template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Create thumbnails from files uploaded to S3 
Parameters:
  AppStage:
    Type: String
    Default: api
    Description: API Gateway stage, used as a prefix for the endpoint URLs
    AllowedPattern: ^[A-Za-z]+$
    MaxLength: 10
    MinLength: 1
    ConstraintDescription: "1-10 Latin letters"
  UploadLimitInMb:
    Type: Number 
    Default: 5
    Description: Maximum upload size in megabytes
    MinValue: 1
    MaxValue: 100
  ThumbnailWidth:
    Type: Number 
    Default: 300
    Description: Thumbnail width in pixels 
    MinValue: 10
    MaxValue: 1000
  AllowedImageExtensions:
    Type: String
    Default: jpg,jpeg,png,gif
    Description: Comma-delimited list of allowed image file extensions (lowercase)
Resources:
  WebAssetsS3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      WebsiteConfiguration:
        ErrorDocument: 404.html
        IndexDocument: index.html
  UploadS3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      CorsConfiguration:
        CorsRules:
          - AllowedHeaders:
              - "*"
            AllowedMethods:
              - POST
            AllowedOrigins: 
              - !GetAtt WebAssetsS3Bucket.WebsiteURL
            MaxAge: 3600
  ThumbnailsS3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      CorsConfiguration:
        CorsRules:
          - AllowedHeaders:
              - "*"
            AllowedMethods:
              - GET
            AllowedOrigins: 
              - !GetAtt WebAssetsS3Bucket.WebsiteURL
            MaxAge: 3600
  WebApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: !Ref AppStage
      Cors: !Sub "'${WebAssetsS3Bucket.WebsiteURL}'"
      MethodSettings:
        - ResourcePath: '/*'
          HttpMethod: '*'
          ThrottlingBurstLimit: 20
          ThrottlingRateLimit: 10
  ShowFormFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: user-form/
      Handler: show_form.lambda_handler
      Runtime: python3.8
      Events:
        ShowForm:
          Type: Api
          Properties:
            Path: /sign/{extension}
            Method: get
            RestApiId: !Ref WebApi
      Environment: 
        Variables:
          UPLOAD_S3_BUCKET: !Ref UploadS3Bucket
          UPLOAD_LIMIT_IN_MB: !Ref UploadLimitInMb
          CORS_ORIGIN: !GetAtt WebAssetsS3Bucket.WebsiteURL
          THUMBNAILS_S3_BUCKET: !Ref ThumbnailsS3Bucket
          ALLOWED_IMAGE_EXTENSIONS: !Ref AllowedImageExtensions
      Policies:
        - S3FullAccessPolicy:
            BucketName: !Ref UploadS3Bucket
        - S3ReadPolicy:
            BucketName: !Ref ThumbnailsS3Bucket
  ImageMagick:
    Type: AWS::Serverless::Application
    Properties:
      Location:
        ApplicationId: arn:aws:serverlessrepo:us-east-1:145266761615:applications/image-magick-lambda-layer
        SemanticVersion: 1.0.0
  ConvertFileFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: image-conversion/
      Handler: index.lambda_handler
      Runtime: python3.8
      Events:
        FileUploaded:
          Type: S3
          Properties:
            Bucket: !Ref UploadS3Bucket
            Events: s3:ObjectCreated:*
      Timeout: 600
      MemorySize: 1024
      ReservedConcurrentExecutions: 10
      Environment: 
        Variables:
          OUTPUT_BUCKET: !Ref ThumbnailsS3Bucket
          THUMB_WIDTH: !Ref ThumbnailWidth
      Policies:
        - S3FullAccessPolicy:
            BucketName: !Ref ThumbnailsS3Bucket
      Layers:
        - !GetAtt ImageMagick.Outputs.LayerVersion
  ConvertFunctionCanReadUploads:
    Type: AWS::IAM::Policy
    Properties: 
      PolicyName: ConvertFunctionCanReadUploads
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
              - "s3:GetObject"
            Resource: 
              - !Sub "${UploadS3Bucket.Arn}/*"
      Roles:
        - !Ref ConvertFileFunctionRole
  DeployToS3:
    Type: AWS::Serverless::Application
    Properties:
      Location:
        ApplicationId: arn:aws:serverlessrepo:us-east-1:375983427419:applications/deploy-to-s3
        SemanticVersion: 1.0.0
  SiteSource:
    Type: AWS::Serverless::Function
    Properties:
      Layers: 
        - !GetAtt DeployToS3.Outputs.Arn
      CodeUri: web-site/
      AutoPublishAlias: production
      Runtime: python3.8
      Handler: deployer.resource_handler
      Timeout: 600
      Policies:
        - S3FullAccessPolicy:
            BucketName: !Ref WebAssetsS3Bucket
  DeploymentResource:
    Type: AWS::CloudFormation::CustomResource
    Properties:
      ServiceToken: !GetAtt SiteSource.Arn
      Version: !Ref "SiteSource.Version"
      TargetBucket: !Ref WebAssetsS3Bucket
      Substitutions:
        FilePattern: "*.html"
        Values:
          API_URL: !Sub "https://${WebApi}.execute-api.${AWS::Region}.amazonaws.com/${AppStage}/"
      Acl: 'public-read'
      CacheControlMaxAge: 600
Outputs:
  UserFormApi:
    Description: "API Gateway endpoint URL"
    Value: !Sub "https://${WebApi}.execute-api.${AWS::Region}.amazonaws.com/${AppStage}/"
  UploadBucket:
    Description: "S3 Bucket for user information"
    Value: !Ref UploadS3Bucket
  ThumbnailsS3Bucket:
    Description: "S3 Bucket for thumbnails"
    Value: !Ref ThumbnailsS3Bucket
  WebUrl:
    Description: "Public web URL"
    Value: !GetAtt WebAssetsS3Bucket.WebsiteURL
Metadata:
  AWS::ServerlessRepo::Application:
    Name: image-thumbnails
    Description: >
      A sample application for the Running Serverless book tutorial by Gojko Adzic rewritten in Python
    Author: Thomas Braam
    SemanticVersion: 1.0.0
    SpdxLicenseId: MIT
    LicenseUrl: LICENSE.md
    ReadmeUrl: README.md 
    Labels: ['layer', 'image', 'lambda', 'imagemagick', 'python']
    HomePageUrl: https://runningserverless.com
    SourceCodeUrl: https://runningserverless.com