SNS topic subscription not deleted on stack remove

[caulagi]

This is a Bug Report

Description

I created a function for handling a SNS event with serverless which created a subscription for the topic. However, when I removed the stack, subscription for the topic was not removed even the topic itself was removed.

$ sls deploy -v
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
CloudFormation - CREATE_IN_PROGRESS - AWS::CloudFormation::Stack - sns-test-dev
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::CloudFormation::Stack - sns-test-dev
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (42.65 KB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
CloudFormation - UPDATE_IN_PROGRESS - AWS::CloudFormation::Stack - sns-test-dev
CloudFormation - CREATE_IN_PROGRESS - AWS::Logs::LogGroup - HelloLogGroup
CloudFormation - CREATE_IN_PROGRESS - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_IN_PROGRESS - AWS::Logs::LogGroup - HelloLogGroup
CloudFormation - CREATE_IN_PROGRESS - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_COMPLETE - AWS::Logs::LogGroup - HelloLogGroup
CloudFormation - CREATE_COMPLETE - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Function - HelloLambdaFunction
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Function - HelloLambdaFunction
CloudFormation - CREATE_COMPLETE - AWS::Lambda::Function - HelloLambdaFunction
CloudFormation - CREATE_IN_PROGRESS - AWS::SNS::Topic - SNSTopicSnstest
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Permission - HelloLambdaPermissionSnstestSNS
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Permission - HelloLambdaPermissionSnstestSNS
CloudFormation - CREATE_IN_PROGRESS - AWS::SNS::Topic - SNSTopicSnstest
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Version - HelloLambdaVersionZRo1gUAuiOGK2Tn3fYC2kBJieXvghZe1LXK15Z1afM
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Version - HelloLambdaVersionZRo1gUAuiOGK2Tn3fYC2kBJieXvghZe1LXK15Z1afM
CloudFormation - CREATE_COMPLETE - AWS::Lambda::Version - HelloLambdaVersionZRo1gUAuiOGK2Tn3fYC2kBJieXvghZe1LXK15Z1afM
CloudFormation - CREATE_COMPLETE - AWS::Lambda::Permission - HelloLambdaPermissionSnstestSNS
CloudFormation - CREATE_COMPLETE - AWS::SNS::Topic - SNSTopicSnstest
CloudFormation - UPDATE_COMPLETE_CLEANUP_IN_PROGRESS - AWS::CloudFormation::Stack - sns-test-dev
CloudFormation - UPDATE_COMPLETE - AWS::CloudFormation::Stack - sns-test-dev
Serverless: Stack update finished...
Service Information
service: sns-test
stage: dev
region: us-east-1
stack: sns-test-dev
api keys:
  None
endpoints:
  None
functions:
  hello: sns-test-dev-hello

Stack Outputs
HelloLambdaFunctionQualifiedArn: arn:aws:lambda:us-east-1:<redacted>:function:sns-test-dev-hello:2
ServerlessDeploymentBucketName: sns-test-dev-serverlessdeploymentbucket-12mrob9jpkila

$ sls remove -v
Serverless: Getting all objects in S3 bucket...
Serverless: Removing objects in S3 bucket...
Serverless: Removing Stack...
Serverless: Checking Stack removal progress...
CloudFormation - DELETE_IN_PROGRESS - AWS::CloudFormation::Stack - sns-test-dev
CloudFormation - DELETE_IN_PROGRESS - AWS::SNS::Topic - SNSTopicSnstest
CloudFormation - DELETE_SKIPPED - AWS::Lambda::Version - HelloLambdaVersionZRo1gUAuiOGK2Tn3fYC2kBJieXvghZe1LXK15Z1afM
CloudFormation - DELETE_IN_PROGRESS - AWS::Lambda::Permission - HelloLambdaPermissionSnstestSNS
CloudFormation - DELETE_COMPLETE - AWS::SNS::Topic - SNSTopicSnstest
Serverless: Stack removal finished...

What went wrong?

SNS subscription was not removed.

What was the config you used?

service: sns-test

provider:
  name: aws
  runtime: nodejs8.10

functions:
  hello:
    handler: handler.hello
    events:
        - sns: sns-test

Additional Data

• Serverless Framework Version you're using: 1.28.0
• Operating System:
• Stack Trace:
• Provider Error messages:

[aalvrz]

I can confirm this behavior. No topic subscriptions get deleted when running serverless remove.

[hlgr360]

Same here - SNS subscriptions are not removed upon 'serverless remove'. I have a SQS queue subscribed to a SNS topic

SnsDispatch:
  Type: AWS::SNS::Topic
  DependsOn: 
    - QueueMgmt      
  Properties: 
    TopicName: acdmgmt
    DisplayName: acdmgmt
    Subscription:
      - Endpoint:
          Fn::GetAtt:
            - QueueMgmt
            - Arn
        Protocol: "sqs"

[walery]

When you delete a topic, subscriptions to the topic will not be "deleted" immediately, but become orphans. SNS will periodically clean these orphans, usually every 10 hours, but not guaranteed.

Source: https://forums.aws.amazon.com/thread.jspa?threadID=219168

Because of this, I believe this ticket can be closed.

[caulagi]

Thanks @walery!

[reegz]

When you delete a topic, subscriptions to the topic will not be "deleted" immediately, but become orphans. SNS will periodically clean these orphans, usually every 10 hours, but not guaranteed.

Source: https://forums.aws.amazon.com/thread.jspa?threadID=219168

Because of this, I believe this ticket can be closed.

Hi @walery ,

I've not seen this behaviour over a period of a few days. Is there any way to force a cleanup?

Thanks

[walery]

I've not seen this behaviour over a period of a few days.

Hmm. This works for me. That's why update the ticket.

Is there any way to force a cleanup?

I think then only manual way. I'm sorry, I can't give you better answer...

[cnh57811]

I experienced this same issue and was able to resolve it by structuring my resources slightly differently. My subscriptions were not being deleted upon a sls remove when my subscription was 'inlined' with the Topic resource:

  subsDoNotDeleteTopic:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: subs-do-not-delete
      Subscription:
        - Endpoint: +12345678900
          Protocol: sms

However, when I removed the 'inline' subscription from under the Topic resource and created a separate Subscription resource that then referenced the Topic resource, the sls remove worked as expected and deleted the subscription.

  workingTopic:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: subs-delete-correctly

  workingSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint: +12345678999
      Protocol: sms
      TopicArn:
        Ref: workingTopic