Example of invoking a lambda by ARN and providing fixed input JSON to the lambda as the event - for AWS CloudFormation in YAML

lambda-schedule-rule-template.yaml

AWSTemplateFormatVersion: "2010-09-09"
Description: A Schedule to invoke a Lambda
Parameters:
  LambdaArn:
    Type: String
    Description: ARN of the lambda to be invoked
Resources:
  InvokeLambdaRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: invoke-lambda-role
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
        - Action:
          - sts:AssumeRole
          Effect: Allow
          Principal:
            Service:
            - events.amazonaws.com
  InvokeLambdaRule:
    Type: AWS::Events::Rule
    Properties:
      Name: invoke-lambda-rule
      Description: Schedule for invocating the Lambda
      ScheduleExpression: rate(5 minutes)
      RoleArn:
        Fn::GetAtt: [ InvokeLambdaRole, Arn ]
      Targets:
        - Arn:
            Ref: LambdaArn
          Id: splunk-dbreader-lambda
          Input: '{"SecretsArn": "arn:aws:secretsmanager:ap-southeast-2:123456789012:secret:mysecret", "S3Bucket": "my-bucket"}'
  InvokeLambdaRulePermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName:
        Ref: LambdaArn
      Action: lambda:InvokeFunction
      Principal: events.amazonaws.com
      SourceArn: 
        Fn::GetAtt: [ InvokeLambdaRule, Arn ]