AWS Cloudformation: Give Cloudwatch * Permissions to invoke Lambda - amazon-web-services

Question

This is what I am trying to do:
LambdaInvokePermission:
Type: AWS::Lambda::Permission
Properties:
--snip--
SourceArn: !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:rule/*-${Environment}
However it seems to dislike the * syntax.
I have tried just SourceArn: !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:rule/* and SourceArn: '*' but these also give failure messages like
The rule * could not be found.
Does anyone know the correct syntax for this?

Answer 1

You need to specify the exact name of the cloudwatch rule that will trigger this lambda function.
Example: arn:aws:events:us-east-1:123456789012:rule/my-scheduled-rule.
The SourceArn property of AWS::Lambda::Permission expects a String value: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lambda-permission.html#cfn-lambda-permission-sourcearn.
You cannot have multiple cloudwatch rules as the SourceArn(not a list) in a single AWS::Lambda::Permission block with a wildcard '*'. To have multiple cloudwatch rules trigger the same lambda function, you will need to add another AWS::Lambda::Permission block in your cloudformation template.