template.yaml

# Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
#
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AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Functionless URL Shortner

###################################################################################################
##   Template Parameters                                                                         ##
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Parameters:
  AppName:
    Type: String
    Description: Name of application (no spaces). Value must be globally unique
    Default: shortener
  UseLocalClient:
    Type: String
    Description: Enables public client and local client for testing. (Less secure)
    Default: 'false'
  GithubRepository:
    Type: String
    Description: Forked GitHub repository URL
  PersonalAcessToken:
    Type: String
    Description: Github personal access token
    NoEcho: true
  CustomDomain:
    Type: String
    Description: Cstom domain added to client # only configures cognito for now. Manually handle domain on amplify console for client
    Default: none

###################################################################################################
##   Template Conditions                                                                         ##
###################################################################################################
Conditions:
  IsLocal: !Equals [!Ref UseLocalClient, 'true']
  HasCustomDomain: !Not [!Equals [!Ref CustomDomain, 'none']]

###################################################################################################
##   Template Resources                                                                          ##
###################################################################################################
Resources:
  ##   API Gateway                                                                                 
  SiteAPI:
    Type: AWS::Serverless::Api
    Properties:
      StageName: Prod
      EndpointConfiguration: REGIONAL
      TracingEnabled: true
      MethodSettings:
        - HttpMethod: "*"
          ResourcePath: "/*"
          LoggingLevel: INFO
          DataTraceEnabled: true
          MetricsEnabled: true
          ThrottlingRateLimit: 2000
          ThrottlingBurstLimit: 1000
        - HttpMethod: "GET"
          ResourcePath: "/{linkId}"
          ThrottlingRateLimit: 10000
          ThrottlingBurstLimit: 4000
      DefinitionBody:
        'Fn::Transform':
          Name: 'AWS::Include'
          Parameters:
            Location: './api.yaml'

  ##   URL DynamoDB Table
  LinkTable:
    Type: AWS::DynamoDB::Table
    Properties:
      BillingMode: PAY_PER_REQUEST
      KeySchema:
        - AttributeName: id
          KeyType: HASH
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
        - AttributeName: owner
          AttributeType: S
      GlobalSecondaryIndexes:
        - IndexName: OwnerIndex
          KeySchema:
            - AttributeName: owner
              KeyType: HASH
          Projection:
            ProjectionType: ALL
  
  ##   Cognito user pool
  UserPool:
    Type: AWS::Cognito::UserPool 
    Properties: 
      UserPoolName: !Sub ${AppName}-UserPool 
      Policies: 
        PasswordPolicy: 
          MinimumLength: 8
      AutoVerifiedAttributes:
        - email
      UsernameAttributes: 
        - email 
      Schema: 
        - AttributeDataType: String 
          Name: email 
          Required: false

  ##   Cognito user pool domain
  UserPoolDomain:
    Type: AWS::Cognito::UserPoolDomain
    Properties: 
      Domain: !Sub ${AppName}-${AWS::AccountId}
      UserPoolId: !Ref UserPool

  ##   Cognito user pool client
  UserPoolClient:
    Type: AWS::Cognito::UserPoolClient 
    Properties: 
      UserPoolId: !Ref UserPool 
      ClientName: !Sub ${AppName}-UserPoolClient 
      GenerateSecret: false
      SupportedIdentityProviders:
        - COGNITO
      CallbackURLs:
        - !Join [ ".", [ https://master, !GetAtt AmplifyApp.DefaultDomain ]]
        - !If [IsLocal, http://localhost:8080, !Ref "AWS::NoValue"]
        - !If [HasCustomDomain, !Ref CustomDomain, !Ref "AWS::NoValue"]
      LogoutURLs:
        - !Join [ ".", [ https://master, !GetAtt AmplifyApp.DefaultDomain ]]
        - !If [IsLocal, http://localhost:8080, !Ref "AWS::NoValue"]
        - !If [HasCustomDomain, !Ref CustomDomain, !Ref "AWS::NoValue"]
      AllowedOAuthFlowsUserPoolClient: true
      AllowedOAuthFlows:
        - code
      AllowedOAuthScopes:
        - email
        - openid

  ##   CloudFront distribution
  CloudFrontDistro:
    Type: AWS::CloudFront::Distribution
    Properties: 
      DistributionConfig:
        Comment: URL Shortener CDN
        DefaultCacheBehavior:
          AllowedMethods: ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
          CachedMethods: ["GET", "HEAD", "OPTIONS"]
          Compress: true
          DefaultTTL: 0
          ForwardedValues:
            Headers:
            - Access-Control-Request-Headers
            - Access-Control-Request-Method
            - Origin
            - Authorization
            QueryString: false
          TargetOriginId: "URLShortenerAPIGW"
          ViewerProtocolPolicy: redirect-to-https
        CustomErrorResponses:
        - ErrorCachingMinTTL: 0
          ErrorCode: 400
        - ErrorCachingMinTTL: 1
          ErrorCode: 403
        - ErrorCachingMinTTL: 5
          ErrorCode: 500
        Logging:
          Bucket: !GetAtt CloudFrontAccessLogsBucket.DomainName
        Enabled: true
        Origins:
          - CustomOriginConfig:
              OriginProtocolPolicy: https-only
            DomainName: !Sub ${SiteAPI}.execute-api.${AWS::Region}.amazonaws.com
            Id: "URLShortenerAPIGW"
            OriginPath: /Prod

  ##   CloudFront access logs storage
  CloudFrontAccessLogsBucket:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: LogDeliveryWrite
      OwnershipControls:
        Rules:
          - ObjectOwnership: ObjectWriter

  ##   Amplify Application for hosting
  AmplifyApp:
    Type: AWS::Amplify::App
    Properties:
      Name: Url-Shortener-Client
      Description: Basic client for URL Shortner
      Repository: !Ref GithubRepository
      AccessToken: !Ref PersonalAcessToken
      BuildSpec: |-
        version: 0.1
        frontend:
          phases:
            preBuild:
              commands:
                - cd client
                - npm ci
            build:
              commands:
                - npm run build
          artifacts:
            baseDirectory: client/dist
            files:
              - '**/*'
          cache:
            paths:
              - node_modules/**/*
      IAMServiceRole: !GetAtt AmplifyRole.Arn

  ##   Amplify Branch for hosting
  AmplifyBranch:
    Type: AWS::Amplify::Branch
    Properties:
      BranchName: master
      AppId: !GetAtt AmplifyApp.AppId
      Description: Master Branch
      EnableAutoBuild: true

###################################################################################################
##   IAM Roles                                                                                   ##
###################################################################################################

  ##   Dynamo DB Read Role
  DDBReadRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          -
            Effect: "Allow"
            Principal:
              Service: "apigateway.amazonaws.com"
            Action: 
              - "sts:AssumeRole"
      Policies:
        - PolicyName: DDBReadPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              Action:
              - dynamodb:GetItem
              - dynamodb:Scan
              - dynamodb:Query
              Effect: Allow
              Resource:
                - !GetAtt LinkTable.Arn
                - !Sub
                  - ${TableArn}/index/*
                  - {TableArn: !GetAtt LinkTable.Arn}

  ##   Dynamo DB Read/Write Role
  DDBCrudRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          -
            Effect: "Allow"
            Principal:
              Service: "apigateway.amazonaws.com"
            Action: 
              - "sts:AssumeRole"
      Policies:
        - PolicyName: DDBCrudPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              Action:
              - dynamodb:DeleteItem
              - dynamodb:UpdateItem
              Effect: Allow
              Resource: !GetAtt LinkTable.Arn

  ##   Amplify Hosting Role
  AmplifyRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - amplify.amazonaws.com
            Action:
              - sts:AssumeRole
      Policies:
        - PolicyName: Amplify
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action: "amplify:*"
                Resource: "*"

## CloudWatchRole for aws gateway account
  Account:
    Type: 'AWS::ApiGateway::Account'
    Properties:
      CloudWatchRoleArn: !GetAtt CloudWatchRole.Arn
      
  CloudWatchRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - apigateway.amazonaws.com
            Action: 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonAPIGatewayPushToCloudWatchLogs

###################################################################################################
##   Metrics outputs                                                                            ##
###################################################################################################

  NotifyTopic:
    Type: AWS::SNS::Topic

  APIGateway4xxAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "URL Shortener API 4xx Alarm"
      AlarmDescription: "4xx monitor"
      MetricName: "4XXError"
      Namespace: "AWS/ApiGateway"
      Dimensions:
          - Name: "ApiName"
            Value: "URL Shortener API"
      Statistic: "Average"
      Period: 60
      EvaluationPeriods: 1
      Threshold: .01
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref NotifyTopic

  APIGateway5xxAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "URL Shortener API 5xx Alarm"
      AlarmDescription: "5xx monitor"
      MetricName: "5XXError"
      Namespace: "AWS/ApiGateway"
      Dimensions:
          - Name: "ApiName"
            Value: "URL Shortener API"
      Statistic: "Average"
      Period: 60
      EvaluationPeriods: 1
      Threshold: .01
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref NotifyTopic

  APIGatewayLatencyAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "URL Shortener API Latency Alarm"
      AlarmDescription: "Latency monitor"
      MetricName: "Latency"
      Namespace: "AWS/ApiGateway"
      Dimensions:
          - Name: "ApiName"
            Value: "URL Shortener API"
      ExtendedStatistic: "p99"
      Period: 300
      EvaluationPeriods: 1
      Threshold: 75
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref NotifyTopic

  DDB5xxAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "URL Shortener DDB 5xx Alarm"
      AlarmDescription: "System monitor"
      MetricName: "SystemErrors"
      Namespace: "AWS/DynamoDB"
      Dimensions:
          - Name: "TableName"
            Value: !Ref LinkTable
      Statistic: "Average"
      Period: 60
      EvaluationPeriods: 1
      Threshold: .01
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref NotifyTopic

  DDB4xxAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "URL Shortener DDB 4xx Alarm"
      AlarmDescription: "User monitor"
      MetricName: "UserErrors"
      Namespace: "AWS/DynamoDB"
      Dimensions:
          - Name: "TableName"
            Value: !Ref LinkTable
      Statistic: "Average"
      Period: 60
      EvaluationPeriods: 1
      Threshold: .10
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref NotifyTopic

  CloudFrontTotalErrorRateAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "Url Shortener CloudFront Errors"
      AlarmDescription: "CDN error monitor"
      MetricName: TotalErrorRate
      Namespace: AWS/CloudFront
      Dimensions:
        - Name: DistributionId
          Value: !Ref CloudFrontDistro
      Statistic: Sum
      Period: 60
      EvaluationPeriods: 1
      ComparisonOperator: GreaterThanOrEqualToThreshold
      Threshold: 5
      AlarmActions:
        - !Ref NotifyTopic

  CloudFrontTotalCacheHitRateAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmName: "Url Shortener CloudFront Cache Hit Rate"
      AlarmDescription: "CDN eache monitor"
      MetricName: CacheHitRate
      Namespace: AWS/CloudFront
      Dimensions:
        - Name: DistributionId
          Value: !Ref CloudFrontDistro
      Statistic: Average
      Period: 300
      EvaluationPeriods: 1
      ComparisonOperator: LessThanOrEqualToThreshold
      Threshold: .80
      AlarmActions:
        - !Ref NotifyTopic


###################################################################################################
##   Template outputs                                                                            ##
###################################################################################################

Outputs:
  VueAppName:
    Description: Name of your application
    Value: !Ref AppName

  VueAppAPIRoot:
    Description: API Gateway endpoint URL for linker
    Value: !Sub "https://${CloudFrontDistro.DomainName}"
 
  VueAppAuthDomain: 
    Description: Domain used for authentication
    Value: !Sub https://${AppName}-${AWS::AccountId}.auth.${AWS::Region}.amazoncognito.com

  VueAppClientId: 
    Description: Cognito User Pool Client Id
    Value: !Ref UserPoolClient

  ClientDomainAddress:
    Description: Domain for client
    Value: !Join [ ".", [ https://master, !GetAtt AmplifyApp.DefaultDomain ]]

  AmplifyAppId:
    Description: Amplify application ID
    Value: !GetAtt AmplifyApp.AppId
  
  AmplifyEnvironmentUpdateCommand:
    Description: Command to add environment variables to the Amplify application
    Value: !Sub
      - aws amplify update-app --app-id ${AmplifyID} --environment-variables VUE_APP_NAME=${AppName},VUE_APP_CLIENT_ID=${UserPoolClient},VUE_APP_API_ROOT=${APIRoot},VUE_APP_AUTH_DOMAIN=${APIAuthDomain}
      - AmplifyID: !GetAtt AmplifyApp.AppId
        APIRoot: !Join ["", [ "https://", !GetAtt CloudFrontDistro.DomainName]]
        APIAuthDomain: !Sub https://${AppName}-${AWS::AccountId}.auth.${AWS::Region}.amazoncognito.com

  AmplifyDeployCommand:
    Description: Command to deploy the Amplify application
    Value: !Sub
      - aws amplify start-job --app-id ${AmplifyID} --branch-name master --job-type RELEASE
      - AmplifyID: !GetAtt AmplifyApp.AppId