template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  DeliveryServiceURL:
    Type: String

Globals:
  Function:
    Timeout: 10

Resources:

  ### Event Bus
  AppEventBus:
    Type: AWS::Events::EventBus
    Properties: 
      Name: !Sub AppEventBus-${AWS::StackName}

  ### Event Sourcing / Event Store
  EventStoreTable: # customerId, timestamp, eventType, eventDetail
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "who"
          AttributeType: "S"
        - AttributeName: "timeWhat"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "who" # C + customerId
          KeyType: "HASH"
        - AttributeName: "timeWhat" # Timestamp + event type
          KeyType: "RANGE"

  EventStoreFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: event-store/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          STORE_TABLE: !Ref EventStoreTable
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLInsert
            Resource: !GetAtt EventStoreTable.Arn
      Events:
        StoreEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern: {"source": [{"prefix": ""}]} # To match all events
            DeadLetterConfig:
              Type: SQS

  ## Helpers layers
  HelpersLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: SAM-Events-Advance-Helpers
      Description: Layer that will be shared across multiple microservices
      LicenseInfo: 'Available under the MIT license.'
      ContentUri: ./helpers-layer
      CompatibleRuntimes:
        - python3.9

  ### Order

  OrderTable: # customerId, orderId, status (CREATED, RESERVED, PAID, DELIVERING, DELIVERED, CANCELED), itemId, itemPrice, deliveryPrice, totalPrice, paymentId, deliveryAddress, orderDate (timestamp), updateDate (timestamp)
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "customerId"
          AttributeType: "S"
        - AttributeName: "orderId"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "customerId"
          KeyType: "HASH"
        - AttributeName: "orderId" # Timestamp with ms precision
          KeyType: "RANGE"

  OrderFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: order/
      Handler: app.lambda_handler
      Runtime: python3.9
      Layers:
        - !Ref HelpersLayer
      Environment:
        Variables:
          ORDER_TABLE: !Ref OrderTable
          EVENT_BUS: !Ref AppEventBus
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
              - dynamodb:PartiQLInsert
              - dynamodb:PartiQLUpdate
              - dynamodb:PartiQLDelete
            Resource: !GetAtt OrderTable.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Events:
        OrderEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern:
              detail-type:
              - OrderCreate
              - PaymentMade
              - PaymentFailed
              - PaymentCanceled
              - DeliveryStarted
              - DeliveryWasDelivered
              - DeliveryWasCanceled
            DeadLetterConfig:
              Type: SQS
        OrderGet:
          Type: HttpApi
          Properties:
            Path: /order/{action}/{customerId}/{what}
            Method: GET
        OrderPost:
          Type: HttpApi
          Properties:
            Path: /order/{action}
            Method: POST

  ### Inventory

  InventoryTable: # itemId, description, image (S3 URL in the format “s3://…”), price, available, reserved
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "itemId"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "itemId"
          KeyType: "HASH"

  InventoryFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: inventory/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          INVENTORY_TABLE: !Ref InventoryTable
          EVENT_BUS: !Ref AppEventBus
      Layers:
        - !Ref HelpersLayer
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
              - dynamodb:PartiQLInsert
              - dynamodb:PartiQLUpdate
              - dynamodb:PartiQLDelete
            Resource: !GetAtt InventoryTable.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Events:
        InventoryEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern:
              detail-type:
              - OrderCreated
              - OrderCanceled
              - ItemReserved
              - PaymentMade
              - PaymentFailed
            DeadLetterConfig:
              Type: SQS

  ### Payment

  PaymentTable: # paymentId, paymentMethod (CREDIT_CARD for all in this simulation), amount, status (PAID, CANCELED)
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "paymentId"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "paymentId"
          KeyType: "HASH"

  PaymentFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: payment/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          PAYMENT_TABLE: !Ref PaymentTable
          PAYMENT_FAIL_PROBABILITY: 0.2 # Between 0 and 1
          EVENT_BUS: !Ref AppEventBus
      Layers:
        - !Ref HelpersLayer
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
              - dynamodb:PartiQLInsert
              - dynamodb:PartiQLUpdate
              - dynamodb:PartiQLDelete
            Resource: !GetAtt PaymentTable.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Events:
        PaymentEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern:
              detail-type:
              - DeliveryEstimated
              - ItemReturned
            DeadLetterConfig:
              Type: SQS

  ### Customer

  CustomerTable: # customerId, name, address (single field for simplicity, includes zip code, town, and state/country), email
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "customerId"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "customerId"
          KeyType: "HASH"

  CustomerFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: customer/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          CUSTOMER_TABLE: !Ref CustomerTable
          EVENT_BUS: !Ref AppEventBus
      Layers:
        - !Ref HelpersLayer
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
            Resource: !GetAtt CustomerTable.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Events:
        CustomerEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern:
              detail-type:
              - ItemDescribed
            DeadLetterConfig:
              Type: SQS

  ### Delivery

  MyPlaceIndex:
    Type: AWS::Location::PlaceIndex
    Properties: 
      IndexName: !Sub my-place-index-${AWS::StackName}
      DataSource: Esri
      PricingPlan: RequestBasedUsage

  MyRouteCalculator:
    Type: AWS::Location::RouteCalculator
    Properties: 
      CalculatorName: !Sub my-route-calculator-${AWS::StackName}
      DataSource: Esri
      PricingPlan: RequestBasedUsage
  
  DeliveryTable: # customerId, orderId, address, status (CREATED, DELIVERING, DELIVERED, CANCELED)
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions: 
        - AttributeName: "customerId"
          AttributeType: "S"
        - AttributeName: "orderId"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "customerId"
          KeyType: "HASH"
        - AttributeName: "orderId" # Timestamp with ms precision
          KeyType: "RANGE"

  DeliveryFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: delivery/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          PLACE_INDEX: !Ref MyPlaceIndex
          ROUTE_CALCULATOR: !Ref MyRouteCalculator
          DELIVERY_TABLE: !Ref DeliveryTable
          EVENT_BUS: !Ref AppEventBus
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
              - dynamodb:PartiQLInsert
              - dynamodb:PartiQLUpdate
              - dynamodb:PartiQLDelete
            Resource: !GetAtt DeliveryTable.Arn
          - Effect: Allow
            Action:
              - geo:SearchPlaceIndexForText
            Resource: !GetAtt MyPlaceIndex.Arn
          - Effect: Allow
            Action:
              - geo:CalculateRoute 
            Resource: !GetAtt MyRouteCalculator.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Layers:
        - !Ref HelpersLayer
      Events:
        DeliveryEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref AppEventBus
            Pattern:
              detail-type:
              - CustomerDescribed
              - ItemRemoved
              - Delivered
              - DeliveryCanceled

### API Destination for the delivery endpoint
  DeliveryConnection:
    Type: AWS::Events::Connection
    Properties:
      AuthorizationType: API_KEY
      Description: 'Connection with an API key'
      AuthParameters:
        ApiKeyAuthParameters:
          ApiKeyName: ApiKeyName
          ApiKeyValue: DeliveryServiceApiKeyValue

  DeliveryApiDestination:
    Type: AWS::Events::ApiDestination
    Properties:
      Name: 'DeliveryApiDestination'
      ConnectionArn: !GetAtt DeliveryConnection.Arn
      InvocationEndpoint: !Ref DeliveryServiceURL
      HttpMethod: POST
      InvocationRateLimitPerSecond: 10

  DeliveryEventRule: 
    Type: AWS::Events::Rule
    Properties: 
      Description: "Delivery Service EventRule"
      EventBusName: !Ref AppEventBus
      EventPattern: 
        detail-type:
          - DeliveryMarkedAsStarted
      Targets: 
        - Arn: !GetAtt DeliveryApiDestination.Arn
          RoleArn: !GetAtt DeliveryEBTargetRole.Arn
          Id: "DeliveryApiDestination"
          DeadLetterConfig:
            Arn: !GetAtt DeliveryServiceDLQueue.Arn
          RetryPolicy:
            MaximumEventAgeInSeconds: 60
            MaximumRetryAttempts: 4


  DeliveryEBTargetRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - events.amazonaws.com
            Action:
              - sts:AssumeRole
      Policies:
        - PolicyName: AllowAPIdestinationAccess
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action: 'events:InvokeApiDestination'
                Resource: !GetAtt DeliveryApiDestination.Arn

### DLQ for the API Destination
  DeliveryServiceDLQueue:
    Type: AWS::SQS::Queue
  
  DeliveryServiceDLQueuePolicy:
    Type: AWS::SQS::QueuePolicy
    Properties:
      Queues: 
        - !Ref DeliveryServiceDLQueue
      PolicyDocument:
        Statement: 
          - Effect: Allow
            Action: 'sqs:SendMessage'
            Resource: !GetAtt DeliveryServiceDLQueue.Arn
            Principal:
              Service: events.amazonaws.com
            Condition:
              ArnEquals:
                aws:SourceArn: !GetAtt DeliveryEventRule.Arn

  DeliveryDLQFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      CodeUri: delivery/
      Handler: app.delivery_dlq_handler
      Runtime: python3.9
      Layers:
        - !Ref HelpersLayer
      Policies:
        - Statement:
          - Effect: Allow
            Action:
              - dynamodb:PartiQLSelect
              - dynamodb:PartiQLInsert
              - dynamodb:PartiQLUpdate
              - dynamodb:PartiQLDelete
            Resource: !GetAtt DeliveryTable.Arn
          - Effect: Allow
            Action:
              - events:PutEvents
            Resource: !GetAtt AppEventBus.Arn
      Environment:
        Variables:
          EVENT_BUS: !Ref AppEventBus
          DELIVERY_TABLE: !Ref DeliveryTable
      Events:
        DQLSQSEvent:
          Type: SQS
          Properties:
            Queue: !GetAtt DeliveryServiceDLQueue.Arn
            BatchSize: 1

Outputs:

  EventStoreTable:
    Description: "Event Store Table"
    Value: !Ref EventStoreTable
  InventoryTable:
    Description: "Inventory Table"
    Value: !Ref InventoryTable
  PaymentTable:
    Description: "Payment Table"
    Value: !Ref PaymentTable
  CustomerTable:
    Description: "Customer Table"
    Value: !Ref CustomerTable
  DeliveryTable:
    Description: "Delivery Table"
    Value: !Ref DeliveryTable
  OrderTable:
    Description: "Order Table"
    Value: !Ref OrderTable
  OrderApi:
    Description: "API Gateway endpoint URL for Order function"
    Value: !Sub "https://${ServerlessHttpApi}.execute-api.${AWS::Region}.amazonaws.com/order/create/{customerId}/{itemId}"