serverless.yml

service: aws-serverless-websockets
provider:
  name: aws
  runtime: nodejs12.x
  environment:
    CONNECTION_DB_TABLE: ${self:resources.Resources.MyAppTable.Properties.TableName}
  iamRoleStatements:
    - Effect: Allow
      Action:
        - "dynamodb:PutItem"
        - "dynamodb:GetItem"
        - "dynamodb:DeleteItem"
        - "dynamodb:Scan"
      Resource:
        - Fn::GetAtt: [MyAppTable, Arn]
    - Effect: Allow
      Action:
        - "execute-api:ManageConnections"
      Resource:
        - "arn:aws:execute-api:*:*:**/@connections/*"

functions:
  connectHandler:
    handler: handler.connectHandler
    events:
      - websocket:
          route: $connect
  disconnectHandler:
    handler: handler.disconnectHandler
    events:
      - websocket:
          route: $disconnect
  defaultHandler:
    handler: handler.defaultHandler
    events:
      - websocket:
          route: $default
  broadcastHandler:
    handler: handler.broadcastHandler
    events:
      - websocket:
          route: broadcastMessage

resources:
  Resources:
    MyAppTable:
      Type: "AWS::DynamoDB::Table"
      Properties:
        AttributeDefinitions:
          - AttributeName: "connectionId"
            AttributeType: "S"
        KeySchema:
          - AttributeName: "connectionId"
            KeyType: "HASH"
        BillingMode: PAY_PER_REQUEST
        TableName: myAppConnectionTable