boto/boto — pull request #1414 by phobologic (2013-03-28 21:35:16+00:00)
Title: Make subscribe_sqs_queue idempotent

This patch changes the sid from being a random UUID4 string to an md5
hash of the combined topic & queue ARN. Since the Sid is now a known
value we can check to see if a Statement with the given Sid already
exists. If it does, do not add it again.

The reason for this is that as subscribe_sqs_queue is it isn't
idempotent. It will add the same statement (with a new Sid) repeatedly
until you hit the limits of the SQS Policy (20 statements, 8192 bytes).