Merge pull request #1667 from iainb/enforce-message-size

SNS - Enforce 'Message too long' exception when publishing messages

moto/sns/models.py

@@ -24,6 +24,7 @@ from .utils import make_arn_for_topic, make_arn_for_subscription
 
 DEFAULT_ACCOUNT_ID = 123456789012
 DEFAULT_PAGE_SIZE = 100
+MAXIMUM_MESSAGE_LENGTH = 262144  # 256 KiB
 
 
 class Topic(BaseModel):
@@ -327,6 +328,9 @@ class SNSBackend(BaseBackend):
             # Note that the AWS docs around length are wrong: https://github.com/spulec/moto/issues/1503
             raise ValueError('Subject must be less than 100 characters')
 
+        if len(message) > MAXIMUM_MESSAGE_LENGTH:
+            raise InvalidParameterValue("An error occurred (InvalidParameter) when calling the Publish operation: Invalid parameter: Message too long")
+
         try:
             topic = self.get_topic(arn)
             message_id = topic.publish(message, subject=subject,