org.apache.hadoop.hbase.procedure2.Procedure Maven / Gradle / Ivy
The newest version!
/**
* 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.procedure2;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.ProcedureInfo;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.hbase.exceptions.TimeoutIOException;
import org.apache.hadoop.hbase.procedure2.util.StringUtils;
import org.apache.hadoop.hbase.protobuf.generated.ProcedureProtos;
import org.apache.hadoop.hbase.protobuf.generated.ProcedureProtos.ProcedureState;
import org.apache.hadoop.hbase.util.ByteStringer;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.NonceKey;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.protobuf.ByteString;
/**
* Base Procedure class responsible to handle the Procedure Metadata
* e.g. state, startTime, lastUpdate, stack-indexes, ...
*
* execute() is called each time the procedure is executed.
* it may be called multiple times in case of failure and restart, so the
* code must be idempotent.
* the return is a set of sub-procedures or null in case the procedure doesn't
* have sub-procedures. Once the sub-procedures are successfully completed
* the execute() method is called again, you should think at it as a stack:
* -> step 1
* ---> step 2
* -> step 1
*
* rollback() is called when the procedure or one of the sub-procedures is failed.
* the rollback step is supposed to cleanup the resources created during the
* execute() step. in case of failure and restart rollback() may be called
* multiple times, so the code must be idempotent.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public abstract class Procedure implements Comparable {
// unchanged after initialization
private String owner = null;
private Long parentProcId = null;
private Long procId = null;
private long startTime;
// runtime state, updated every operation
private ProcedureState state = ProcedureState.INITIALIZING;
private Integer timeout = null;
private int[] stackIndexes = null;
private int childrenLatch = 0;
private long lastUpdate;
private RemoteProcedureException exception = null;
private byte[] result = null;
private NonceKey nonceKey = null;
/**
* The main code of the procedure. It must be idempotent since execute()
* may be called multiple time in case of machine failure in the middle
* of the execution.
* @param env the environment passed to the ProcedureExecutor
* @return a set of sub-procedures or null if there is nothing else to execute.
* @throws ProcedureYieldException the procedure will be added back to the queue and retried later
* @throws InterruptedException the procedure will be added back to the queue and retried later
*/
protected abstract Procedure[] execute(TEnvironment env)
throws ProcedureYieldException, InterruptedException;
/**
* The code to undo what done by the execute() code.
* It is called when the procedure or one of the sub-procedure failed or an
* abort was requested. It should cleanup all the resources created by
* the execute() call. The implementation must be idempotent since rollback()
* may be called multiple time in case of machine failure in the middle
* of the execution.
* @param env the environment passed to the ProcedureExecutor
* @throws IOException temporary failure, the rollback will retry later
* @throws InterruptedException the procedure will be added back to the queue and retried later
*/
protected abstract void rollback(TEnvironment env)
throws IOException, InterruptedException;
/**
* The abort() call is asynchronous and each procedure must decide how to deal
* with that, if they want to be abortable. The simplest implementation
* is to have an AtomicBoolean set in the abort() method and then the execute()
* will check if the abort flag is set or not.
* abort() may be called multiple times from the client, so the implementation
* must be idempotent.
*
* NOTE: abort() is not like Thread.interrupt() it is just a notification
* that allows the procedure implementor where to abort to avoid leak and
* have a better control on what was executed and what not.
*/
protected abstract boolean abort(TEnvironment env);
/**
* The user-level code of the procedure may have some state to
* persist (e.g. input arguments) to be able to resume on failure.
* @param stream the stream that will contain the user serialized data
*/
protected abstract void serializeStateData(final OutputStream stream)
throws IOException;
/**
* Called on store load to allow the user to decode the previously serialized
* state.
* @param stream the stream that contains the user serialized data
*/
protected abstract void deserializeStateData(final InputStream stream)
throws IOException;
/**
* The user should override this method, and try to take a lock if necessary.
* A lock can be anything, and it is up to the implementor.
* Example: in our Master we can execute request in parallel for different tables
* create t1 and create t2 can be executed at the same time.
* anything else on t1/t2 is queued waiting that specific table create to happen.
*
* @return true if the lock was acquired and false otherwise
*/
protected boolean acquireLock(final TEnvironment env) {
return true;
}
/**
* The user should override this method, and release lock if necessary.
*/
protected void releaseLock(final TEnvironment env) {
// no-op
}
/**
* Called when the procedure is loaded for replay.
* The procedure implementor may use this method to perform some quick
* operation before replay.
* e.g. failing the procedure if the state on replay may be unknown.
*/
protected void beforeReplay(final TEnvironment env) {
// no-op
}
/**
* Called when the procedure is marked as completed (success or rollback).
* The procedure implementor may use this method to cleanup in-memory states.
* This operation will not be retried on failure.
*/
protected void completionCleanup(final TEnvironment env) {
// no-op
}
/**
* By default, the executor will try ro run procedures start to finish.
* Return true to make the executor yield between each execution step to
* give other procedures time to run their steps.
* @param env the environment passed to the ProcedureExecutor
* @return Return true if the executor should yield on completion of an execution step.
* Defaults to return false.
*/
protected boolean isYieldAfterExecutionStep(final TEnvironment env) {
return false;
}
/**
* By default, the executor will keep the procedure result around util
* the eviction TTL is expired. The client can cut down the waiting time
* by requesting that the result is removed from the executor.
* In case of system started procedure, we can force the executor to auto-ack.
* @param env the environment passed to the ProcedureExecutor
* @return true if the executor should wait the client ack for the result.
* Defaults to return true.
*/
protected boolean shouldWaitClientAck(final TEnvironment env) {
return true;
}
@Override
public String toString() {
// Return the simple String presentation of the procedure.
return toStringSimpleSB().toString();
}
/**
* Build the StringBuilder for the simple form of
* procedure string.
* @return the StringBuilder
*/
protected StringBuilder toStringSimpleSB() {
StringBuilder sb = new StringBuilder();
toStringClassDetails(sb);
if (procId != null) {
sb.append(" id=");
sb.append(getProcId());
}
if (hasParent()) {
sb.append(" parent=");
sb.append(getParentProcId());
}
if (hasOwner()) {
sb.append(" owner=");
sb.append(getOwner());
}
sb.append(" state=");
toStringState(sb);
return sb;
}
/**
* Extend the toString() information with more procedure
* details
*/
public String toStringDetails() {
StringBuilder sb = toStringSimpleSB();
sb.append(" startTime=");
sb.append(getStartTime());
sb.append(" lastUpdate=");
sb.append(getLastUpdate());
int[] stackIndices = getStackIndexes();
if (stackIndices != null) {
sb.append("\n");
sb.append("stackIndexes=");
sb.append(Arrays.toString(stackIndices));
}
return sb.toString();
}
protected String toStringClass() {
StringBuilder sb = new StringBuilder();
toStringClassDetails(sb);
return sb.toString();
}
/**
* Called from {@link #toString()} when interpolating {@link Procedure} state
* @param builder Append current {@link ProcedureState}
*/
protected void toStringState(StringBuilder builder) {
builder.append(getState());
}
/**
* Extend the toString() information with the procedure details
* e.g. className and parameters
* @param builder the string builder to use to append the proc specific information
*/
protected void toStringClassDetails(StringBuilder builder) {
builder.append(getClass().getName());
}
/**
* @return the serialized result if any, otherwise null
*/
public byte[] getResult() {
return result;
}
/**
* The procedure may leave a "result" on completion.
* @param result the serialized result that will be passed to the client
*/
protected void setResult(final byte[] result) {
this.result = result;
}
public long getProcId() {
return procId;
}
public boolean hasParent() {
return parentProcId != null;
}
public boolean hasException() {
return exception != null;
}
public boolean hasTimeout() {
return timeout != null;
}
public long getParentProcId() {
return parentProcId;
}
public NonceKey getNonceKey() {
return nonceKey;
}
/**
* @return true if the procedure is in a RUNNABLE state.
*/
protected synchronized boolean isRunnable() {
return state == ProcedureState.RUNNABLE;
}
/**
* @return true if the procedure has failed.
* true may mean failed but not yet rolledback or failed and rolledback.
*/
public synchronized boolean isFailed() {
return exception != null || state == ProcedureState.ROLLEDBACK;
}
/**
* @return true if the procedure is finished successfully.
*/
public synchronized boolean isSuccess() {
return state == ProcedureState.FINISHED && exception == null;
}
/**
* @return true if the procedure is finished. The Procedure may be completed
* successfuly or failed and rolledback.
*/
public synchronized boolean isFinished() {
switch (state) {
case ROLLEDBACK:
return true;
case FINISHED:
return exception == null;
default:
break;
}
return false;
}
/**
* @return true if the procedure is waiting for a child to finish or for an external event.
*/
public synchronized boolean isWaiting() {
switch (state) {
case WAITING:
case WAITING_TIMEOUT:
return true;
default:
break;
}
return false;
}
public synchronized RemoteProcedureException getException() {
return exception;
}
public long getStartTime() {
return startTime;
}
public synchronized long getLastUpdate() {
return lastUpdate;
}
public synchronized long elapsedTime() {
return lastUpdate - startTime;
}
/**
* @param timeout timeout in msec
*/
protected void setTimeout(final int timeout) {
this.timeout = timeout;
}
/**
* @return the timeout in msec
*/
public int getTimeout() {
return timeout;
}
/**
* @return the remaining time before the timeout
*/
public long getTimeRemaining() {
return Math.max(0, timeout - (EnvironmentEdgeManager.currentTime() - startTime));
}
@VisibleForTesting
@InterfaceAudience.Private
public void setOwner(final String owner) {
this.owner = StringUtils.isEmpty(owner) ? null : owner;
}
public String getOwner() {
return owner;
}
public boolean hasOwner() {
return owner != null;
}
@VisibleForTesting
@InterfaceAudience.Private
protected synchronized void setState(final ProcedureState state) {
this.state = state;
updateTimestamp();
}
@InterfaceAudience.Private
protected synchronized ProcedureState getState() {
return state;
}
protected void setFailure(final String source, final Throwable cause) {
setFailure(new RemoteProcedureException(source, cause));
}
protected synchronized void setFailure(final RemoteProcedureException exception) {
this.exception = exception;
if (!isFinished()) {
setState(ProcedureState.FINISHED);
}
}
protected void setAbortFailure(final String source, final String msg) {
setFailure(source, new ProcedureAbortedException(msg));
}
@InterfaceAudience.Private
protected synchronized boolean setTimeoutFailure() {
if (state == ProcedureState.WAITING_TIMEOUT) {
long timeDiff = EnvironmentEdgeManager.currentTime() - lastUpdate;
setFailure("ProcedureExecutor", new TimeoutIOException(
"Operation timed out after " + StringUtils.humanTimeDiff(timeDiff)));
return true;
}
return false;
}
/**
* Called by the ProcedureExecutor to assign the ID to the newly created procedure.
*/
@VisibleForTesting
@InterfaceAudience.Private
protected void setProcId(final long procId) {
this.procId = procId;
this.startTime = EnvironmentEdgeManager.currentTime();
setState(ProcedureState.RUNNABLE);
}
/**
* Called by the ProcedureExecutor to assign the parent to the newly created procedure.
*/
@InterfaceAudience.Private
protected void setParentProcId(final long parentProcId) {
this.parentProcId = parentProcId;
}
/**
* Called by the ProcedureExecutor to set the value to the newly created procedure.
*/
@VisibleForTesting
@InterfaceAudience.Private
protected void setNonceKey(final NonceKey nonceKey) {
this.nonceKey = nonceKey;
}
/**
* Internal method called by the ProcedureExecutor that starts the
* user-level code execute().
*/
@InterfaceAudience.Private
protected Procedure[] doExecute(final TEnvironment env)
throws ProcedureYieldException, InterruptedException {
try {
updateTimestamp();
return execute(env);
} finally {
updateTimestamp();
}
}
/**
* Internal method called by the ProcedureExecutor that starts the
* user-level code rollback().
*/
@InterfaceAudience.Private
protected void doRollback(final TEnvironment env)
throws IOException, InterruptedException {
try {
updateTimestamp();
rollback(env);
} finally {
updateTimestamp();
}
}
/**
* Called on store load to initialize the Procedure internals after
* the creation/deserialization.
*/
@InterfaceAudience.Private
protected void setStartTime(final long startTime) {
this.startTime = startTime;
}
/**
* Called on store load to initialize the Procedure internals after
* the creation/deserialization.
*/
private synchronized void setLastUpdate(final long lastUpdate) {
this.lastUpdate = lastUpdate;
}
protected synchronized void updateTimestamp() {
this.lastUpdate = EnvironmentEdgeManager.currentTime();
}
/**
* Called by the ProcedureExecutor on procedure-load to restore the latch state
*/
@InterfaceAudience.Private
protected synchronized void setChildrenLatch(final int numChildren) {
this.childrenLatch = numChildren;
}
/**
* Called by the ProcedureExecutor on procedure-load to restore the latch state
*/
@InterfaceAudience.Private
protected synchronized void incChildrenLatch() {
// TODO: can this be inferred from the stack? I think so...
this.childrenLatch++;
}
/**
* Called by the ProcedureExecutor to notify that one of the sub-procedures
* has completed.
*/
@InterfaceAudience.Private
protected synchronized boolean childrenCountDown() {
assert childrenLatch > 0;
return --childrenLatch == 0;
}
@InterfaceAudience.Private
protected synchronized boolean hasChildren() {
return childrenLatch > 0;
}
/**
* Called by the RootProcedureState on procedure execution.
* Each procedure store its stack-index positions.
*/
@InterfaceAudience.Private
protected synchronized void addStackIndex(final int index) {
if (stackIndexes == null) {
stackIndexes = new int[] { index };
} else {
int count = stackIndexes.length;
stackIndexes = Arrays.copyOf(stackIndexes, count + 1);
stackIndexes[count] = index;
}
}
@InterfaceAudience.Private
protected synchronized boolean removeStackIndex() {
if (stackIndexes != null && stackIndexes.length > 1) {
stackIndexes = Arrays.copyOf(stackIndexes, stackIndexes.length - 1);
return false;
} else {
stackIndexes = null;
return true;
}
}
/**
* Called on store load to initialize the Procedure internals after
* the creation/deserialization.
*/
@InterfaceAudience.Private
protected synchronized void setStackIndexes(final List stackIndexes) {
this.stackIndexes = new int[stackIndexes.size()];
for (int i = 0; i < this.stackIndexes.length; ++i) {
this.stackIndexes[i] = stackIndexes.get(i);
}
}
@InterfaceAudience.Private
protected synchronized boolean wasExecuted() {
return stackIndexes != null;
}
@InterfaceAudience.Private
protected synchronized int[] getStackIndexes() {
return stackIndexes;
}
@Override
public int compareTo(final Procedure other) {
long diff = getProcId() - other.getProcId();
return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
}
/**
* Get an hashcode for the specified Procedure ID
* @return the hashcode for the specified procId
*/
public static long getProcIdHashCode(final long procId) {
long h = procId;
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
/*
* Helper to lookup the root Procedure ID given a specified procedure.
*/
@InterfaceAudience.Private
protected static Long getRootProcedureId(final Map procedures, Procedure proc) {
while (proc.hasParent()) {
proc = procedures.get(proc.getParentProcId());
if (proc == null) return null;
}
return proc.getProcId();
}
protected static Procedure newInstance(final String className) throws IOException {
try {
Class clazz = Class.forName(className);
if (!Modifier.isPublic(clazz.getModifiers())) {
throw new Exception("the " + clazz + " class is not public");
}
Constructor ctor = clazz.getConstructor();
assert ctor != null : "no constructor found";
if (!Modifier.isPublic(ctor.getModifiers())) {
throw new Exception("the " + clazz + " constructor is not public");
}
return (Procedure)ctor.newInstance();
} catch (Exception e) {
throw new IOException("The procedure class " + className +
" must be accessible and have an empty constructor", e);
}
}
protected static void validateClass(final Procedure proc) throws IOException {
try {
Class clazz = proc.getClass();
if (!Modifier.isPublic(clazz.getModifiers())) {
throw new Exception("the " + clazz + " class is not public");
}
Constructor ctor = clazz.getConstructor();
assert ctor != null;
if (!Modifier.isPublic(ctor.getModifiers())) {
throw new Exception("the " + clazz + " constructor is not public");
}
} catch (Exception e) {
throw new IOException("The procedure class " + proc.getClass().getName() +
" must be accessible and have an empty constructor", e);
}
}
/**
* Helper to create the ProcedureInfo from Procedure.
*/
@InterfaceAudience.Private
public static ProcedureInfo createProcedureInfo(final Procedure proc, final NonceKey nonceKey) {
RemoteProcedureException exception = proc.hasException() ? proc.getException() : null;
return new ProcedureInfo(
proc.getProcId(),
proc.toStringClass(),
proc.getOwner(),
proc.getState(),
proc.hasParent() ? proc.getParentProcId() : -1,
nonceKey,
exception != null ?
RemoteProcedureException.toProto(exception.getSource(), exception.getCause()) : null,
proc.getLastUpdate(),
proc.getStartTime(),
proc.getResult());
}
/**
* Helper to convert the procedure to protobuf.
* Used by ProcedureStore implementations.
*/
@InterfaceAudience.Private
public static ProcedureProtos.Procedure convert(final Procedure proc)
throws IOException {
Preconditions.checkArgument(proc != null);
validateClass(proc);
ProcedureProtos.Procedure.Builder builder = ProcedureProtos.Procedure.newBuilder()
.setClassName(proc.getClass().getName())
.setProcId(proc.getProcId())
.setState(proc.getState())
.setStartTime(proc.getStartTime())
.setLastUpdate(proc.getLastUpdate());
if (proc.hasParent()) {
builder.setParentId(proc.getParentProcId());
}
if (proc.hasTimeout()) {
builder.setTimeout(proc.getTimeout());
}
if (proc.hasOwner()) {
builder.setOwner(proc.getOwner());
}
int[] stackIds = proc.getStackIndexes();
if (stackIds != null) {
for (int i = 0; i < stackIds.length; ++i) {
builder.addStackId(stackIds[i]);
}
}
if (proc.hasException()) {
RemoteProcedureException exception = proc.getException();
builder.setException(
RemoteProcedureException.toProto(exception.getSource(), exception.getCause()));
}
byte[] result = proc.getResult();
if (result != null) {
builder.setResult(ByteStringer.wrap(result));
}
ByteString.Output stateStream = ByteString.newOutput();
proc.serializeStateData(stateStream);
if (stateStream.size() > 0) {
builder.setStateData(stateStream.toByteString());
}
if (proc.getNonceKey() != null) {
builder.setNonceGroup(proc.getNonceKey().getNonceGroup());
builder.setNonce(proc.getNonceKey().getNonce());
}
return builder.build();
}
/**
* Helper to convert the protobuf procedure.
* Used by ProcedureStore implementations.
*
* TODO: OPTIMIZATION: some of the field never change during the execution
* (e.g. className, procId, parentId, ...).
* We can split in 'data' and 'state', and the store
* may take advantage of it by storing the data only on insert().
*/
@InterfaceAudience.Private
public static Procedure convert(final ProcedureProtos.Procedure proto)
throws IOException {
// Procedure from class name
Procedure proc = Procedure.newInstance(proto.getClassName());
// set fields
proc.setProcId(proto.getProcId());
proc.setState(proto.getState());
proc.setStartTime(proto.getStartTime());
proc.setLastUpdate(proto.getLastUpdate());
if (proto.hasParentId()) {
proc.setParentProcId(proto.getParentId());
}
if (proto.hasOwner()) {
proc.setOwner(proto.getOwner());
}
if (proto.hasTimeout()) {
proc.setTimeout(proto.getTimeout());
}
if (proto.getStackIdCount() > 0) {
proc.setStackIndexes(proto.getStackIdList());
}
if (proto.hasException()) {
assert proc.getState() == ProcedureState.FINISHED ||
proc.getState() == ProcedureState.ROLLEDBACK :
"The procedure must be failed (waiting to rollback) or rolledback";
proc.setFailure(RemoteProcedureException.fromProto(proto.getException()));
}
if (proto.hasResult()) {
proc.setResult(proto.getResult().toByteArray());
}
if (proto.getNonce() != HConstants.NO_NONCE) {
NonceKey nonceKey = new NonceKey(proto.getNonceGroup(), proto.getNonce());
proc.setNonceKey(nonceKey);
}
// we want to call deserialize even when the stream is empty, mainly for testing.
proc.deserializeStateData(proto.getStateData().newInput());
return proc;
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy