The unclearly documented error exceptions of Boto3 (Python) DynamoDB - e.g. ConditionalCheckFailedException

conditional_check_fail.py

from botocore import exceptions


try:
 # to update table conditionally
 
except exceptions.ClientError as e:
            if e.response['Error']['Code'] == 'ConditionalCheckFailedException':
                print("ConditionalCheckFailedException detected")
                # do something else, like raise a custom error based on the condition
                raise DocDoesNotExistError("dang it!")


# Possible custom error response
class DocDoesNotExistError(Exception):
    """Generic exception class for API _errors_"""
    def __init__(self, msg, original_exception=None):
        if original_exception:
            self.message = "DocDoesNotExistError: " + msg + (": %s" % original_exception)
        else:
            self.message = "DocDoesNotExistError: " + msg
        super(DocDoesNotExistError, self).__init__(self.message)
        self.original_exception = original_exception