/**
* 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.ipc;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.SocketTimeoutException;
import java.util.HashMap;
import java.util.Map;
import javax.net.SocketFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.ObjectWritable;
import org.apache.hadoop.io.UTF8;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.retry.RetryPolicy;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.security.SaslRpcServer;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.token.SecretManager;
import org.apache.hadoop.security.token.TokenIdentifier;
/** A simple RPC mechanism.
*
* A <i>protocol</i> is a Java interface. All parameters and return types must
* be one of:
*
* <ul> <li>a primitive type, <code>boolean</code>, <code>byte</code>,
* <code>char</code>, <code>short</code>, <code>int</code>, <code>long</code>,
* <code>float</code>, <code>double</code>, or <code>void</code>; or</li>
*
* <li>a {@link String}; or</li>
*
* <li>a {@link Writable}; or</li>
*
* <li>an array of the above types</li> </ul>
*
* All methods in the protocol should throw only IOException. No field data of
* the protocol instance is transmitted.
*/
public class RPC {
private static final Log LOG =
LogFactory.getLog(RPC.class);
private RPC() {} // no public ctor
/** A method invocation, including the method name and its parameters.*/
private static class Invocation implements Writable, Configurable {
private String methodName;
private Class[] parameterClasses;
private Object[] parameters;
private Configuration conf;
public Invocation() {}
public Invocation(Method method, Object[] parameters) {
this.methodName = method.getName();
this.parameterClasses = method.getParameterTypes();
this.parameters = parameters;
}
/** The name of the method invoked. */
public String getMethodName() { return methodName; }
/** The parameter classes. */
public Class[] getParameterClasses() { return parameterClasses; }
/** The parameter instances. */
public Object[] getParameters() { return parameters; }
public void readFields(DataInput in) throws IOException {
methodName = UTF8.readString(in);
parameters = new Object[in.readInt()];
parameterClasses = new Class[parameters.length];
ObjectWritable objectWritable = new ObjectWritable();
for (int i = 0; i < parameters.length; i++) {
parameters[i] = ObjectWritable.readObject(in, objectWritable, this.conf);
parameterClasses[i] = objectWritable.getDeclaredClass();
}
}
public void write(DataOutput out) throws IOException {
UTF8.writeString(out, methodName);
out.writeInt(parameterClasses.length);
for (int i = 0; i < parameterClasses.length; i++) {
ObjectWritable.writeObject(out, parameters[i], parameterClasses[i],
conf);
}
}
public String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append(methodName);
buffer.append("(");
for (int i = 0; i < parameters.length; i++) {
if (i != 0)
buffer.append(", ");
buffer.append(parameters[i]);
}
buffer.append(")");
return buffer.toString();
}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
}
/* Cache a client using its socket factory as the hash key */
static private class ClientCache {
private Map<SocketFactory, Client> clients =
new HashMap<SocketFactory, Client>();
/**
* Construct & cache an IPC client with the user-provided SocketFactory
* if no cached client exists.
*
* @param conf Configuration
* @return an IPC client
*/
private synchronized Client getClient(Configuration conf,
SocketFactory factory) {
// Construct & cache client. The configuration is only used for timeout,
// and Clients have connection pools. So we can either (a) lose some
// connection pooling and leak sockets, or (b) use the same timeout for all
// configurations. Since the IPC is usually intended globally, not
// per-job, we choose (a).
Client client = clients.get(factory);
if (client == null) {
client = new Client(ObjectWritable.class, conf, factory);
clients.put(factory, client);
} else {
client.incCount();
}
return client;
}
/**
* Construct & cache an IPC client with the default SocketFactory
* if no cached client exists.
*
* @param conf Configuration
* @return an IPC client
*/
private synchronized Client getClient(Configuration conf) {
return getClient(conf, SocketFactory.getDefault());
}
/**
* Stop a RPC client connection
* A RPC client is closed only when its reference count becomes zero.
*/
private void stopClient(Client client) {
synchronized (this) {
client.decCount();
if (client.isZeroReference()) {
clients.remove(client.getSocketFactory());
}
}
if (client.isZeroReference()) {
client.stop();
}
}
}
private static ClientCache CLIENTS=new ClientCache();
//for unit testing only
static Client getClient(Configuration conf) {
return CLIENTS.getClient(conf);
}
private static class Invoker implements InvocationHandler {
private Client.ConnectionId remoteId;
private Client client;
private boolean isClosed = false;
private Invoker(Class<? extends VersionedProtocol> protocol,
InetSocketAddress address, UserGroupInformation ticket,
Configuration conf, SocketFactory factory,
int rpcTimeout, RetryPolicy connectionRetryPolicy) throws IOException {
this.remoteId = Client.ConnectionId.getConnectionId(address, protocol,
ticket, rpcTimeout, connectionRetryPolicy, conf);
this.client = CLIENTS.getClient(conf, factory);
}
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
final boolean logDebug = LOG.isDebugEnabled();
long startTime = 0;
if (logDebug) {
startTime = System.currentTimeMillis();
}
ObjectWritable value = (ObjectWritable)
client.call(new Invocation(method, args), remoteId);
if (logDebug) {
long callTime = System.currentTimeMillis() - startTime;
LOG.debug("Call: " + method.getName() + " " + callTime);
}
return value.get();
}
/* close the IPC client that's responsible for this invoker's RPCs */
synchronized private void close() {
if (!isClosed) {
isClosed = true;
CLIENTS.stopClient(client);
}
}
}
/**
* A version mismatch for the RPC protocol.
*/
public static class VersionMismatch extends IOException {
private String interfaceName;
private long clientVersion;
private long serverVersion;
/**
* Create a version mismatch exception
* @param interfaceName the name of the protocol mismatch
* @param clientVersion the client's version of the protocol
* @param serverVersion the server's version of the protocol
*/
public VersionMismatch(String interfaceName, long clientVersion,
long serverVersion) {
super("Protocol " + interfaceName + " version mismatch. (client = " +
clientVersion + ", server = " + serverVersion + ")");
this.interfaceName = interfaceName;
this.clientVersion = clientVersion;
this.serverVersion = serverVersion;
}
/**
* Get the interface name
* @return the java class name
* (eg. org.apache.hadoop.mapred.InterTrackerProtocol)
*/
public String getInterfaceName() {
return interfaceName;
}
/**
* Get the client's preferred version
*/
public long getClientVersion() {
return clientVersion;
}
/**
* Get the server's agreed to version.
*/
public long getServerVersion() {
return serverVersion;
}
}
public static VersionedProtocol waitForProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion,
InetSocketAddress addr,
Configuration conf
) throws IOException {
return waitForProxy(protocol, clientVersion, addr, conf, 0, Long.MAX_VALUE);
}
/**
* Get a proxy connection to a remote server
* @param protocol protocol class
* @param clientVersion client version
* @param addr remote address
* @param conf configuration to use
* @param connTimeout time in milliseconds before giving up
* @return the proxy
* @throws IOException if the far end through a RemoteException
*/
static VersionedProtocol waitForProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion,
InetSocketAddress addr,
Configuration conf,
long connTimeout)
throws IOException {
return waitForProxy(protocol, clientVersion, addr, conf, 0, connTimeout);
}
static VersionedProtocol waitForProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion,
InetSocketAddress addr,
Configuration conf,
int rpcTimeout,
long connTimeout)
throws IOException {
long startTime = System.currentTimeMillis();
IOException ioe;
while (true) {
try {
return getProxy(protocol, clientVersion, addr, conf, rpcTimeout);
} catch(ConnectException se) { // namenode has not been started
LOG.info("Server at " + addr + " not available yet, Zzzzz...");
ioe = se;
} catch(SocketTimeoutException te) { // namenode is busy
LOG.info("Problem connecting to server: " + addr);
ioe = te;
}
// check if timed out
if (System.currentTimeMillis()-connTimeout >= startTime) {
throw ioe;
}
// wait for retry
try {
Thread.sleep(1000);
} catch (InterruptedException ie) {
// IGNORE
}
}
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, Configuration conf,
SocketFactory factory) throws IOException {
UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
return getProxy(protocol, clientVersion, addr, ugi, conf, factory, 0);
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, Configuration conf,
SocketFactory factory, int rpcTimeout) throws IOException {
UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
return getProxy(protocol, clientVersion, addr, ugi, conf, factory, rpcTimeout);
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, UserGroupInformation ticket,
Configuration conf, SocketFactory factory) throws IOException {
return getProxy(protocol, clientVersion, addr, ticket, conf, factory, 0);
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, UserGroupInformation ticket,
Configuration conf, SocketFactory factory, int rpcTimeout) throws IOException {
return getProxy(protocol, clientVersion, addr, ticket, conf, factory,
rpcTimeout, null, true);
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, UserGroupInformation ticket,
Configuration conf, SocketFactory factory, int rpcTimeout,
RetryPolicy connectionRetryPolicy,
boolean checkVersion) throws IOException {
if (UserGroupInformation.isSecurityEnabled()) {
SaslRpcServer.init(conf);
}
final Invoker invoker = new Invoker(protocol, addr, ticket, conf, factory,
rpcTimeout, connectionRetryPolicy);
VersionedProtocol proxy = (VersionedProtocol)Proxy.newProxyInstance(
protocol.getClassLoader(), new Class[]{protocol}, invoker);
if (checkVersion) {
checkVersion(protocol, clientVersion, proxy);
}
return proxy;
}
/** Get server version and then compare it with client version. */
public static void checkVersion(Class<? extends VersionedProtocol> protocol,
long clientVersion, VersionedProtocol proxy) throws IOException {
long serverVersion = proxy.getProtocolVersion(protocol.getName(),
clientVersion);
if (serverVersion != clientVersion) {
throw new VersionMismatch(protocol.getName(), clientVersion,
serverVersion);
}
}
/**
* Construct a client-side proxy object with the default SocketFactory
*
* @param protocol
* @param clientVersion
* @param addr
* @param conf
* @return a proxy instance
* @throws IOException
*/
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, Configuration conf)
throws IOException {
return getProxy(protocol, clientVersion, addr, conf,
NetUtils.getDefaultSocketFactory(conf), 0);
}
public static VersionedProtocol getProxy(
Class<? extends VersionedProtocol> protocol,
long clientVersion, InetSocketAddress addr, Configuration conf, int rpcTimeout)
throws IOException {
return getProxy(protocol, clientVersion, addr, conf,
NetUtils.getDefaultSocketFactory(conf), rpcTimeout);
}
/**
* Stop this proxy and release its invoker's resource
* @param proxy the proxy to be stopped
*/
public static void stopProxy(VersionedProtocol proxy) {
if (proxy!=null) {
((Invoker)Proxy.getInvocationHandler(proxy)).close();
}
}
/**
* Expert: Make multiple, parallel calls to a set of servers.
* @deprecated Use {@link #call(Method, Object[][], InetSocketAddress[], UserGroupInformation, Configuration)} instead
*/
public static Object[] call(Method method, Object[][] params,
InetSocketAddress[] addrs, Configuration conf)
throws IOException, InterruptedException {
return call(method, params, addrs, null, conf);
}
/** Expert: Make multiple, parallel calls to a set of servers. */
public static Object[] call(Method method, Object[][] params,
InetSocketAddress[] addrs,
UserGroupInformation ticket, Configuration conf)
throws IOException, InterruptedException {
Invocation[] invocations = new Invocation[params.length];
for (int i = 0; i < params.length; i++)
invocations[i] = new Invocation(method, params[i]);
Client client = CLIENTS.getClient(conf);
try {
Writable[] wrappedValues =
client.call(invocations, addrs, method.getDeclaringClass(), ticket, conf);
if (method.getReturnType() == Void.TYPE) {
return null;
}
Object[] values =
(Object[])Array.newInstance(method.getReturnType(), wrappedValues.length);
for (int i = 0; i < values.length; i++)
if (wrappedValues[i] != null)
values[i] = ((ObjectWritable)wrappedValues[i]).get();
return values;
} finally {
CLIENTS.stopClient(client);
}
}
/** Construct a server for a protocol implementation instance listening on a
* port and address. */
public static Server getServer(final Object instance, final String bindAddress, final int port, Configuration conf)
throws IOException {
return getServer(instance, bindAddress, port, 1, false, conf);
}
/** Construct a server for a protocol implementation instance listening on a
* port and address. */
public static Server getServer(final Object instance, final String bindAddress, final int port,
final int numHandlers,
final boolean verbose, Configuration conf)
throws IOException {
return getServer(instance, bindAddress, port, numHandlers, verbose, conf, null);
}
/** Construct a server for a protocol implementation instance listening on a
* port and address, with a secret manager. */
public static Server getServer(final Object instance, final String bindAddress, final int port,
final int numHandlers,
final boolean verbose, Configuration conf,
SecretManager<? extends TokenIdentifier> secretManager)
throws IOException {
return new Server(instance, conf, bindAddress, port, numHandlers, verbose, secretManager);
}
/** An RPC Server. */
public static class Server extends org.apache.hadoop.ipc.Server {
private Object instance;
private boolean verbose;
/** Construct an RPC server.
* @param instance the instance whose methods will be called
* @param conf the configuration to use
* @param bindAddress the address to bind on to listen for connection
* @param port the port to listen for connections on
*/
public Server(Object instance, Configuration conf, String bindAddress, int port)
throws IOException {
this(instance, conf, bindAddress, port, 1, false, null);
}
private static String classNameBase(String className) {
String[] names = className.split("\\.", -1);
if (names == null || names.length == 0) {
return className;
}
return names[names.length-1];
}
/** Construct an RPC server.
* @param instance the instance whose methods will be called
* @param conf the configuration to use
* @param bindAddress the address to bind on to listen for connection
* @param port the port to listen for connections on
* @param numHandlers the number of method handler threads to run
* @param verbose whether each call should be logged
*/
public Server(Object instance, Configuration conf, String bindAddress, int port,
int numHandlers, boolean verbose,
SecretManager<? extends TokenIdentifier> secretManager)
throws IOException {
super(bindAddress, port, Invocation.class, numHandlers, conf,
classNameBase(instance.getClass().getName()), secretManager);
this.instance = instance;
this.verbose = verbose;
}
public Writable call(Class<?> protocol, Writable param, long receivedTime)
throws IOException {
try {
Invocation call = (Invocation)param;
if (verbose) log("Call: " + call);
Method method =
protocol.getMethod(call.getMethodName(),
call.getParameterClasses());
method.setAccessible(true);
long startTime = System.currentTimeMillis();
Object value = method.invoke(instance, call.getParameters());
int processingTime = (int) (System.currentTimeMillis() - startTime);
int qTime = (int) (startTime-receivedTime);
if (LOG.isDebugEnabled()) {
LOG.debug("Served: " + call.getMethodName() +
" queueTime= " + qTime +
" procesingTime= " + processingTime);
}
rpcMetrics.addRpcQueueTime(qTime);
rpcMetrics.addRpcProcessingTime(processingTime);
rpcMetrics.addRpcProcessingTime(call.getMethodName(), processingTime);
if (verbose) log("Return: "+value);
return new ObjectWritable(method.getReturnType(), value);
} catch (InvocationTargetException e) {
Throwable target = e.getTargetException();
if (target instanceof IOException) {
throw (IOException)target;
} else {
IOException ioe = new IOException(target.toString());
ioe.setStackTrace(target.getStackTrace());
throw ioe;
}
} catch (Throwable e) {
if (!(e instanceof IOException)) {
LOG.error("Unexpected throwable object ", e);
}
IOException ioe = new IOException(e.toString());
ioe.setStackTrace(e.getStackTrace());
throw ioe;
}
}
}
private static void log(String value) {
if (value!= null && value.length() > 55)
value = value.substring(0, 55)+"...";
LOG.info(value);
}
}