Method set_policy

python/example_code/kms/key_policies.py:92–135

Sets the policy of a key. Setting a policy entirely overwrites the existing policy, so care is taken to add a statement to the existing list of statements rather than simply writing a new policy. :param key_id: The ARN or ID of the key to set the policy to.

(self, key_id: str, policy: dict[str, any])

    # snippet-start:[python.example_code.kms.PutKeyPolicy]
    def set_policy(self, key_id: str, policy: dict[str, any]) -> None:
        """
        Sets the policy of a key. Setting a policy entirely overwrites the existing
        policy, so care is taken to add a statement to the existing list of statements
        rather than simply writing a new policy.

        :param key_id: The ARN or ID of the key to set the policy to.
        :param policy: The existing policy of the key.
        :return: None
        """
        principal = input(
            "Enter the ARN of an IAM role to set as the principal on the policy: "
        )
        if key_id != "" and principal != "":
            # The updated policy replaces the existing policy. Add a new statement to
            # the list along with the original policy statements.
            policy["Statement"].append(
                {
                    "Sid": "Allow access for ExampleRole",
                    "Effect": "Allow",
                    "Principal": {"AWS": principal},
                    "Action": [
                        "kms:Encrypt",
                        "kms:GenerateDataKey*",
                        "kms:Decrypt",
                        "kms:DescribeKey",
                        "kms:ReEncrypt*",
                    ],
                    "Resource": "*",
                }
            )
            try:
                self.kms_client.put_key_policy(KeyId=key_id, Policy=json.dumps(policy))
            except ClientError as err:
                logger.error(
                    "Couldn't set policy for key %s. Here's why %s",
                    key_id,
                    err.response["Error"]["Message"],
                )
                raise
            else:
                print(f"Set policy for key {key_id}.")
        else:
            print("Skipping set policy demo.")

    # snippet-end:[python.example_code.kms.PutKeyPolicy]