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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.config.server.host;
import com.google.common.collect.Collections2;
import com.yahoo.config.provision.ApplicationId;
import com.yahoo.config.provision.TenantName;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.stream.Collectors;
/**
* A host registry with a mapping between hosts (hostname as a String) and some type T
* TODO: Maybe we should have a Host type, but using String for now.
*
* @author Ulf Lilleengen
*/
public class HostRegistry implements HostValidator {
private static final Logger log = Logger.getLogger(HostRegistry.class.getName());
private final Map<String, ApplicationId> host2KeyMap = new ConcurrentHashMap<>();
public ApplicationId getKeyForHost(String hostName) {
return host2KeyMap.get(hostName);
}
public synchronized void update(ApplicationId key, Collection<String> newHosts) {
verifyHosts(key, newHosts);
Collection<String> currentHosts = getHostsForKey(key);
log.log(Level.FINE, () -> "Setting hosts for key '" + key + "', " +
"newHosts: " + newHosts + ", " +
"currentHosts: " + currentHosts);
Collection<String> removedHosts = getRemovedHosts(newHosts, currentHosts);
removeHosts(removedHosts);
addHosts(key, newHosts);
}
@Override
public synchronized void verifyHosts(ApplicationId applicationId, Collection<String> newHosts) {
for (String host : newHosts) {
if (hostAlreadyTaken(host, applicationId)) {
throw new IllegalArgumentException("'" + applicationId + "' tried to allocate host '" + host +
"', but the host is already taken by '" + host2KeyMap.get(host) + "'");
}
}
}
public synchronized void removeHostsForKey(ApplicationId key) {
host2KeyMap.entrySet().removeIf(entry -> entry.getValue().equals(key));
}
public synchronized void removeHostsForKey(TenantName key) {
host2KeyMap.entrySet().removeIf(entry -> entry.getValue().tenant().equals(key));
}
public synchronized Collection<String> getAllHosts() {
return Collections.unmodifiableCollection(new ArrayList<>(host2KeyMap.keySet()));
}
public synchronized Collection<String> getHostsForKey(ApplicationId key) {
return host2KeyMap.entrySet().stream()
.filter(entry -> entry.getValue().equals(key))
.map(Map.Entry::getKey)
.collect(Collectors.toSet());
}
private boolean hostAlreadyTaken(String host, ApplicationId key) {
return host2KeyMap.containsKey(host) && !key.equals(host2KeyMap.get(host));
}
private static Collection<String> getRemovedHosts(Collection<String> newHosts, Collection<String> previousHosts) {
return Collections2.filter(previousHosts, host -> !newHosts.contains(host));
}
private void removeHosts(Collection<String> removedHosts) {
for (String host : removedHosts) {
log.log(Level.FINE, () -> "Removing " + host);
host2KeyMap.remove(host);
}
}
private void addHosts(ApplicationId key, Collection<String> newHosts) {
for (String host : newHosts) {
log.log(Level.FINE, () -> "Adding " + host);
host2KeyMap.put(host, key);
}
}
}
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