weekly misc items: November 16, 2020

Invalid parameter: TopicArn (Service: AmazonSNS; Status Code: 400; Error Code: InvalidParameter; Request ID: <request-id>; Proxy: null)

learned that if you provide the wrong topic ARN, it can cause this error.

we are using python’s troposphere library to help build cloudformation templates. i was trying to create a new queue to subscribe to a topic. we have our own code that wraps the troposphere functionality, but essentially using troposphere’s Template, did something like this:

# create the topic
jbhunt_topic = template.add_resource(
TopicName=<troposphere-join-object>, # resource display name

and the queue:

# create the queue
jbhunt_topic_queue = template.add_resource(
TopicName=<troposphere-join-object>, # resource display name

i had the wrong topic arn here:

# create the subscription

2. trying to create and event notification for a prefix in s3, where messages will get sent to sqs. i try to specify destination using Choose from your SQS queues

but i get this error:

Unable to validate the following destination configurations

turns out i need to add an Access policy in the queue properties to allow s3 access to this queue:

"Version": "2012-10-17",
"Id": "arn:aws:sqs:<region>:<account_id>:<queue-name>/SQSDefaultPolicy",
"Statement": [
"Sid": "<sid-id>",
"Effect": "Allow",
"Principal": {
"Service": "s3.amazonaws.com"
"Action": [
"Resource": "arn:aws:sqs:<region>:<account_id>:<queue-name>",
"Condition": {
"ArnLike": {
"aws:SourceArn": "arn:aws:s3:*:*:<bucket name>"

there is a policy generator you can use AWS Policy Generator to help with this:



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