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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.config.server.application;
import com.google.common.collect.ImmutableSet;
import com.yahoo.concurrent.ThreadFactoryFactory;
import com.yahoo.config.provision.ApplicationId;
import com.yahoo.config.provision.TenantName;
import com.yahoo.log.LogLevel;
import com.yahoo.path.Path;
import com.yahoo.text.Utf8;
import com.yahoo.transaction.Transaction;
import com.yahoo.vespa.config.server.ReloadHandler;
import com.yahoo.vespa.config.server.tenant.TenantRepository;
import com.yahoo.vespa.curator.Curator;
import com.yahoo.vespa.curator.transaction.CuratorOperations;
import com.yahoo.vespa.curator.transaction.CuratorTransaction;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Logger;
/**
* The applications of a tenant, backed by ZooKeeper.
*
* Each application is stored as a single node under /config/v2/tenants/<tenant>/applications/<applications>,
* named the same as the application id and containing the id of the session storing the content of the application.
*
* @author Ulf Lilleengen
*/
public class TenantApplications {
private static final Logger log = Logger.getLogger(TenantApplications.class.getName());
private final Curator curator;
private final Path applicationsPath;
// One thread pool for all instances of this class
private static final ExecutorService pathChildrenExecutor =
Executors.newCachedThreadPool(ThreadFactoryFactory.getDaemonThreadFactory(TenantApplications.class.getName()));
private final Curator.DirectoryCache directoryCache;
private final ReloadHandler reloadHandler;
private final TenantName tenant;
private TenantApplications(Curator curator, Path applicationsPath, ReloadHandler reloadHandler, TenantName tenant) {
this.curator = curator;
this.applicationsPath = applicationsPath;
curator.create(applicationsPath);
this.reloadHandler = reloadHandler;
this.tenant = tenant;
this.directoryCache = curator.createDirectoryCache(applicationsPath.getAbsolute(), false, false, pathChildrenExecutor);
this.directoryCache.start();
this.directoryCache.addListener(this::childEvent);
}
public static TenantApplications create(Curator curator, ReloadHandler reloadHandler, TenantName tenant) {
try {
return new TenantApplications(curator, TenantRepository.getApplicationsPath(tenant), reloadHandler, tenant);
} catch (Exception e) {
throw new RuntimeException(TenantRepository.logPre(tenant) + "Error creating application repo", e);
}
}
/**
* List the active applications of a tenant in this config server.
*
* @return a list of {@link ApplicationId}s that are active.
*/
public List<ApplicationId> listApplications() {
try {
List<String> appNodes = curator.framework().getChildren().forPath(applicationsPath.getAbsolute());
List<ApplicationId> applicationIds = new ArrayList<>();
for (String appNode : appNodes) {
parseApplication(appNode).ifPresent(applicationIds::add);
}
return applicationIds;
} catch (Exception e) {
throw new RuntimeException(TenantRepository.logPre(tenant)+"Unable to list applications", e);
}
}
private Optional<ApplicationId> parseApplication(String appNode) {
try {
return Optional.of(ApplicationId.fromSerializedForm(appNode));
} catch (IllegalArgumentException e) {
log.log(LogLevel.INFO, TenantRepository.logPre(tenant)+"Unable to parse application with id '" + appNode + "', ignoring.");
return Optional.empty();
}
}
/**
* Register active application and adds it to the repo. If it already exists it is overwritten.
*
* @param applicationId An {@link ApplicationId} that represents an active application.
* @param sessionId Id of the session containing the application package for this id.
*/
public Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId) {
if (listApplications().contains(applicationId)) {
return new CuratorTransaction(curator).add(CuratorOperations.setData(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
} else {
return new CuratorTransaction(curator).add(CuratorOperations.create(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
}
}
/**
* Return the stored session id for a given application.
*
* @param applicationId an {@link ApplicationId}
* @return session id of given application id.
* @throws IllegalArgumentException if the application does not exist
*/
public long getSessionIdForApplication(ApplicationId applicationId) {
String path = applicationsPath.append(applicationId.serializedForm()).getAbsolute();
try {
return Long.parseLong(Utf8.toString(curator.framework().getData().forPath(path)));
} catch (Exception e) {
throw new IllegalArgumentException(TenantRepository.logPre(applicationId) + "Unable to read the session id from '" + path + "'", e);
}
}
/**
* Returns a transaction which deletes this application
*
* @param applicationId an {@link ApplicationId} to delete.
*/
public CuratorTransaction deleteApplication(ApplicationId applicationId) {
Path path = applicationsPath.append(applicationId.serializedForm());
return CuratorTransaction.from(CuratorOperations.delete(path.getAbsolute()), curator);
}
/**
* Closes the application repo. Once a repo has been closed, it should not be used again.
*/
public void close() {
directoryCache.close();
}
private void childEvent(CuratorFramework client, PathChildrenCacheEvent event) {
switch (event.getType()) {
case CHILD_ADDED:
applicationAdded(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
break;
// Event CHILD_REMOVED will be triggered on all config servers if deleteApplication() above is called on one of them
case CHILD_REMOVED:
applicationRemoved(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
break;
case CHILD_UPDATED:
// do nothing, application just got redeployed
break;
default:
break;
}
// We may have lost events and may need to remove applications.
// New applications are added when session is added, not here. See RemoteSessionRepo.
removeUnusedApplications();
}
private void applicationRemoved(ApplicationId applicationId) {
reloadHandler.removeApplication(applicationId);
log.log(LogLevel.INFO, TenantRepository.logPre(applicationId) + "Application removed: " + applicationId);
}
private void applicationAdded(ApplicationId applicationId) {
log.log(LogLevel.DEBUG, TenantRepository.logPre(applicationId) + "Application added: " + applicationId);
}
/**
* Removes unused applications
*
*/
public void removeUnusedApplications() {
ImmutableSet<ApplicationId> activeApplications = ImmutableSet.copyOf(listApplications());
reloadHandler.removeApplicationsExcept(activeApplications);
}
}
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