class Google::Cloud::Storage::Policy
# Policy
An abstract Cloud
IAM Policy
for the Cloud
Storage
service. See concrete subclasses {Google::Cloud::Storage::PolicyV1} and {Google::Cloud::Storage::PolicyV3}.
A common pattern for updating a resource's metadata, such as its Policy
, is to read the current data from the service, update the data locally, and then send the modified data for writing. This pattern may result in a conflict if two or more processes attempt the sequence simultaneously. IAM solves this problem with the {Google::Cloud::Storage::Policy#etag} property, which is used to verify whether the policy has changed since the last request. When you make a request to with an `etag` value, Cloud
IAM compares the `etag` value in the request with the existing `etag` value associated with the policy. It writes the policy only if the `etag` values match.
When you update a policy, first read the policy (and its current `etag`) from the service, then modify the policy locally, and then write the modified policy to the service. See {Google::Cloud::Storage::Bucket#policy} and {Google::Cloud::Storage::Bucket#policy=}.
@see cloud.google.com/iam/docs/managing-policies Managing
policies
@see cloud.google.com/storage/docs/json_api/v1/buckets/setIamPolicy
Buckets: setIamPolicy
@attr [String] etag Used to verify whether the policy has changed since
the last request. The policy will be written only if the `etag` values match.
@attr [Integer] version The syntax schema version of the policy. Each version
of the policy contains a specific syntax schema that can be used by bindings. The newer version may contain role bindings with the newer syntax schema that is unsupported by earlier versions. This field is not intended to be used for any purposes other than policy syntax schema control. The following policy versions are valid: * 1 - The first version of Cloud IAM policy schema. Supports binding one role to one or more members. Does not support conditional bindings. * 3 - Introduces the condition field in the role binding, which further constrains the role binding via context-based and attribute-based rules. See [Understanding policies](https://cloud.google.com/iam/docs/policies) and [Overview of Cloud IAM Conditions](https://cloud.google.com/iam/docs/conditions-overview) for more information.
Attributes
Public Class Methods
@private Creates a Policy
object.
# File lib/google/cloud/storage/policy.rb, line 77 def initialize etag, version @etag = etag @version = version end