/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.sqoop.authentication;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.UserGroupInformation;

import java.io.IOException;

public class KerberosAuthenticator {

  private final Configuration configuration;

  private final String principal;

  private final String keytabLocation;

  public KerberosAuthenticator(Configuration configuration, String principal, String keytabLocation) {
    this.configuration = configuration;
    this.principal = principal;
    this.keytabLocation = keytabLocation;
  }

  public UserGroupInformation authenticate() {
    UserGroupInformation.setConfiguration(configuration);
    try {
      return UserGroupInformation.loginUserFromKeytabAndReturnUGI(principal, keytabLocation);
    } catch (IOException e) {
      throw new RuntimeException("Kerberos authentication failed!", e);
    }
  }

  public Configuration getConfiguration() {
    return configuration;
  }

  public String getPrincipal() {
    return principal;
  }

  public String getKeytabLocation() {
    return keytabLocation;
  }
}
