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/*
* Copyright DataStax, Inc.
*
* Licensed 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 com.datastax.driver.core;
import com.datastax.driver.core.policies.AddressTranslator;
import com.google.common.util.concurrent.ListenableFuture;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantLock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A Cassandra node.
*
* This class keeps the information the driver maintain on a given Cassandra node.
*/
public class Host {
private static final Logger logger = LoggerFactory.getLogger(Host.class);
static final Logger statesLogger = LoggerFactory.getLogger(Host.class.getName() + ".STATES");
// The address we'll use to connect to the node
private final InetSocketAddress address;
// The broadcast_address as known by Cassandra.
// We use that internally because
// that's the 'peer' in the 'System.peers' table and avoids querying the full peers table in
// ControlConnection.refreshNodeInfo.
private volatile InetSocketAddress broadcastSocketAddress;
// The listen_address as known by Cassandra.
// This is usually the same as broadcast_address unless
// specified otherwise in cassandra.yaml file.
private volatile InetSocketAddress listenSocketAddress;
private volatile UUID hostId;
private volatile UUID schemaVersion;
// Can be set concurrently but the value should always be the same.
private volatile ShardingInfo shardingInfo = null;
enum State {
ADDED,
DOWN,
UP
}
volatile State state;
/** Ensures state change notifications for that host are handled serially */
final ReentrantLock notificationsLock = new ReentrantLock(true);
final ConvictionPolicy convictionPolicy;
private final Cluster.Manager manager;
// Tracks later reconnection attempts to that host so we avoid adding multiple tasks.
final AtomicReference> reconnectionAttempt =
new AtomicReference>();
final ExecutionInfo defaultExecutionInfo;
private volatile String datacenter;
private volatile String rack;
private volatile VersionNumber cassandraVersion;
private volatile Set tokens;
private volatile String dseWorkload;
private volatile boolean dseGraphEnabled;
private volatile VersionNumber dseVersion;
// ClusterMetadata keeps one Host object per inet address and we rely on this (more precisely,
// we rely on the fact that we can use Object equality as a valid equality), so don't use
// that constructor but ClusterMetadata.getHost instead.
Host(
InetSocketAddress address,
ConvictionPolicy.Factory convictionPolicyFactory,
Cluster.Manager manager) {
if (address == null || convictionPolicyFactory == null) throw new NullPointerException();
this.address = address;
this.convictionPolicy = convictionPolicyFactory.create(this, manager.reconnectionPolicy());
this.manager = manager;
this.defaultExecutionInfo = new ExecutionInfo(this);
this.state = State.ADDED;
}
void setLocationInfo(String datacenter, String rack) {
this.datacenter = datacenter;
this.rack = rack;
}
void setVersion(String cassandraVersion) {
VersionNumber versionNumber = null;
try {
if (cassandraVersion != null) {
versionNumber = VersionNumber.parse(cassandraVersion);
}
} catch (IllegalArgumentException e) {
logger.warn(
"Error parsing Cassandra version {}. This shouldn't have happened", cassandraVersion);
}
this.cassandraVersion = versionNumber;
}
void setBroadcastSocketAddress(InetSocketAddress broadcastAddress) {
this.broadcastSocketAddress = broadcastAddress;
}
void setListenSocketAddress(InetSocketAddress listenAddress) {
this.listenSocketAddress = listenAddress;
}
void setDseVersion(String dseVersion) {
VersionNumber versionNumber = null;
try {
if (dseVersion != null) {
versionNumber = VersionNumber.parse(dseVersion);
}
} catch (IllegalArgumentException e) {
logger.warn("Error parsing DSE version {}. This shouldn't have happened", dseVersion);
}
this.dseVersion = versionNumber;
}
void setDseWorkload(String dseWorkload) {
this.dseWorkload = dseWorkload;
}
void setDseGraphEnabled(boolean dseGraphEnabled) {
this.dseGraphEnabled = dseGraphEnabled;
}
void setHostId(UUID hostId) {
this.hostId = hostId;
}
void setSchemaVersion(UUID schemaVersion) {
this.schemaVersion = schemaVersion;
}
boolean supports(ProtocolVersion version) {
return getCassandraVersion() == null
|| version.minCassandraVersion().compareTo(getCassandraVersion().nextStable()) <= 0;
}
/**
* Returns the address that the driver will use to connect to the node.
*
* This is a shortcut for {@code getSocketAddress().getAddress()}.
*
* @return the address.
* @see #getSocketAddress()
*/
public InetAddress getAddress() {
return address.getAddress();
}
/**
* Returns the address and port that the driver will use to connect to the node.
*
*
This is the node's broadcast RPC address, possibly translated if an {@link
* AddressTranslator} has been configured for this cluster.
*
*
The broadcast RPC address is inferred from the following cassandra.yaml file settings:
*
*
* - {@code rpc_address}, {@code rpc_interface} or {@code broadcast_rpc_address}
*
- {@code native_transport_port}
*
*
* @return the address and port.
* @see The
* cassandra.yaml configuration file
*/
public InetSocketAddress getSocketAddress() {
return address;
}
/**
* Returns the node broadcast address, if known. Otherwise {@code null}.
*
* This is a shortcut for {@code getBroadcastSocketAddress().getAddress()}.
*
* @return the node broadcast address, if known. Otherwise {@code null}.
* @see #getBroadcastSocketAddress()
* @see The
* cassandra.yaml configuration file
*/
public InetAddress getBroadcastAddress() {
return broadcastSocketAddress != null ? broadcastSocketAddress.getAddress() : null;
}
/**
* Returns the node broadcast address (that is, the address by which it should be contacted by
* other peers in the cluster), if known. Otherwise {@code null}.
*
*
Note that the port of the returned address will be 0 for versions of Cassandra older than
* 4.0.
*
*
This corresponds to the {@code broadcast_address} cassandra.yaml file setting and is by
* default the same as {@link #getListenSocketAddress()}, unless specified otherwise in
* cassandra.yaml. This is NOT the address clients should use to contact this node.
*
*
This information is always available for peer hosts. For the control host, it's only
* available if CASSANDRA-9436 is fixed on the server side (Cassandra versions >= 2.0.16, 2.1.6,
* 2.2.0 rc1). For older versions, note that if the driver loses the control connection and
* reconnects to a different control host, the old control host becomes a peer, and therefore its
* broadcast address is updated.
*
* @return the node broadcast address, if known. Otherwise {@code null}.
* @see The
* cassandra.yaml configuration file
*/
public InetSocketAddress getBroadcastSocketAddress() {
return broadcastSocketAddress;
}
/**
* Returns the node listen address, if known. Otherwise {@code null}.
*
*
This is a shortcut for {@code getListenSocketAddress().getAddress()}.
*
* @return the node listen address, if known. Otherwise {@code null}.
* @see #getListenSocketAddress()
* @see The
* cassandra.yaml configuration file
*/
public InetAddress getListenAddress() {
return listenSocketAddress != null ? listenSocketAddress.getAddress() : null;
}
/**
* Returns the node listen address (that is, the address the node uses to contact other peers in
* the cluster), if known. Otherwise {@code null}.
*
*
Note that the port of the returned address will be 0 for versions of Cassandra older than
* 4.0.
*
*
This corresponds to the {@code listen_address} cassandra.yaml file setting. This is NOT
* the address clients should use to contact this node.
*
*
This information is available for the control host if CASSANDRA-9603 is fixed on the server
* side (Cassandra versions >= 2.0.17, 2.1.8, 2.2.0 rc2). It's currently not available for peer
* hosts. Note that the current driver code already tries to read a {@code listen_address} column
* in {@code system.peers}; when a future Cassandra version adds it, it will be picked by the
* driver without any further change needed.
*
* @return the node listen address, if known. Otherwise {@code null}.
* @see The
* cassandra.yaml configuration file
*/
public InetSocketAddress getListenSocketAddress() {
return listenSocketAddress;
}
/**
* Returns the name of the datacenter this host is part of.
*
*
The returned datacenter name is the one as known by Cassandra. It is also possible for this
* information to be unavailable. In that case this method returns {@code null}, and the caller
* should always be aware of this possibility.
*
* @return the Cassandra datacenter name or null if datacenter is unavailable.
*/
public String getDatacenter() {
return datacenter;
}
/**
* Returns the name of the rack this host is part of.
*
*
The returned rack name is the one as known by Cassandra. It is also possible for this
* information to be unavailable. In that case this method returns {@code null}, and the caller
* should always be aware of this possibility.
*
* @return the Cassandra rack name or null if the rack is unavailable
*/
public String getRack() {
return rack;
}
/**
* The Cassandra version the host is running.
*
*
It is also possible for this information to be unavailable. In that case this method returns
* {@code null}, and the caller should always be aware of this possibility.
*
* @return the Cassandra version the host is running.
*/
public VersionNumber getCassandraVersion() {
return cassandraVersion;
}
/**
* The DSE version the host is running.
*
*
It is also possible for this information to be unavailable. In that case this method returns
* {@code null}, and the caller should always be aware of this possibility.
*
* @return the DSE version the host is running.
* @deprecated Please use the Java driver
* for DSE if you are connecting to a DataStax Enterprise (DSE) cluster. This method might
* not function properly with future versions of DSE.
*/
@Deprecated
public VersionNumber getDseVersion() {
return dseVersion;
}
/**
* The DSE Workload the host is running.
*
*
It is also possible for this information to be unavailable. In that case this method returns
* {@code null}, and the caller should always be aware of this possibility.
*
* @return the DSE workload the host is running.
* @deprecated Please use the Java driver
* for DSE if you are connecting to a DataStax Enterprise (DSE) cluster. This method might
* not function properly with future versions of DSE.
*/
@Deprecated
public String getDseWorkload() {
return dseWorkload;
}
/**
* Returns whether the host is running DSE Graph.
*
* @return whether the node is running DSE Graph.
* @deprecated Please use the Java driver
* for DSE if you are connecting to a DataStax Enterprise (DSE) cluster. This method might
* not function properly with future versions of DSE.
*/
@Deprecated
public boolean isDseGraphEnabled() {
return dseGraphEnabled;
}
/**
* Return the host id value for the host.
*
*
The host id is the main identifier used by Cassandra on the server for internal
* communication (gossip). It is referenced as the column {@code host_id} in the {@code
* system.local} or {@code system.peers} table.
*
* @return the node's host id value.
*/
public UUID getHostId() {
return hostId;
}
/**
* Return the current schema version for the host.
*
*
Schema versions in Cassandra are used to ensure all the nodes agree on the current Cassandra
* schema when it is modified. For more information see {@link
* ExecutionInfo#isSchemaInAgreement()}
*
* @return the node's current schema version value.
*/
public UUID getSchemaVersion() {
return schemaVersion;
}
/**
* Returns the tokens that this host owns.
*
* @return the (immutable) set of tokens.
*/
public Set getTokens() {
return tokens;
}
void setTokens(Set tokens) {
this.tokens = tokens;
}
public ShardingInfo getShardingInfo() {
return shardingInfo;
}
public void setShardingInfo(ShardingInfo shardingInfo) {
this.shardingInfo = shardingInfo;
}
/**
* Returns whether the host is considered up by the driver.
*
* Please note that this is only the view of the driver and may not reflect reality. In
* particular a node can be down but the driver hasn't detected it yet, or it can have been
* restarted and the driver hasn't detected it yet (in particular, for hosts to which the driver
* does not connect (because the {@code LoadBalancingPolicy.distance} method says so), this
* information may be durably inaccurate). This information should thus only be considered as best
* effort and should not be relied upon too strongly.
*
* @return whether the node is considered up.
*/
public boolean isUp() {
return state == State.UP;
}
/**
* Returns a description of the host's state, as seen by the driver.
*
*
This is exposed for debugging purposes only; the format of this string might change between
* driver versions, so clients should not make any assumptions about it.
*
* @return a description of the host's state.
*/
public String getState() {
return state.name();
}
/**
* Returns a {@code ListenableFuture} representing the completion of the reconnection attempts
* scheduled after a host is marked {@code DOWN}.
*
*
If the caller cancels this future, the driver will not try to reconnect to this host
* until it receives an UP event for it. Note that this could mean never, if the node was marked
* down because of a driver-side error (e.g. read timeout) but no failure was detected by
* Cassandra. The caller might decide to trigger an explicit reconnection attempt at a later point
* with {@link #tryReconnectOnce()}.
*
* @return the future, or {@code null} if no reconnection attempt was in progress.
*/
public ListenableFuture getReconnectionAttemptFuture() {
return reconnectionAttempt.get();
}
/**
* Triggers an asynchronous reconnection attempt to this host.
*
*
This method is intended for load balancing policies that mark hosts as {@link
* HostDistance#IGNORED IGNORED}, but still need a way to periodically check these hosts' states
* (UP / DOWN).
*
*
For a host that is at distance {@code IGNORED}, this method will try to reconnect exactly
* once: if reconnection succeeds, the host is marked {@code UP}; otherwise, no further attempts
* will be scheduled. It has no effect if the node is already {@code UP}, or if a reconnection
* attempt is already in progress.
*
*
Note that if the host is not a distance {@code IGNORED}, this method will
* trigger a periodic reconnection attempt if the reconnection fails.
*/
public void tryReconnectOnce() {
this.manager.startSingleReconnectionAttempt(this);
}
@Override
public boolean equals(Object other) {
if (other instanceof Host) {
Host that = (Host) other;
return this.address.equals(that.address);
}
return false;
}
@Override
public int hashCode() {
return address.hashCode();
}
boolean wasJustAdded() {
return state == State.ADDED;
}
@Override
public String toString() {
return address.toString();
}
void setDown() {
state = State.DOWN;
}
void setUp() {
state = State.UP;
}
/**
* Interface for listeners that are interested in hosts added, up, down and removed events.
*
*
It is possible for the same event to be fired multiple times, particularly for up or down
* events. Therefore, a listener should ignore the same event if it has already been notified of a
* node's state.
*/
public interface StateListener {
/**
* Called when a new node is added to the cluster.
*
*
The newly added node should be considered up.
*
* @param host the host that has been newly added.
*/
void onAdd(Host host);
/**
* Called when a node is determined to be up.
*
* @param host the host that has been detected up.
*/
void onUp(Host host);
/**
* Called when a node is determined to be down.
*
* @param host the host that has been detected down.
*/
void onDown(Host host);
/**
* Called when a node is removed from the cluster.
*
* @param host the removed host.
*/
void onRemove(Host host);
/**
* Gets invoked when the tracker is registered with a cluster, or at cluster startup if the
* tracker was registered at initialization with {@link
* com.datastax.driver.core.Cluster.Initializer#register(LatencyTracker)}.
*
* @param cluster the cluster that this tracker is registered with.
*/
void onRegister(Cluster cluster);
/**
* Gets invoked when the tracker is unregistered from a cluster, or at cluster shutdown if the
* tracker was not unregistered.
*
* @param cluster the cluster that this tracker was registered with.
*/
void onUnregister(Cluster cluster);
}
/**
* A {@code StateListener} that tracks when it gets registered or unregistered with a cluster.
*
*
This interface exists only for backward-compatibility reasons: starting with the 3.0 branch
* of the driver, its methods are on the parent interface directly.
*/
public interface LifecycleAwareStateListener extends StateListener {
/**
* Gets invoked when the listener is registered with a cluster, or at cluster startup if the
* listener was registered at initialization with {@link
* com.datastax.driver.core.Cluster#register(Host.StateListener)}.
*
* @param cluster the cluster that this listener is registered with.
*/
@Override
void onRegister(Cluster cluster);
/**
* Gets invoked when the listener is unregistered from a cluster, or at cluster shutdown if the
* listener was not unregistered.
*
* @param cluster the cluster that this listener was registered with.
*/
@Override
void onUnregister(Cluster cluster);
}
}