Improve the error messages returned from jinja template processing. Try to find the actual line with an error in it.

crc/api/common.py

@@ -3,6 +3,7 @@ import json
 from SpiffWorkflow import WorkflowException
 from SpiffWorkflow.exceptions import WorkflowTaskExecException
 from flask import g
+from jinja2 import TemplateError
 from werkzeug.exceptions import InternalServerError
 
 from crc import ma, app
@@ -111,8 +112,6 @@ class ApiError(Exception):
             return ApiError.from_task_spec(code, message, exp.sender)
 
 
-
-
 class ApiErrorSchema(ma.Schema):
     class Meta:
         fields = ("code", "message", "workflow_name", "file_name", "task_name", "task_id",

crc/services/workflow_service.py

@@ -1,6 +1,8 @@
 import copy
 import json
 import string
+import sys
+import traceback
 from datetime import datetime
 import random
 import string
@@ -758,12 +760,24 @@ class WorkflowService(object):
 
         try:
             return JinjaService.get_content(raw_doc, spiff_task.data)
-        except jinja2.exceptions.TemplateError as ue:
-            raise ApiError.from_task(code="template_error", message="Error processing template for task %s: %s" %
-                                                          (spiff_task.task_spec.name, str(ue)), task=spiff_task)
+        except jinja2.exceptions.TemplateSyntaxError as tse:
+            error_line = documentation.splitlines()[tse.lineno - 1]
+            raise ApiError.from_task(code="template_error", message="Jinja Template Error:  %s" % str(tse),
+                                     task=spiff_task, line_number=tse.lineno, error_line=error_line)
+        except jinja2.exceptions.TemplateError as te:
+            # Figure out the line number in the template that caused the error.
+            cl, exc, tb = sys.exc_info()
+            line_number = None
+            error_line = None
+            for frameSummary in traceback.extract_tb(tb):
+                if frameSummary.filename == '<template>':
+                    line_number = frameSummary.lineno
+                    error_line = documentation.splitlines()[line_number - 1]
+            raise ApiError.from_task(code="template_error", message="Jinja Template Error: %s" % str(te),
+                                     task=spiff_task, line_number=line_number, error_line=error_line)
         except TypeError as te:
-            raise ApiError.from_task(code="template_error", message="Error processing template for task %s: %s" %
-                                                          (spiff_task.task_spec.name, str(te)), task=spiff_task)
+            raise ApiError.from_task(code="template_error", message="Jinja Template Error: %s" % str(te),
+                                     task=spiff_task)
         except Exception as e:
             app.logger.error(str(e), exc_info=True)
 

tests/test_verify_end_event.py

@@ -13,11 +13,15 @@ class TestValidateEndEvent(BaseTest):
         mock_get.return_value.ok = True
         mock_get.return_value.text = self.protocol_builder_response('study_details.json')
 
-        error_string = """ApiError: Error processing template for task EndEvent_1qvyxg7: expected token 'end of statement block', got '='. In file verify_end_event.bpmn. """
+        error_string = """Jinja Template Error:  expected token 'end of statement block', got '='"""
 
         self.load_example_data()
         spec_model = self.load_test_spec('verify_end_event')
         try:
             WorkflowService.test_spec(spec_model.id)
         except ApiError as e:
-            self.assertEqual(str(e), error_string)
+            self.assertEqual(error_string, e.message)
+            self.assertEqual('template_error', e.code)
+            self.assertEqual(8, e.line_number)
+            self.assertEqual('{%- if value = 1 -%}', e.error_line)
+            self.assertEqual('verify_end_event.bpmn', e.file_name)