connecting relationships with signals

atdb/taskdatabase/models.py

@@ -21,8 +21,9 @@ class Task(models.Model):
     task_type = models.CharField(max_length=20, default="task")
 
     # note: the apparent naming reversal is intentional. Predecessors are somebody elses successors.
-    predecessors = models.ForeignKey('self', related_name='task_successors', on_delete=models.SET_NULL, null=True,blank=True)
-    successors = models.ForeignKey('self', related_name='task_predecessors', on_delete=models.SET_NULL, null=True,blank=True)
+    desired_predecessor_id = models.CharField(max_length=12, blank=True, null=True)
+    predecessor = models.ForeignKey('self', related_name='task_successors', on_delete=models.SET_NULL, null=True,blank=True)
+    successor = models.ForeignKey('self', related_name='task_predecessors', on_delete=models.SET_NULL, null=True,blank=True)
 
     workflow = models.ForeignKey(Workflow, related_name='tasks', on_delete=models.SET_NULL, null=True)
 

atdb/taskdatabase/serializers.py

@@ -12,10 +12,10 @@ class TaskSerializer(serializers.ModelSerializer):
     class Meta:
         model = Task
         fields = ('id','task_type','taskID',
-                  'predecessors','successors',
+                  'desired_predecessor_id','predecessor','successor',
                   'project','sas_id','priority','purge_policy','skip',
                   'desired_workflow_id','desired_workflow_uri','workflow',
-                  'status','desired_status','desired_workflow_uri',
+                  'status','desired_status',
                   'inputs','outputs','status_history')
 
 

atdb/taskdatabase/services/signals.py

@@ -34,6 +34,46 @@ def pre_save_task_handler(sender, **kwargs):
     handle_pre_save(sender, **kwargs)
 
 
+def add_workflow(myTaskObject):
+    desired_workflow_id = myTaskObject.desired_workflow_id
+    desired_workflow_uri = myTaskObject.desired_workflow_uri
+
+    # first try to find the workflow by desired workflow_id
+    try:
+        desired_workflow = Workflow.objects.get(id=desired_workflow_id)
+    except:
+        desired_workflow = None
+
+    if (desired_workflow == None):
+        # then try workflow_uri
+        desired_workflow = Workflow.objects.get(workflow_uri=desired_workflow_uri)
+
+    # first check if works needs to be done at all
+    if (myTaskObject.workflow != desired_workflow):
+        # set the new status
+        myTaskObject.workflow = desired_workflow
+
+    return myTaskObject
+
+
+def add_predecessor(myTaskObject):
+    # connect the task to a workflow after posting a (flat) task through the REST API
+
+    try:
+        desired_predecessor_id = myTaskObject.desired_predecessor_id
+
+        # first try to find the workflow by desired workflow_id
+        desired_predecessor = Task.objects.get(id=desired_predecessor_id)
+
+        if (myTaskObject.predecessor != desired_predecessor):
+            # set the new status
+            myTaskObject.predecessor = desired_predecessor
+    except:
+        pass
+
+    return myTaskObject
+
+
 def handle_pre_save(sender, **kwargs):
     """
     pre_save handler. Mainly to check status changes and dispatch jobs in needed.
@@ -61,19 +101,9 @@ def handle_pre_save(sender, **kwargs):
         myStatus.save()
 
     # connect the task to a workflow after posting a (flat) task through the REST API
-    desired_workflow_id = myTaskObject.desired_workflow_id
-    desired_workflow_uri = myTaskObject.desired_workflow_uri
+    myTaskObject = add_workflow(myTaskObject)
+    myTaskObject = add_predecessor(myTaskObject)
 
-    # first try to find the workflow by desired workflow_id
-    desired_workflow = Workflow.objects.get(id=desired_workflow_id)
-    if (desired_workflow == None):
-        # then try workflow_uri
-        desired_workflow = Workflow.objects.get(uri=desired_workflow_uri)
-
-    # first check if works needs to be done at all
-    if (myTaskObject.workflow != desired_workflow):
-        # set the new status
-        myTaskObject.workflow = desired_workflow
 
     # temporarily disconnect the post_save handler to save the dataproduct (again) and avoiding recursion.
     # I don't use pre_save, because then the 'created' key is not available, which is the most handy way to