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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.proxy;
import com.yahoo.concurrent.DaemonThreadFactory;
import com.yahoo.config.ConfigurationRuntimeException;
import com.yahoo.config.subscription.ConfigSourceSet;
import com.yahoo.config.subscription.impl.JRTConfigRequester;
import com.yahoo.jrt.Request;
import com.yahoo.jrt.Spec;
import com.yahoo.jrt.Supervisor;
import com.yahoo.jrt.Target;
import com.yahoo.jrt.Transport;
import com.yahoo.log.LogLevel;
import com.yahoo.vespa.config.ConfigCacheKey;
import com.yahoo.vespa.config.JRTConnectionPool;
import com.yahoo.vespa.config.RawConfig;
import com.yahoo.vespa.config.TimingValues;
import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Logger;
/**
* An Rpc client to a config source
*
* @author hmusum
*/
class RpcConfigSourceClient implements ConfigSourceClient {
private final static Logger log = Logger.getLogger(RpcConfigSourceClient.class.getName());
private final Supervisor supervisor = new Supervisor(new Transport());
private final RpcServer rpcServer;
private final ConfigSourceSet configSourceSet;
private final HashMap<ConfigCacheKey, Subscriber> activeSubscribers = new HashMap<>();
private final Object activeSubscribersLock = new Object();
private final MemoryCache memoryCache;
private final DelayedResponses delayedResponses;
private final TimingValues timingValues;
private final ExecutorService exec;
private final JRTConfigRequester requester;
RpcConfigSourceClient(RpcServer rpcServer,
ConfigSourceSet configSourceSet,
MemoryCache memoryCache,
TimingValues timingValues,
DelayedResponses delayedResponses) {
this.rpcServer = rpcServer;
this.configSourceSet = configSourceSet;
this.memoryCache = memoryCache;
this.delayedResponses = delayedResponses;
this.timingValues = timingValues;
checkConfigSources();
exec = Executors.newCachedThreadPool(new DaemonThreadFactory("subscriber-"));
requester = new JRTConfigRequester(new JRTConnectionPool(configSourceSet), timingValues);
}
/**
* Checks if config sources are available
*/
private void checkConfigSources() {
if (configSourceSet == null || configSourceSet.getSources() == null || configSourceSet.getSources().size() == 0) {
log.log(LogLevel.WARNING, "No config sources defined, could not check connection");
} else {
Request req = new Request("ping");
for (String configSource : configSourceSet.getSources()) {
Spec spec = new Spec(configSource);
Target target = supervisor.connect(spec);
target.invokeSync(req, 30.0);
if (target.isValid()) {
log.log(LogLevel.DEBUG, () -> "Created connection to config source at " + spec.toString());
return;
} else {
log.log(LogLevel.INFO, "Could not connect to config source at " + spec.toString());
}
target.close();
}
String extra = "";
log.log(LogLevel.INFO, "Could not connect to any config source in set " + configSourceSet.toString() +
", please make sure config server(s) are running. " + extra);
}
}
/**
* Retrieves the requested config from the cache or the remote server.
* <p>
* If the requested config is different from the one in cache, the cached request is returned immediately.
* If they are equal, this method returns null.
* <p>
* If the config was not in cache, this method starts a <em>Subscriber</em> in a separate thread
* that gets the config and calls updateSubscribers().
*
* @param input The config to retrieve - can be empty (no payload), or have a valid payload.
* @return A Config with a payload.
*/
@Override
public RawConfig getConfig(RawConfig input, JRTServerConfigRequest request) {
// Always add to delayed responses (we remove instead if we find config in cache)
// This is to avoid a race where we might end up not adding to delayed responses
// nor subscribing to config if another request for the same config
// happens at the same time
DelayedResponse delayedResponse = new DelayedResponse(request);
delayedResponses.add(delayedResponse);
final ConfigCacheKey configCacheKey = new ConfigCacheKey(input.getKey(), input.getDefMd5());
RawConfig cachedConfig = memoryCache.get(configCacheKey);
boolean needToGetConfig = true;
RawConfig ret = null;
if (cachedConfig != null) {
log.log(LogLevel.DEBUG, () -> "Found config " + configCacheKey + " in cache, generation=" + cachedConfig.getGeneration() +
",configmd5=" + cachedConfig.getConfigMd5());
log.log(LogLevel.SPAM, () -> "input config=" + input + ",cached config=" + cachedConfig);
if (ProxyServer.configOrGenerationHasChanged(cachedConfig, request)) {
log.log(LogLevel.SPAM, () -> "Cached config is not equal to requested, will return it");
if (delayedResponses.remove(delayedResponse)) {
// unless another thread already did it
ret = cachedConfig;
}
}
if (!cachedConfig.isError() && cachedConfig.getGeneration() > 0) {
needToGetConfig = false;
}
}
if (needToGetConfig) {
subscribeToConfig(input, configCacheKey);
}
return ret;
}
private void subscribeToConfig(RawConfig input, ConfigCacheKey configCacheKey) {
synchronized (activeSubscribersLock) {
if (activeSubscribers.containsKey(configCacheKey)) {
log.log(LogLevel.DEBUG, () -> "Already a subscriber running for: " + configCacheKey);
} else {
log.log(LogLevel.DEBUG, () -> "Could not find good config in cache, creating subscriber for: " + configCacheKey);
UpstreamConfigSubscriber subscriber = new UpstreamConfigSubscriber(input, this, configSourceSet,
timingValues, requester, memoryCache);
try {
subscriber.subscribe();
activeSubscribers.put(configCacheKey, subscriber);
exec.execute(subscriber);
} catch (ConfigurationRuntimeException e) {
log.log(LogLevel.INFO, "Subscribe for '" + configCacheKey + "' failed, closing subscriber");
subscriber.cancel();
}
}
}
}
@Override
public void cancel() {
shutdownSourceConnections();
}
/**
* Takes down connection(s) to config sources and running tasks
*/
@Override
public void shutdownSourceConnections() {
synchronized (activeSubscribersLock) {
for (Subscriber subscriber : activeSubscribers.values()) {
subscriber.cancel();
}
activeSubscribers.clear();
}
exec.shutdown();
requester.close();
}
@Override
public String getActiveSourceConnection() {
return requester.getConnectionPool().getCurrent().getAddress();
}
@Override
public List<String> getSourceConnections() {
return new ArrayList<>(configSourceSet.getSources());
}
/**
* This method will be called when a response with changed config is received from upstream
* (content or generation has changed) or the server timeout has elapsed.
*
* @param config new config
*/
public void updateSubscribers(RawConfig config) {
log.log(LogLevel.DEBUG, () -> "Config updated for " + config.getKey() + "," + config.getGeneration());
DelayQueue<DelayedResponse> responseDelayQueue = delayedResponses.responses();
log.log(LogLevel.SPAM, () -> "Delayed response queue: " + responseDelayQueue);
if (responseDelayQueue.size() == 0) {
log.log(LogLevel.DEBUG, () -> "There exists no matching element on delayed response queue for " + config.getKey());
return;
} else {
log.log(LogLevel.DEBUG, () -> "Delayed response queue has " + responseDelayQueue.size() + " elements");
}
boolean found = false;
for (DelayedResponse response : responseDelayQueue.toArray(new DelayedResponse[0])) {
JRTServerConfigRequest request = response.getRequest();
if (request.getConfigKey().equals(config.getKey())
// Generation 0 is special, used when returning empty sentinel config
&& (config.getGeneration() >= request.getRequestGeneration() || config.getGeneration() == 0)) {
if (delayedResponses.remove(response)) {
found = true;
log.log(LogLevel.DEBUG, () -> "Call returnOkResponse for " + config.getKey() + "," + config.getGeneration());
rpcServer.returnOkResponse(request, config);
} else {
log.log(LogLevel.INFO, "Could not remove " + config.getKey() + " from delayedResponses queue, already removed");
}
}
}
if (!found) {
log.log(LogLevel.DEBUG, () -> "Found no recipient for " + config.getKey() + " in delayed response queue");
}
log.log(LogLevel.DEBUG, () -> "Finished updating config for " + config.getKey() + "," + config.getGeneration());
}
}
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