S3 Static Hosting + CloudFormation + CORS + YAML

s3_cf_cors.yaml

---
Parameters:
  S3BucketName:
    Description: "The name of the S3 bucket that will store the website files"
    Type: String

Resources:
  WebsiteBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName:
        Ref: S3BucketName
      AccessControl: PublicRead
      WebsiteConfiguration:
        IndexDocument: index.html
        # ErrorDocument: error.html 
      CorsConfiguration:
        # THIS was the part where my brain melted
        CorsRules:
          - 
            AllowedMethods: 
              - GET
            AllowedOrigins: 
              - "*"
            AllowedHeaders: 
              - "*"

  WebsiteBucketBucketPolicy:
      Type: AWS::S3::BucketPolicy
      Properties:
        PolicyDocument:
          Id: PublicAccessPolicy
          Version: 2012-10-17
          Statement:
            - Sid: PublicReadForGetBucketObjects
              Effect: Allow
              Principal: '*'
              Action: 's3:GetObject'
              Resource: !Join 
                - ''
                - - 'arn:aws:s3:::'
                  - !Ref WebsiteBucket
                  - /*
        Bucket: !Ref WebsiteBucket

Outputs:
  WebsiteURL:
    Value: !GetAtt 
      - WebsiteBucket
      - WebsiteURL
    Description: URL for website hosted on S3