/*
* Copyright © 2014 Cask Data, 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 co.cask.tigon.internal.app.runtime.flow;
import co.cask.tigon.api.flow.flowlet.Flowlet;
import co.cask.tigon.api.flow.flowlet.FlowletContext;
import co.cask.tigon.internal.app.runtime.AbstractProgramController;
import co.cask.tigon.internal.app.runtime.ProgramOptionConstants;
import com.google.common.base.Preconditions;
import com.google.common.io.Closeables;
import com.google.common.util.concurrent.Service;
import org.apache.twill.common.ServiceListenerAdapter;
import org.apache.twill.common.Threads;
import org.apache.twill.discovery.ServiceDiscovered;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collection;
/**
* A {@link co.cask.tigon.internal.app.runtime.ProgramController} for controlling a running flowlet.
*/
final class FlowletProgramController extends AbstractProgramController {
private static final Logger LOG = LoggerFactory.getLogger(FlowletProgramController.class);
private final BasicFlowletContext flowletContext;
private final FlowletProcessDriver driver;
private final Collection<ConsumerSupplier<?>> consumerSuppliers;
/**
* Constructs an instance. The instance must be constructed before the flowlet driver starts.
*/
FlowletProgramController(String programName, String flowletName,
BasicFlowletContext flowletContext, FlowletProcessDriver driver,
Collection<ConsumerSupplier<?>> consumerSuppliers) {
super(programName + ":" + flowletName, flowletContext.getRunId());
this.flowletContext = flowletContext;
this.driver = driver;
this.consumerSuppliers = consumerSuppliers;
listenDriveState(driver);
}
@Override
protected void doSuspend() throws Exception {
LOG.info("Suspending flowlet: " + flowletContext);
driver.suspend();
// Close all consumers
for (ConsumerSupplier consumerSupplier : consumerSuppliers) {
consumerSupplier.close();
}
LOG.info("Flowlet suspended: " + flowletContext);
}
@Override
protected void doResume() throws Exception {
LOG.info("Resuming flowlet: " + flowletContext);
// Open consumers
for (ConsumerSupplier consumerSupplier : consumerSuppliers) {
consumerSupplier.open(flowletContext.getInstanceCount());
}
driver.resume();
LOG.info("Flowlet resumed: " + flowletContext);
}
@Override
protected void doStop() throws Exception {
LOG.info("Stopping flowlet: " + flowletContext);
try {
driver.stopAndWait();
} finally {
// Close all consumers
for (ConsumerSupplier consumerSupplier : consumerSuppliers) {
Closeables.closeQuietly(consumerSupplier);
}
flowletContext.close();
}
LOG.info("Flowlet stopped: " + flowletContext);
}
@Override
protected void doCommand(String name, Object value) throws Exception {
Preconditions.checkState(getState() == State.SUSPENDED,
"Cannot change instance count when flowlet is running.");
if (!ProgramOptionConstants.INSTANCES.equals(name) || !(value instanceof Integer)) {
return;
}
int instances = (Integer) value;
LOG.info("Change flowlet instance count: " + flowletContext + ", new count is " + instances);
changeInstanceCount(flowletContext, instances);
LOG.info("Flowlet instance count changed: " + flowletContext + ", new count is " + instances);
}
/**
* @return a {@link FlowletContext} for the current {@link Flowlet}.
*/
public FlowletContext getFlowletContext() {
return flowletContext;
}
private void changeInstanceCount(BasicFlowletContext flowletContext, int instanceCount) {
Preconditions.checkState(getState() == State.SUSPENDED,
"Cannot change instance count of a flowlet without suspension.");
flowletContext.setInstanceCount(instanceCount);
}
private void listenDriveState(FlowletProcessDriver driver) {
driver.addListener(new ServiceListenerAdapter() {
@Override
public void running() {
started();
}
@Override
public void failed(Service.State from, Throwable failure) {
LOG.error("Flowlet terminated with exception", failure);
error(failure);
}
@Override
public void terminated(Service.State from) {
if (getState() != State.STOPPING) {
LOG.warn("Flowlet terminated by itself");
// Close all consumers
for (ConsumerSupplier consumerSupplier : consumerSuppliers) {
Closeables.closeQuietly(consumerSupplier);
}
}
}
}, Threads.SAME_THREAD_EXECUTOR);
}
@Override
public ServiceDiscovered discover(String service) {
return null;
}
}