registry
 
 from .version import isInvenTreeUpToDate
@@ -1095,6 +1097,12 @@ def update_exchange_rates(force: bool = False):
         logger.exception('Error updating exchange rates: %s', type(e))
 
 
+@receiver(post_currency_change, dispatch_uid='receive_update_exchange_rates')
+def receive_update_exchange_rates(*args, **kwargs):
+    """Trigger exchange rate update."""
+    update_exchange_rates(True)
+
+
 @tracer.start_as_current_span('run_backup')
 @scheduled_task(ScheduledTask.DAILY)
 def run_backup():

src/backend/InvenTree/common/currency.py

@@ -12,6 +12,7 @@ from moneyed import CURRENCIES
 
 import InvenTree.helpers
 import InvenTree.ready
+from common.signals import post_currency_change
 
 logger = structlog.get_logger('inventree')
 
@@ -99,24 +100,14 @@ def after_change_currency(setting) -> None:
     - Update exchange rates
     - Recalculate prices for all parts
     """
-    import InvenTree.ready
-    import InvenTree.tasks
-
     if InvenTree.ready.isImportingData():
         return
 
     if not InvenTree.ready.canAppAccessDatabase():
         return
 
-    from part import tasks as part_tasks
-
-    # Immediately update exchange rates
-    InvenTree.tasks.update_exchange_rates(force=True)
-
-    # Offload update of part prices to a background task
-    InvenTree.tasks.offload_task(
-        part_tasks.check_missing_pricing, force_async=True, group='pricing'
-    )
+    # trigger signal
+    post_currency_change.send(setting)
 
 
 def validate_currency_codes(value):

src/backend/InvenTree/common/signals.py

@@ -0,0 +1,9 @@
+"""Signals for InvenTree actions.
+
+These should be used slectevily, mostly to avoid circular imports and tight coupeling with modular/extensible parts of the codebase.
+"""
+
+from django.dispatch import Signal
+
+post_currency_change = Signal()
+"""Send after the default currency was changed."""

src/backend/InvenTree/part/tasks.py

@@ -5,6 +5,7 @@ from typing import Optional
 
 from django.core.exceptions import ValidationError
 from django.db.models import Model
+from django.dispatch import receiver
 from django.utils.translation import gettext_lazy as _
 
 import structlog
@@ -15,6 +16,7 @@ import common.notifications
 import InvenTree.helpers
 import InvenTree.helpers_model
 from common.settings import get_global_setting
+from common.signals import post_currency_change
 from InvenTree.tasks import (
     ScheduledTask,
     batch_offload_tasks,
@@ -314,6 +316,12 @@ def check_missing_pricing(limit=250):
                 pricing.schedule_for_update()
 
 
+@receiver(post_currency_change, dispatch_uid='dispatch_check_missing_pricing')
+def dispatch_check_missing_pricing(*args, **kwargs):
+    """Trigger pricing update."""
+    offload_task(check_missing_pricing, force_async=True, group='pricing')
+
+
 @tracer.start_as_current_span('scheduled_stocktake_reports')
 @scheduled_task(ScheduledTask.DAILY)
 def scheduled_stocktake_reports():