Configuring CORS

If you do not have the Yandex Cloud CLI yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder through the --folder-name or --folder-id parameter.

1. See the description of the CLI command for updating a bucket:

   yc storage bucket update --help
   

2. Get a list of buckets in the default folder:

   yc storage bucket list
   

   Result:

   +------------------+----------------------+-------------+-----------------------+---------------------+
   |       NAME       |      FOLDER ID       |  MAX SIZE   | DEFAULT STORAGE CLASS |     CREATED AT      |
   +------------------+----------------------+-------------+-----------------------+---------------------+
   | first-bucket     | b1gmit33ngp6******** | 53687091200 | STANDARD              | 2022-12-16 13:58:18 |
   +------------------+----------------------+-------------+-----------------------+---------------------+
   

3. Save the name (from the NAME column) of the bucket to configure CORS for.

4. Run this command:

   yc storage bucket update \
     --name <bucket_name> \
     --cors <CORS_parameter>='[<array_of_values>]',<CORS_parameter>='[<array_of_values>]',...
   

   Where:

   • --name: Name of the bucket to configure CORS for.

   • --cors: CORS parameters:

     • allowed-methods: List of methods. The possible values are method-get, method-put, method-post, method-delete, and method-head. This is a required parameter.
     • allowed-origins: List of websites allowed to send CORS requests to the bucket. This is a required parameter.
     • allowed-headers: List of allowed headers. This is an optional parameter.
     • expose-headers: List of headers that can be exposed to browser JavaScript apps. This is an optional parameter.
     • max-age-seconds: Time for which the browser caches object request results, in seconds. This is an optional parameter.

     Parameter values are specified in quotes and square brackets. List items in values are separated by commas with no spaces, e.g., --cors allowed-methods='[method-get,method-head]',allowed-origins='[example.com]'.

     Permissions you specify in the command will override the current CORS settings of the bucket. To get the current permissions, use the yc storage bucket get <bucket_name> --full command.

     Result:

     name: first-bucket
     folder_id: b1gmit33ngp6********
     default_storage_class: STANDARD
     versioning: VERSIONING_DISABLED
     max_size: "53687091200"
     acl: {}
     created_at: "2022-11-25T11:48:42.024638Z"
     

To delete the CORS configuration, run this command:

yc storage bucket update \
  --name <bucket_name> \
  --remove-cors

To upload a configuration using the AWS CLI:

1. Define the CORS object configuration in JSON format. Here is an example:

   {
     "CORSRules": [
       {
         "AllowedHeaders": ["*"],
         "AllowedMethods": ["GET", "HEAD", "PUT", "DELETE"],
         "MaxAgeSeconds": 3000,
         "AllowedOrigins": ["*"]
       }
     ]
   }
   

   Once the configuration is complete, save it to a file, e.g., cors.json.

2. Upload the configuration to a bucket, e.g., shared-bucket:

   aws s3api put-bucket-cors \
     --bucket shared-bucket \
     --cors-configuration file://cors.json \
     --endpoint-url=https://storage.yandexcloud.net
   

If you don't have Terraform, install it and configure the Yandex Cloud provider.

Retrieve static access keys: a secret key and key ID used for Object Storage authentication.

1. In the configuration file, define the parameters of the resources you want to create:

   provider "yandex" {
     cloud_id  = "<cloud_ID>"
     folder_id = "<folder_ID>"
     zone      = "<availability_zone>"
     token     = "<OAuth_token>"
     }
   
   resource "yandex_iam_service_account" "sa" {
     name = "<service_account_name>"
   }
   
   // Assigning a role to a service account
   resource "yandex_resourcemanager_folder_iam_member" "sa-admin" {
     folder_id = "<folder_ID>"
     role      = "storage.admin"
     member    = "serviceAccount:${yandex_iam_service_account.sa.id}"
   }
   
   // Creating a static access key
   resource "yandex_iam_service_account_static_access_key" "sa-static-key" {
     service_account_id = yandex_iam_service_account.sa.id
     description        = "static access key for object storage"
   }
   
   resource "yandex_storage_bucket" "b" {
     bucket = "s3-website-test.hashicorp.com"
     acl    = "public-read"
   
     access_key = yandex_iam_service_account_static_access_key.sa-static-key.access_key
     secret_key = yandex_iam_service_account_static_access_key.sa-static-key.secret_key
   
     cors_rule {
       allowed_headers = ["*"]
       allowed_methods = ["PUT", "POST"]
       allowed_origins = ["https://s3-website-test.hashicorp.com"]
       expose_headers  = ["ETag"]
       max_age_seconds = 3000
     }
   }
   

   Where:

   • access_key: Static access key ID.
   • secret_key: Secret access key value.
   • bucket: Bucket name. This is a required parameter.
   • acl: ACL policy to apply. This is an optional parameter.

   CORS parameters:

   • allowed_headers: Allowed headers. This is an optional parameter.
   • allowed_methods: Allowed methods. The possible values are GET, PUT, POST, DELETE or HEAD. This is a required parameter.
   • allowed_origins: Website allowed to send CORS requests to the bucket. This is a required parameter.
   • expose_headers: Header that can be exposed to browser JavaScript apps. This is an optional parameter.
   • max_age_seconds: Time for which the browser caches object request results, in seconds. This is an optional parameter.
   • server_side_encryption_configuration: Bucket's server-side encryption configuration. This is an optional parameter.

   For more information about the resources you can create with Terraform, see this provider reference.

2. Make sure the configuration files are correct.

   1. In the command line, go to the directory where you created the configuration file.

   2. Run a check using this command:

      terraform plan
      

   If you described the configuration correctly, the terminal will display a list of the resources being created and their parameters. If the configuration contains any errors, Terraform will point them out.

3. Deploy the cloud resources.

   1. If the configuration does not contain any errors, run this command:

      terraform apply
      

   2. Confirm creating the resources.

   This will create all the resources you need in the specified folder. You can check the new resources and their settings using the management console.

To manage CORS configurations for buckets, use the update REST API method for the Bucket resource, the BucketService/Update gRPC API call, or the upload S3 API method.