serverless.yml

# Welcome to Serverless!
#
# This file is the main config file for your service.
# It's very minimal at this point and uses default values.
# You can always add more config options for more control.
# We've included some commented out config examples here.
# Just uncomment any of them to get that config option.
#
# For full config options, check the docs:
#    docs.serverless.com
#
# Happy Coding!

service: s3-presigned-url

provider:
  name: aws
  runtime: nodejs12.x
  environment:
    S3_BUCKET: { Ref: S3Bucket }
  iamRoleStatements: # Signed URL will have same permissions as the IAM Role
    - Effect: Allow
      Action:
        - s3:PutObject
      Resource: { Fn::Join: ['', [{ Fn::GetAtt: [S3Bucket, Arn] }, '/*']] } # arn:aws:s3:::bucketName/*

functions:
  signedUrl:
    handler: handler.signedUrl
    events:
      - http: GET /signed-upload-url

resources:
  Resources:
    S3Bucket:
      Type: AWS::S3::Bucket
      Properties:
        CorsConfiguration:
          CorsRules:
            - AllowedHeaders: ['*']
              AllowedMethods: [GET, POST, PUT]
              AllowedOrigins: ['*']
    S3BucketPolicy: # Allow uploaded files to be public and downloadable
      Type: AWS::S3::BucketPolicy
      Properties:
        Bucket: { Ref: S3Bucket }
        PolicyDocument:
          Statement:
            - Action:
                - 's3:GetObject'
              Effect: 'Allow'
              Resource: { Fn::Join: ['', [{ Fn::GetAtt: [S3Bucket, Arn] }, '/*']] } # arn:aws:s3:::bucketName/*
              Principal: '*'