Allowed to use empty AWS credentials (accessKeyId, secretAccessKey)

[antonbezpalov-flixbus]

Hi, in our case we use AWS IAM roles as credentials that don't require to use AWS accessKeyId and secretAccessKey for S3 buckets (and others services). Unfortunately with current implementation if we configure jsreport.config.json like this:

"fs-store-aws-s3-persistence": {
      "accessKeyId": "",
      "secretAccessKey": "",
     ...
    }

it throws an error in fileSystemS3.js:11.

If we use some dummy credentials:

"fs-store-aws-s3-persistence": {
      "accessKeyId": "secret",
      "secretAccessKey": "secret",
     ...
    }

AWS S3 service starts to check accessKeyId and secretAccessKey and forbid to connect.

Our suggestion is to check not for falsy values but for undefined/null values which will allow to use empty strings. So if somebody is using AWS IAM roles as credentials it is possible to configure like that:

"fs-store-aws-s3-persistence": {
      "accessKeyId": "",
      "secretAccessKey": "",
      "bucket": "bucket-name",
     ...
    }

[pofider]

Thanks. You can get this in 1.2.3 npm release.