How to print Graphene-Django / Graphene-Python Exceptions to the Console for Debugging? - debugging

Question

When a GraphQL Error occurs, I cannot easily know where it occured. I have to spend unnecessary time trying to track it down. How do I get a Traceback printed in the console of my text editor?

Answer 1

I answered my own question by accessing the GraphQL error(s) with result.errors, iterating through the list, and using python's print_tb function to print the Traceback.
Does anyone have a different or better way of doing it?
Example usage of the print_graphql_errors function:
from django.conf.settings import DEBUG
result = schema.execute(
mutation_str, context_value=request, variable_values=variable_values
)
if result.errors is None:
return self.handle_success(result)
if DEBUG:
print_graphql_errors(result.errors)
return self.handle_failure(result)
The print_graphql_errors function:
from traceback import print_tb
from django.conf.settings import DEBUG
def print_graphql_errors(errors, raise_error=False):
if not DEBUG:
raise Exception(
'DevError: This function should not be called in production'
)
assert errors, 'DevError: The "errors" parameter cannot be None'
print_after = []
current_error = None
print('######################################################################')
print('Manually Generated Traceback (with the print_graphql_errors function):')
print(f'There are {len(errors)} errors:')
for i, error in enumerate(errors):
print(f'{i + 1}) ', error)
print('######################################################################')
for error in errors:
current_error = error
# FYI: This object has these attributes: (example attribute values)
# tb_frame <frame at 0x000002DDB844D548, file 'site-packages\\graphql\\execution\\executor.py', line 455, code resolve_or_error>
# tb_lasti 16
# tb_lineno 447
# tb_next <traceback object at 0x000002DDBAFBA388>
# print('error.locations:', error.locations)
# print('error.positions:', error.positions)
try:
print_tb(error.stack)
except AttributeError as e:
print(e.__traceback__)
print(f'Warning: An error occured while trying to print the traceback: {e}. It has the following attributes instead: {dir(error)}')
print_after.append(error)
if len(print_after):
print('###################################################################')
print(f'Number of errors without the "stack" attribute: {len(print_after)}')
print('###################################################################')
if raise_error:
for error in print_after:
raise error
raise current_error