Add SNS trigger to a specific lambda version using cloudformation stack - aws-lambda

Question

I am able to add SNS as an event source for my lambda function.But I am unable to add SNS trigger to a specific lambda version ie to a qualified function name.
Here's my cloud formation snippet code:
LambdaCore:
Type: 'AWS::Lambda::Function'
Properties:
Code:
S3Bucket: !Ref S3Bucket
S3Key: !Ref S3Key
Description: Lambda Core with X-ray
FunctionName: !Ref LambdaCore
Handler: !Ref LambdaCoreHandler
MemorySize: '512'
DeadLetterConfig:
TargetArn: !GetAtt
- DeadLetterQueue
- Arn
Role: !GetAtt
- LambdaRoleForCore
- Arn
Runtime: java8
Timeout: '300'
TracingConfig:
Mode: Active
VpcConfig:
SecurityGroupIds: !Ref SecurityGroups
SubnetIds: !Ref Subnets
Version:
Type: AWS::Lambda::Version
DependsOn:
- LambdaCore
Properties:
FunctionName: !Ref LambdaCore
Description: v1
InputEventLambdaSubscription:
Type: 'AWS::SNS::Subscription'
DependsOn:
- SNSTopic
- LambdaCore
Properties:
Endpoint: !Ref
- LambdaCore
- Arn
Protocol: lambda
TopicArn: !Ref SNSTopic
PermissionForSNSToInvokeCore:
Type: 'AWS::Lambda::Permission'
DependsOn:
- LambdaCore
- SNSTopic
Properties:
FunctionName: !GetAtt
- LambdaCore
- Arn
Action: 'lambda:InvokeFunction'
Principal: sns.amazonaws.com
SourceArn: !Ref SNSTopic

Answer 1

If you want to have the subscription point to the version you need to use the version ARN in the subscription. The ARN of AWS::Lambda::Version will look just like a lambda ARN except that it includes the :<version> at the end.
A couple of other things.
You don't need to do DependsOn when the thing you are including in the dependency is a Ref or GetAtt in the resource.
The short form of GetAtt is a lot easier to look at an understand.
LambdaCore:
Type: 'AWS::Lambda::Function'
Properties:
Code:
S3Bucket: !Ref S3Bucket
S3Key: !Ref S3Key
Description: Lambda Core with X-ray
FunctionName: !Ref LambdaCore
Handler: !Ref LambdaCoreHandler
MemorySize: '512'
DeadLetterConfig:
TargetArn: !GetAtt DeadLetterQueue.Arn
Role: !GetAtt LambdaRoleForCore.Arn
Runtime: java8
Timeout: '300'
TracingConfig:
Mode: Active
VpcConfig:
SecurityGroupIds: !Ref SecurityGroups
SubnetIds: !Ref Subnets
Version:
Type: AWS::Lambda::Version
Properties:
FunctionName: !Ref LambdaCore
Description: v1
InputEventLambdaSubscription:
Type: 'AWS::SNS::Subscription'
Properties:
# this will return the ARN of the lambda with the version on it
Endpoint: !Ref Version
Protocol: lambda
TopicArn: !Ref SNSTopic
PermissionForSNSToInvokeCore:
Type: 'AWS::Lambda::Permission'
Properties:
FunctionName: !GetAtt LambdaCore.Arn
Action: 'lambda:InvokeFunction'
Principal: sns.amazonaws.com
SourceArn: !Ref SNSTopic