serverless.yml

service: web-poc

custom:
  dev:
    COOKIE_SECRET: ${ssm:web_cookie_secret_dev}
    SESSION_TABLE_MIN_READ_TP: 1
    SESSION_TABLE_MAX_READ_TP: 10
    SESSION_TABLE_MIN_WRITE_TP: 1
    SESSION_TABLE_MAX_WRITE_TP: 10
    GOOGLE_TAG_MANAGER_ID: ''
    AMPLITUDE_KEY: ${ssm:web_amplitude_dev_key}
  uat:
  prod:

provider:
  name: aws
  runtime: nodejs8.10
  stage: dev
  region: eu-west-2
  versionFunctions: false
  environment:
    NODE_PORT: 80
    DYNAMODB_LIVE: true
    STORYBOOK: true
    LOG_LEVEL: info
    STAGE: ${opt:stage, self:provider.stage}
    DYNAMODB_SESSION_TABLE: ${opt:stage, self:provider.stage}-${self:service}-web-sessions-sse
    COOKIE_SECRET: ${self:custom.${opt:stage, self:provider.stage}.COOKIE_SECRET}
    GOOGLE_TAG_MANAGER_ID: ${self:custom.${opt:stage, self:provider.stage}.GOOGLE_TAG_MANAGER_ID}
    AMPLITUDE_KEY: ${self:custom.${opt:stage, self:provider.stage}.AMPLITUDE_KEY}

  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:PutItem
        - dynamodb:UpdateItem
        - dynamodb:GetItem
      Resource: "arn:aws:dynamodb:${opt:region, self:provider.region}:*:table/${self:provider.environment.DYNAMODB_SESSION_TABLE}"

package:
  excludeDevDependencies: false
  exclude:
    - '**/*'
  include:
    - node_modules/**
    - dist/**
    - config/**
    - .env

functions:
  app:
    handler: dist/server/lambda-index.handler
    timeout: 30
    reservedConcurrency: 100
    events:
      - http: 'ANY /'
      - http: 'ANY {proxy+}'

resources:
  Resources:
    TokenTable:
      Type: "AWS::DynamoDB::Table"
      Properties:
        TableName: ${self:provider.environment.DYNAMODB_SESSION_TABLE}
        SSESpecification:
          SSEEnabled: true
        ProvisionedThroughput:
          ReadCapacityUnits: 1
          WriteCapacityUnits: 1
        KeySchema:
          - AttributeName: sessionId
            KeyType: HASH
        AttributeDefinitions:
          - AttributeName: sessionId
            AttributeType: S
        TimeToLiveSpecification:
          Enabled: true
          AttributeName: expire
    GatewayResponse:
      Type: 'AWS::ApiGateway::GatewayResponse'
      Properties:
        ResponseType: DEFAULT_5XX
        ResponseTemplates:
          text/html: ${file(./dist/server/error-page.js):html}
        RestApiId: 
          Ref: 'ApiGatewayRestApi'
    WriteCapacityScalableTarget:
      Type: AWS::ApplicationAutoScaling::ScalableTarget
      Properties:
        MaxCapacity: ${self:custom.${opt:stage, self:provider.stage}.SESSION_TABLE_MAX_WRITE_TP}
        MinCapacity: ${self:custom.${opt:stage, self:provider.stage}.SESSION_TABLE_MIN_WRITE_TP}
        ResourceId: 
          Fn::Join: 
            - /
            - - table
              - Ref: "TokenTable"
        RoleARN:
          Fn::GetAtt: "ScalingRole.Arn"
        ScalableDimension: dynamodb:table:WriteCapacityUnits
        ServiceNamespace: dynamodb
    ReadCapacityScalableTarget:
      Type: AWS::ApplicationAutoScaling::ScalableTarget
      Properties:
        MaxCapacity: ${self:custom.${opt:stage, self:provider.stage}.SESSION_TABLE_MAX_READ_TP}
        MinCapacity: ${self:custom.${opt:stage, self:provider.stage}.SESSION_TABLE_MIN_READ_TP}
        ResourceId: 
          Fn::Join: 
            - /
            - - table
              - Ref: "TokenTable"
        RoleARN:
          Fn::GetAtt: "ScalingRole.Arn"
        ScalableDimension: dynamodb:table:ReadCapacityUnits
        ServiceNamespace: dynamodb
    ScalingRole:
      Type: AWS::IAM::Role
      Properties:
        AssumeRolePolicyDocument:
          Version: "2012-10-17"
          Statement:
            -
              Effect: "Allow"
              Principal:
                Service:
                  - application-autoscaling.amazonaws.com
              Action:
                - "sts:AssumeRole"
        Path: "/"
        Policies:
          -
            PolicyName: "root"
            PolicyDocument:
              Version: "2012-10-17"
              Statement:
                -
                  Effect: "Allow"
                  Action:
                    - "dynamodb:DescribeTable"
                    - "dynamodb:UpdateTable"
                    - "cloudwatch:PutMetricAlarm"
                    - "cloudwatch:DescribeAlarms"
                    - "cloudwatch:GetMetricStatistics"
                    - "cloudwatch:SetAlarmState"
                    - "cloudwatch:DeleteAlarms"
                  Resource: "*"
    WriteScalingPolicy:
      Type: AWS::ApplicationAutoScaling::ScalingPolicy
      Properties:
        PolicyName: WriteAutoScalingPolicy
        PolicyType: TargetTrackingScaling
        ScalingTargetId: 
          Ref: "WriteCapacityScalableTarget"
        TargetTrackingScalingPolicyConfiguration:
          TargetValue: 50.0
          ScaleInCooldown: 60
          ScaleOutCooldown: 60
          PredefinedMetricSpecification:
            PredefinedMetricType: DynamoDBWriteCapacityUtilization
    ReadScalingPolicy:
      Type: AWS::ApplicationAutoScaling::ScalingPolicy
      Properties:
        PolicyName: ReadAutoScalingPolicy
        PolicyType: TargetTrackingScaling
        ScalingTargetId: 
          Ref: "ReadCapacityScalableTarget"
        TargetTrackingScalingPolicyConfiguration:
          TargetValue: 50.0
          ScaleInCooldown: 60
          ScaleOutCooldown: 60
          PredefinedMetricSpecification:
            PredefinedMetricType: DynamoDBReadCapacityUtilization