New service to get the `primary workflow` for a workflow_spec, using a workflow_spec_id.

This is necessary because `primary` is a file parameter, not a workflow_spec parameter.

- you can ask a workflow file whether it is primary, but
- you cannot ask a workflow_spec for its primary workflow file

Now, you can use `workflow_service.get_primary_workflow(workflow_spec_id)`

crc/services/workflow_service.py

@@ -22,7 +22,7 @@ from jinja2 import Template
 from crc import db, app
 from crc.api.common import ApiError
 from crc.models.api_models import Task, MultiInstanceType, WorkflowApi
-from crc.models.file import LookupDataModel
+from crc.models.file import LookupDataModel, FileModel
 from crc.models.study import StudyModel
 from crc.models.task_event import TaskEventModel
 from crc.models.user import UserModel, UserModelSchema
@@ -811,3 +811,12 @@ class WorkflowService(object):
     def get_standalone_workflow_specs():
         specs = db.session.query(WorkflowSpecModel).filter_by(standalone=True).all()
         return specs
+
+    @staticmethod
+    def get_primary_workflow(workflow_spec_id):
+        # Returns the FileModel of the primary workflow for a workflow_spec
+        primary = None
+        file = db.session.query(FileModel).filter(FileModel.workflow_spec_id==workflow_spec_id, FileModel.primary==True).first()
+        if file:
+            primary = file
+        return primary