I am creating S3, SQS, and KMS resources using aws cdk. I enabled encryption on the S3 and SQS resources. When I enabled the notification from S3 to SQS, I am getting a circular dependency error. When I remove the KMS settings from my code, it works.
GitHub repo: https://github.com/techcoderunner/s3-sqs-kms-sample
from aws_cdk import aws_kms as kms
from aws_cdk import aws_s3 as s3
from aws_cdk import aws_sqs as sqs
from aws_cdk import aws_s3_notifications as s3notif
kms_key = kms.Key(self, 'ssl_s3_sqs_kms_key',
alias='sslS3SqsKmsKey',
description='This is kms key',
enabled=True,
enable_key_rotation=True,
policy=kms_policy_document,
)
# Create the S3 bucket
bucket = s3.Bucket(
self, "ssl_s3_bucket_raw_kms",
bucket_name="ssl-s3-bucket-kms-raw",
encryption=s3.BucketEncryption.KMS,
encryption_key=kms_key,
)
# Create the SQS queue
queue = sqs.Queue(
self, "ssl_sqs_event_queue",
queue_name="ssl-sqs-kms-event-queue",
encryption=sqs.QueueEncryption.KMS,
encryption_master_key=kms_key,
)
# Create S3 notification object which points to SQS
notification = s3notif.SqsDestination(queue)
filter1 = s3.NotificationKeyFilter(prefix="home/")
# Attach notificaton event to S3 bucket
bucket.add_event_notification(s3.EventType.OBJECT_CREATED,notification,filter1)
I opened a GitHub bug report for this.
It looks like the root problem is that the following condition is added to the KMS key:
CDK output template ssls3sqskmskey83E47315.Properties.KeyPolicy.Statement[1]:
{
"Action": [
"kms:Decrypt",
"kms:Encrypt",
"kms:ReEncrypt*",
"kms:GenerateDataKey*"
],
"Condition": {
"ArnLike": {
"aws:SourceArn": {
"Fn::GetAtt": [
"ssls3bucketrawkms4B1E1122",
"Arn"
]
}
}
},
},
The S3 bucket depends on the KMS key for encryption, and the KMS key has a condition that depends on the S3 bucket.
I was able to deploy the stack after using escape hatches to delete the condition:
# Delete the circular reference
cfn_kms_key = kms_key.node.default_child
cfn_kms_key.add_property_deletion_override("KeyPolicy.Statement.1")