/*
*
* 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.regionserver.wal;
import java.io.IOException;
import org.apache.hadoop.hbase.Coprocessor;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.coprocessor.*;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.wal.WAL;
import org.apache.hadoop.hbase.wal.WALKey;
/**
* Implements the coprocessor environment and runtime support for coprocessors
* loaded within a {@link WAL}.
*/
@InterfaceAudience.Private
public class WALCoprocessorHost
extends CoprocessorHost<WALCoprocessorHost.WALEnvironment> {
/**
* Encapsulation of the environment of each coprocessor
*/
static class WALEnvironment extends CoprocessorHost.Environment
implements WALCoprocessorEnvironment {
private final WAL wal;
final boolean useLegacyPre;
final boolean useLegacyPost;
@Override
public WAL getWAL() {
return wal;
}
/**
* Constructor
* @param implClass - not used
* @param impl the coprocessor instance
* @param priority chaining priority
* @param seq load sequence
* @param conf configuration
* @param wal WAL
*/
public WALEnvironment(Class<?> implClass, final Coprocessor impl,
final int priority, final int seq, final Configuration conf,
final WAL wal) {
super(impl, priority, seq, conf);
this.wal = wal;
// Pick which version of the API we'll call.
// This way we avoid calling the new version on older WALObservers so
// we can maintain binary compatibility.
// See notes in javadoc for WALObserver
useLegacyPre = useLegacyMethod(impl.getClass(), "preWALWrite", ObserverContext.class,
HRegionInfo.class, WALKey.class, WALEdit.class);
useLegacyPost = useLegacyMethod(impl.getClass(), "postWALWrite", ObserverContext.class,
HRegionInfo.class, WALKey.class, WALEdit.class);
}
}
private final WAL wal;
/**
* Constructor
* @param log the write ahead log
* @param conf the configuration
*/
public WALCoprocessorHost(final WAL log, final Configuration conf) {
// We don't want to require an Abortable passed down through (FS)HLog, so
// this means that a failure to load of a WAL coprocessor won't abort the
// server. This isn't ideal, and means that security components that
// utilize a WALObserver will have to check the observer initialization
// state manually. However, WALObservers will eventually go away so it
// should be an acceptable state of affairs.
super(null);
this.wal = log;
// load system default cp's from configuration.
loadSystemCoprocessors(conf, WAL_COPROCESSOR_CONF_KEY);
}
@Override
public WALEnvironment createEnvironment(final Class<?> implClass,
final Coprocessor instance, final int priority, final int seq,
final Configuration conf) {
return new WALEnvironment(implClass, instance, priority, seq, conf,
this.wal);
}
/**
* @param info
* @param logKey
* @param logEdit
* @return true if default behavior should be bypassed, false otherwise
* @throws IOException
*/
public boolean preWALWrite(final HRegionInfo info, final WALKey logKey, final WALEdit logEdit)
throws IOException {
boolean bypass = false;
if (this.coprocessors == null || this.coprocessors.isEmpty()) return bypass;
ObserverContext<WALCoprocessorEnvironment> ctx = null;
for (WALEnvironment env: coprocessors) {
if (env.getInstance() instanceof WALObserver) {
final WALObserver observer = (WALObserver)env.getInstance();
ctx = ObserverContext.createAndPrepare(env, ctx);
Thread currentThread = Thread.currentThread();
ClassLoader cl = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(env.getClassLoader());
if (env.useLegacyPre) {
if (logKey instanceof HLogKey) {
observer.preWALWrite(ctx, info, (HLogKey)logKey, logEdit);
} else {
legacyWarning(observer.getClass(),
"There are wal keys present that are not HLogKey.");
}
} else {
observer.preWALWrite(ctx, info, logKey, logEdit);
}
} catch (Throwable e) {
handleCoprocessorThrowable(env, e);
} finally {
currentThread.setContextClassLoader(cl);
}
bypass |= ctx.shouldBypass();
if (ctx.shouldComplete()) {
break;
}
}
}
return bypass;
}
/**
* @param info
* @param logKey
* @param logEdit
* @throws IOException
*/
public void postWALWrite(final HRegionInfo info, final WALKey logKey, final WALEdit logEdit)
throws IOException {
if (this.coprocessors == null || this.coprocessors.isEmpty()) return;
ObserverContext<WALCoprocessorEnvironment> ctx = null;
for (WALEnvironment env: coprocessors) {
if (env.getInstance() instanceof WALObserver) {
final WALObserver observer = (WALObserver)env.getInstance();
ctx = ObserverContext.createAndPrepare(env, ctx);
Thread currentThread = Thread.currentThread();
ClassLoader cl = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(env.getClassLoader());
if (env.useLegacyPost) {
if (logKey instanceof HLogKey) {
observer.postWALWrite(ctx, info, (HLogKey)logKey, logEdit);
} else {
legacyWarning(observer.getClass(),
"There are wal keys present that are not HLogKey.");
}
} else {
observer.postWALWrite(ctx, info, logKey, logEdit);
}
} catch (Throwable e) {
handleCoprocessorThrowable(env, e);
} finally {
currentThread.setContextClassLoader(cl);
}
if (ctx.shouldComplete()) {
break;
}
}
}
}
}