AWS SAM Template get rule name with intrinsic function - amazon-web-services

Question

Let's say I have a scheduled function declared in a SAM template.yaml
myScheduledFunction:
Type: AWS::Serverless::Function
Properties:
CodeUri: ./bin
Handler: myScheduledFunction
Policies:
- AWSLambdaBasicExecutionRole
Events:
CloudwatchEvents:
Type: Schedule
Properties:
Schedule: rate(1 minute)
Enabled: true
and then I have another function that enable/disable the scheduled rule
myFunction:
Type: AWS::Serverless::Function
Properties:
CodeUri: ./bin
Handler: myFunction
Environment:
Variables:
RULE_NAME: !Ref MyRuleName
Policies:
- AWSLambdaBasicExecutionRole
- EventBridgePutEventsPolicy:
EventBusName: default
Events:
SomeEvent: ...
Now, how can I reference the rule name in environment variable RULE_NAME: !Ref MyRuleName?
It is possible to do it in SAM? Maybe using something like !GetAtt myScheduledFunction.RuleName?
I couldn't find anything regarding this and I know that there is a way to do it in Cloudformation, but I would know if it is possible in SAM as well, thanks.

Answer 1

I don't think this is possible to retrieve with the template as written. A work around would be to create the CloudWatch rule as a top-level resource instead of creating it in the Events property.
For example:
myScheduledFunction:
Type: AWS::Serverless::Function
Properties:
CodeUri: ./bin
Handler: myScheduledFunction
Policies:
- AWSLambdaBasicExecutionRole
myRule:
Type: AWS::Events::Rule
Properties:
Description: "ScheduledRule"
ScheduleExpression: "rate(1 minutes)"
State: "ENABLED"
Targets:
- Arn:
Fn::GetAtt:
- "myScheduledFunction"
- "Arn"
PermissionForEventsToInvokeLambda:
Type: AWS::Lambda::Permission
Properties:
FunctionName:
Ref: "myScheduledFunction"
Action: "lambda:InvokeFunction"
Principal: "events.amazonaws.com"
SourceArn:
Fn::GetAtt:
- "myRule"
- "Arn"
myFunction:
Type: AWS::Serverless::Function
Properties:
CodeUri: ./bin
Handler: myFunction
Environment:
Variables:
RULE_NAME: !Ref myRule
Policies:
- AWSLambdaBasicExecutionRole
- EventBridgePutEventsPolicy:
EventBusName: default
Events:
SomeEvent: ...
This code snippet for the rule/permission was taken from the Cloudwatch Rule cloudformation documentation.