Merge pull request #1858 from eeintech/exchange_rate_task

Exchange rate as worker task

InvenTree/InvenTree/tasks.py

@@ -51,11 +51,14 @@ def schedule_task(taskname, **kwargs):
         pass
 
 
-def offload_task(taskname, *args, **kwargs):
+def offload_task(taskname, force_sync=False, *args, **kwargs):
     """
-    Create an AsyncTask.
-    This is different to a 'scheduled' task,
-    in that it only runs once!
+        Create an AsyncTask if workers are running.
+        This is different to a 'scheduled' task,
+        in that it only runs once!
+
+        If workers are not running or force_sync flag
+        is set then the task is ran synchronously.
     """
 
     try:
@@ -63,10 +66,48 @@ def offload_task(taskname, *args, **kwargs):
     except (AppRegistryNotReady):
         logger.warning("Could not offload task - app registry not ready")
         return
+    import importlib
+    from InvenTree.status import is_worker_running
 
-    task = AsyncTask(taskname, *args, **kwargs)
+    if is_worker_running() and not force_sync:
+        # Running as asynchronous task
+        try:
+            task = AsyncTask(taskname, *args, **kwargs)
+            task.run()
+        except ImportError:
+            logger.warning(f"WARNING: '{taskname}' not started - Function not found")
+    else:
+        # Split path
+        try:
+            app, mod, func = taskname.split('.')
+            app_mod = app + '.' + mod
+        except ValueError:
+            logger.warning(f"WARNING: '{taskname}' not started - Malformed function path")
+            return
 
-    task.run()
+        # Import module from app
+        try:
+            _mod = importlib.import_module(app_mod)
+        except ModuleNotFoundError:
+            logger.warning(f"WARNING: '{taskname}' not started - No module named '{app_mod}'")
+            return
+
+        # Retrieve function
+        try:
+            _func = getattr(_mod, func)
+        except AttributeError:
+            # getattr does not work for local import
+            _func = None
+
+        try:
+            if not _func:
+                _func = eval(func)
+        except NameError:
+            logger.warning(f"WARNING: '{taskname}' not started - No function named '{func}'")
+            return
+        
+        # Workers are not running: run it as synchronous task
+        _func()
 
 
 def heartbeat():

InvenTree/InvenTree/views.py

@@ -31,8 +31,6 @@ from stock.models import StockLocation, StockItem
 from common.models import InvenTreeSetting, ColorTheme
 from users.models import check_user_role, RuleSet
 
-import InvenTree.tasks
-
 from .forms import DeleteForm, EditUserForm, SetPasswordForm
 from .forms import SettingCategorySelectForm
 from .helpers import str2bool
@@ -827,8 +825,13 @@ class CurrencyRefreshView(RedirectView):
         On a POST request we will attempt to refresh the exchange rates
         """
 
-        # Will block for a little bit
-        InvenTree.tasks.update_exchange_rates()
+        from InvenTree.tasks import offload_task
+
+        # Define associated task from InvenTree.tasks list of methods
+        taskname = 'InvenTree.tasks.update_exchange_rates'
+
+        # Run it
+        offload_task(taskname, force_sync=True)
 
         return redirect(reverse_lazy('settings'))