template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  resolution-service

  SAM Template for resolution-service

Globals:
  Function:
    Timeout: 30

###################################################################################################
##   Template Parameters                                                                         ##
###################################################################################################

Parameters:
    TargetTableName:
      Type: String
    Image404:
      Type: String
    Region:
      Type: String

###################################################################################################
##   Template Resources                                                                          ##
###################################################################################################

Resources:
  ##   Lambda Function
  NameResolutionFunction:
    Type: AWS::Serverless::Function 
    Properties:
      CodeUri: apps/
      Handler: app.lambda_handler
      Runtime: python3.7
      Description: An AWS Lambda function with API Gateway that receives a short URL, finds a record in the DynamoDB table, redirects user to the long URL.
      MemorySize: 128
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref TargetTableName
      Environment:
        Variables:
          DEBUG: 1
          TargetTable: !Ref TargetTableName
          Region: !Ref Region
          Image404: !Ref Image404
      Events:
        ResolutionServiceApi:
          Type: Api
          Properties:
            RestApiId: !Ref ResolutionServiceApiGateway
            Path: /{arklabel}/53696/{shortid}
            Method: GET

  ##   API Gateway
  ResolutionServiceApiGateway:
    Type: AWS::Serverless::Api
    Properties:
      Name: !Join [ "-", [ "Resolution Service API", !Ref TargetTableName] ]
      StageName: Prod
      EndpointConfiguration: Edge
      TracingEnabled: true
      DefinitionBody:
        openapi: "3.0.1"
        info:
          title: "Resolution Service API"
          version: "1.0.3"

        x-amazon-apigateway-request-validators:
          all:
            validateRequestBody: true
            validateRequestParameters: true
          params:
            validateRequestBody: false
            validateRequestParameters: true
          body:
            validateRequestBody: true
            validateRequestParameters: false

        paths:
          /{arklabel}/53696/{shortid}:
            ## URL redirector
            get:
              summary: Get a url by ID and redirect
              responses:
                "301":
                  description: "301 redirect"
                  headers:
                    Location:
                      type: "string"
              ## API Gateway Integration
              x-amazon-apigateway-integration:
                uri:
                  Fn::Sub: 'arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${NameResolutionFunction.Arn}/invocations' #NameResolutionFunction.Arn
                httpMethod: "POST"
                requestTemplates:
                  application/json: "{\"arklabel\": \"ark:\", \"short_id\": \"$input.params('shortid')\"}"
                passthroughBehavior: "when_no_templates"
                responses:
                  "":
                    statusCode: "301"
                    responseParameters:
                      method.response.header.Location: "integration.response.body.location"
                type: aws


  ##   CloudFront distribution
  CloudFrontDistro:
    Type: AWS::CloudFront::Distribution
    Properties:
      DistributionConfig:
        Comment: Name Resolution CDN
        DefaultCacheBehavior:
          AllowedMethods: ["GET", "HEAD"]
          CachedMethods: ["GET", "HEAD"]
          Compress: true
          DefaultTTL: 0
          ForwardedValues:
            Headers:
            - Origin
            QueryString: false
          TargetOriginId: "ResolutionServiceAPIGW"
          ViewerProtocolPolicy: redirect-to-https
        Enabled: true
        Origins:
          - CustomOriginConfig:
              OriginProtocolPolicy: https-only
            DomainName: !Sub ${ResolutionServiceApiGateway}.execute-api.${AWS::Region}.amazonaws.com
            Id: "ResolutionServiceAPIGW"
            OriginPath: /Prod

Outputs:
  NameResolutionFunction:
    Description: "Name Resolution Lambda Function ARN"
    Value: !GetAtt NameResolutionFunction.Arn
  NameResolutionFunctionIamRole:
    Description: "Implicit IAM Role created for Name Resolution function"
    Value: !GetAtt NameResolutionFunctionRole.Arn
  ResolutionServiceApiGateway:
    Description: 'API Gateway endpoint URL for Prod stage for Name Resolution function'
    Value: !Sub 'https://${ResolutionServiceApiGateway}.execute-api.${AWS::Region}.amazonaws.com/Prod/{arklabel}/53696/{shortid}'
  ResolutionServiceApiGatewayRestApiId:
    Description: 'API Gateway Rest API Id for Name Resolution API Gateway'
    Value: !Ref ResolutionServiceApiGateway
  ResolutionServiceApiGatewayRootResourceId:
    Description: 'API Gateway Root Resource Id for Name Resolution API Gateway'
    Value: !GetAtt ResolutionServiceApiGateway.RootResourceId