org.apache.solr.common.cloud.ZkStateReader Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.solr.common.cloud;
import java.io.Closeable;
import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;
import org.apache.solr.client.solrj.cloud.autoscaling.AutoScalingConfig;
import org.apache.solr.common.AlreadyClosedException;
import org.apache.solr.common.Callable;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.common.params.AutoScalingParams;
import org.apache.solr.common.params.CollectionAdminParams;
import org.apache.solr.common.params.CoreAdminParams;
import org.apache.solr.common.util.ExecutorUtil;
import org.apache.solr.common.util.ObjectReleaseTracker;
import org.apache.solr.common.util.Pair;
import org.apache.solr.common.util.SolrjNamedThreadFactory;
import org.apache.solr.common.util.Utils;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static java.util.Arrays.asList;
import static java.util.Collections.EMPTY_MAP;
import static java.util.Collections.emptyMap;
import static java.util.Collections.emptySet;
import static java.util.Collections.emptySortedSet;
import static java.util.Collections.unmodifiableSet;
import static org.apache.solr.common.util.Utils.fromJSON;
public class ZkStateReader implements Closeable {
public static final int STATE_UPDATE_DELAY = Integer.getInteger("solr.OverseerStateUpdateDelay", 2000); // delay between cloud state updates
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
public static final String BASE_URL_PROP = "base_url";
public static final String NODE_NAME_PROP = "node_name";
public static final String CORE_NODE_NAME_PROP = "core_node_name";
public static final String ROLES_PROP = "roles";
public static final String STATE_PROP = "state";
// if this flag equals to false and the replica does not exist in cluster state, set state op become no op (default is true)
public static final String FORCE_SET_STATE_PROP = "force_set_state";
/** SolrCore name. */
public static final String CORE_NAME_PROP = "core";
public static final String COLLECTION_PROP = "collection";
public static final String ELECTION_NODE_PROP = "election_node";
public static final String SHARD_ID_PROP = "shard";
public static final String REPLICA_PROP = "replica";
public static final String SHARD_RANGE_PROP = "shard_range";
public static final String SHARD_STATE_PROP = "shard_state";
public static final String SHARD_PARENT_PROP = "shard_parent";
public static final String NUM_SHARDS_PROP = "numShards";
public static final String LEADER_PROP = "leader";
public static final String SHARED_STORAGE_PROP = "shared_storage";
public static final String PROPERTY_PROP = "property";
public static final String PROPERTY_PROP_PREFIX = "property.";
public static final String PROPERTY_VALUE_PROP = "property.value";
public static final String MAX_AT_ONCE_PROP = "maxAtOnce";
public static final String MAX_WAIT_SECONDS_PROP = "maxWaitSeconds";
public static final String STATE_TIMESTAMP_PROP = "stateTimestamp";
public static final String COLLECTIONS_ZKNODE = "/collections";
public static final String LIVE_NODES_ZKNODE = "/live_nodes";
public static final String ALIASES = "/aliases.json";
public static final String CLUSTER_STATE = "/clusterstate.json";
public static final String CLUSTER_PROPS = "/clusterprops.json";
public static final String COLLECTION_PROPS_ZKNODE = "collectionprops.json";
public static final String REJOIN_AT_HEAD_PROP = "rejoinAtHead";
public static final String SOLR_SECURITY_CONF_PATH = "/security.json";
public static final String SOLR_AUTOSCALING_CONF_PATH = "/autoscaling.json";
public static final String SOLR_AUTOSCALING_EVENTS_PATH = "/autoscaling/events";
public static final String SOLR_AUTOSCALING_TRIGGER_STATE_PATH = "/autoscaling/triggerState";
public static final String SOLR_AUTOSCALING_NODE_ADDED_PATH = "/autoscaling/nodeAdded";
public static final String SOLR_AUTOSCALING_NODE_LOST_PATH = "/autoscaling/nodeLost";
public static final String REPLICATION_FACTOR = "replicationFactor";
public static final String MAX_SHARDS_PER_NODE = "maxShardsPerNode";
public static final String AUTO_ADD_REPLICAS = "autoAddReplicas";
public static final String MAX_CORES_PER_NODE = "maxCoresPerNode";
public static final String PULL_REPLICAS = "pullReplicas";
public static final String NRT_REPLICAS = "nrtReplicas";
public static final String TLOG_REPLICAS = "tlogReplicas";
public static final String ROLES = "/roles.json";
public static final String CONFIGS_ZKNODE = "/configs";
public final static String CONFIGNAME_PROP="configName";
public static final String LEGACY_CLOUD = "legacyCloud";
/**
* @deprecated use {@link org.apache.solr.common.params.CollectionAdminParams#DEFAULTS} instead.
*/
@Deprecated
public static final String COLLECTION_DEF = "collectionDefaults";
public static final String URL_SCHEME = "urlScheme";
public static final String REPLICA_TYPE = "type";
/** A view of the current state of all collections; combines all the different state sources into a single view. */
protected volatile ClusterState clusterState;
private static final int GET_LEADER_RETRY_INTERVAL_MS = 50;
private static final int GET_LEADER_RETRY_DEFAULT_TIMEOUT = Integer.parseInt(System.getProperty("zkReaderGetLeaderRetryTimeoutMs", "4000"));;
public static final String LEADER_ELECT_ZKNODE = "leader_elect";
public static final String SHARD_LEADERS_ZKNODE = "leaders";
public static final String ELECTION_NODE = "election";
/** Collections tracked in the legacy (shared) state format, reflects the contents of clusterstate.json. */
private Map legacyCollectionStates = emptyMap();
/** Last seen ZK version of clusterstate.json. */
private int legacyClusterStateVersion = 0;
/** Collections with format2 state.json, "interesting" and actively watched. */
private final ConcurrentHashMap watchedCollectionStates = new ConcurrentHashMap<>();
/** Collections with format2 state.json, not "interesting" and not actively watched. */
private final ConcurrentHashMap lazyCollectionStates = new ConcurrentHashMap<>();
/** Collection properties being actively watched */
private final ConcurrentHashMap> watchedCollectionProps = new ConcurrentHashMap<>();
private volatile SortedSet liveNodes = emptySortedSet();
private volatile Map clusterProperties = Collections.emptyMap();
private final ZkConfigManager configManager;
private ConfigData securityData;
private final Runnable securityNodeListener;
private ConcurrentHashMap> collectionWatches = new ConcurrentHashMap<>();
private ConcurrentHashMap> collectionPropsWatches = new ConcurrentHashMap<>();
private Set cloudCollectionsListeners = ConcurrentHashMap.newKeySet();
private final ExecutorService notifications = ExecutorUtil.newMDCAwareCachedThreadPool("watches");
private Set liveNodesListeners = ConcurrentHashMap.newKeySet();
/** Used to submit notifications to Collection Properties watchers in order **/
private final ExecutorService collectionPropsNotifications = ExecutorUtil.newMDCAwareSingleThreadExecutor(new SolrjNamedThreadFactory("collectionPropsNotifications"));
private static final long LAZY_CACHE_TIME = TimeUnit.NANOSECONDS.convert(STATE_UPDATE_DELAY, TimeUnit.MILLISECONDS);
/**
* Get current {@link AutoScalingConfig}.
* @return current configuration from autoscaling.json. NOTE:
* this data is retrieved from ZK on each call.
*/
public AutoScalingConfig getAutoScalingConfig() throws KeeperException, InterruptedException {
return getAutoScalingConfig(null);
}
/**
* Get current {@link AutoScalingConfig}.
* @param watcher optional {@link Watcher} to set on a znode to watch for config changes.
* @return current configuration from autoscaling.json. NOTE:
* this data is retrieved from ZK on each call.
*/
public AutoScalingConfig getAutoScalingConfig(Watcher watcher) throws KeeperException, InterruptedException {
Stat stat = new Stat();
Map map = new HashMap<>();
try {
byte[] bytes = zkClient.getData(SOLR_AUTOSCALING_CONF_PATH, watcher, stat, true);
if (bytes != null && bytes.length > 0) {
map = (Map) fromJSON(bytes);
}
} catch (KeeperException.NoNodeException e) {
// ignore
}
map.put(AutoScalingParams.ZK_VERSION, stat.getVersion());
return new AutoScalingConfig(map);
}
private static class CollectionWatch {
int coreRefCount = 0;
Set stateWatchers = ConcurrentHashMap.newKeySet();
public boolean canBeRemoved() {
return coreRefCount + stateWatchers.size() == 0;
}
}
public static final Set KNOWN_CLUSTER_PROPS = unmodifiableSet(new HashSet<>(asList(
LEGACY_CLOUD,
URL_SCHEME,
AUTO_ADD_REPLICAS,
CoreAdminParams.BACKUP_LOCATION,
MAX_CORES_PER_NODE,
CollectionAdminParams.DEFAULTS)));
/**
* Returns config set name for collection.
*
* @param collection to return config set name for
*/
public String readConfigName(String collection) {
String configName = null;
String path = COLLECTIONS_ZKNODE + "/" + collection;
log.debug("Loading collection config from: [{}]", path);
try {
byte[] data = zkClient.getData(path, null, null, true);
if (data != null) {
ZkNodeProps props = ZkNodeProps.load(data);
configName = props.getStr(CONFIGNAME_PROP);
}
if (configName != null) {
String configPath = CONFIGS_ZKNODE + "/" + configName;
if (!zkClient.exists(configPath, true)) {
log.error("Specified config=[{}] does not exist in ZooKeeper at location=[{}]", configName, configPath);
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "Specified config does not exist in ZooKeeper: " + configName);
} else {
log.debug("path=[{}] [{}]=[{}] specified config exists in ZooKeeper", configPath, CONFIGNAME_PROP, configName);
}
} else {
throw new ZooKeeperException(ErrorCode.INVALID_STATE, "No config data found at path: " + path);
}
} catch (KeeperException| InterruptedException e) {
SolrZkClient.checkInterrupted(e);
throw new SolrException(ErrorCode.SERVER_ERROR, "Error loading config name for collection " + collection, e);
}
return configName;
}
private final SolrZkClient zkClient;
private final boolean closeClient;
private volatile boolean closed = false;
private Set waitLatches = ConcurrentHashMap.newKeySet();
public ZkStateReader(SolrZkClient zkClient) {
this(zkClient, null);
}
public ZkStateReader(SolrZkClient zkClient, Runnable securityNodeListener) {
this.zkClient = zkClient;
this.configManager = new ZkConfigManager(zkClient);
this.closeClient = false;
this.securityNodeListener = securityNodeListener;
assert ObjectReleaseTracker.track(this);
}
public ZkStateReader(String zkServerAddress, int zkClientTimeout, int zkClientConnectTimeout) {
this.zkClient = new SolrZkClient(zkServerAddress, zkClientTimeout, zkClientConnectTimeout,
// on reconnect, reload cloud info
new OnReconnect() {
@Override
public void command() {
try {
ZkStateReader.this.createClusterStateWatchersAndUpdate();
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.error("Interrupted", e);
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "Interrupted", e);
}
}
});
this.configManager = new ZkConfigManager(zkClient);
this.closeClient = true;
this.securityNodeListener = null;
assert ObjectReleaseTracker.track(this);
}
public ZkConfigManager getConfigManager() {
return configManager;
}
/**
* Forcibly refresh cluster state from ZK. Do this only to avoid race conditions because it's expensive.
*
* It is cheaper to call {@link #forceUpdateCollection(String)} on a single collection if you must.
*
* @lucene.internal
*/
public void forciblyRefreshAllClusterStateSlow() throws KeeperException, InterruptedException {
synchronized (getUpdateLock()) {
if (clusterState == null) {
// Never initialized, just run normal initialization.
createClusterStateWatchersAndUpdate();
return;
}
// No need to set watchers because we should already have watchers registered for everything.
refreshCollectionList(null);
refreshLiveNodes(null);
refreshLegacyClusterState(null);
// Need a copy so we don't delete from what we're iterating over.
Collection safeCopy = new ArrayList<>(watchedCollectionStates.keySet());
Set updatedCollections = new HashSet<>();
for (String coll : safeCopy) {
DocCollection newState = fetchCollectionState(coll, null);
if (updateWatchedCollection(coll, newState)) {
updatedCollections.add(coll);
}
}
constructState(updatedCollections);
}
}
/**
* Forcibly refresh a collection's internal state from ZK. Try to avoid having to resort to this when
* a better design is possible.
*/
//TODO shouldn't we call ZooKeeper.sync() at the right places to prevent reading a stale value? We do so for aliases.
public void forceUpdateCollection(String collection) throws KeeperException, InterruptedException {
synchronized (getUpdateLock()) {
if (clusterState == null) {
log.warn("ClusterState watchers have not been initialized");
return;
}
ClusterState.CollectionRef ref = clusterState.getCollectionRef(collection);
if (ref == null || legacyCollectionStates.containsKey(collection)) {
// We either don't know anything about this collection (maybe it's new?) or it's legacy.
// First update the legacy cluster state.
log.debug("Checking legacy cluster state for collection {}", collection);
refreshLegacyClusterState(null);
if (!legacyCollectionStates.containsKey(collection)) {
// No dice, see if a new collection just got created.
LazyCollectionRef tryLazyCollection = new LazyCollectionRef(collection);
if (tryLazyCollection.get() != null) {
// What do you know, it exists!
log.debug("Adding lazily-loaded reference for collection {}", collection);
lazyCollectionStates.putIfAbsent(collection, tryLazyCollection);
constructState(Collections.singleton(collection));
}
}
} else if (ref.isLazilyLoaded()) {
log.debug("Refreshing lazily-loaded state for collection {}", collection);
if (ref.get() != null) {
return;
}
// Edge case: if there's no external collection, try refreshing legacy cluster state in case it's there.
refreshLegacyClusterState(null);
} else if (watchedCollectionStates.containsKey(collection)) {
// Exists as a watched collection, force a refresh.
log.debug("Forcing refresh of watched collection state for {}", collection);
DocCollection newState = fetchCollectionState(collection, null);
if (updateWatchedCollection(collection, newState)) {
constructState(Collections.singleton(collection));
}
} else {
log.error("Collection {} is not lazy or watched!", collection);
}
}
}
/** Refresh the set of live nodes. */
public void updateLiveNodes() throws KeeperException, InterruptedException {
refreshLiveNodes(null);
}
public Integer compareStateVersions(String coll, int version) {
DocCollection collection = clusterState.getCollectionOrNull(coll);
if (collection == null) return null;
if (collection.getZNodeVersion() < version) {
log.debug("Server older than client {}<{}", collection.getZNodeVersion(), version);
DocCollection nu = getCollectionLive(this, coll);
if (nu == null) return -1 ;
if (nu.getZNodeVersion() > collection.getZNodeVersion()) {
if (updateWatchedCollection(coll, nu)) {
synchronized (getUpdateLock()) {
constructState(Collections.singleton(coll));
}
}
collection = nu;
}
}
if (collection.getZNodeVersion() == version) {
return null;
}
log.debug("Wrong version from client [{}]!=[{}]", version, collection.getZNodeVersion());
return collection.getZNodeVersion();
}
public synchronized void createClusterStateWatchersAndUpdate() throws KeeperException,
InterruptedException {
// We need to fetch the current cluster state and the set of live nodes
log.debug("Updating cluster state from ZooKeeper... ");
// Sanity check ZK structure.
if (!zkClient.exists(CLUSTER_STATE, true)) {
throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE,
"Cannot connect to cluster at " + zkClient.getZkServerAddress() + ": cluster not found/not ready");
}
// on reconnect of SolrZkClient force refresh and re-add watches.
loadClusterProperties();
refreshLiveNodes(new LiveNodeWatcher());
refreshLegacyClusterState(new LegacyClusterStateWatcher());
refreshStateFormat2Collections();
refreshCollectionList(new CollectionsChildWatcher());
refreshAliases(aliasesManager);
if (securityNodeListener != null) {
addSecurityNodeWatcher(pair -> {
ConfigData cd = new ConfigData();
cd.data = pair.first() == null || pair.first().length == 0 ? EMPTY_MAP : Utils.getDeepCopy((Map) fromJSON(pair.first()), 4, false);
cd.version = pair.second() == null ? -1 : pair.second().getVersion();
securityData = cd;
securityNodeListener.run();
});
securityData = getSecurityProps(true);
}
collectionPropsWatches.forEach((k,v) -> {
new PropsWatcher(k).refreshAndWatch(true);
});
}
private void addSecurityNodeWatcher(final Callable> callback)
throws KeeperException, InterruptedException {
zkClient.exists(SOLR_SECURITY_CONF_PATH,
new Watcher() {
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
try {
synchronized (ZkStateReader.this.getUpdateLock()) {
log.debug("Updating [{}] ... ", SOLR_SECURITY_CONF_PATH);
// remake watch
final Watcher thisWatch = this;
final Stat stat = new Stat();
final byte[] data = getZkClient().getData(SOLR_SECURITY_CONF_PATH, thisWatch, stat, true);
try {
callback.call(new Pair<>(data, stat));
} catch (Exception e) {
log.error("Error running collections node listener", e);
}
}
} catch (KeeperException.ConnectionLossException | KeeperException.SessionExpiredException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.warn("Interrupted", e);
}
}
}, true);
}
/**
* Construct the total state view from all sources.
* Must hold {@link #getUpdateLock()} before calling this.
*
* @param changedCollections collections that have changed since the last call,
* and that should fire notifications
*/
private void constructState(Set changedCollections) {
Set liveNodes = this.liveNodes; // volatile read
// Legacy clusterstate is authoritative, for backwards compatibility.
// To move a collection's state to format2, first create the new state2 format node, then remove legacy entry.
Map result = new LinkedHashMap<>(legacyCollectionStates);
// Add state format2 collections, but don't override legacy collection states.
for (Map.Entry entry : watchedCollectionStates.entrySet()) {
result.putIfAbsent(entry.getKey(), new ClusterState.CollectionRef(entry.getValue()));
}
// Finally, add any lazy collections that aren't already accounted for.
for (Map.Entry entry : lazyCollectionStates.entrySet()) {
result.putIfAbsent(entry.getKey(), entry.getValue());
}
this.clusterState = new ClusterState(liveNodes, result, legacyClusterStateVersion);
log.debug("clusterStateSet: legacy [{}] interesting [{}] watched [{}] lazy [{}] total [{}]",
legacyCollectionStates.keySet().size(),
collectionWatches.keySet().size(),
watchedCollectionStates.keySet().size(),
lazyCollectionStates.keySet().size(),
clusterState.getCollectionStates().size());
if (log.isTraceEnabled()) {
log.trace("clusterStateSet: legacy [{}] interesting [{}] watched [{}] lazy [{}] total [{}]",
legacyCollectionStates.keySet(),
collectionWatches.keySet(),
watchedCollectionStates.keySet(),
lazyCollectionStates.keySet(),
clusterState.getCollectionStates());
}
notifyCloudCollectionsListeners();
for (String collection : changedCollections) {
notifyStateWatchers(liveNodes, collection, clusterState.getCollectionOrNull(collection));
}
}
/**
* Refresh legacy (shared) clusterstate.json
*/
private void refreshLegacyClusterState(Watcher watcher) throws KeeperException, InterruptedException {
try {
final Stat stat = new Stat();
final byte[] data = zkClient.getData(CLUSTER_STATE, watcher, stat, true);
final ClusterState loadedData = ClusterState.load(stat.getVersion(), data, emptySet(), CLUSTER_STATE);
synchronized (getUpdateLock()) {
if (this.legacyClusterStateVersion >= stat.getVersion()) {
// Nothing to do, someone else updated same or newer.
return;
}
Set updatedCollections = new HashSet<>();
for (String coll : this.collectionWatches.keySet()) {
ClusterState.CollectionRef ref = this.legacyCollectionStates.get(coll);
// legacy collections are always in-memory
DocCollection oldState = ref == null ? null : ref.get();
ClusterState.CollectionRef newRef = loadedData.getCollectionStates().get(coll);
DocCollection newState = newRef == null ? null : newRef.get();
if (newState == null) {
// check that we haven't just migrated
newState = watchedCollectionStates.get(coll);
}
if (!Objects.equals(oldState, newState)) {
updatedCollections.add(coll);
}
}
this.legacyCollectionStates = loadedData.getCollectionStates();
this.legacyClusterStateVersion = stat.getVersion();
constructState(updatedCollections);
}
} catch (KeeperException.NoNodeException e) {
// Ignore missing legacy clusterstate.json.
synchronized (getUpdateLock()) {
this.legacyCollectionStates = emptyMap();
this.legacyClusterStateVersion = 0;
constructState(Collections.emptySet());
}
}
}
/**
* Refresh state format2 collections.
*/
private void refreshStateFormat2Collections() {
for (String coll : collectionWatches.keySet()) {
new StateWatcher(coll).refreshAndWatch();
}
}
// We don't get a Stat or track versions on getChildren() calls, so force linearization.
private final Object refreshCollectionListLock = new Object();
/**
* Search for any lazy-loadable state format2 collections.
*
* A stateFormat=1 collection which is not interesting to us can also
* be put into the {@link #lazyCollectionStates} map here. But that is okay
* because {@link #constructState(Set)} will give priority to collections in the
* shared collection state over this map.
* In fact this is a clever way to avoid doing a ZK exists check on
* the /collections/collection_name/state.json znode
* Such an exists check is done in {@link ClusterState#hasCollection(String)} and
* {@link ClusterState#getCollectionsMap()} methods
* have a safeguard against exposing wrong collection names to the users
*/
private void refreshCollectionList(Watcher watcher) throws KeeperException, InterruptedException {
synchronized (refreshCollectionListLock) {
List children = null;
try {
children = zkClient.getChildren(COLLECTIONS_ZKNODE, watcher, true);
} catch (KeeperException.NoNodeException e) {
log.warn("Error fetching collection names: [{}]", e.getMessage());
// fall through
}
if (children == null || children.isEmpty()) {
lazyCollectionStates.clear();
return;
}
// Don't lock getUpdateLock() here, we don't need it and it would cause deadlock.
// Don't mess with watchedCollections, they should self-manage.
// First, drop any children that disappeared.
this.lazyCollectionStates.keySet().retainAll(children);
for (String coll : children) {
// We will create an eager collection for any interesting collections, so don't add to lazy.
if (!collectionWatches.containsKey(coll)) {
// Double check contains just to avoid allocating an object.
LazyCollectionRef existing = lazyCollectionStates.get(coll);
if (existing == null) {
lazyCollectionStates.putIfAbsent(coll, new LazyCollectionRef(coll));
}
}
}
}
}
// We don't get a Stat or track versions on getChildren() calls, so force linearization.
private final Object refreshCollectionsSetLock = new Object();
// Ensures that only the latest getChildren fetch gets applied.
private final AtomicReference> lastFetchedCollectionSet = new AtomicReference<>();
/**
* Register a CloudCollectionsListener to be called when the set of collections within a cloud changes.
*/
public void registerCloudCollectionsListener(CloudCollectionsListener cloudCollectionsListener) {
cloudCollectionsListeners.add(cloudCollectionsListener);
notifyNewCloudCollectionsListener(cloudCollectionsListener);
}
/**
* Remove a registered CloudCollectionsListener.
*/
public void removeCloudCollectionsListener(CloudCollectionsListener cloudCollectionsListener) {
cloudCollectionsListeners.remove(cloudCollectionsListener);
}
private void notifyNewCloudCollectionsListener(CloudCollectionsListener listener) {
listener.onChange(Collections.emptySet(), lastFetchedCollectionSet.get());
}
private void notifyCloudCollectionsListeners() {
notifyCloudCollectionsListeners(false);
}
private void notifyCloudCollectionsListeners(boolean notifyIfSame) {
synchronized (refreshCollectionsSetLock) {
final Set newCollections = getCurrentCollections();
final Set oldCollections = lastFetchedCollectionSet.getAndSet(newCollections);
if (!newCollections.equals(oldCollections) || notifyIfSame) {
cloudCollectionsListeners.forEach(listener -> listener.onChange(oldCollections, newCollections));
}
}
}
private Set getCurrentCollections() {
Set collections = new HashSet<>();
collections.addAll(legacyCollectionStates.keySet());
collections.addAll(watchedCollectionStates.keySet());
collections.addAll(lazyCollectionStates.keySet());
return collections;
}
private class LazyCollectionRef extends ClusterState.CollectionRef {
private final String collName;
private long lastUpdateTime;
private DocCollection cachedDocCollection;
public LazyCollectionRef(String collName) {
super(null);
this.collName = collName;
this.lastUpdateTime = -1;
}
@Override
public synchronized DocCollection get(boolean allowCached) {
gets.incrementAndGet();
if (!allowCached || lastUpdateTime < 0 || System.nanoTime() - lastUpdateTime > LAZY_CACHE_TIME) {
boolean shouldFetch = true;
if (cachedDocCollection != null) {
Stat exists = null;
try {
exists = zkClient.exists(getCollectionPath(collName), null, true);
} catch (Exception e) {}
if (exists != null && exists.getVersion() == cachedDocCollection.getZNodeVersion()) {
shouldFetch = false;
}
}
if (shouldFetch) {
cachedDocCollection = getCollectionLive(ZkStateReader.this, collName);
lastUpdateTime = System.nanoTime();
}
}
return cachedDocCollection;
}
@Override
public boolean isLazilyLoaded() {
return true;
}
@Override
public String toString() {
return "LazyCollectionRef(" + collName + ")";
}
}
// We don't get a Stat or track versions on getChildren() calls, so force linearization.
private final Object refreshLiveNodesLock = new Object();
// Ensures that only the latest getChildren fetch gets applied.
private final AtomicReference> lastFetchedLiveNodes = new AtomicReference<>();
/**
* Refresh live_nodes.
*/
private void refreshLiveNodes(Watcher watcher) throws KeeperException, InterruptedException {
synchronized (refreshLiveNodesLock) {
SortedSet newLiveNodes;
try {
List nodeList = zkClient.getChildren(LIVE_NODES_ZKNODE, watcher, true);
newLiveNodes = new TreeSet<>(nodeList);
} catch (KeeperException.NoNodeException e) {
newLiveNodes = emptySortedSet();
}
lastFetchedLiveNodes.set(newLiveNodes);
}
// Can't lock getUpdateLock() until we release the other, it would cause deadlock.
SortedSet oldLiveNodes, newLiveNodes;
synchronized (getUpdateLock()) {
newLiveNodes = lastFetchedLiveNodes.getAndSet(null);
if (newLiveNodes == null) {
// Someone else won the race to apply the last update, just exit.
return;
}
oldLiveNodes = this.liveNodes;
this.liveNodes = newLiveNodes;
if (clusterState != null) {
clusterState.setLiveNodes(newLiveNodes);
}
}
if (oldLiveNodes.size() != newLiveNodes.size()) {
log.info("Updated live nodes from ZooKeeper... ({}) -> ({})", oldLiveNodes.size(), newLiveNodes.size());
}
if (log.isDebugEnabled()) {
log.debug("Updated live nodes from ZooKeeper... {} -> {}", oldLiveNodes, newLiveNodes);
}
if (!oldLiveNodes.equals(newLiveNodes)) { // fire listeners
liveNodesListeners.forEach(listener -> {
if (listener.onChange(new TreeSet<>(oldLiveNodes), new TreeSet<>(newLiveNodes))) {
removeLiveNodesListener(listener);
}
});
}
}
public void registerLiveNodesListener(LiveNodesListener listener) {
// fire it once with current live nodes
if (listener.onChange(new TreeSet<>(getClusterState().getLiveNodes()), new TreeSet<>(getClusterState().getLiveNodes()))) {
removeLiveNodesListener(listener);
}
liveNodesListeners.add(listener);
}
public void removeLiveNodesListener(LiveNodesListener listener) {
liveNodesListeners.remove(listener);
}
/**
* @return information about the cluster from ZooKeeper
*/
public ClusterState getClusterState() {
return clusterState;
}
public Object getUpdateLock() {
return this;
}
public void close() {
this.closed = true;
notifications.shutdownNow();
waitLatches.parallelStream().forEach(c -> { c.countDown(); });
ExecutorUtil.shutdownAndAwaitTermination(notifications);
ExecutorUtil.shutdownAndAwaitTermination(collectionPropsNotifications);
if (closeClient) {
zkClient.close();
}
assert ObjectReleaseTracker.release(this);
}
public String getLeaderUrl(String collection, String shard, int timeout) throws InterruptedException {
ZkCoreNodeProps props = new ZkCoreNodeProps(getLeaderRetry(collection, shard, timeout));
return props.getCoreUrl();
}
public Replica getLeader(Set liveNodes, DocCollection docCollection, String shard) {
Replica replica = docCollection != null ? docCollection.getLeader(shard) : null;
if (replica != null && liveNodes.contains(replica.getNodeName())) {
return replica;
}
return null;
}
public Replica getLeader(String collection, String shard) {
if (clusterState != null) {
DocCollection docCollection = clusterState.getCollectionOrNull(collection);
Replica replica = docCollection != null ? docCollection.getLeader(shard) : null;
if (replica != null && getClusterState().liveNodesContain(replica.getNodeName())) {
return replica;
}
}
return null;
}
/**
* Get shard leader properties, with retry if none exist.
*/
public Replica getLeaderRetry(String collection, String shard) throws InterruptedException {
return getLeaderRetry(collection, shard, GET_LEADER_RETRY_DEFAULT_TIMEOUT);
}
/**
* Get shard leader properties, with retry if none exist.
*/
public Replica getLeaderRetry(String collection, String shard, int timeout) throws InterruptedException {
AtomicReference leader = new AtomicReference<>();
try {
waitForState(collection, timeout, TimeUnit.MILLISECONDS, (n, c) -> {
if (c == null)
return false;
Replica l = getLeader(n, c, shard);
if (l != null) {
leader.set(l);
return true;
}
return false;
});
} catch (TimeoutException | InterruptedException e) {
throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE, "No registered leader was found after waiting for "
+ timeout + "ms " + ", collection: " + collection + " slice: " + shard + " saw state=" + clusterState.getCollectionOrNull(collection)
+ " with live_nodes=" + clusterState.getLiveNodes());
}
return leader.get();
}
/**
* Get path where shard leader properties live in zookeeper.
*/
public static String getShardLeadersPath(String collection, String shardId) {
return COLLECTIONS_ZKNODE + "/" + collection + "/"
+ SHARD_LEADERS_ZKNODE + (shardId != null ? ("/" + shardId)
: "") + "/leader";
}
/**
* Get path where shard leader elections ephemeral nodes are.
*/
public static String getShardLeadersElectPath(String collection, String shardId) {
return COLLECTIONS_ZKNODE + "/" + collection + "/"
+ LEADER_ELECT_ZKNODE + (shardId != null ? ("/" + shardId + "/" + ELECTION_NODE)
: "");
}
public List getReplicaProps(String collection, String shardId, String thisCoreNodeName) {
return getReplicaProps(collection, shardId, thisCoreNodeName, null);
}
public List getReplicaProps(String collection, String shardId, String thisCoreNodeName,
Replica.State mustMatchStateFilter) {
return getReplicaProps(collection, shardId, thisCoreNodeName, mustMatchStateFilter, null);
}
public List getReplicaProps(String collection, String shardId, String thisCoreNodeName,
Replica.State mustMatchStateFilter, Replica.State mustNotMatchStateFilter) {
//TODO: We don't need all these getReplicaProps method overloading. Also, it's odd that the default is to return replicas of type TLOG and NRT only
return getReplicaProps(collection, shardId, thisCoreNodeName, mustMatchStateFilter, null, EnumSet.of(Replica.Type.TLOG, Replica.Type.NRT));
}
public List getReplicaProps(String collection, String shardId, String thisCoreNodeName,
Replica.State mustMatchStateFilter, Replica.State mustNotMatchStateFilter, final EnumSet acceptReplicaType) {
assert thisCoreNodeName != null;
ClusterState clusterState = this.clusterState;
if (clusterState == null) {
return null;
}
final DocCollection docCollection = clusterState.getCollectionOrNull(collection);
if (docCollection == null || docCollection.getSlicesMap() == null) {
throw new ZooKeeperException(ErrorCode.BAD_REQUEST,
"Could not find collection in zk: " + collection);
}
Map slices = docCollection.getSlicesMap();
Slice replicas = slices.get(shardId);
if (replicas == null) {
throw new ZooKeeperException(ErrorCode.BAD_REQUEST, "Could not find shardId in zk: " + shardId);
}
Map shardMap = replicas.getReplicasMap();
List nodes = new ArrayList<>(shardMap.size());
for (Entry entry : shardMap.entrySet().stream().filter((e)->acceptReplicaType.contains(e.getValue().getType())).collect(Collectors.toList())) {
ZkCoreNodeProps nodeProps = new ZkCoreNodeProps(entry.getValue());
String coreNodeName = entry.getValue().getName();
if (clusterState.liveNodesContain(nodeProps.getNodeName()) && !coreNodeName.equals(thisCoreNodeName)) {
if (mustMatchStateFilter == null || mustMatchStateFilter == Replica.State.getState(nodeProps.getState())) {
if (mustNotMatchStateFilter == null || mustNotMatchStateFilter != Replica.State.getState(nodeProps.getState())) {
nodes.add(nodeProps);
}
}
}
}
if (nodes.size() == 0) {
// no replicas
return null;
}
return nodes;
}
public SolrZkClient getZkClient() {
return zkClient;
}
/**
* Get a cluster property
*
* N.B. Cluster properties are updated via ZK watchers, and so may not necessarily
* be completely up-to-date. If you need to get the latest version, then use a
* {@link ClusterProperties} instance.
*
* @param key the property to read
* @param defaultValue a default value to use if no such property exists
* @param the type of the property
* @return the cluster property, or a default if the property is not set
*/
@SuppressWarnings("unchecked")
public T getClusterProperty(String key, T defaultValue) {
T value = (T) Utils.getObjectByPath( clusterProperties, false, key);
if (value == null)
return defaultValue;
return value;
}
/**Same as the above but allows a full json path as a list of parts
*
* @param keyPath path to the property example ["collectionDefauls", "numShards"]
* @param defaultValue a default value to use if no such property exists
* @return the cluster property, or a default if the property is not set
*/
public T getClusterProperty(List keyPath, T defaultValue) {
T value = (T) Utils.getObjectByPath( clusterProperties, false, keyPath);
if (value == null)
return defaultValue;
return value;
}
/**
* Get all cluster properties for this cluster
*
* N.B. Cluster properties are updated via ZK watchers, and so may not necessarily
* be completely up-to-date. If you need to get the latest version, then use a
* {@link ClusterProperties} instance.
*
* @return a Map of cluster properties
*/
public Map getClusterProperties() {
return Collections.unmodifiableMap(clusterProperties);
}
private final Watcher clusterPropertiesWatcher = event -> {
// session events are not change events, and do not remove the watcher
if (Watcher.Event.EventType.None.equals(event.getType())) {
return;
}
loadClusterProperties();
};
@SuppressWarnings("unchecked")
private void loadClusterProperties() {
try {
while (true) {
try {
byte[] data = zkClient.getData(ZkStateReader.CLUSTER_PROPS, clusterPropertiesWatcher, new Stat(), true);
this.clusterProperties = ClusterProperties.convertCollectionDefaultsToNestedFormat((Map) Utils.fromJSON(data));
log.debug("Loaded cluster properties: {}", this.clusterProperties);
return;
} catch (KeeperException.NoNodeException e) {
this.clusterProperties = Collections.emptyMap();
log.debug("Loaded empty cluster properties");
// set an exists watch, and if the node has been created since the last call,
// read the data again
if (zkClient.exists(ZkStateReader.CLUSTER_PROPS, clusterPropertiesWatcher, true) == null)
return;
}
}
} catch (KeeperException | InterruptedException e) {
log.error("Error reading cluster properties from zookeeper", SolrZkClient.checkInterrupted(e));
}
}
/**
* Get collection properties for a given collection. If the collection is watched, simply return it from the cache,
* otherwise fetch it directly from zookeeper.
*/
public Map getCollectionProperties(final String collection) {
Map properties = watchedCollectionProps.get(collection);
if (properties == null) {
try {
properties = fetchCollectionProperties(collection, null);
// Not storing the value in watchedCollectionProps, because it can gat stale, since we have no watcher set.
} catch (Exception e) {
throw new SolrException(ErrorCode.SERVER_ERROR, "Error reading collection properties", SolrZkClient.checkInterrupted(e));
}
}
return properties;
}
static String getCollectionPropsPath(final String collection) {
return COLLECTIONS_ZKNODE + '/' + collection + '/' + COLLECTION_PROPS_ZKNODE;
}
@SuppressWarnings("unchecked")
private Map fetchCollectionProperties(String collection, Watcher watcher) throws KeeperException, InterruptedException {
final String znodePath = getCollectionPropsPath(collection);
while (true) {
try {
byte[] data = zkClient.getData(znodePath, watcher, null, true);
return (Map) Utils.fromJSON(data);
} catch (ClassCastException e) {
throw new SolrException(ErrorCode.SERVER_ERROR, "Unable to parse collection properties for collection " + collection, e);
} catch (KeeperException.NoNodeException e) {
if (watcher != null) {
// Leave an exists watch in place in case a collectionprops.json is created later.
Stat exists = zkClient.exists(znodePath, watcher, true);
if (exists != null) {
// Rare race condition, we tried to fetch the data and couldn't find it, then we found it exists.
// Loop and try again.
continue;
}
}
return Collections.emptyMap();
}
}
}
/**
* Returns the content of /security.json from ZooKeeper as a Map
* If the files doesn't exist, it returns null.
*/
public ConfigData getSecurityProps(boolean getFresh) {
if (!getFresh) {
if (securityData == null) return new ConfigData(EMPTY_MAP,-1);
return new ConfigData(securityData.data, securityData.version);
}
try {
Stat stat = new Stat();
if(getZkClient().exists(SOLR_SECURITY_CONF_PATH, true)) {
final byte[] data = getZkClient().getData(ZkStateReader.SOLR_SECURITY_CONF_PATH, null, stat, true);
return data != null && data.length > 0 ?
new ConfigData((Map) Utils.fromJSON(data), stat.getVersion()) :
null;
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new SolrException(ErrorCode.SERVER_ERROR,"Error reading security properties", e) ;
} catch (KeeperException e) {
throw new SolrException(ErrorCode.SERVER_ERROR,"Error reading security properties", e) ;
}
return null;
}
/**
* Returns the baseURL corresponding to a given node's nodeName --
* NOTE: does not (currently) imply that the nodeName (or resulting
* baseURL) exists in the cluster.
* @lucene.experimental
*/
public String getBaseUrlForNodeName(final String nodeName) {
return Utils.getBaseUrlForNodeName(nodeName, getClusterProperty(URL_SCHEME, "http"));
}
/** Watches a single collection's format2 state.json. */
class StateWatcher implements Watcher {
private final String coll;
StateWatcher(String coll) {
this.coll = coll;
}
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
if (!collectionWatches.containsKey(coll)) {
// This collection is no longer interesting, stop watching.
log.debug("Uninteresting collection {}", coll);
return;
}
Set liveNodes = ZkStateReader.this.liveNodes;
log.info("A cluster state change: [{}] for collection [{}] has occurred - updating... (live nodes size: [{}])",
event, coll, liveNodes.size());
refreshAndWatch();
}
/**
* Refresh collection state from ZK and leave a watch for future changes.
* As a side effect, updates {@link #clusterState} and {@link #watchedCollectionStates}
* with the results of the refresh.
*/
public void refreshAndWatch() {
try {
DocCollection newState = fetchCollectionState(coll, this);
updateWatchedCollection(coll, newState);
synchronized (getUpdateLock()) {
constructState(Collections.singleton(coll));
}
} catch (KeeperException.SessionExpiredException | KeeperException.ConnectionLossException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("Unwatched collection: [{}]", coll, e);
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
log.error("Unwatched collection: [{}]", coll, e);
}
}
}
/** Watches the legacy clusterstate.json. */
class LegacyClusterStateWatcher implements Watcher {
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
int liveNodesSize = ZkStateReader.this.clusterState == null ? 0 : ZkStateReader.this.clusterState.getLiveNodes().size();
log.debug("A cluster state change: [{}], has occurred - updating... (live nodes size: [{}])", event, liveNodesSize);
refreshAndWatch();
}
/** Must hold {@link #getUpdateLock()} before calling this method. */
public void refreshAndWatch() {
try {
refreshLegacyClusterState(this);
} catch (KeeperException.NoNodeException e) {
throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE,
"Cannot connect to cluster at " + zkClient.getZkServerAddress() + ": cluster not found/not ready");
} catch (KeeperException.SessionExpiredException | KeeperException.ConnectionLossException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.warn("Interrupted", e);
}
}
}
/** Watches collection properties */
class PropsWatcher implements Watcher {
private final String coll;
PropsWatcher(String coll) {
this.coll = coll;
}
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
if (!collectionPropsWatches.containsKey(coll)) {
// No one can be notified of the change, we can ignore it and "unset" the watch
log.debug("Ignoring property change for collection {}", coll);
return;
}
log.info("A collection property change: [{}] for collection [{}] has occurred - updating...",
event, coll);
refreshAndWatch(true);
}
/**
* Refresh collection properties from ZK and leave a watch for future changes. Updates the properties in
* watchedCollectionProps with the results of the refresh. Optionally notifies watchers
*/
void refreshAndWatch(boolean notifyWatchers) {
try {
synchronized (coll) { // We only have one PropsWatcher instance per collection, so it's fine to sync on coll
Map properties = fetchCollectionProperties(coll, this);
watchedCollectionProps.put(coll, properties);
/*
* Note that if two events were fired close to each other and the second one arrived first, we would read the collectionprops.json
* twice for the same data and notify watchers (in case of notifyWatchers==true) twice for the same data, however it's guaranteed
* that after processing both events, watchedCollectionProps will have the latest data written to ZooKeeper and that the watchers
* won't be called with out of order data
*
*/
if (notifyWatchers) {
notifyPropsWatchers(coll, properties);
}
}
} catch (KeeperException.SessionExpiredException | KeeperException.ConnectionLossException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("Lost collection property watcher for {} due to ZK error", coll, e);
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
log.error("Lost collection property watcher for {} due to the thread being interrupted", coll, e);
}
}
}
/** Watches /collections children . */
class CollectionsChildWatcher implements Watcher {
@Override
public void process(WatchedEvent event) {
if (ZkStateReader.this.closed) {
return;
}
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
log.debug("A collections change: [{}], has occurred - updating...", event);
refreshAndWatch();
synchronized (getUpdateLock()) {
constructState(Collections.emptySet());
}
}
/** Must hold {@link #getUpdateLock()} before calling this method. */
public void refreshAndWatch() {
try {
refreshCollectionList(this);
} catch (KeeperException.SessionExpiredException | KeeperException.ConnectionLossException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.warn("Interrupted", e);
}
}
}
/** Watches the live_nodes and syncs changes. */
class LiveNodeWatcher implements Watcher {
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
log.debug("A live node change: [{}], has occurred - updating... (live nodes size: [{}])", event, liveNodes.size());
refreshAndWatch();
}
public void refreshAndWatch() {
try {
refreshLiveNodes(this);
} catch (KeeperException.SessionExpiredException | KeeperException.ConnectionLossException e) {
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.warn("Interrupted", e);
}
}
}
public static DocCollection getCollectionLive(ZkStateReader zkStateReader, String coll) {
try {
return zkStateReader.fetchCollectionState(coll, null);
} catch (KeeperException e) {
throw new SolrException(ErrorCode.BAD_REQUEST, "Could not load collection from ZK: " + coll, e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new SolrException(ErrorCode.BAD_REQUEST, "Could not load collection from ZK: " + coll, e);
}
}
private DocCollection fetchCollectionState(String coll, Watcher watcher) throws KeeperException, InterruptedException {
String collectionPath = getCollectionPath(coll);
while (true) {
try {
Stat stat = new Stat();
byte[] data = zkClient.getData(collectionPath, watcher, stat, true);
ClusterState state = ClusterState.load(stat.getVersion(), data,
Collections.emptySet(), collectionPath);
ClusterState.CollectionRef collectionRef = state.getCollectionStates().get(coll);
return collectionRef == null ? null : collectionRef.get();
} catch (KeeperException.NoNodeException e) {
if (watcher != null) {
// Leave an exists watch in place in case a state.json is created later.
Stat exists = zkClient.exists(collectionPath, watcher, true);
if (exists != null) {
// Rare race condition, we tried to fetch the data and couldn't find it, then we found it exists.
// Loop and try again.
continue;
}
}
return null;
}
}
}
public static String getCollectionPathRoot(String coll) {
return COLLECTIONS_ZKNODE+"/"+coll;
}
public static String getCollectionPath(String coll) {
return getCollectionPathRoot(coll) + "/state.json";
}
/**
* Notify this reader that a local Core is a member of a collection, and so that collection
* state should be watched.
*
* Not a public API. This method should only be called from ZkController.
*
* The number of cores per-collection is tracked, and adding multiple cores from the same
* collection does not increase the number of watches.
*
* @param collection the collection that the core is a member of
*
* @see ZkStateReader#unregisterCore(String)
*/
public void registerCore(String collection) {
AtomicBoolean reconstructState = new AtomicBoolean(false);
collectionWatches.compute(collection, (k, v) -> {
if (v == null) {
reconstructState.set(true);
v = new CollectionWatch<>();
}
v.coreRefCount++;
return v;
});
if (reconstructState.get()) {
new StateWatcher(collection).refreshAndWatch();
}
}
/**
* Notify this reader that a local core that is a member of a collection has been closed.
*
* Not a public API. This method should only be called from ZkController.
*
* If no cores are registered for a collection, and there are no {@link CollectionStateWatcher}s
* for that collection either, the collection watch will be removed.
*
* @param collection the collection that the core belongs to
*/
public void unregisterCore(String collection) {
AtomicBoolean reconstructState = new AtomicBoolean(false);
collectionWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
if (v.coreRefCount > 0)
v.coreRefCount--;
if (v.canBeRemoved()) {
watchedCollectionStates.remove(collection);
lazyCollectionStates.put(collection, new LazyCollectionRef(collection));
reconstructState.set(true);
return null;
}
return v;
});
if (reconstructState.get()) {
synchronized (getUpdateLock()) {
constructState(Collections.emptySet());
}
}
}
/**
* Register a CollectionStateWatcher to be called when the state of a collection changes
*/
public void registerCollectionStateWatcher(String collection, CollectionStateWatcher stateWatcher) {
AtomicBoolean watchSet = new AtomicBoolean(false);
collectionWatches.compute(collection, (k, v) -> {
if (v == null) {
v = new CollectionWatch<>();
watchSet.set(true);
}
v.stateWatchers.add(stateWatcher);
return v;
});
if (watchSet.get()) {
new StateWatcher(collection).refreshAndWatch();
}
DocCollection state = clusterState.getCollectionOrNull(collection);
if (stateWatcher.onStateChanged(liveNodes, state) == true) {
removeCollectionStateWatcher(collection, stateWatcher);
}
}
/**
* Block until a CollectionStatePredicate returns true, or the wait times out
*
* Note that the predicate may be called again even after it has returned true, so
* implementors should avoid changing state within the predicate call itself.
*
* @param collection the collection to watch
* @param wait how long to wait
* @param unit the units of the wait parameter
* @param predicate the predicate to call on state changes
* @throws InterruptedException on interrupt
* @throws TimeoutException on timeout
*/
public void waitForState(final String collection, long wait, TimeUnit unit, CollectionStatePredicate predicate)
throws InterruptedException, TimeoutException {
if (closed) {
throw new AlreadyClosedException();
}
final CountDownLatch latch = new CountDownLatch(1);
waitLatches.add(latch);
AtomicReference docCollection = new AtomicReference<>();
CollectionStateWatcher watcher = (n, c) -> {
docCollection.set(c);
boolean matches = predicate.matches(n, c);
if (matches)
latch.countDown();
return matches;
};
registerCollectionStateWatcher(collection, watcher);
try {
// wait for the watcher predicate to return true, or time out
if (!latch.await(wait, unit))
throw new TimeoutException("Timeout waiting to see state for collection=" + collection + " :" + docCollection.get());
}
finally {
removeCollectionStateWatcher(collection, watcher);
waitLatches.remove(latch);
}
}
/**
* Block until a LiveNodesStatePredicate returns true, or the wait times out
*
* Note that the predicate may be called again even after it has returned true, so
* implementors should avoid changing state within the predicate call itself.
*
* @param wait how long to wait
* @param unit the units of the wait parameter
* @param predicate the predicate to call on state changes
* @throws InterruptedException on interrupt
* @throws TimeoutException on timeout
*/
public void waitForLiveNodes(long wait, TimeUnit unit, LiveNodesPredicate predicate)
throws InterruptedException, TimeoutException {
if (closed) {
throw new AlreadyClosedException();
}
final CountDownLatch latch = new CountDownLatch(1);
waitLatches.add(latch);
LiveNodesListener listener = (o, n) -> {
boolean matches = predicate.matches(o, n);
if (matches)
latch.countDown();
return matches;
};
registerLiveNodesListener(listener);
try {
// wait for the watcher predicate to return true, or time out
if (!latch.await(wait, unit))
throw new TimeoutException("Timeout waiting for live nodes, currently they are: " + getClusterState().getLiveNodes());
}
finally {
removeLiveNodesListener(listener);
waitLatches.remove(latch);
}
}
/**
* Remove a watcher from a collection's watch list.
*
* This allows Zookeeper watches to be removed if there is no interest in the
* collection.
*
* @param collection the collection
* @param watcher the watcher
*/
public void removeCollectionStateWatcher(String collection, CollectionStateWatcher watcher) {
AtomicBoolean reconstructState = new AtomicBoolean(false);
collectionWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
v.stateWatchers.remove(watcher);
if (v.canBeRemoved()) {
watchedCollectionStates.remove(collection);
lazyCollectionStates.put(collection, new LazyCollectionRef(collection));
reconstructState.set(true);
return null;
}
return v;
});
if (reconstructState.get()) {
synchronized (getUpdateLock()) {
constructState(Collections.emptySet());
}
}
}
/* package-private for testing */
Set getStateWatchers(String collection) {
final Set watchers = new HashSet<>();
collectionWatches.compute(collection, (k, v) -> {
if (v != null) {
watchers.addAll(v.stateWatchers);
}
return v;
});
return watchers;
}
// returns true if the state has changed
private boolean updateWatchedCollection(String coll, DocCollection newState) {
if (newState == null) {
log.debug("Removing cached collection state for [{}]", coll);
watchedCollectionStates.remove(coll);
return true;
}
boolean updated = false;
// CAS update loop
while (true) {
if (!collectionWatches.containsKey(coll)) {
break;
}
DocCollection oldState = watchedCollectionStates.get(coll);
if (oldState == null) {
if (watchedCollectionStates.putIfAbsent(coll, newState) == null) {
log.debug("Add data for [{}] ver [{}]", coll, newState.getZNodeVersion());
updated = true;
break;
}
} else {
if (oldState.getZNodeVersion() >= newState.getZNodeVersion()) {
// no change to state, but we might have been triggered by the addition of a
// state watcher, so run notifications
updated = true;
break;
}
if (watchedCollectionStates.replace(coll, oldState, newState)) {
log.debug("Updating data for [{}] from [{}] to [{}]", coll, oldState.getZNodeVersion(), newState.getZNodeVersion());
updated = true;
break;
}
}
}
// Resolve race with unregisterCore.
if (!collectionWatches.containsKey(coll)) {
watchedCollectionStates.remove(coll);
log.debug("Removing uninteresting collection [{}]", coll);
}
return updated;
}
public void registerCollectionPropsWatcher(final String collection, CollectionPropsWatcher propsWatcher) {
AtomicBoolean watchSet = new AtomicBoolean(false);
collectionPropsWatches.compute(collection, (k, v) -> {
if (v == null) {
v = new CollectionWatch<>();
watchSet.set(true);
}
v.stateWatchers.add(propsWatcher);
return v;
});
if (watchSet.get()) {
new PropsWatcher(collection).refreshAndWatch(false);
}
}
public void removeCollectionPropsWatcher(String collection, CollectionPropsWatcher watcher) {
collectionPropsWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
v.stateWatchers.remove(watcher);
if (v.canBeRemoved()) {
watchedCollectionProps.remove(collection);
return null;
}
return v;
});
}
public static class ConfigData {
public Map data;
public int version;
public ConfigData() {
}
public ConfigData(Map data, int version) {
this.data = data;
this.version = version;
}
}
private void notifyStateWatchers(Set liveNodes, String collection, DocCollection collectionState) {
if (this.closed) {
return;
}
try {
notifications.submit(new Notification(liveNodes, collection, collectionState));
}
catch (RejectedExecutionException e) {
if (closed == false) {
log.error("Couldn't run collection notifications for {}", collection, e);
}
}
}
private class Notification implements Runnable {
final Set liveNodes;
final String collection;
final DocCollection collectionState;
private Notification(Set liveNodes, String collection, DocCollection collectionState) {
this.liveNodes = liveNodes;
this.collection = collection;
this.collectionState = collectionState;
}
@Override
public void run() {
List watchers = new ArrayList<>();
collectionWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
watchers.addAll(v.stateWatchers);
return v;
});
for (CollectionStateWatcher watcher : watchers) {
try {
if (watcher.onStateChanged(liveNodes, collectionState)) {
removeCollectionStateWatcher(collection, watcher);
}
} catch (Exception exception) {
log.warn("Error on calling watcher", exception);
}
}
}
}
//
// Aliases related
//
/** Access to the {@link Aliases}. */
public final AliasesManager aliasesManager = new AliasesManager();
/**
* Get an immutable copy of the present state of the aliases. References to this object should not be retained
* in any context where it will be important to know if aliases have changed.
*
* @return The current aliases, Aliases.EMPTY if not solr cloud, or no aliases have existed yet. Never returns null.
*/
public Aliases getAliases() {
return aliasesManager.getAliases();
}
// called by createClusterStateWatchersAndUpdate()
private void refreshAliases(AliasesManager watcher) throws KeeperException, InterruptedException {
synchronized (getUpdateLock()) {
constructState(Collections.emptySet());
zkClient.exists(ALIASES, watcher, true);
}
aliasesManager.update();
}
/**
* A class to manage the aliases instance, including watching for changes.
* There should only ever be one instance of this class
* per instance of ZkStateReader. Normally it will not be useful to create a new instance since
* this watcher automatically re-registers itself every time it is updated.
*/
public class AliasesManager implements Watcher { // the holder is a Zk watcher
// note: as of this writing, this class if very generic. Is it useful to use for other ZK managed things?
private final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
private volatile Aliases aliases = Aliases.EMPTY;
public Aliases getAliases() {
return aliases; // volatile read
}
/**
* Writes an updated {@link Aliases} to zk.
* It will retry if there are races with other modifications, giving up after 30 seconds with a SolrException.
* The caller should understand it's possible the aliases has further changed if it examines it.
*/
public void applyModificationAndExportToZk(UnaryOperator op) {
// The current aliases hasn't been update()'ed yet -- which is impossible? Any way just update it first.
if (aliases.getZNodeVersion() == -1) {
try {
boolean updated = update();
assert updated;
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, e.toString(), e);
} catch (KeeperException e) {
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, e.toString(), e);
}
}
final long deadlineNanos = System.nanoTime() + TimeUnit.SECONDS.toNanos(30);
// note: triesLeft tuning is based on ConcurrentCreateRoutedAliasTest
for (int triesLeft = 30; triesLeft > 0; triesLeft--) {
// we could synchronize on "this" but there doesn't seem to be a point; we have a retry loop.
Aliases curAliases = getAliases();
Aliases modAliases = op.apply(curAliases);
final byte[] modAliasesJson = modAliases.toJSON();
if (curAliases == modAliases) {
log.debug("Current aliases has the desired modification; no further ZK interaction needed.");
return;
}
try {
try {
final Stat stat = getZkClient().setData(ALIASES, modAliasesJson, curAliases.getZNodeVersion(), true);
setIfNewer(Aliases.fromJSON(modAliasesJson, stat.getVersion()));
return;
} catch (KeeperException.BadVersionException e) {
log.debug(e.toString(), e);
log.warn("Couldn't save aliases due to race with another modification; will update and retry until timeout");
// considered a backoff here, but we really do want to compete strongly since the normal case is
// that we will do one update and succeed. This is left as a hot loop for limited tries intentionally.
// More failures than that here probably indicate a bug or a very strange high write frequency usage for
// aliases.json, timeouts mean zk is being very slow to respond, or this node is being crushed
// by other processing and just can't find any cpu cycles at all.
update();
if (deadlineNanos < System.nanoTime()) {
throw new SolrException(ErrorCode.SERVER_ERROR, "Timed out trying to update aliases! " +
"Either zookeeper or this node may be overloaded.");
}
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, e.toString(), e);
} catch (KeeperException e) {
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, e.toString(), e);
}
}
throw new SolrException(ErrorCode.SERVER_ERROR, "Too many successive version failures trying to update aliases");
}
/**
* Ensures the internal aliases is up to date. If there is a change, return true.
*
* @return true if an update was performed
*/
public boolean update() throws KeeperException, InterruptedException {
log.debug("Checking ZK for most up to date Aliases {}", ALIASES);
// Call sync() first to ensure the subsequent read (getData) is up to date.
zkClient.getSolrZooKeeper().sync(ALIASES, null, null);
Stat stat = new Stat();
final byte[] data = zkClient.getData(ALIASES, null, stat, true);
return setIfNewer(Aliases.fromJSON(data, stat.getVersion()));
}
// ZK Watcher interface
@Override
public void process(WatchedEvent event) {
// session events are not change events, and do not remove the watcher
if (EventType.None.equals(event.getType())) {
return;
}
try {
log.debug("Aliases: updating");
// re-register the watch
Stat stat = new Stat();
final byte[] data = zkClient.getData(ALIASES, this, stat, true);
// note: it'd be nice to avoid possibly needlessly parsing if we don't update aliases but not a big deal
setIfNewer(Aliases.fromJSON(data, stat.getVersion()));
} catch (NoNodeException e) {
// /aliases.json will not always exist
} catch (KeeperException.ConnectionLossException | KeeperException.SessionExpiredException e) {
// note: aliases.json is required to be present
log.warn("ZooKeeper watch triggered, but Solr cannot talk to ZK: [{}]", e.getMessage());
} catch (KeeperException e) {
log.error("A ZK error has occurred", e);
throw new ZooKeeperException(ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
log.warn("Interrupted", e);
}
}
/**
* Update the internal aliases reference with a new one, provided that its ZK version has increased.
*
* @param newAliases the potentially newer version of Aliases
*/
private boolean setIfNewer(Aliases newAliases) {
assert newAliases.getZNodeVersion() >= 0;
synchronized (this) {
int cmp = Integer.compare(aliases.getZNodeVersion(), newAliases.getZNodeVersion());
if (cmp < 0) {
log.debug("Aliases: cmp={}, new definition is: {}", cmp, newAliases);
aliases = newAliases;
this.notifyAll();
return true;
} else {
log.debug("Aliases: cmp={}, not overwriting ZK version.", cmp);
assert cmp != 0 || Arrays.equals(aliases.toJSON(), newAliases.toJSON()) : aliases + " != " + newAliases;
return false;
}
}
}
}
private void notifyPropsWatchers(String collection, Map properties) {
try {
collectionPropsNotifications.submit(new PropsNotification(collection, properties));
} catch (RejectedExecutionException e) {
if (!closed) {
log.error("Couldn't run collection properties notifications for {}", collection, e);
}
}
}
private class PropsNotification implements Runnable {
final String collection;
final Map collectionProperties;
private PropsNotification(String collection, Map collectionProperties) {
this.collection = collection;
this.collectionProperties = collectionProperties;
}
@Override
public void run() {
List watchers = new ArrayList<>();
collectionPropsWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
watchers.addAll(v.stateWatchers);
return v;
});
for (CollectionPropsWatcher watcher : watchers) {
if (watcher.onStateChanged(collectionProperties)) {
removeCollectionPropsWatcher(collection, watcher);
}
}
}
}
}
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