io.mantisrx.server.master.ServiceLifecycle Maven / Gradle / Ivy
/*
* Copyright 2019 Netflix, Inc.
*
* 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.
*/
package io.mantisrx.server.master;
import io.mantisrx.server.core.BaseService;
import java.util.Iterator;
import java.util.LinkedList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Manage lifecycle of services. Services added in an order are started in the same order and shutdown in the reverse
* order. Each service being added is implicitly given the previously added service as its predecessor. This class
* currently represents a model of a linear list of services, each depending on only the previous service in the list.
*/
public class ServiceLifecycle {
private static final Logger logger = LoggerFactory.getLogger(ServiceLifecycle.class);
private LinkedList servicesList = new LinkedList();
void addService(BaseService service) {
if (!servicesList.isEmpty()) {
service.addPredecessor(servicesList.getLast());
}
servicesList.add(service);
}
void start() {
for (BaseService service : servicesList) {
try {
logger.info("Starting service " + service.getMyServiceCount() + ": " + service);
service.start();
logger.info("Successfully started service " + service.getMyServiceCount() + ": " + service);
} catch (Exception e) {
logger.error(String.format("Failed to start service %d: %s: %s", service.getMyServiceCount(), service, e.getMessage()), e);
throw e;
}
}
}
void becomeLeader() {
for (BaseService service : servicesList) {
service.enterActiveMode();
}
}
void shutdown() {
if (!servicesList.isEmpty()) {
Iterator iterator = servicesList.descendingIterator();
while (iterator.hasNext()) {
BaseService service = iterator.next();
logger.info("Shutting down service " + service.getMyServiceCount() + ": " + service);
service.shutdown();
logger.info("Successfully shut down service " + service.getMyServiceCount() + ": " + service);
}
}
}
}