Sharing Object Storage buckets in read-only mode

Before you start

To complete the actions presented below, you must have:

• Owner status or IAM permissions allowing you to perform actions in the intended Organization
• Installed the AWS CLI
• An Object Storage bucket

You can implement a bucket policy to grant a Scaleway Organization or Project Read rights to a bucket in a different Project.

Principle

For example, you are logged in to Organization A and you have a bucket (A1) inside Project A. You wish to share the bucket in read-only mode with users in Organization B, Project B.

To do so, you have to apply a policy to bucket A1 that grants access to Organization B or Project B and include which API calls they are allowed to make.

To guarantee that they can only view contents, include "s3:ListBucket" and "s3:GetObject" under Action in the bucket-policy.json file you create.

Specify which resources they can access under Resource:

• "<BUCKET_NAME>": Grants access to the bucket, but not to the objects inside. If the s3:ListBucket action is applied, this resource specification is required.

• "<BUCKET_NAME>/*": Grants access to all objects inside a bucket, but not to the bucket itself. If the s3:GetObject action is applied, this resource specification is required.

• "<BUCKET_NAME>/<PREFIX>/*": Grants access only to objects with the specified prefix inside a bucket, but not to the bucket itself. For example, if you apply a bucket policy that specifies "my_files/movie/*" under Resource, you would grant access to all objects with the movie/ prefix, but not to other objects in my_files/ bucket. If the s3:GetObject action is applied, this resource specification is required.

Creating the bucket policy

1. Create a file named bucket-policy.json and add the following code to it:

{
    "Version": "2012-10-17",
    "Id": "Mybucketpolicy",
    "Statement": [
        {
            "Sid": "DelegateAccess",
            "Effect": "Allow",
            "Principal": {
                "SCW": "project_id:<PROJECT_ID>"
            },
            "Action": [
                "s3:ListBucket",
                "s3:GetObject"
            ],
            "Resource": [
                "<BUCKET_NAME>",
                "<BUCKET_NAME>/*"
            ]
        }
    ]
}

2. Apply the policy using the PutBucketPolicy API call or run the following aws-cli command:

   aws s3api put-bucket-policy --bucket <SOURCE_BUCKET> --profile default_project --policy file://bucket-policy.json

   Note

   Refer to the dedicated documentation for more information on how to create bucket policies.

You can now provide the user in Organization B with the name of your bucket. If the policy is correctly applied, they will be able to see bucket A1 included in their bucket list when running List_Buckets. If they know the name of an object, they can view its details by running Get_Object.