Error creating lambda to invoke from SNS Topic events in different region

1
votes

I am trying to create a lambda function which can be invoked from SNS Topic events in the different region. My lambda is in EU-WEST-1 and the SNS Topic to be subscribed to is in EU-CENTRAL-1.

I am using the Serverless framework to deploy lambda. If I try to subscribe to a topic in the same region, it works successfully. But when I try to subscribe to a topic in a different region, I am getting error "Invalid parameter - TopicArn".

If I go to AWS console, I can successfully add a trigger to lambda to invoke from SNS in a different region.

I also tried running a NodeJS script to add cross-region SNS-lambda subscription. I am getting same "Invalid parameter - TopicArn" error from sns.Subscribe() method.

Is there a way to programmatically or via cloud formation subscribe lambda to SNS topic in a different region?

2
amazon-web-servicesaws-lambdaaws-sdk
I'm just curious. Why are the Lambda function and SNS topic on different regions? – Noel Llevares
We have enabled sns failover which, which publishes messages to another region in case of failover. We want to be able to process those. – Tushar Kesare
You should use SQS if you need guaranteed delivery. Using another SNS as failover for SNS does not give you 100% guarantee. – Noel Llevares
You may need to add SNS permission (so that SNS can invoke the Lambda function). – krishna_mee2004

2 Answers

2
votes

By default your SNS client is pointing to EU-CENTRAL-1. Try set setRegion on snsClient like this,

snsClient.setRegion(Region.getRegion(Regions.EU-WEST-1));
0
votes

Yes it is possible to subscribe lambda to SNS topic in a different region. Use the "Region" parameter.

In CloudFormation (json) that would be:

"LambdaAmazonIpSpaceChangedSubscription" : {
  "Type" : "AWS::SNS::Subscription",
  "Properties" : {
    "Endpoint" : {"Fn::GetAtt" : ["LambdaFunction", "Arn"] },
    "Protocol" : "lambda",
    "TopicArn" : "arn:aws:sns:us-east-1:806199016981:AmazonIpSpaceChanged",
    "Region": "us-east-1"
  }
},