com.ngdata.sep.impl.SepReplicationSource.java Source code

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Here is the source code for com.ngdata.sep.impl.SepReplicationSource.java

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/*
 * Copyright 2012 NGDATA nv
 *
 * 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.ngdata.sep.impl;

import static com.ngdata.sep.impl.SepModelImpl.toExternalSubscriptionName;

import java.io.IOException;
import java.util.ServiceLoader;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.UUID;

import com.ngdata.sep.WALEditFilter;
import com.ngdata.sep.WALEditFilterProvider;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.regionserver.wal.HLog;
import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
import org.apache.hadoop.hbase.replication.regionserver.ReplicationSource;
import org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceManager;
import org.apache.hadoop.hbase.replication.ReplicationQueues;
import org.apache.hadoop.hbase.replication.ReplicationPeers;

/**
 * Custom replication source for distributing Side-Effect Processor (SEP) events to listeners
 * elsewhere on the cluster, as well as remaining compatible with stock HBase replication servers.
 * <p>
 * When a {@code SepReplicationSource} is replicating to a standard replication sink, all
 * replication entries are delegated to the stock HBase {@code ReplicationSource}. When a
 * {@code SepReplicationSource} is replicating to a custom SEP handler, the replication entries will
 * be filtered to only send the minimal necessary information for the remote SEP event processor.
 */
public class SepReplicationSource extends ReplicationSource {

    private WALEditFilter walEditFilter;
    private final Log log = LogFactory.getLog(getClass());

    void setWALEditFilter(WALEditFilter walEditFilter) {
        this.walEditFilter = walEditFilter;
    }

    WALEditFilter loadEditFilter(String peerClusterId, Iterable<WALEditFilterProvider> editFilterProviders) {
        for (WALEditFilterProvider editFilterProvider : editFilterProviders) {
            WALEditFilter editFilter = editFilterProvider
                    .getWALEditFilter(toExternalSubscriptionName(peerClusterId));
            if (editFilter != null) {
                log.debug("Loaded WALEditFilter " + editFilter);
                return editFilter;
            }
        }
        log.debug("No custom WALEditFilter loaded");
        return null;
    }

    @Override
    public void init(Configuration conf, FileSystem fs, ReplicationSourceManager manager, ReplicationQueues queues,
            ReplicationPeers peers, Stoppable stopper, String peerClusterZnode, UUID uuid) throws IOException {
        super.init(conf, fs, manager, queues, peers, stopper, peerClusterZnode, uuid);
        log.debug("init on cluster " + getPeerClusterId() + " on node " + getPeerClusterZnode());
        setWALEditFilter(loadEditFilter(getPeerClusterId(), ServiceLoader.load(WALEditFilterProvider.class)));
    }

    @Override
    protected void removeNonReplicableEdits(HLog.Entry edit) {
        super.removeNonReplicableEdits(edit);
        if (walEditFilter != null) {
            walEditFilter.apply(edit);
        }
    }

}