Cannot add a Lambda target to an existing CloudWatch rule

Question

I want to add a Lambda target to an existing CloudWatch rule. I used the following to refer to the existing rule:

rule = events.Rule.from_event_rule_arn(self, "Rule",event_rule_arn='')

Later I add a target with:

rule.add_target(targets.LambdaFunction(lambdaFn))

When I execute a cdk synth or deploy, I get the following error:

AttributeError: '+' object has no attribute 'add_target'

I know the IRule element does not have that method but I cannot find a clear way how to achieve what I need.

I also try using event source in Lambda but got the following error:

Unrecognized event source, must be kinesis, dynamodb stream or sqs.

Answer 1

I do not think this is possible. You need to reference the lambda function and manage the rule from the stack to which the rule belongs.

Answer 2

As MilanG suggests, it is not possible to do.

My use case needs to create several Lambda functions and set the same trigger to them and CloudWatch Rules is not a fit for it because of a 5 targets per rule hard limit. I use SNS instead as follows:

sns_topic = aws_sns.Topic.from_topic_arn(scope, id, topic_arn=config)

lambdaFn.add_event_source(aws_lambda_event_sources.SnsEventSource(sns_topic))