ca7-serverless.yml

service: sls-svc-ws
frameworkVersion: '2'

provider:
  name: aws
  runtime: go1.x
  lambdaHashingVersion: 20201221
  stage: dev
  region: ap-northeast-1
  websocketsApiName: chat-api-websocket-api
  # The route selection expression
  websocketsApiRouteSelectionExpression: $request.body.action
  environment:
    # CLI options can be accessed with opt
    STAGE: ${opt:stage, 'dev'}
    # Generated CloudFormation resources can be referenced 
    # using CloudFormation syntax. Refer to JSON files in 
    # generated .serverless directory for resources names.
    API_GATEWAY_DOMAIN:
      Fn::GetAtt: [ WebsocketsApi, ApiEndpoint ]
    # CloudFormation resources defined in the Resources 
    # section can also be accessed.
    CONNECTIONS_TABLE:
      Ref: ConnectionTable
  # IAM roles are defined for the entire service. 
  # Implementing zero trust roles per Lambda can be 
  # done with manual CloudFormation.
  iam:
    role:
      statements:
        - Effect: Allow
          Action:
            - dynamodb:Query
            - dynamodb:GetItem
            - dynamodb:PutItem
            - dynamodb:DeleteItem
            - dynamodb:Scan
          Resource:
            Fn::GetAtt: [ ConnectionTable, Arn ]

package:
  patterns:
    - '!./**'
    - ./bin/**

functions:
  connect:
    # Go binary will be output here
    handler: bin/connect
    events:
      - websocket:
          # Predefined $connect route will
          # be integrated with this function
          route: $connect

resources:
  # Raw CloudFormation can be added here
  Resources:
    # This is the definition of the DynamoDB table for
    # storing references to active WebSocket connections. 
    ConnectionTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: sls-chat-app-connections
        # We only need to define the key here, and can
        # freely manage other attributes in the application
        # layer due to the NoSQL nature of DynamoDB.
        AttributeDefinitions:
          - AttributeName: connection_id
            AttributeType: S
        KeySchema:
          - AttributeName: connection_id
            KeyType: HASH
        # PAY_PER_REQUEST sets on-demand pricing
        BillingMode: PAY_PER_REQUEST