template.json

{
    "AWSTemplateFormatVersion": "2010-09-09",
    "Transform": "AWS::Serverless-2016-10-31",
    "Resources": {
        "HttpApi": {
            "Type": "AWS::Serverless::HttpApi"
        },
        "HttpHandler": {
            "Type": "AWS::Serverless::Function",
            "Properties": {
                "FunctionName": "HttpHandler",
                "Handler": "bootstrap.is.real.handler",
                "Runtime": "provided.al2",
                "CodeUri": "./http_handler",
                "Events": {
                    "HttpApiEvent": {
                        "Type": "HttpApi",
                        "Properties": {
                            "ApiId": {"Ref": "HttpApi"}
                        }
                    }
                },
                "Environment": {
                    "Variables": {
                        "DispatchMessageTopic": {"Ref": "MessageDispatcher"},
                        "MessageStoreTable": {"Ref": "MessageStore"}
                    }
                }
            }
        },
        "MessageDispatcher": {
            "Type": "AWS::SNS::Topic"
        },
        "MessageHandler": {
            "Type": "AWS::Serverless::Function",
            "Properties": {
                "FunctionName": "MessageHandler",
                "Handler": "bootstrap.is.real.handler",
                "Runtime": "provided.al2",
                "CodeUri": "./message_handler",
                "Events": {
                    "SNSEvent": {
                        "Type": "SNS",
                        "Properties": {
                            "Topic": {"Ref": "MessageDispatcher"}
                        }
                    }
                },
                "Environment": {
                    "Variables": {
                        "MessageStoreTable": {"Ref": "MessageStore"}
                    }
                }
            }
        },
        "MessageStore": {
            "Type": "AWS::Serverless::SimpleTable",
            "Properties": {
                "PrimaryKey": {
                    "Name": "message_id",
                    "Type": "String"
                }
            }
        },
        "HttpApiToFunctionConnector": {
            "Type": "AWS::Serverless::Connector",
            "Properties": {
                "Source": {"Id": "HttpApi"},
                "Destination": {"Id": "HttpHandler"},
                "Permissions": ["Write"]
            }
        },
        "HttpHandlerToMessageDispatcherConnector": {
            "Type": "AWS::Serverless::Connector",
            "Properties": {
                "Source": {"Id": "HttpHandler"},
                "Destination": {"Id": "MessageDispatcher"},
                "Permissions": ["Write"]
            }
        },
        "MessageTopicToFunctionConnector": {
            "Type": "AWS::Serverless::Connector",
            "Properties": {
                "Source": {"Id": "MessageDispatcher"},
                "Destination": {"Id": "MessageHandler"},
                "Permissions": ["Write"]
            }
        },
        "MessageFunctionToStoreConnector": {
            "Type": "AWS::Serverless::Connector",
            "Properties": {
                "Source": {"Id": "MessageHandler"},
                "Destination": {"Id": "MessageStore"},
                "Permissions": ["Read", "Write"]
            }
        },
        "HttpHandlerToStoreConnector": {
            "Type": "AWS::Serverless::Connector",
            "Properties": {
                "Source": {"Id": "HttpHandler"},
                "Destination": {"Id": "MessageStore"},
                "Permissions": ["Read"]
            }
        }
    },
    "Outputs": {
        "HttpApiUrl": {
            "Description": "URL of API endpoint",
            "Value": {"Fn::Sub": "https://${HttpApi}.execute-api.${AWS::Region}.${AWS::URLSuffix}/"}
        },
        "HttpApiId": {
            "Description": "ID of HTTP API",
            "Value": {"Ref": "HttpApi"}
        },
        "MessageDispatcherTopic": {
            "Description": "SNS topic used to dispatch message commands to the backend",
            "Value": {"Ref": "MessageDispatcher"}
        },
        "MessageStoreTable": {
            "Description": "Message store table",
            "Value": {"Ref": "MessageStore"}
        }
    }
}