template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Sample AWS Step Function app

Globals:

    Function:
        Runtime: nodejs10.x
        Timeout: 30
        Tags:
            Project: GreetByName

Resources:

    ValidateNameFunction:
        Type: AWS::Serverless::Function
        Properties:
            Description: Validate name
            CodeUri: ./src/
            Handler: ValidateName.handler

    GreetNameFunction:
        Type: AWS::Serverless::Function
        Properties:
            Description: Greet name
            CodeUri: ./src/
            Handler: GreetName.handler

    InvalidNameFunction:
        Type: AWS::Serverless::Function
        Properties:
            Description: Invalid name
            CodeUri: ./src/
            Handler: InvalidName.handler

    ResultQueue:
        Type: AWS::SQS::Queue

    ResultTopic:
        Type: AWS::SNS::Topic
        Properties:
            Subscription:
            - Endpoint: !GetAtt ResultQueue.Arn
              Protocol: sqs

    AllowTopicToPublishOnQueue:
        Type: AWS::SQS::QueuePolicy
        Properties:
            Queues: [ !Ref ResultQueue ]
            PolicyDocument:
                Version: '2012-10-17'
                Statement:
                    -   Effect: "Allow"
                        Action:
                            - "sqs:SendMessage"
                        Principal: "*"
                        Resource: !GetAtt ResultQueue.Arn
                        Condition:
                            ArnEquals:
                                aws:SourceArn: !Ref ResultTopic

    StepFunctionsServiceRole:
        Type: "AWS::IAM::Role"
        Properties:
            Path: !Join ["", ["/", !Ref "AWS::StackName", "/"]]
            ManagedPolicyArns:
                - "arn:aws:iam::aws:policy/AWSStepFunctionsFullAccess"
            AssumeRolePolicyDocument:
                Version: "2012-10-17"
                Statement:
                    -
                        Sid: "AllowStepFunctionsServiceToAssumeRole"
                        Effect: "Allow"
                        Action:
                            - "sts:AssumeRole"
                        Principal:
                            Service:
                                - !Sub "states.${AWS::Region}.amazonaws.com"
            Policies:
                -   
                    PolicyName: "InvokeFunctions"
                    PolicyDocument:
                        Version: '2012-10-17'
                        Statement:
                            -   Effect: "Allow"
                                Action:
                                    - "lambda:InvokeFunction"
                                Resource: 
                                    - !Sub ${ValidateNameFunction.Arn}
                                    - !Sub ${GreetNameFunction.Arn}
                                    - !Sub ${InvalidNameFunction.Arn}
                -   
                    PolicyName: "Publish2Topic"
                    PolicyDocument:
                        Version: '2012-10-17'
                        Statement:
                            -   Effect: "Allow"
                                Action:
                                    - "sns:Publish"
                                Resource: 
                                    - !Ref ResultTopic

    GreetByNameStateMachine:
        Type: "AWS::StepFunctions::StateMachine"
        Properties:
            RoleArn: !GetAtt StepFunctionsServiceRole.Arn
            DefinitionString: !Sub |-
                {
                    "Comment": "Greeting by Name",
                    "StartAt": "ValidateName",
                    "States": {
                        "ValidateName": {
                            "Type": "Task",
                            "Resource": "${ValidateNameFunction.Arn}",
                            "Catch": [
                                {
                                    "ErrorEquals": [
                                        "NameError"
                                    ],
                                    "Next": "InvalidName"
                                }
                            ],
                            "Next": "GreetName"
                        },
                        "InvalidName": {
                            "Type": "Task",
                            "Resource": "${InvalidNameFunction.Arn}",
                            "Next": "Publish2SNS"
                        },
                        "GreetName": {
                            "Type": "Task",
                            "Resource": "${GreetNameFunction.Arn}",
                            "Next": "Publish2SNS"
                        },
                        "Publish2SNS": {
                            "Type": "Task",
                            "Resource": "arn:aws:states:::sns:publish",
                            "Parameters": {
                                "TopicArn": "${ResultTopic}",
                                "Message.$": "$.message",
                                "MessageAttributes": {
                                    "Attribute1": {
                                        "DataType": "String",
                                        "StringValue": "value of my attribute no 1"
                                    },
                                    "Attr ibute2": {
                                        "DataType": "String",
                                        "StringValue": "value of my attribute no 2"
                                    }
                                }
                            },
                            "End": true
                        }
                    }
                }

Outputs:

    ResultTopicName:
        Description: Result SNS Topic Name
        Value: !Ref ResultTopic
        
    ResultQueueUrl:
        Description: Result SQS Queue URL
        Value: !Ref ResultQueue