PMTiles/serverless/aws/protomaps-template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description: Serve Z/X/Y tiles through CloudFront + Lambda from an existing S3 bucket.
Parameters:
  BucketName:
    Description: 'Name of an existing S3 bucket with .pmtiles tilesets. Should be in the same region as your CloudFormation stack.'
    Type: String
    MinLength: 1

  AllowedOrigins:
    Description: 'Comma-separated list of domains (e.g. example.com) allowed by browser CORS policy, or * for all origins.'
    Type: List<String>
    Default: "*"

  PublicHostname:
    Description: 'Optional. Replace *.cloudfront.net in TileJSON with a custom hostname (e.g. example.com). See docs on how this value is cached.'
    Type: String

Outputs:
  CloudFrontDistributionUrl:
    Description: 'URL of the CloudFront distribution'
    Value: !Sub "https://${CloudFrontDistribution.DomainName}"
    Export:
      Name: !Sub "${AWS::StackName}-CloudFrontDistributionURL"

Conditions:
  IsPublicHostnameProvided:
    Fn::Not:
      - Fn::Equals:
          - Ref: PublicHostname
          - ''
Resources:
  LogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub "/aws/lambda/${AWS::StackName}"
      RetentionInDays: 7

  LambdaExecutionRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      Policies:
        - PolicyName: !Sub "${AWS::StackName}-LambdaLoggingPolicy"
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - logs:CreateLogStream
                  - logs:PutLogEvents
                Resource: !Sub "arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/${AWS::StackName}:log-stream:*"
        - PolicyName: !Sub "${AWS::StackName}-LambdaS3AccessPolicy"
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action: s3:GetObject
                Resource: !Sub arn:aws:s3:::${BucketName}/*


  LambdaFunctionUrl:
    Type: 'AWS::Lambda::Url'
    Properties:
      AuthType: NONE
      TargetFunctionArn: !GetAtt LambdaFunction.Arn
      InvokeMode: BUFFERED

  LambdaFunctionUrlPermission:
    Type: 'AWS::Lambda::Permission'
    Properties:
      Action: lambda:InvokeFunctionUrl
      FunctionName: !Ref LambdaFunction
      Principal: '*'
      FunctionUrlAuthType: NONE

  ViewerRequestCloudFrontFunction:
    Type: AWS::CloudFront::Function
    Properties:
      Name: !Sub "${AWS::StackName}-ViewerRequestCloudFrontFunction"
      AutoPublish: true
      FunctionCode: |
        function handler(event) {
          const request = event.request;
          request.headers['x-distribution-domain-name'] = { value: event.context.distributionDomainName };
          return request;
        }
      FunctionConfig:
        Comment: 'Add x-distribution-domain header.'
        Runtime: cloudfront-js-2.0

  CloudFrontDistribution:
    Type: 'AWS::CloudFront::Distribution'
    DeletionPolicy: Delete
    Properties:
      DistributionConfig:
        Origins:
          - Id: LambdaOrigin
            DomainName: !Select [2, !Split ["/", !GetAtt LambdaFunctionUrl.FunctionUrl]]
            CustomOriginConfig:
              OriginProtocolPolicy: https-only
        DefaultCacheBehavior:
          TargetOriginId: LambdaOrigin
          ViewerProtocolPolicy: redirect-to-https
          CachePolicyId: !Ref CachePolicyId
          ResponseHeadersPolicyId: !Ref ResponseHeadersPolicyId
          OriginRequestPolicyId: b689b0a8-53d0-40ab-baf2-68738e2966ac
          FunctionAssociations:
            Fn::If:
              - IsPublicHostnameProvided
              - !Ref "AWS::NoValue"
              -
                - EventType: viewer-request
                  FunctionARN: !GetAtt ViewerRequestCloudFrontFunction.FunctionARN
        Enabled: true
        HttpVersion: http2and3
        Comment: "CloudFront Distribution"
        PriceClass: PriceClass_All  # Change this to save cost and distribute to fewer countries. Check https://aws.amazon.com/cloudfront/pricing/

  CachePolicyId:
    Type: 'AWS::CloudFront::CachePolicy'
    Properties:
      CachePolicyConfig:
        Name: !Sub "${AWS::StackName}-CachePolicyConfig"
        DefaultTTL: 86400
        MaxTTL: 31536000
        MinTTL: 0
        ParametersInCacheKeyAndForwardedToOrigin:
          EnableAcceptEncodingBrotli: true
          EnableAcceptEncodingGzip: true
          HeadersConfig:
            HeaderBehavior: none
          CookiesConfig:
            CookieBehavior: none
          QueryStringsConfig:
            QueryStringBehavior: none

  ResponseHeadersPolicyId:
    Type: 'AWS::CloudFront::ResponseHeadersPolicy'
    # DeletionPolicy: Delete
    Properties:
      ResponseHeadersPolicyConfig:
        Name: !Sub "${AWS::StackName}-ResponseHeadersPolicyConfig"
        CorsConfig:
          AccessControlAllowOrigins:
            Items: !Ref AllowedOrigins
          AccessControlAllowHeaders:
            Items:
              - '*'
          AccessControlAllowMethods:
            Items:
              - GET
              - HEAD
              - OPTIONS
          AccessControlExposeHeaders:
            Items:
              - ETag
          AccessControlAllowCredentials: false # Set to true if you want to include credentials
          OriginOverride: true
        Comment: 'CORS policy for Protomaps'

  LambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      FunctionName: !Sub "${AWS::StackName}-LambdaFunction"
      Runtime: nodejs20.x
      Architectures: [arm64]
      Role: !GetAtt LambdaExecutionRole.Arn
      Handler: index.handler
      MemorySize: 512
      LoggingConfig:
        LogGroup: !Ref LogGroup
      Environment:
        Variables:
          BUCKET: !Ref BucketName
          PUBLIC_HOSTNAME: !Ref PublicHostname
      Code:
        S3Bucket: !Ref BucketName
        S3Key: lambda_function.zip