/*
* 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.io.UnsupportedEncodingException;
import java.lang.invoke.MethodHandles;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
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.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 org.apache.solr.common.Callable;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.common.params.CoreAdminParams;
import org.apache.solr.common.util.ExecutorUtil;
import org.apache.solr.common.util.Pair;
import org.apache.solr.common.util.Utils;
import org.apache.zookeeper.KeeperException;
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.unmodifiableSet;
import static org.apache.solr.common.util.Utils.fromJSON;
public class ZkStateReader implements Closeable {
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";
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 PROPERTY_PROP = "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 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 REJOIN_AT_HEAD_PROP = "rejoinAtHead";
public static final String SOLR_SECURITY_CONF_PATH = "/security.json";
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 REALTIME_REPLICAS = "realtimeReplicas";
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";
public static final String URL_SCHEME = "urlScheme";
/** 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 = 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<String, ClusterState.CollectionRef> 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<String, DocCollection> watchedCollectionStates = new ConcurrentHashMap<>();
/** Collections with format2 state.json, not "interesting" and not actively watched. */
private final ConcurrentHashMap<String, LazyCollectionRef> lazyCollectionStates = new ConcurrentHashMap<>();
private volatile Set<String> liveNodes = emptySet();
private volatile Map<String, Object> clusterProperties = Collections.emptyMap();
private final ZkConfigManager configManager;
private ConfigData securityData;
private final Runnable securityNodeListener;
private ConcurrentHashMap<String, CollectionWatch> collectionWatches = new ConcurrentHashMap<>();
private final ExecutorService notifications = ExecutorUtil.newMDCAwareCachedThreadPool("watches");
private static class CollectionWatch {
int coreRefCount = 0;
Set<CollectionStateWatcher> stateWatchers = ConcurrentHashMap.newKeySet();
public boolean canBeRemoved() {
return coreRefCount + stateWatchers.size() == 0;
}
}
public static final Set<String> KNOWN_CLUSTER_PROPS = unmodifiableSet(new HashSet<>(asList(
LEGACY_CLOUD,
URL_SCHEME,
AUTO_ADD_REPLICAS,
CoreAdminParams.BACKUP_LOCATION,
MAX_CORES_PER_NODE)));
/**
* 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 Aliases aliases = new Aliases();
private volatile boolean closed = false;
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;
}
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;
}
public ZkConfigManager getConfigManager() {
return configManager;
}
/**
* Forcibly refresh cluster state from ZK. Do this only to avoid race conditions because it's expensive.
*
* @deprecated Don't call this, call {@link #forceUpdateCollection(String)} on a single collection if you must.
*/
@Deprecated
public void updateClusterState() 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<String> safeCopy = new ArrayList<>(watchedCollectionStates.keySet());
Set<String> 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.
*/
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 Aliases getAliases() {
return aliases;
}
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());
synchronized (ZkStateReader.this.getUpdateLock()) {
constructState(Collections.emptySet());
zkClient.exists(ALIASES,
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 aliases... ");
// remake watch
final Watcher thisWatch = this;
final Stat stat = new Stat();
final byte[] data = zkClient.getData(ALIASES, thisWatch, stat, true);
ZkStateReader.this.aliases = ClusterState.load(data);
LOG.debug("New alias definition is: " + ZkStateReader.this.aliases.toString());
}
} 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(SolrException.ErrorCode.SERVER_ERROR, "A ZK error has occurred", e);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
LOG.warn("Interrupted", e);
}
}
}, true);
}
updateAliases();
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);
}
}
private void addSecuritynodeWatcher(final Callable<Pair<byte[], Stat>> 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<String> changedCollections) {
Set<String> 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<String, ClusterState.CollectionRef> result = new LinkedHashMap<>(legacyCollectionStates);
// Add state format2 collections, but don't override legacy collection states.
for (Map.Entry<String, DocCollection> 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<String, LazyCollectionRef> 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());
}
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<String> 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#getCollections()} 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<String> 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));
}
}
}
}
}
private class LazyCollectionRef extends ClusterState.CollectionRef {
private final String collName;
public LazyCollectionRef(String collName) {
super(null);
this.collName = collName;
}
@Override
public DocCollection get() {
gets.incrementAndGet();
// TODO: consider limited caching
return getCollectionLive(ZkStateReader.this, collName);
}
@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<Set<String>> lastFetchedLiveNodes = new AtomicReference<>();
/**
* Refresh live_nodes.
*/
private void refreshLiveNodes(Watcher watcher) throws KeeperException, InterruptedException {
synchronized (refreshLiveNodesLock) {
Set<String> newLiveNodes;
try {
List<String> nodeList = zkClient.getChildren(LIVE_NODES_ZKNODE, watcher, true);
newLiveNodes = new HashSet<>(nodeList);
} catch (KeeperException.NoNodeException e) {
newLiveNodes = emptySet();
}
lastFetchedLiveNodes.set(newLiveNodes);
}
// Can't lock getUpdateLock() until we release the other, it would cause deadlock.
Set<String> 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... {} -> {}", new TreeSet<>(oldLiveNodes), new TreeSet<>(newLiveNodes));
}
}
/**
* @return information about the cluster from ZooKeeper
*/
public ClusterState getClusterState() {
return clusterState;
}
public Object getUpdateLock() {
return this;
}
public void close() {
this.closed = true;
notifications.shutdown();
if (closeClient) {
zkClient.close();
}
}
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(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 {
long timeoutAt = System.nanoTime() + TimeUnit.NANOSECONDS.convert(timeout, TimeUnit.MILLISECONDS);
while (true) {
Replica leader = getLeader(collection, shard);
if (leader != null) return leader;
if (System.nanoTime() >= timeoutAt || closed) break;
Thread.sleep(GET_LEADER_RETRY_INTERVAL_MS);
}
throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE, "No registered leader was found after waiting for "
+ timeout + "ms " + ", collection: " + collection + " slice: " + shard);
}
/**
* 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<ZkCoreNodeProps> getReplicaProps(String collection, String shardId, String thisCoreNodeName) {
return getReplicaProps(collection, shardId, thisCoreNodeName, null);
}
public List<ZkCoreNodeProps> getReplicaProps(String collection, String shardId, String thisCoreNodeName,
Replica.State mustMatchStateFilter) {
return getReplicaProps(collection, shardId, thisCoreNodeName, mustMatchStateFilter, null);
}
public List<ZkCoreNodeProps> getReplicaProps(String collection, String shardId, String thisCoreNodeName,
Replica.State mustMatchStateFilter, Replica.State mustNotMatchStateFilter) {
assert thisCoreNodeName != null;
ClusterState clusterState = this.clusterState;
if (clusterState == null) {
return null;
}
Map<String,Slice> slices = clusterState.getSlicesMap(collection);
if (slices == null) {
throw new ZooKeeperException(ErrorCode.BAD_REQUEST,
"Could not find collection in zk: " + collection);
}
Slice replicas = slices.get(shardId);
if (replicas == null) {
throw new ZooKeeperException(ErrorCode.BAD_REQUEST, "Could not find shardId in zk: " + shardId);
}
Map<String,Replica> shardMap = replicas.getReplicasMap();
List<ZkCoreNodeProps> nodes = new ArrayList<>(shardMap.size());
for (Entry<String,Replica> entry : shardMap.entrySet()) {
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;
}
public void updateAliases() throws KeeperException, InterruptedException {
final byte[] data = zkClient.getData(ALIASES, null, null, true);
this.aliases = ClusterState.load(data);
}
/**
* 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 <T> the type of the property
* @return the cluster property, or a default if the property is not set
*/
@SuppressWarnings("unchecked")
public <T> T getClusterProperty(String key, T defaultValue) {
T value = (T) clusterProperties.get(key);
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<String, Object> 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 = (Map<String, Object>) 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));
}
}
/**
* 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<String, Object>) 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 getBaseUrlForNodeName(nodeName, getClusterProperty(URL_SCHEME, "http"));
}
public static String getBaseUrlForNodeName(final String nodeName, String urlScheme) {
final int _offset = nodeName.indexOf("_");
if (_offset < 0) {
throw new IllegalArgumentException("nodeName does not contain expected '_' separator: " + nodeName);
}
final String hostAndPort = nodeName.substring(0,_offset);
try {
final String path = URLDecoder.decode(nodeName.substring(1+_offset), "UTF-8");
return urlScheme + "://" + hostAndPort + (path.isEmpty() ? "" : ("/" + path));
} catch (UnsupportedEncodingException e) {
throw new IllegalStateException("JVM Does not seem to support UTF-8", e);
}
}
/** 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<String> 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 /collections children . */
class CollectionsChildWatcher 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 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.<String>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 {
final CountDownLatch latch = new CountDownLatch(1);
CollectionStateWatcher watcher = (n, 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();
}
finally {
removeCollectionStateWatcher(collection, watcher);
}
}
/**
* 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) {
collectionWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
v.stateWatchers.remove(watcher);
if (v.canBeRemoved())
return null;
return v;
});
}
/* package-private for testing */
Set<CollectionStateWatcher> getStateWatchers(String collection) {
final Set<CollectionStateWatcher> 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 static class ConfigData {
public Map<String, Object> data;
public int version;
public ConfigData() {
}
public ConfigData(Map<String, Object> data, int version) {
this.data = data;
this.version = version;
}
}
private void notifyStateWatchers(Set<String> liveNodes, String collection, DocCollection collectionState) {
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<String> liveNodes;
final String collection;
final DocCollection collectionState;
private Notification(Set<String> liveNodes, String collection, DocCollection collectionState) {
this.liveNodes = liveNodes;
this.collection = collection;
this.collectionState = collectionState;
}
@Override
public void run() {
List<CollectionStateWatcher> watchers = new ArrayList<>();
collectionWatches.compute(collection, (k, v) -> {
if (v == null)
return null;
watchers.addAll(v.stateWatchers);
return v;
});
for (CollectionStateWatcher watcher : watchers) {
if (watcher.onStateChanged(liveNodes, collectionState)) {
removeCollectionStateWatcher(collection, watcher);
}
}
}
}
}