Background post save: wait for not commited object

1 files changed, 16 insertions, 5 deletions

diff --git a/ishtar_common/utils.py b/ishtar_common/utils.py
index 641fbd156..d22a89916 100644
--- a/ishtar_common/utils.py
+++ b/ishtar_common/utils.py
@@ -36,6 +36,7 @@ import six
 import subprocess
 import sys
 import tempfile
+import time
 import xmltodict
 import zipfile
 
@@ -418,9 +419,18 @@ def deserialize_args_for_tasks(sender, kwargs, extra_kwargs=None):
     if not isinstance(sender, (tuple, list)):  # not task
         return sender, kwargs["instance"]
     sender = apps.get_model(*sender)
-    try:
-        instance = sender.objects.get(pk=kwargs['instance'])
-    except sender.DoesNotExist:
+    instance = None
+    retried = 0
+    # object can be in cache of another thread but not yet commited
+    # waiting for it
+    while not instance and retried < 6:
+        if retried:
+            time.sleep(.5)
+        if sender.objects.filter(pk=kwargs['instance']).count():
+            instance = sender.objects.get(pk=kwargs['instance'])
+        else:
+            retried += 1
+    if not instance:
         return sender, None  # object is not here anymore
     if extra_kwargs:
         for kw in extra_kwargs:
@@ -456,7 +466,9 @@ def cached_label_changed(sender, **kwargs):
     #     return
     # cache.set(cache_key, True, settings.CACHE_TASK_TIMEOUT)
 
-    if not settings.USE_BACKGROUND_TASK:
+    if not settings.USE_BACKGROUND_TASK or not instance.pk \
+            or not sender.objects.filter(pk=instance.pk).count():
+        # no background task or not yet fully saved
         return _cached_label_changed(sender, **kwargs)
 
     if getattr(instance, "_cascade_change", False):
@@ -474,7 +486,6 @@ def _cached_label_changed(sender, **kwargs):
     if not instance:
         return
     force_update = kwargs.get('force_update', False)
-
     if hasattr(instance, "need_update") and instance.need_update:
         force_update = True
         instance.skip_history_when_saving = True