[Extensions] Create an interface that Job Scheduler can use to manage user info associated with a scheduled job

[cwperks]

Job Scheduler is responsible for invoking scheduled jobs registered by plugins/extensions. In the new security model for extensions, user info is stored in a single secure index that is not owned by the respective plugin/extensions that create scheduled jobs. Job Scheduler needs to an interface to invoke methods to save user details, delete user details (when job is deleted) and another method to issue an access token to be used for job execution.

Some pseudo-code of a ScheduledJobIdentityManager:

/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

package org.opensearch.identity;

import org.opensearch.identity.tokens.AuthToken;

/**
 * An interface with methods used to provide security for scheduled jobs
 *
 * @opensearch.experimental
 */
public interface ScheduledJobIdentityManager {

    /**
     * Method implemented by an identity plugin to store user information for a scheduled job
     * @param jobId The id of the scheduled job
     * @param indexName The index where scheduled job details is stored
     */
    void saveUserDetails(String jobId, String indexName);

    /**
     * Method implemented by an identity plugin to delete user information for a scheduled job
     * @param jobId The id of the scheduled job
     * @param indexName The index where scheduled job details is stored
     */
    void deleteUserDetails(String jobId, String indexName);

    /**
     * Method implemented by an identity plugin to issue an access token for a scheduler job runner
     * @param jobId The id of the scheduled job
     * @param indexName The index where scheduled job details is stored
     */
    AuthToken issueAccessTokenOnBehalfOfUser(String jobId, String indexName);
}

[stephen-crawford]

[Triage] This is part of the Extensions project.