001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.fs.adl.oauth2;
020
021import org.apache.hadoop.classification.InterfaceAudience;
022import org.apache.hadoop.classification.InterfaceStability;
023import org.apache.hadoop.conf.Configuration;
024
025import java.io.IOException;
026import java.util.Date;
027
028/**
029 * Provide an Azure Active Directory supported
030 * OAuth2 access token to be used to authenticate REST calls against Azure data
031 * lake file system {@link org.apache.hadoop.fs.adl.AdlFileSystem}.
032 */
033@InterfaceAudience.Public
034@InterfaceStability.Evolving
035public abstract class AzureADTokenProvider {
036
037  /**
038   * Initialize with supported configuration. This method is invoked when the
039   * {@link org.apache.hadoop.fs.adl.AdlFileSystem#initialize
040   * (URI, Configuration)} method is invoked.
041   *
042   * @param configuration Configuration object
043   * @throws IOException if instance can not be configured.
044   */
045  public abstract void initialize(Configuration configuration)
046      throws IOException;
047
048  /**
049   * Obtain the access token that should be added to https connection's header.
050   * Will be called depending upon {@link #getExpiryTime()} expiry time is set,
051   * so implementations should be performant. Implementations are responsible
052   * for any refreshing of the token.
053   *
054   * @return String containing the access token
055   * @throws IOException if there is an error fetching the token
056   */
057  public abstract String getAccessToken() throws IOException;
058
059  /**
060   * Obtain expiry time of the token. If implementation is performant enough to
061   * maintain expiry and expect {@link #getAccessToken()} call for every
062   * connection then safe to return current or past time.
063   *
064   * However recommended to use the token expiry time received from Azure Active
065   * Directory.
066   *
067   * @return Date to expire access token retrieved from AAD.
068   */
069  public abstract Date getExpiryTime();
070}