package com.thinkbiganalytics.nifi.security;
/*-
* #%L
* thinkbig-nifi-security-api
* %%
* Copyright (C) 2017 ThinkBig Analytics
* %%
* Licensed 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
* #L%
*/
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.nifi.logging.ComponentLog;
import java.io.IOException;
/**
* Periodically attempts to renew the Kerberos user's ticket for the given UGI.
*
* This class will attempt to call ugi.checkTGTAndReloginFromKeytab() which
* will re-login the user if the ticket expired or is close to expiry. Between
* relogin attempts this thread will sleep for the provided amount of time.
*/
public class KerberosTicketRenewer implements Runnable {
private final UserGroupInformation ugi;
private final long renewalPeriod;
private final ComponentLog logger;
private volatile boolean stopped = false;
/**
* @param ugi the user to renew the ticket for
* @param renewalPeriod the amount of time in milliseconds to wait between renewal attempts
* @param logger the logger from the component that started the renewer
*/
public KerberosTicketRenewer(final UserGroupInformation ugi, final long renewalPeriod, final ComponentLog logger) {
this.ugi = ugi;
this.renewalPeriod = renewalPeriod;
this.logger = logger;
}
@Override
public void run() {
stopped = false;
while (!stopped) {
try {
logger.debug("Invoking renewal attempt for Kerberos ticket");
// While we run this "frequently", the Hadoop implementation will only perform the login at 80% of ticket lifetime.
ugi.checkTGTAndReloginFromKeytab();
} catch (IOException e) {
logger.error("Failed to renew Kerberos ticket", e);
}
// Wait for a bit before checking again.
try {
Thread.sleep(renewalPeriod);
} catch (InterruptedException e) {
logger.error("Renewal thread interrupted", e);
Thread.currentThread().interrupt();
return;
}
}
}
public void stop() {
stopped = true;
}
}