cloudformation.yml

AWSTemplateFormatVersion: 2010-09-09
Description: Chat example server
Transform: AWS::Serverless-2016-10-31

Resources:
  ConnectionsDynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      # see DynamoDBConnectionManager
      TableName: Connections
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
      BillingMode: PAY_PER_REQUEST
      KeySchema:
        # connection id
        - AttributeName: id
          KeyType: HASH

  SubscriptionsDynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      # see DynamoDBSubscriptionManager
      TableName: Subscriptions
      AttributeDefinitions:
        - AttributeName: event
          AttributeType: S
        - AttributeName: subscriptionId
          AttributeType: S
      BillingMode: PAY_PER_REQUEST
      KeySchema:
        - AttributeName: event
          KeyType: HASH
        - AttributeName: subscriptionId
          KeyType: RANGE

  SubscriptionOperationsDynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      # see DynamoDBSubscriptionManager
      TableName: Subscriptions
      AttributeDefinitions:
        - AttributeName: subscriptionId
          AttributeType: S
      BillingMode: PAY_PER_REQUEST
      KeySchema:
        - AttributeName: subscriptionId
          KeyType: HASH
            

  EventsDynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      # see DynamoDBEventStore
      TableName: Events
      KeySchema:
        - AttributeName: id
          KeyType: HASH
      BillingMode: PAY_PER_REQUEST
      # see ISubscriptionEvent
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
      StreamSpecification:
        StreamViewType: NEW_IMAGE

  ServerFunction:
    # server handler function
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: ./dist
      FunctionName: chat-example-server
      Handler: index.handler
      MemorySize: 512
      Runtime: nodejs8.10
      Tags:
        Project: serverless-chat-example
      Timeout: 6

      Policies:
        - AWSLambdaExecute # Managed Policy
        - Version: '2012-10-17' # Policy Document
          Statement:
            # AWS Api Gateway manager permission (we need this to be able to send events to clients)
            - Effect: Allow
              Action:
                - execute-api:ManageConnections
              Resource: 'arn:aws:execute-api:*:*:*/development/POST/@connections/*'
            - Effect: Allow
              Action:
                - dynamodb:DeleteItem
                - dynamodb:GetItem
                - dynamodb:PutItem
              Resource: !GetAtt ConnectionsDynamoDBTable.Arn
            - Effect: Allow
              Action:
                - dynamodb:DescribeStream
                - dynamodb:GetRecords
                - dynamodb:GetShardIterator
                - dynamodb:ListStreams
              Resource: !GetAtt EventsDynamoDBTable.StreamArn
            - Effect: Allow
              Action:
                - dynamodb:PutItem
              Resource: !GetAtt EventsDynamoDBTable.Arn
            - Effect: Allow
              Action:
                - dynamodb:BatchWriteItem
                - dynamodb:DeleteItem
                - dynamodb:GetItem
                - dynamodb:PutItem
                - dynamodb:Query
                - dynamodb:Scan
              Resource: !GetAtt SubscriptionsDynamoDBTable.Arn
            - Effect: Allow
              Action:
                - dynamodb:BatchWriteItem
                - dynamodb:DeleteItem
                - dynamodb:GetItem
                - dynamodb:PutItem
              Resource: !GetAtt SubscriptionOperationsDynamoDBTable.Arn

      # attach event sources
      Events:
        HTTPEndpoint:
          Type: Api
          Properties:
            Path: /
            Method: POST
        DynamoDBEventStream:
          Type: DynamoDB
          Properties:
            Stream: !GetAtt EventsDynamoDBTable.StreamArn
            StartingPosition: LATEST
            BatchSize: 100

Outputs:
  ConnectionsTableARN:
    Description: 'DynamoDB connections table ARN'
    Value: !GetAtt ConnectionsDynamoDBTable.Arn
  EventsTableARN:
    Description: 'DynamoDB events table ARN'
    Value: !GetAtt EventsDynamoDBTable.Arn
  EventsTableStreamARN:
    Description: 'DynamoDB events table ARN'
    Value: !GetAtt EventsDynamoDBTable.StreamArn
  SubscriptionsTableARN:
    Description: 'DynamoDB subscriptions table ARN'
    Value: !GetAtt SubscriptionsDynamoDBTable.Arn
  ServerFunctionARN:
    Description: 'Server function ARN'
    Value: !GetAtt ServerFunction.Arn