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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.hadoop.hbase.replication;
import java.io.IOException;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.apache.hadoop.hbase.Abortable;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.TableDescriptors;
import org.apache.hadoop.hbase.wal.WAL.Entry;
import org.apache.hadoop.hbase.replication.regionserver.MetricsSource;
/**
* ReplicationEndpoint is a plugin which implements replication
* to other HBase clusters, or other systems. ReplicationEndpoint implementation
* can be specified at the peer creation time by specifying it
* in the {@link ReplicationPeerConfig}. A ReplicationEndpoint is run in a thread
* in each region server in the same process.
*
* ReplicationEndpoint is closely tied to ReplicationSource in a producer-consumer
* relation. ReplicationSource is an HBase-private class which tails the logs and manages
* the queue of logs plus management and persistence of all the state for replication.
* ReplicationEndpoint on the other hand is responsible for doing the actual shipping
* and persisting of the WAL entries in the other cluster.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
public interface ReplicationEndpoint extends ReplicationPeerConfigListener {
// TODO: This class needs doc. Has a Context and a ReplicationContext. Then has #start, #stop.
// How they relate? Do we #start before #init(Context)? We fail fast if you don't?
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
class Context {
private final Configuration localConf;
private final Configuration conf;
private final FileSystem fs;
private final TableDescriptors tableDescriptors;
private final ReplicationPeer replicationPeer;
private final String peerId;
private final UUID clusterId;
private final MetricsSource metrics;
private final Abortable abortable;
@InterfaceAudience.Private
public Context(
final Configuration localConf,
final Configuration conf,
final FileSystem fs,
final String peerId,
final UUID clusterId,
final ReplicationPeer replicationPeer,
final MetricsSource metrics,
final TableDescriptors tableDescriptors,
final Abortable abortable) {
this.localConf = localConf;
this.conf = conf;
this.fs = fs;
this.clusterId = clusterId;
this.peerId = peerId;
this.replicationPeer = replicationPeer;
this.metrics = metrics;
this.tableDescriptors = tableDescriptors;
this.abortable = abortable;
}
public Configuration getConfiguration() {
return conf;
}
public Configuration getLocalConfiguration() {
return localConf;
}
public FileSystem getFilesystem() {
return fs;
}
public UUID getClusterId() {
return clusterId;
}
public String getPeerId() {
return peerId;
}
public ReplicationPeerConfig getPeerConfig() {
return replicationPeer.getPeerConfig();
}
public ReplicationPeer getReplicationPeer() {
return replicationPeer;
}
public MetricsSource getMetrics() {
return metrics;
}
public TableDescriptors getTableDescriptors() {
return tableDescriptors;
}
public Abortable getAbortable() { return abortable; }
}
/**
* Initialize the replication endpoint with the given context.
* @param context replication context
* @throws IOException error occur when initialize the endpoint.
*/
void init(Context context) throws IOException;
/** Whether or not, the replication endpoint can replicate to it's source cluster with the same
* UUID */
boolean canReplicateToSameCluster();
/**
* Returns a UUID of the provided peer id. Every HBase cluster instance has a persisted
* associated UUID. If the replication is not performed to an actual HBase cluster (but
* some other system), the UUID returned has to uniquely identify the connected target system.
* @return a UUID or null if the peer cluster does not exist or is not connected.
*/
UUID getPeerUUID();
/**
* Returns a WALEntryFilter to use for filtering out WALEntries from the log. Replication
* infrastructure will call this filter before sending the edits to shipEdits().
* @return a {@link WALEntryFilter} or null.
*/
WALEntryFilter getWALEntryfilter();
/**
* A context for {@link ReplicationEndpoint#replicate(ReplicateContext)} method.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
static class ReplicateContext {
List entries;
int size;
String walGroupId;
@InterfaceAudience.Private
public ReplicateContext() {
}
public ReplicateContext setEntries(List entries) {
this.entries = entries;
return this;
}
public ReplicateContext setSize(int size) {
this.size = size;
return this;
}
public ReplicateContext setWalGroupId(String walGroupId) {
this.walGroupId = walGroupId;
return this;
}
public List getEntries() {
return entries;
}
public int getSize() {
return size;
}
public String getWalGroupId(){
return walGroupId;
}
}
/**
* Replicate the given set of entries (in the context) to the other cluster.
* Can block until all the given entries are replicated. Upon this method is returned,
* all entries that were passed in the context are assumed to be persisted in the
* target cluster.
* @param replicateContext a context where WAL entries and other
* parameters can be obtained.
*/
boolean replicate(ReplicateContext replicateContext);
// The below methods are inspired by Guava Service. See
// https://github.com/google/guava/wiki/ServiceExplained for overview of Guava Service.
// Below we implement a subset only with different names on some methods so we can implement
// the below internally using Guava (without exposing our implementation to
// ReplicationEndpoint implementors.
/**
* Returns {@code true} if this service is RUNNING.
*/
boolean isRunning();
/**
* @return Return {@code true} is this service is STARTING (but not yet RUNNING).
*/
boolean isStarting();
/**
* Initiates service startup and returns immediately. A stopped service may not be restarted.
* Equivalent of startAsync call in Guava Service.
* @throws IllegalStateException if the service is not new, if it has been run already.
*/
void start();
/**
* Waits for the {@link ReplicationEndpoint} to be up and running.
*
* @throws IllegalStateException if the service reaches a state from which it is not possible to
* enter the (internal) running state. e.g. if the state is terminated when this method is
* called then this will throw an IllegalStateException.
*/
void awaitRunning();
/**
* Waits for the {@link ReplicationEndpoint} to to be up and running for no more
* than the given time.
*
* @param timeout the maximum time to wait
* @param unit the time unit of the timeout argument
* @throws TimeoutException if the service has not reached the given state within the deadline
* @throws IllegalStateException if the service reaches a state from which it is not possible to
* enter the (internal) running state. e.g. if the state is terminated when this method is
* called then this will throw an IllegalStateException.
*/
void awaitRunning(long timeout, TimeUnit unit) throws TimeoutException;
/**
* If the service is starting or running, this initiates service shutdown and returns immediately.
* If the service has already been stopped, this method returns immediately without taking action.
* Equivalent of stopAsync call in Guava Service.
*/
void stop();
/**
* Waits for the {@link ReplicationEndpoint} to reach the terminated (internal) state.
*
* @throws IllegalStateException if the service FAILED.
*/
void awaitTerminated();
/**
* Waits for the {@link ReplicationEndpoint} to reach a terminal state for no
* more than the given time.
*
* @param timeout the maximum time to wait
* @param unit the time unit of the timeout argument
* @throws TimeoutException if the service has not reached the given state within the deadline
* @throws IllegalStateException if the service FAILED.
*/
void awaitTerminated(long timeout, TimeUnit unit) throws TimeoutException;
/**
* Returns the {@link Throwable} that caused this service to fail.
*
* @throws IllegalStateException if this service's state isn't FAILED.
*/
Throwable failureCause();
}