Resurrect Channel.id() with global uniqueness

- Fixes #1810
- Add a new interface ChannelId and its default implementation which generates globally unique channel ID.
- Replace AbstractChannel.hashCode with ChannelId.hashCode() and ChannelId.shortValue()
- Add variants of ByteBuf.hexDump() which accept byte[] instead of ByteBuf.
This commit is contained in:
Trustin Lee 2013-11-15 22:50:53 +09:00
parent ef4bc99849
commit 40003ed250
6 changed files with 574 additions and 21 deletions

View File

@ -75,6 +75,38 @@ public final class ByteBufUtil {
return new String(buf);
}
/**
* Returns a <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
* of the specified byte array.
*/
public static String hexDump(byte[] array) {
return hexDump(array, 0, array.length);
}
/**
* Returns a <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
* of the specified byte array's sub-region.
*/
public static String hexDump(byte[] array, int fromIndex, int length) {
if (length < 0) {
throw new IllegalArgumentException("length: " + length);
}
if (length == 0) {
return "";
}
int endIndex = fromIndex + length;
char[] buf = new char[length << 1];
int srcIdx = fromIndex;
int dstIdx = 0;
for (; srcIdx < endIndex; srcIdx ++, dstIdx += 2) {
System.arraycopy(HEXDUMP_TABLE, (array[srcIdx] & 0xFF) << 1, buf, dstIdx, 2);
}
return new String(buf);
}
/**
* Calculates the hash code of the specified buffer. This method is
* useful when implementing a new buffer type.

View File

@ -20,7 +20,6 @@ import io.netty.util.DefaultAttributeMap;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.EmptyArrays;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.ThreadLocalRandom;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
@ -50,7 +49,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
private MessageSizeEstimator.Handle estimatorHandle;
private final Channel parent;
private final long hashCode = ThreadLocalRandom.current().nextLong();
private final ChannelId id = DefaultChannelId.newInstance();
private final Unsafe unsafe;
private final DefaultChannelPipeline pipeline;
private final ChannelFuture succeededFuture = new SucceededChannelFuture(this, null);
@ -79,6 +78,11 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
pipeline = new DefaultChannelPipeline(this);
}
@Override
public final ChannelId id() {
return id;
}
@Override
public boolean isWritable() {
ChannelOutboundBuffer buf = unsafe.outboundBuffer();
@ -285,7 +289,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
*/
@Override
public final int hashCode() {
return (int) hashCode;
return id.hashCode();
}
/**
@ -303,21 +307,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
return 0;
}
long ret = hashCode - o.hashCode();
if (ret > 0) {
return 1;
}
if (ret < 0) {
return -1;
}
ret = System.identityHashCode(this) - System.identityHashCode(o);
if (ret != 0) {
return (int) ret;
}
// Jackpot! - different objects with same hashes
throw new Error();
return id().compareTo(o.id());
}
/**
@ -345,11 +335,30 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
srcAddr = remoteAddr;
dstAddr = localAddr;
}
strVal = String.format("[id: 0x%08x, %s %s %s]", (int) hashCode, srcAddr, active? "=>" : ":>", dstAddr);
StringBuilder buf = new StringBuilder(96);
buf.append("[id: 0x");
buf.append(id.asShortText());
buf.append(", ");
buf.append(srcAddr);
buf.append(active? " => " : " :> ");
buf.append(dstAddr);
buf.append(']');
strVal = buf.toString();
} else if (localAddr != null) {
strVal = String.format("[id: 0x%08x, %s]", (int) hashCode, localAddr);
StringBuilder buf = new StringBuilder(64);
buf.append("[id: 0x");
buf.append(id.asShortText());
buf.append(", ");
buf.append(localAddr);
buf.append(']');
strVal = buf.toString();
} else {
strVal = String.format("[id: 0x%08x]", (int) hashCode);
StringBuilder buf = new StringBuilder(16);
buf.append("[id: 0x");
buf.append(id.asShortText());
buf.append(']');
strVal = buf.toString();
}
strValActive = active;

View File

@ -73,6 +73,11 @@ import java.net.SocketAddress;
*/
public interface Channel extends AttributeMap, Comparable<Channel> {
/**
* Returns the globally unique identifier of this {@link Channel}.
*/
ChannelId id();
/**
* Return the {@link EventLoop} this {@link Channel} was registered too.
*/

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@ -0,0 +1,56 @@
/*
* Copyright 2013 The Netty Project
*
* The Netty Project 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 io.netty.channel;
import java.io.Serializable;
/**
* Represents the globally unique identifier of a {@link Channel}.
* <p>
* The identifier is generated from various sources listed in the following:
* <ul>
* <li>MAC address (EUI-48 or EUI-64) or the network adapter, preferrably a globally unique one,</li>
* <li>the current process ID,</li>
* <li>{@link System#currentTimeMillis()},</li>
* <li>{@link System#nanoTime()},</li>
* <li>a random 32-bit integer, and</li>
* <li>a sequentially incremented 32-bit integer.</li>
* </ul>
* </p>
* <p>
* The global uniqueness of the generated identifier mostly depends on the MAC address and the current process ID,
* which are auto-detected at the class-loading time in best-effort manner. If all attempts to acquire them fail,
* a warning message is logged, and random values will be used instead. Alternatively, you can specify them manually
* via system properties:
* <ul>
* <li>{@code io.netty.machineId} - hexadecimal representation of 48 (or 64) bit integer,
* optionally separated by colon or hyphen.</li>
* <li>{@code io.netty.processId} - an integer between 0 and 65535</li>
* </ul>
* </p>
*/
public interface ChannelId extends Serializable, Comparable<ChannelId> {
/**
* Returns the short but globally non-unique string representation of the {@link ChannelId}.
*/
String asShortText();
/**
* Returns the long yet globally unique string representation of the {@link ChannelId}.
*/
String asLongText();
}

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@ -0,0 +1,375 @@
/*
* Copyright 2013 The Netty Project
*
* The Netty Project 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 io.netty.channel;
import io.netty.buffer.ByteBufUtil;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.ThreadLocalRandom;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.lang.management.ManagementFactory;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.regex.Pattern;
/**
* The default {@link ChannelId} implementation.
*/
final class DefaultChannelId implements ChannelId {
private static final long serialVersionUID = 3884076183504074063L;
private static final InternalLogger logger = InternalLoggerFactory.getInstance(DefaultChannelId.class);
private static final Pattern MACHINE_ID_PATTERN = Pattern.compile("^(?:[0-9a-fA-F][:-]?){6,8}$");
private static final int MACHINE_ID_LEN = 8;
private static final byte[] MACHINE_ID;
private static final int PROCESS_ID_LEN = 2;
private static final int MAX_PROCESS_ID = 65535;
private static final int PROCESS_ID;
private static final int SEQUENCE_LEN = 4;
private static final int TIMESTAMP_LEN = 8;
private static final int RANDOM_LEN = 4;
private static final AtomicInteger nextSequence = new AtomicInteger();
static ChannelId newInstance() {
DefaultChannelId id = new DefaultChannelId();
id.init();
return id;
}
static {
byte[] machineId = null;
String customMachineId = SystemPropertyUtil.get("io.netty.machineId");
if (customMachineId != null) {
if (MACHINE_ID_PATTERN.matcher(customMachineId).matches()) {
machineId = parseMachineId(customMachineId);
logger.debug("-Dio.netty.machineId: {} (user-set)", customMachineId);
} else {
logger.warn("-Dio.netty.machineId: {} (malformed)", customMachineId);
}
}
if (machineId == null) {
machineId = defaultMachineId();
if (logger.isDebugEnabled()) {
logger.debug("-Dio.netty.machineId: {} (auto-detected)", formatAddress(machineId));
}
}
MACHINE_ID = machineId;
int processId = -1;
String customProcessId = SystemPropertyUtil.get("io.netty.processId");
if (customProcessId != null) {
try {
processId = Integer.parseInt(customProcessId);
} catch (NumberFormatException e) {
// Malformed input.
}
if (processId < 0 || processId > MAX_PROCESS_ID) {
processId = -1;
logger.warn("-Dio.netty.processId: {} (malformed)", customProcessId);
} else if (logger.isDebugEnabled()) {
logger.debug("-Dio.netty.processId: {} (user-set)", processId);
}
}
if (processId < 0) {
processId = defaultProcessId();
if (logger.isDebugEnabled()) {
logger.debug("-Dio.netty.processId: {} (auto-detected)", processId);
}
}
PROCESS_ID = processId;
}
@SuppressWarnings("DynamicRegexReplaceableByCompiledPattern")
private static byte[] parseMachineId(String value) {
// Strip separators.
value = value.replaceAll("[:-]", "");
byte[] machineId = new byte[MACHINE_ID_LEN];
for (int i = 0; i < value.length(); i += 2) {
machineId[i] = (byte) Integer.parseInt(value.substring(i, i + 2), 16);
}
return machineId;
}
private static byte[] defaultMachineId() {
// Find the best MAC address available.
final byte[] NOT_FOUND = { -1 };
byte[] bestMacAddr = NOT_FOUND;
Enumeration<NetworkInterface> ifaces = null;
try {
ifaces = NetworkInterface.getNetworkInterfaces();
} catch (SocketException e) {
logger.warn("Failed to find the loopback interface", e);
}
if (ifaces != null) {
while (ifaces.hasMoreElements()) {
NetworkInterface iface = ifaces.nextElement();
try {
if (iface.isLoopback() || iface.isPointToPoint() || iface.isVirtual()) {
continue;
}
} catch (SocketException e) {
logger.debug("Failed to determine the type of a network interface: {}", iface, e);
continue;
}
byte[] macAddr;
try {
macAddr = iface.getHardwareAddress();
} catch (SocketException e) {
logger.debug("Failed to get the hardware address of a network interface: {}", iface, e);
continue;
}
if (isBetterAddress(bestMacAddr, macAddr)) {
bestMacAddr = macAddr;
}
}
}
if (bestMacAddr == NOT_FOUND) {
bestMacAddr = new byte[MACHINE_ID_LEN];
ThreadLocalRandom.current().nextBytes(bestMacAddr);
logger.warn(
"Failed to find a usable hardware address from the network interfaces; using random bytes: {}",
formatAddress(bestMacAddr));
}
if (bestMacAddr.length != MACHINE_ID_LEN) {
bestMacAddr = Arrays.copyOf(bestMacAddr, MACHINE_ID_LEN);
}
return bestMacAddr;
}
private static boolean isBetterAddress(byte[] current, byte[] candidate) {
if (candidate == null) {
return false;
}
// Must be EUI-48 or longer.
if (candidate.length < 6) {
return false;
}
// Must not be filled with only 0 or 1.
boolean onlyZero = true;
boolean onlyOne = true;
for (byte b: candidate) {
if (b != 0) {
onlyZero = false;
}
if (b != -1) {
onlyOne = false;
}
}
if (onlyZero || onlyOne) {
return false;
}
// Must not be a multicast address
if ((candidate[0] & 1) != 0) {
return false;
}
// Prefer longer globally unique addresses.
if ((current[0] & 2) == 0) {
if ((candidate[0] & 2) == 0) {
return candidate.length > current.length;
} else {
return false;
}
} else {
if ((candidate[0] & 2) == 0) {
return true;
} else {
return candidate.length > current.length;
}
}
}
private static String formatAddress(byte[] addr) {
StringBuilder buf = new StringBuilder(24);
for (byte b: addr) {
buf.append(String.format("%02x:", b & 0xff));
}
return buf.substring(0, buf.length() - 1);
}
private static int defaultProcessId() {
String value = ManagementFactory.getRuntimeMXBean().getName();
int atIndex = value.indexOf('@');
if (atIndex >= 0) {
value = value.substring(0, atIndex);
}
int pid;
try {
pid = Integer.parseInt(value);
} catch (NumberFormatException e) {
pid = -1;
}
if (pid < 0 || pid > MAX_PROCESS_ID) {
pid = ThreadLocalRandom.current().nextInt(MAX_PROCESS_ID + 1);
logger.warn("Failed to find the current process ID; using a random value: {}", pid);
}
return pid;
}
private final byte[] data = new byte[MACHINE_ID_LEN + PROCESS_ID_LEN + SEQUENCE_LEN + TIMESTAMP_LEN + RANDOM_LEN];
private int hashCode;
private transient String shortValue;
private transient String longValue;
public DefaultChannelId() { }
private void init() {
int i = 0;
// machineId
System.arraycopy(MACHINE_ID, 0, data, i, MACHINE_ID_LEN);
i += MACHINE_ID_LEN;
// processId
i = writeShort(i, PROCESS_ID);
// sequence
i = writeInt(i, nextSequence.getAndIncrement());
// timestamp (kind of)
i = writeLong(i, Long.reverse(System.nanoTime()) ^ System.currentTimeMillis());
// random
int random = ThreadLocalRandom.current().nextInt();
hashCode = random;
i = writeInt(i, random);
assert i == data.length;
}
private int writeShort(int i, int value) {
data[i ++] = (byte) (value >>> 8);
data[i ++] = (byte) value;
return i;
}
private int writeInt(int i, int value) {
data[i ++] = (byte) (value >>> 24);
data[i ++] = (byte) (value >>> 16);
data[i ++] = (byte) (value >>> 8);
data[i ++] = (byte) value;
return i;
}
private int writeLong(int i, long value) {
data[i ++] = (byte) (value >>> 56);
data[i ++] = (byte) (value >>> 48);
data[i ++] = (byte) (value >>> 40);
data[i ++] = (byte) (value >>> 32);
data[i ++] = (byte) (value >>> 24);
data[i ++] = (byte) (value >>> 16);
data[i ++] = (byte) (value >>> 8);
data[i ++] = (byte) value;
return i;
}
@Override
public String asShortText() {
String shortValue = this.shortValue;
if (shortValue == null) {
this.shortValue = shortValue = ByteBufUtil.hexDump(
data, MACHINE_ID_LEN + PROCESS_ID_LEN + SEQUENCE_LEN + TIMESTAMP_LEN, RANDOM_LEN);
}
return shortValue;
}
@Override
public String asLongText() {
String longValue = this.longValue;
if (longValue == null) {
this.longValue = longValue = newLongValue();
}
return longValue;
}
private String newLongValue() {
StringBuilder buf = new StringBuilder(data.length + 4);
int i = 0;
i = appendHexDumpField(buf, i, MACHINE_ID_LEN);
i = appendHexDumpField(buf, i, PROCESS_ID_LEN);
i = appendHexDumpField(buf, i, SEQUENCE_LEN);
i = appendHexDumpField(buf, i, TIMESTAMP_LEN);
i = appendHexDumpField(buf, i, RANDOM_LEN);
assert i == data.length;
return buf.substring(0, buf.length() - 1);
}
private int appendHexDumpField(StringBuilder buf, int i, int length) {
buf.append(ByteBufUtil.hexDump(data, i, length));
buf.append('-');
i += length;
return i;
}
@Override
public int hashCode() {
return hashCode;
}
@Override
public int compareTo(ChannelId o) {
return 0;
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof DefaultChannelId)) {
return false;
}
return Arrays.equals(data, ((DefaultChannelId) obj).data);
}
@Override
public String toString() {
return asShortText();
}
}

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@ -0,0 +1,76 @@
/*
* Copyright 2013 The Netty Project
*
* The Netty Project 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 io.netty.channel;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufInputStream;
import io.netty.buffer.ByteBufOutputStream;
import io.netty.buffer.Unpooled;
import org.junit.Test;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import static org.hamcrest.CoreMatchers.*;
import static org.junit.Assert.*;
@SuppressWarnings("DynamicRegexReplaceableByCompiledPattern")
public class DefaultChannelIdTest {
@Test
public void testShortText() {
String text = DefaultChannelId.newInstance().asShortText();
assertTrue(text.matches("^[0-9a-f]{8}$"));
}
@Test
public void testLongText() {
String text = DefaultChannelId.newInstance().asLongText();
assertTrue(text.matches("^[0-9a-f]{16}-[0-9a-f]{4}-[0-9a-f]{8}-[0-9a-f]{16}-[0-9a-f]{8}$"));
}
@Test
public void testIdempotentMachineId() {
String a = DefaultChannelId.newInstance().asLongText().substring(0, 16);
String b = DefaultChannelId.newInstance().asLongText().substring(0, 16);
assertThat(a, is(b));
}
@Test
public void testIdempotentProcessId() {
String a = DefaultChannelId.newInstance().asLongText().substring(17, 21);
String b = DefaultChannelId.newInstance().asLongText().substring(17, 21);
assertThat(a, is(b));
}
@Test
public void testSerialization() throws Exception {
ChannelId a = DefaultChannelId.newInstance();
ChannelId b;
ByteBuf buf = Unpooled.buffer();
ObjectOutputStream out = new ObjectOutputStream(new ByteBufOutputStream(buf));
out.writeObject(a);
out.flush();
ObjectInputStream in = new ObjectInputStream(new ByteBufInputStream(buf));
b = (ChannelId) in.readObject();
assertThat(a, is(b));
assertThat(a, is(not(sameInstance(b))));
assertThat(a.asLongText(), is(b.asLongText()));
}
}