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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  
20  package org.apache.hadoop.hbase.ipc;
21  
22  import java.io.BufferedInputStream;
23  import java.io.BufferedOutputStream;
24  import java.io.DataInputStream;
25  import java.io.DataOutputStream;
26  import java.io.FilterInputStream;
27  import java.io.IOException;
28  import java.io.InputStream;
29  import java.io.OutputStream;
30  import java.net.ConnectException;
31  import java.net.InetSocketAddress;
32  import java.net.Socket;
33  import java.net.SocketAddress;
34  import java.net.SocketException;
35  import java.net.SocketTimeoutException;
36  import java.net.UnknownHostException;
37  import java.nio.ByteBuffer;
38  import java.security.PrivilegedExceptionAction;
39  import java.util.HashMap;
40  import java.util.Iterator;
41  import java.util.LinkedList;
42  import java.util.Map;
43  import java.util.Map.Entry;
44  import java.util.Random;
45  import java.util.concurrent.ConcurrentSkipListMap;
46  import java.util.concurrent.atomic.AtomicBoolean;
47  import java.util.concurrent.atomic.AtomicLong;
48  
49  import javax.net.SocketFactory;
50  import javax.security.sasl.SaslException;
51  
52  import org.apache.commons.logging.Log;
53  import org.apache.commons.logging.LogFactory;
54  import org.apache.hadoop.hbase.classification.InterfaceAudience;
55  import org.apache.hadoop.hbase.classification.InterfaceStability;
56  import org.apache.hadoop.conf.Configuration;
57  import org.apache.hadoop.hbase.CellScanner;
58  import org.apache.hadoop.hbase.DoNotRetryIOException;
59  import org.apache.hadoop.hbase.HBaseIOException;
60  import org.apache.hadoop.hbase.HConstants;
61  import org.apache.hadoop.hbase.ServerName;
62  import org.apache.hadoop.hbase.codec.Codec;
63  import org.apache.hadoop.hbase.codec.KeyValueCodec;
64  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
65  import org.apache.hadoop.hbase.protobuf.generated.AuthenticationProtos;
66  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.CellBlockMeta;
67  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.ConnectionHeader;
68  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.ExceptionResponse;
69  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.RequestHeader;
70  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.ResponseHeader;
71  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.UserInformation;
72  import org.apache.hadoop.hbase.protobuf.generated.TracingProtos.RPCTInfo;
73  import org.apache.hadoop.hbase.security.AuthMethod;
74  import org.apache.hadoop.hbase.security.HBaseSaslRpcClient;
75  import org.apache.hadoop.hbase.security.SaslUtil.QualityOfProtection;
76  import org.apache.hadoop.hbase.security.SecurityInfo;
77  import org.apache.hadoop.hbase.security.User;
78  import org.apache.hadoop.hbase.security.UserProvider;
79  import org.apache.hadoop.hbase.security.token.AuthenticationTokenSelector;
80  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
81  import org.apache.hadoop.hbase.util.ExceptionUtil;
82  import org.apache.hadoop.hbase.util.Pair;
83  import org.apache.hadoop.hbase.util.PoolMap;
84  import org.apache.hadoop.hbase.util.PoolMap.PoolType;
85  import org.apache.hadoop.io.IOUtils;
86  import org.apache.hadoop.io.Text;
87  import org.apache.hadoop.io.compress.CompressionCodec;
88  import org.apache.hadoop.ipc.RemoteException;
89  import org.apache.hadoop.net.NetUtils;
90  import org.apache.hadoop.security.SecurityUtil;
91  import org.apache.hadoop.security.UserGroupInformation;
92  import org.apache.hadoop.security.token.Token;
93  import org.apache.hadoop.security.token.TokenIdentifier;
94  import org.apache.hadoop.security.token.TokenSelector;
95  import org.cloudera.htrace.Span;
96  import org.cloudera.htrace.Trace;
97  
98  import com.google.common.annotations.VisibleForTesting;
99  import com.google.protobuf.BlockingRpcChannel;
100 import com.google.protobuf.Descriptors.MethodDescriptor;
101 import com.google.protobuf.Message;
102 import com.google.protobuf.Message.Builder;
103 import com.google.protobuf.RpcController;
104 import com.google.protobuf.ServiceException;
105 import com.google.protobuf.TextFormat;
106 
107 
108 /**
109  * Does RPC against a cluster.  Manages connections per regionserver in the cluster.
110  * <p>See HBaseServer
111  */
112 @InterfaceAudience.Private
113 public class RpcClient {
114   // The LOG key is intentionally not from this package to avoid ipc logging at DEBUG (all under
115   // o.a.h.hbase is set to DEBUG as default).
116   public static final Log LOG = LogFactory.getLog("org.apache.hadoop.ipc.RpcClient");
117   protected final PoolMap<ConnectionId, Connection> connections;
118 
119   protected int counter;                            // counter for call ids
120   protected final AtomicBoolean running = new AtomicBoolean(true); // if client runs
121   final protected Configuration conf;
122   final protected int maxIdleTime; // connections will be culled if it was idle for
123                            // maxIdleTime microsecs
124   final protected int maxRetries; //the max. no. of retries for socket connections
125   final protected long failureSleep; // Time to sleep before retry on failure.
126   protected final boolean tcpNoDelay; // if T then disable Nagle's Algorithm
127   protected final boolean tcpKeepAlive; // if T then use keepalives
128   protected int pingInterval; // how often sends ping to the server in msecs
129   protected FailedServers failedServers;
130   private final Codec codec;
131   private final CompressionCodec compressor;
132   private final IPCUtil ipcUtil;
133 
134   protected final SocketFactory socketFactory;           // how to create sockets
135   protected String clusterId;
136   protected final SocketAddress localAddr;
137 
138   private final boolean fallbackAllowed;
139   private UserProvider userProvider;
140 
141   final public static String PING_INTERVAL_NAME = "hbase.ipc.ping.interval";
142   final public static String SOCKET_TIMEOUT = "hbase.ipc.socket.timeout";
143   final static int DEFAULT_PING_INTERVAL = 60000;  // 1 min
144   final static int DEFAULT_SOCKET_TIMEOUT = 20000; // 20 seconds
145   final static int PING_CALL_ID = -1;
146 
147   public final static String FAILED_SERVER_EXPIRY_KEY = "hbase.ipc.client.failed.servers.expiry";
148   public final static int FAILED_SERVER_EXPIRY_DEFAULT = 2000;
149 
150   public static final String IPC_CLIENT_FALLBACK_TO_SIMPLE_AUTH_ALLOWED_KEY =
151       "hbase.ipc.client.fallback-to-simple-auth-allowed";
152   public static final boolean IPC_CLIENT_FALLBACK_TO_SIMPLE_AUTH_ALLOWED_DEFAULT = false;
153 
154   // thread-specific RPC timeout, which may override that of what was passed in.
155   // This is used to change dynamically the timeout (for read only) when retrying: if
156   //  the time allowed for the operation is less than the usual socket timeout, then
157   //  we lower the timeout. This is subject to race conditions, and should be used with
158   //  extreme caution.
159   private static ThreadLocal<Integer> rpcTimeout = new ThreadLocal<Integer>() {
160     @Override
161     protected Integer initialValue() {
162       return HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT;
163     }
164   };
165 
166   /**
167    * A class to manage a list of servers that failed recently.
168    */
169   static class FailedServers {
170     private final LinkedList<Pair<Long, String>> failedServers = new
171         LinkedList<Pair<Long, java.lang.String>>();
172     private final int recheckServersTimeout;
173 
174     FailedServers(Configuration conf) {
175       this.recheckServersTimeout = conf.getInt(
176           FAILED_SERVER_EXPIRY_KEY, FAILED_SERVER_EXPIRY_DEFAULT);
177     }
178 
179     /**
180      * Add an address to the list of the failed servers list.
181      */
182     public synchronized void addToFailedServers(InetSocketAddress address) {
183       final long expiry = EnvironmentEdgeManager.currentTimeMillis() + recheckServersTimeout;
184       failedServers.addFirst(new Pair<Long, String>(expiry, address.toString()));
185     }
186 
187     /**
188      * Check if the server should be considered as bad. Clean the old entries of the list.
189      *
190      * @return true if the server is in the failed servers list
191      */
192     public synchronized boolean isFailedServer(final InetSocketAddress address) {
193       if (failedServers.isEmpty()) {
194         return false;
195       }
196 
197       final String lookup = address.toString();
198       final long now = EnvironmentEdgeManager.currentTimeMillis();
199 
200       // iterate, looking for the search entry and cleaning expired entries
201       Iterator<Pair<Long, String>> it = failedServers.iterator();
202       while (it.hasNext()) {
203         Pair<Long, String> cur = it.next();
204         if (cur.getFirst() < now) {
205           it.remove();
206         } else {
207           if (lookup.equals(cur.getSecond())) {
208             return true;
209           }
210         }
211       }
212 
213       return false;
214     }
215   }
216 
217   @SuppressWarnings("serial")
218   @InterfaceAudience.Public
219   @InterfaceStability.Evolving
220   // Shouldn't this be a DoNotRetryException? St.Ack 10/2/2013
221   public static class FailedServerException extends HBaseIOException {
222     public FailedServerException(String s) {
223       super(s);
224     }
225   }
226 
227   /**
228    * set the ping interval value in configuration
229    *
230    * @param conf Configuration
231    * @param pingInterval the ping interval
232    */
233   // Any reason we couldn't just do tcp keepalive instead of this pingery?
234   // St.Ack 20130121
235   public static void setPingInterval(Configuration conf, int pingInterval) {
236     conf.setInt(PING_INTERVAL_NAME, pingInterval);
237   }
238 
239   /**
240    * Get the ping interval from configuration;
241    * If not set in the configuration, return the default value.
242    *
243    * @param conf Configuration
244    * @return the ping interval
245    */
246   static int getPingInterval(Configuration conf) {
247     return conf.getInt(PING_INTERVAL_NAME, conf.getInt("ipc.ping.interval", DEFAULT_PING_INTERVAL));
248   }
249 
250   /**
251    * Set the socket timeout
252    * @param conf Configuration
253    * @param socketTimeout the socket timeout
254    */
255   public static void setSocketTimeout(Configuration conf, int socketTimeout) {
256     conf.setInt(SOCKET_TIMEOUT, socketTimeout);
257   }
258 
259   /**
260    * @return the socket timeout
261    */
262   static int getSocketTimeout(Configuration conf) {
263     return conf.getInt(SOCKET_TIMEOUT, conf.getInt("ipc.socket.timeout", DEFAULT_SOCKET_TIMEOUT));
264   }
265 
266   /** A call waiting for a value. */
267   protected class Call {
268     final int id;                                 // call id
269     final Message param;                          // rpc request method param object
270     /**
271      * Optionally has cells when making call.  Optionally has cells set on response.  Used
272      * passing cells to the rpc and receiving the response.
273      */
274     CellScanner cells;
275     Message response;                             // value, null if error
276     // The return type.  Used to create shell into which we deserialize the response if any.
277     Message responseDefaultType;
278     IOException error;                            // exception, null if value
279     boolean done;                                 // true when call is done
280     long startTime;
281     final MethodDescriptor md;
282 
283     protected Call(final MethodDescriptor md, Message param, final CellScanner cells,
284         final Message responseDefaultType) {
285       this.param = param;
286       this.md = md;
287       this.cells = cells;
288       this.startTime = System.currentTimeMillis();
289       this.responseDefaultType = responseDefaultType;
290       synchronized (RpcClient.this) {
291         this.id = counter++;
292       }
293     }
294 
295     @Override
296     public String toString() {
297       return "callId: " + this.id + " methodName: " + this.md.getName() + " param {" +
298         (this.param != null? ProtobufUtil.getShortTextFormat(this.param): "") + "}";
299     }
300 
301     /** Indicate when the call is complete and the
302      * value or error are available.  Notifies by default.  */
303     protected synchronized void callComplete() {
304       this.done = true;
305       notify();                                 // notify caller
306     }
307 
308     /** Set the exception when there is an error.
309      * Notify the caller the call is done.
310      *
311      * @param error exception thrown by the call; either local or remote
312      */
313     public void setException(IOException error) {
314       this.error = error;
315       callComplete();
316     }
317 
318     /**
319      * Set the return value when there is no error.
320      * Notify the caller the call is done.
321      *
322      * @param response return value of the call.
323      * @param cells Can be null
324      */
325     public void setResponse(Message response, final CellScanner cells) {
326       this.response = response;
327       this.cells = cells;
328       callComplete();
329     }
330 
331     public long getStartTime() {
332       return this.startTime;
333     }
334   }
335 
336   protected final static Map<AuthenticationProtos.TokenIdentifier.Kind,
337       TokenSelector<? extends TokenIdentifier>> tokenHandlers =
338       new HashMap<AuthenticationProtos.TokenIdentifier.Kind, TokenSelector<? extends TokenIdentifier>>();
339   static {
340     tokenHandlers.put(AuthenticationProtos.TokenIdentifier.Kind.HBASE_AUTH_TOKEN,
341         new AuthenticationTokenSelector());
342   }
343 
344   /**
345    * Creates a connection. Can be overridden by a subclass for testing.
346    * @param remoteId - the ConnectionId to use for the connection creation.
347    */
348   protected Connection createConnection(ConnectionId remoteId, final Codec codec,
349       final CompressionCodec compressor)
350   throws IOException {
351     return new Connection(remoteId, codec, compressor);
352   }
353 
354   /** Thread that reads responses and notifies callers.  Each connection owns a
355    * socket connected to a remote address.  Calls are multiplexed through this
356    * socket: responses may be delivered out of order. */
357   protected class Connection extends Thread {
358     private ConnectionHeader header;              // connection header
359     protected ConnectionId remoteId;
360     protected Socket socket = null;                 // connected socket
361     protected DataInputStream in;
362     protected DataOutputStream out;
363     private InetSocketAddress server;             // server ip:port
364     private String serverPrincipal;  // server's krb5 principal name
365     private AuthMethod authMethod; // authentication method
366     private boolean useSasl;
367     private Token<? extends TokenIdentifier> token;
368     private HBaseSaslRpcClient saslRpcClient;
369     private int reloginMaxBackoff; // max pause before relogin on sasl failure
370     private final Codec codec;
371     private final CompressionCodec compressor;
372 
373     // currently active calls
374     protected final ConcurrentSkipListMap<Integer, Call> calls =
375       new ConcurrentSkipListMap<Integer, Call>();
376     protected final AtomicLong lastActivity =
377       new AtomicLong(); // last I/O activity time
378     protected final AtomicBoolean shouldCloseConnection =
379       new AtomicBoolean();  // indicate if the connection is closed
380     protected IOException closeException; // close reason
381 
382     Connection(ConnectionId remoteId, final Codec codec, final CompressionCodec compressor)
383     throws IOException {
384       if (remoteId.getAddress().isUnresolved()) {
385         throw new UnknownHostException("unknown host: " + remoteId.getAddress().getHostName());
386       }
387       this.server = remoteId.getAddress();
388       this.codec = codec;
389       this.compressor = compressor;
390 
391       UserGroupInformation ticket = remoteId.getTicket().getUGI();
392       SecurityInfo securityInfo = SecurityInfo.getInfo(remoteId.getServiceName());
393       this.useSasl = userProvider.isHBaseSecurityEnabled();
394       if (useSasl && securityInfo != null) {
395         AuthenticationProtos.TokenIdentifier.Kind tokenKind = securityInfo.getTokenKind();
396         if (tokenKind != null) {
397           TokenSelector<? extends TokenIdentifier> tokenSelector =
398               tokenHandlers.get(tokenKind);
399           if (tokenSelector != null) {
400             token = tokenSelector.selectToken(new Text(clusterId),
401                 ticket.getTokens());
402           } else if (LOG.isDebugEnabled()) {
403             LOG.debug("No token selector found for type "+tokenKind);
404           }
405         }
406         String serverKey = securityInfo.getServerPrincipal();
407         if (serverKey == null) {
408           throw new IOException(
409               "Can't obtain server Kerberos config key from SecurityInfo");
410         }
411         serverPrincipal = SecurityUtil.getServerPrincipal(
412             conf.get(serverKey), server.getAddress().getCanonicalHostName().toLowerCase());
413         if (LOG.isDebugEnabled()) {
414           LOG.debug("RPC Server Kerberos principal name for service="
415               + remoteId.getServiceName() + " is " + serverPrincipal);
416         }
417       }
418 
419       if (!useSasl) {
420         authMethod = AuthMethod.SIMPLE;
421       } else if (token != null) {
422         authMethod = AuthMethod.DIGEST;
423       } else {
424         authMethod = AuthMethod.KERBEROS;
425       }
426 
427       if (LOG.isDebugEnabled()) {
428         LOG.debug("Use " + authMethod + " authentication for service " + remoteId.serviceName +
429           ", sasl=" + useSasl);
430       }
431       reloginMaxBackoff = conf.getInt("hbase.security.relogin.maxbackoff", 5000);
432       this.remoteId = remoteId;
433 
434       ConnectionHeader.Builder builder = ConnectionHeader.newBuilder();
435       builder.setServiceName(remoteId.getServiceName());
436       UserInformation userInfoPB;
437       if ((userInfoPB = getUserInfo(ticket)) != null) {
438         builder.setUserInfo(userInfoPB);
439       }
440       if (this.codec != null) {
441         builder.setCellBlockCodecClass(this.codec.getClass().getCanonicalName());
442       }
443       if (this.compressor != null) {
444         builder.setCellBlockCompressorClass(this.compressor.getClass().getCanonicalName());
445       }
446       builder.setVersionInfo(ProtobufUtil.getVersionInfo());
447       this.header = builder.build();
448 
449       this.setName("IPC Client (" + socketFactory.hashCode() +") connection to " +
450         remoteId.getAddress().toString() +
451         ((ticket==null)?" from an unknown user": (" from "
452         + ticket.getUserName())));
453       this.setDaemon(true);
454     }
455 
456     private UserInformation getUserInfo(UserGroupInformation ugi) {
457       if (ugi == null || authMethod == AuthMethod.DIGEST) {
458         // Don't send user for token auth
459         return null;
460       }
461       UserInformation.Builder userInfoPB = UserInformation.newBuilder();
462       if (authMethod == AuthMethod.KERBEROS) {
463         // Send effective user for Kerberos auth
464         userInfoPB.setEffectiveUser(ugi.getUserName());
465       } else if (authMethod == AuthMethod.SIMPLE) {
466         //Send both effective user and real user for simple auth
467         userInfoPB.setEffectiveUser(ugi.getUserName());
468         if (ugi.getRealUser() != null) {
469           userInfoPB.setRealUser(ugi.getRealUser().getUserName());
470         }
471       }
472       return userInfoPB.build();
473     }
474 
475     /** Update lastActivity with the current time. */
476     protected void touch() {
477       lastActivity.set(System.currentTimeMillis());
478     }
479 
480     /**
481      * Add a call to this connection's call queue and notify
482      * a listener; synchronized. If the connection is dead, the call is not added, and the
483      * caller is notified.
484      * This function can return a connection that is already marked as 'shouldCloseConnection'
485      *  It is up to the user code to check this status.
486      * @param call to add
487      */
488     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NN_NAKED_NOTIFY",
489       justification="Notify because new call available for processing")
490     protected synchronized void addCall(Call call) {
491       // If the connection is about to close, we manage this as if the call was already added
492       //  to the connection calls list. If not, the connection creations are serialized, as
493       //  mentioned in HBASE-6364
494       if (this.shouldCloseConnection.get()) {
495         if (this.closeException == null) {
496           call.setException(new IOException(
497               "Call " + call.id + " not added as the connection " + remoteId + " is closing"));
498         } else {
499           call.setException(this.closeException);
500         }
501         synchronized (call) {
502           call.notifyAll();
503         }
504       } else {
505         calls.put(call.id, call);
506         synchronized (call) {
507           notify();
508         }
509       }
510     }
511 
512     /** This class sends a ping to the remote side when timeout on
513      * reading. If no failure is detected, it retries until at least
514      * a byte is read.
515      */
516     protected class PingInputStream extends FilterInputStream {
517       /* constructor */
518       protected PingInputStream(InputStream in) {
519         super(in);
520       }
521 
522       /* Process timeout exception
523        * if the connection is not going to be closed, send a ping.
524        * otherwise, throw the timeout exception.
525        */
526       private void handleTimeout(SocketTimeoutException e) throws IOException {
527         if (shouldCloseConnection.get() || !running.get() || remoteId.rpcTimeout > 0) {
528           throw e;
529         }
530         sendPing();
531       }
532 
533       /** Read a byte from the stream.
534        * Send a ping if timeout on read. Retries if no failure is detected
535        * until a byte is read.
536        * @throws IOException for any IO problem other than socket timeout
537        */
538       @Override
539       public int read() throws IOException {
540         do {
541           try {
542             return super.read();
543           } catch (SocketTimeoutException e) {
544             handleTimeout(e);
545           }
546         } while (true);
547       }
548 
549       /** Read bytes into a buffer starting from offset <code>off</code>
550        * Send a ping if timeout on read. Retries if no failure is detected
551        * until a byte is read.
552        *
553        * @return the total number of bytes read; -1 if the connection is closed.
554        */
555       @Override
556       public int read(byte[] buf, int off, int len) throws IOException {
557         do {
558           try {
559             return super.read(buf, off, len);
560           } catch (SocketTimeoutException e) {
561             handleTimeout(e);
562           }
563         } while (true);
564       }
565     }
566 
567     protected synchronized void setupConnection() throws IOException {
568       short ioFailures = 0;
569       short timeoutFailures = 0;
570       while (true) {
571         try {
572           this.socket = socketFactory.createSocket();
573           this.socket.setTcpNoDelay(tcpNoDelay);
574           this.socket.setKeepAlive(tcpKeepAlive);
575           if (localAddr != null) {
576             this.socket.bind(localAddr);
577           }
578           // connection time out is 20s
579           NetUtils.connect(this.socket, remoteId.getAddress(),
580               getSocketTimeout(conf));
581           if (remoteId.rpcTimeout > 0) {
582             pingInterval = remoteId.rpcTimeout; // overwrite pingInterval
583           }
584           this.socket.setSoTimeout(pingInterval);
585           return;
586         } catch (SocketTimeoutException toe) {
587           /* The max number of retries is 45,
588            * which amounts to 20s*45 = 15 minutes retries.
589            */
590           handleConnectionFailure(timeoutFailures++, maxRetries, toe);
591         } catch (IOException ie) {
592           handleConnectionFailure(ioFailures++, maxRetries, ie);
593         }
594       }
595     }
596 
597     protected void closeConnection() {
598       if (socket == null) {
599         return;
600       }
601 
602       // close the current connection
603       try {
604         if (socket.getOutputStream() != null) {
605           socket.getOutputStream().close();
606         }
607       } catch (IOException ignored) {  // Can happen if the socket is already closed
608       }
609       try {
610         if (socket.getInputStream() != null) {
611           socket.getInputStream().close();
612         }
613       } catch (IOException ignored) {  // Can happen if the socket is already closed
614       }
615       try {
616         if (socket.getChannel() != null) {
617           socket.getChannel().close();
618         }
619       } catch (IOException ignored) {  // Can happen if the socket is already closed
620       }
621       try {
622         socket.close();
623       } catch (IOException e) {
624         LOG.warn("Not able to close a socket", e);
625       }
626 
627       // set socket to null so that the next call to setupIOstreams
628       // can start the process of connect all over again.
629       socket = null;
630     }
631 
632     /**
633      *  Handle connection failures
634      *
635      * If the current number of retries is equal to the max number of retries,
636      * stop retrying and throw the exception; Otherwise backoff N seconds and
637      * try connecting again.
638      *
639      * This Method is only called from inside setupIOstreams(), which is
640      * synchronized. Hence the sleep is synchronized; the locks will be retained.
641      *
642      * @param curRetries current number of retries
643      * @param maxRetries max number of retries allowed
644      * @param ioe failure reason
645      * @throws IOException if max number of retries is reached
646      */
647     private void handleConnectionFailure(int curRetries, int maxRetries, IOException ioe)
648     throws IOException {
649       closeConnection();
650 
651       // throw the exception if the maximum number of retries is reached
652       if (curRetries >= maxRetries || ExceptionUtil.isInterrupt(ioe)) {
653         throw ioe;
654       }
655 
656       // otherwise back off and retry
657       try {
658         Thread.sleep(failureSleep);
659       } catch (InterruptedException ie) {
660         ExceptionUtil.rethrowIfInterrupt(ie);
661       }
662 
663       LOG.info("Retrying connect to server: " + remoteId.getAddress() +
664         " after sleeping " + failureSleep + "ms. Already tried " + curRetries +
665         " time(s).");
666     }
667 
668     /* wait till someone signals us to start reading RPC response or
669      * it is idle too long, it is marked as to be closed,
670      * or the client is marked as not running.
671      *
672      * Return true if it is time to read a response; false otherwise.
673      */
674     protected synchronized boolean waitForWork() {
675       if (calls.isEmpty() && !shouldCloseConnection.get()  && running.get())  {
676         long timeout = maxIdleTime - (System.currentTimeMillis()-lastActivity.get());
677         if (timeout>0) {
678           try {
679             wait(timeout);
680           } catch (InterruptedException ie) {
681             Thread.currentThread().interrupt();
682           }
683         }
684       }
685 
686       if (!calls.isEmpty() && !shouldCloseConnection.get() && running.get()) {
687         return true;
688       } else if (shouldCloseConnection.get()) {
689         return false;
690       } else if (calls.isEmpty()) { // idle connection closed or stopped
691         markClosed(null);
692         return false;
693       } else { // get stopped but there are still pending requests
694         markClosed((IOException)new IOException().initCause(
695             new InterruptedException()));
696         return false;
697       }
698     }
699 
700     public InetSocketAddress getRemoteAddress() {
701       return remoteId.getAddress();
702     }
703 
704     /* Send a ping to the server if the time elapsed
705      * since last I/O activity is equal to or greater than the ping interval
706      */
707     protected synchronized void sendPing() throws IOException {
708       // Can we do tcp keepalive instead of this pinging?
709       long curTime = System.currentTimeMillis();
710       if ( curTime - lastActivity.get() >= pingInterval) {
711         lastActivity.set(curTime);
712         //noinspection SynchronizeOnNonFinalField
713         synchronized (this.out) {
714           out.writeInt(PING_CALL_ID);
715           out.flush();
716         }
717       }
718     }
719 
720     @Override
721     public void run() {
722       if (LOG.isDebugEnabled()) {
723         LOG.debug(getName() + ": starting, connections " + connections.size());
724       }
725 
726       try {
727         while (waitForWork()) { // Wait here for work - read or close connection
728           readResponse();
729         }
730       } catch (Throwable t) {
731         LOG.warn(getName() + ": unexpected exception receiving call responses", t);
732         markClosed(new IOException("Unexpected exception receiving call responses", t));
733       }
734 
735       close();
736 
737       if (LOG.isDebugEnabled())
738         LOG.debug(getName() + ": stopped, connections " + connections.size());
739     }
740 
741     private synchronized void disposeSasl() {
742       if (saslRpcClient != null) {
743         try {
744           saslRpcClient.dispose();
745           saslRpcClient = null;
746         } catch (IOException ioe) {
747           LOG.error("Error disposing of SASL client", ioe);
748         }
749       }
750     }
751 
752     private synchronized boolean shouldAuthenticateOverKrb() throws IOException {
753       UserGroupInformation loginUser = UserGroupInformation.getLoginUser();
754       UserGroupInformation currentUser =
755         UserGroupInformation.getCurrentUser();
756       UserGroupInformation realUser = currentUser.getRealUser();
757       return authMethod == AuthMethod.KERBEROS &&
758           loginUser != null &&
759           //Make sure user logged in using Kerberos either keytab or TGT
760           loginUser.hasKerberosCredentials() &&
761           // relogin only in case it is the login user (e.g. JT)
762           // or superuser (like oozie).
763           (loginUser.equals(currentUser) || loginUser.equals(realUser));
764     }
765 
766     private synchronized boolean setupSaslConnection(final InputStream in2,
767         final OutputStream out2) throws IOException {
768       saslRpcClient = new HBaseSaslRpcClient(authMethod, token, serverPrincipal, fallbackAllowed,
769           conf.get("hbase.rpc.protection", 
770               QualityOfProtection.AUTHENTICATION.name().toLowerCase()));
771       return saslRpcClient.saslConnect(in2, out2);
772     }
773 
774     /**
775      * If multiple clients with the same principal try to connect
776      * to the same server at the same time, the server assumes a
777      * replay attack is in progress. This is a feature of kerberos.
778      * In order to work around this, what is done is that the client
779      * backs off randomly and tries to initiate the connection
780      * again.
781      * The other problem is to do with ticket expiry. To handle that,
782      * a relogin is attempted.
783      * <p>
784      * The retry logic is governed by the {@link #shouldAuthenticateOverKrb}
785      * method. In case when the user doesn't have valid credentials, we don't
786      * need to retry (from cache or ticket). In such cases, it is prudent to
787      * throw a runtime exception when we receive a SaslException from the
788      * underlying authentication implementation, so there is no retry from
789      * other high level (for eg, HCM or HBaseAdmin).
790      * </p>
791      */
792     private synchronized void handleSaslConnectionFailure(
793         final int currRetries,
794         final int maxRetries, final Exception ex, final Random rand,
795         final UserGroupInformation user)
796     throws IOException, InterruptedException{
797       user.doAs(new PrivilegedExceptionAction<Object>() {
798         public Object run() throws IOException, InterruptedException {
799           closeConnection();
800           if (shouldAuthenticateOverKrb()) {
801             if (currRetries < maxRetries) {
802               LOG.debug("Exception encountered while connecting to " +
803                   "the server : " + ex);
804               //try re-login
805               if (UserGroupInformation.isLoginKeytabBased()) {
806                 UserGroupInformation.getLoginUser().reloginFromKeytab();
807               } else {
808                 UserGroupInformation.getLoginUser().reloginFromTicketCache();
809               }
810               disposeSasl();
811               //have granularity of milliseconds
812               //we are sleeping with the Connection lock held but since this
813               //connection instance is being used for connecting to the server
814               //in question, it is okay
815               Thread.sleep((rand.nextInt(reloginMaxBackoff) + 1));
816               return null;
817             } else {
818               String msg = "Couldn't setup connection for " +
819               UserGroupInformation.getLoginUser().getUserName() +
820               " to " + serverPrincipal;
821               LOG.warn(msg);
822               throw (IOException) new IOException(msg).initCause(ex);
823             }
824           } else {
825             LOG.warn("Exception encountered while connecting to " +
826                 "the server : " + ex);
827           }
828           if (ex instanceof RemoteException) {
829             throw (RemoteException)ex;
830           }
831           if (ex instanceof SaslException) {
832             String msg = "SASL authentication failed." +
833               " The most likely cause is missing or invalid credentials." +
834               " Consider 'kinit'.";
835             LOG.fatal(msg, ex);
836             throw new RuntimeException(msg, ex);
837           }
838           throw new IOException(ex);
839         }
840       });
841     }
842 
843     protected synchronized void setupIOstreams()
844     throws IOException, InterruptedException {
845       if (socket != null || shouldCloseConnection.get()) {
846         return;
847       }
848 
849       if (failedServers.isFailedServer(remoteId.getAddress())) {
850         if (LOG.isDebugEnabled()) {
851           LOG.debug("Not trying to connect to " + server +
852               " this server is in the failed servers list");
853         }
854         IOException e = new FailedServerException(
855             "This server is in the failed servers list: " + server);
856         markClosed(e);
857         close();
858         throw e;
859       }
860 
861       try {
862         if (LOG.isDebugEnabled()) {
863           LOG.debug("Connecting to " + server);
864         }
865         short numRetries = 0;
866         final short MAX_RETRIES = 5;
867         Random rand = null;
868         while (true) {
869           setupConnection();
870           InputStream inStream = NetUtils.getInputStream(socket);
871           // This creates a socket with a write timeout. This timeout cannot be changed,
872           //  RpcClient allows to change the timeout dynamically, but we can only
873           //  change the read timeout today.
874           OutputStream outStream = NetUtils.getOutputStream(socket, pingInterval);
875           // Write out the preamble -- MAGIC, version, and auth to use.
876           writeConnectionHeaderPreamble(outStream);
877           if (useSasl) {
878             final InputStream in2 = inStream;
879             final OutputStream out2 = outStream;
880             UserGroupInformation ticket = remoteId.getTicket().getUGI();
881             if (authMethod == AuthMethod.KERBEROS) {
882               if (ticket != null && ticket.getRealUser() != null) {
883                 ticket = ticket.getRealUser();
884               }
885             }
886             boolean continueSasl = false;
887             if (ticket == null) throw new FatalConnectionException("ticket/user is null");
888             try {
889               continueSasl = ticket.doAs(new PrivilegedExceptionAction<Boolean>() {
890                 @Override
891                 public Boolean run() throws IOException {
892                   return setupSaslConnection(in2, out2);
893                 }
894               });
895             } catch (Exception ex) {
896               if (rand == null) {
897                 rand = new Random();
898               }
899               handleSaslConnectionFailure(numRetries++, MAX_RETRIES, ex, rand, ticket);
900               continue;
901             }
902             if (continueSasl) {
903               // Sasl connect is successful. Let's set up Sasl i/o streams.
904               inStream = saslRpcClient.getInputStream(inStream);
905               outStream = saslRpcClient.getOutputStream(outStream);
906             } else {
907               // fall back to simple auth because server told us so.
908               authMethod = AuthMethod.SIMPLE;
909               useSasl = false;
910             }
911           }
912           this.in = new DataInputStream(new BufferedInputStream(new PingInputStream(inStream)));
913           this.out = new DataOutputStream(new BufferedOutputStream(outStream));
914           // Now write out the connection header
915           writeConnectionHeader();
916 
917           // update last activity time
918           touch();
919 
920           // start the receiver thread after the socket connection has been set up
921           start();
922           return;
923         }
924       } catch (Throwable t) {
925         failedServers.addToFailedServers(remoteId.address);
926         IOException e = null;
927         if (t instanceof LinkageError) {
928           // probably the hbase hadoop version does not match the running hadoop version
929           e = new DoNotRetryIOException(t);
930           markClosed(e);
931         } else if (t instanceof IOException) {
932           e = (IOException)t;
933           markClosed(e);
934         } else {
935           e = new IOException("Could not set up IO Streams", t);
936           markClosed(e);
937         }
938         close();
939         throw e;
940       }
941     }
942 
943     /**
944      * Write the RPC header: <MAGIC WORD -- 'HBas'> <ONEBYTE_VERSION> <ONEBYTE_AUTH_TYPE>
945      */
946     private void writeConnectionHeaderPreamble(OutputStream outStream) throws IOException {
947       // Assemble the preamble up in a buffer first and then send it.  Writing individual elements,
948       // they are getting sent across piecemeal according to wireshark and then server is messing
949       // up the reading on occasion (the passed in stream is not buffered yet).
950 
951       // Preamble is six bytes -- 'HBas' + VERSION + AUTH_CODE
952       int rpcHeaderLen = HConstants.RPC_HEADER.array().length;
953       byte [] preamble = new byte [rpcHeaderLen + 2];
954       System.arraycopy(HConstants.RPC_HEADER.array(), 0, preamble, 0, rpcHeaderLen);
955       preamble[rpcHeaderLen] = HConstants.RPC_CURRENT_VERSION;
956       preamble[rpcHeaderLen + 1] = authMethod.code;
957       outStream.write(preamble);
958       outStream.flush();
959     }
960 
961     /**
962      * Write the connection header.
963      * Out is not synchronized because only the first thread does this.
964      */
965     private void writeConnectionHeader() throws IOException {
966       synchronized (this.out) {
967         this.out.writeInt(this.header.getSerializedSize());
968         this.header.writeTo(this.out);
969         this.out.flush();
970       }
971     }
972 
973     /** Close the connection. */
974     protected synchronized void close() {
975       if (!shouldCloseConnection.get()) {
976         LOG.error(getName() + ": the connection is not in the closed state");
977         return;
978       }
979 
980       // release the resources
981       // first thing to do;take the connection out of the connection list
982       synchronized (connections) {
983         connections.removeValue(remoteId, this);
984       }
985 
986       // close the streams and therefore the socket
987       if (this.out != null) {
988         synchronized(this.out) {
989           IOUtils.closeStream(out);
990           this.out = null;
991         }
992       }
993       IOUtils.closeStream(in);
994       this.in = null;
995       disposeSasl();
996 
997       // clean up all calls
998       if (closeException == null) {
999         if (!calls.isEmpty()) {
1000           LOG.warn(getName() + ": connection is closed for no cause and calls are not empty. " +
1001               "#Calls: " + calls.size());
1002 
1003           // clean up calls anyway
1004           closeException = new IOException("Unexpected closed connection");
1005           cleanupCalls();
1006         }
1007       } else {
1008         // log the info
1009         if (LOG.isDebugEnabled()) {
1010           LOG.debug(getName() + ": closing ipc connection to " + server + ": " +
1011               closeException.getMessage(), closeException);
1012         }
1013 
1014         // cleanup calls
1015         cleanupCalls();
1016       }
1017       if (LOG.isDebugEnabled())
1018         LOG.debug(getName() + ": closed");
1019     }
1020 
1021     /**
1022      * Initiates a call by sending the parameter to the remote server.
1023      * Note: this is not called from the Connection thread, but by other
1024      * threads.
1025      * @param call
1026      * @param priority
1027      * @see #readResponse()
1028      */
1029     protected void writeRequest(Call call, final int priority) {
1030       if (shouldCloseConnection.get()) return;
1031       try {
1032         RequestHeader.Builder builder = RequestHeader.newBuilder();
1033         builder.setCallId(call.id);
1034         if (Trace.isTracing()) {
1035           Span s = Trace.currentSpan();
1036           builder.setTraceInfo(RPCTInfo.newBuilder().
1037             setParentId(s.getSpanId()).setTraceId(s.getTraceId()));
1038         }
1039         builder.setMethodName(call.md.getName());
1040         builder.setRequestParam(call.param != null);
1041         ByteBuffer cellBlock = ipcUtil.buildCellBlock(this.codec, this.compressor, call.cells);
1042         if (cellBlock != null) {
1043           CellBlockMeta.Builder cellBlockBuilder = CellBlockMeta.newBuilder();
1044           cellBlockBuilder.setLength(cellBlock.limit());
1045           builder.setCellBlockMeta(cellBlockBuilder.build());
1046         }
1047         // Only pass priority if there one.  Let zero be same as no priority.
1048         if (priority != 0) builder.setPriority(priority);
1049         //noinspection SynchronizeOnNonFinalField
1050         RequestHeader header = builder.build();
1051         synchronized (this.out) { // FindBugs IS2_INCONSISTENT_SYNC
1052           IPCUtil.write(this.out, header, call.param, cellBlock);
1053         }
1054         if (LOG.isDebugEnabled()) {
1055           LOG.debug(getName() + ": wrote request header " + TextFormat.shortDebugString(header));
1056         }
1057       } catch(IOException e) {
1058         synchronized (this) {
1059           if (!shouldCloseConnection.get()) {
1060             markClosed(e);
1061             interrupt();
1062           }
1063         }
1064       }
1065     }
1066 
1067     /* Receive a response.
1068      * Because only one receiver, so no synchronization on in.
1069      */
1070     protected void readResponse() {
1071       if (shouldCloseConnection.get()) return;
1072       touch();
1073       int totalSize = -1;
1074       try {
1075         // See HBaseServer.Call.setResponse for where we write out the response.
1076         // Total size of the response.  Unused.  But have to read it in anyways.
1077         totalSize = in.readInt();
1078 
1079         // Read the header
1080         ResponseHeader responseHeader = ResponseHeader.parseDelimitedFrom(in);
1081         int id = responseHeader.getCallId();
1082         if (LOG.isDebugEnabled()) {
1083           LOG.debug(getName() + ": got response header " +
1084             TextFormat.shortDebugString(responseHeader) + ", totalSize: " + totalSize + " bytes");
1085         }
1086         Call call = calls.get(id);
1087         if (call == null) {
1088           // So we got a response for which we have no corresponding 'call' here on the client-side.
1089           // We probably timed out waiting, cleaned up all references, and now the server decides
1090           // to return a response.  There is nothing we can do w/ the response at this stage. Clean
1091           // out the wire of the response so its out of the way and we can get other responses on
1092           // this connection.
1093           int readSoFar = IPCUtil.getTotalSizeWhenWrittenDelimited(responseHeader);
1094           int whatIsLeftToRead = totalSize - readSoFar;
1095           LOG.debug("Unknown callId: " + id + ", skipping over this response of " +
1096             whatIsLeftToRead + " bytes");
1097           IOUtils.skipFully(in, whatIsLeftToRead);
1098         }
1099         if (responseHeader.hasException()) {
1100           ExceptionResponse exceptionResponse = responseHeader.getException();
1101           RemoteException re = createRemoteException(exceptionResponse);
1102           if (isFatalConnectionException(exceptionResponse)) {
1103             markClosed(re);
1104           } else {
1105             if (call != null) call.setException(re);
1106           }
1107         } else {
1108           Message value = null;
1109           // Call may be null because it may have timedout and been cleaned up on this side already
1110           if (call != null && call.responseDefaultType != null) {
1111             Builder builder = call.responseDefaultType.newBuilderForType();
1112             builder.mergeDelimitedFrom(in);
1113             value = builder.build();
1114           }
1115           CellScanner cellBlockScanner = null;
1116           if (responseHeader.hasCellBlockMeta()) {
1117             int size = responseHeader.getCellBlockMeta().getLength();
1118             byte [] cellBlock = new byte[size];
1119             IOUtils.readFully(this.in, cellBlock, 0, cellBlock.length);
1120             cellBlockScanner = ipcUtil.createCellScanner(this.codec, this.compressor, cellBlock);
1121           }
1122           // it's possible that this call may have been cleaned up due to a RPC
1123           // timeout, so check if it still exists before setting the value.
1124           if (call != null) call.setResponse(value, cellBlockScanner);
1125         }
1126         if (call != null) calls.remove(id);
1127       } catch (IOException e) {
1128         if (e instanceof SocketTimeoutException && remoteId.rpcTimeout > 0) {
1129           // Clean up open calls but don't treat this as a fatal condition,
1130           // since we expect certain responses to not make it by the specified
1131           // {@link ConnectionId#rpcTimeout}.
1132           closeException = e;
1133         } else {
1134           // Treat this as a fatal condition and close this connection
1135           markClosed(e);
1136         }
1137       } finally {
1138         if (remoteId.rpcTimeout > 0) {
1139           cleanupCalls(remoteId.rpcTimeout);
1140         }
1141       }
1142     }
1143 
1144     /**
1145      * @param e
1146      * @return True if the exception is a fatal connection exception.
1147      */
1148     private boolean isFatalConnectionException(final ExceptionResponse e) {
1149       return e.getExceptionClassName().
1150         equals(FatalConnectionException.class.getName());
1151     }
1152 
1153     /**
1154      * @param e
1155      * @return RemoteException made from passed <code>e</code>
1156      */
1157     private RemoteException createRemoteException(final ExceptionResponse e) {
1158       String innerExceptionClassName = e.getExceptionClassName();
1159       boolean doNotRetry = e.getDoNotRetry();
1160       return e.hasHostname()?
1161         // If a hostname then add it to the RemoteWithExtrasException
1162         new RemoteWithExtrasException(innerExceptionClassName,
1163           e.getStackTrace(), e.getHostname(), e.getPort(), doNotRetry):
1164         new RemoteWithExtrasException(innerExceptionClassName,
1165           e.getStackTrace(), doNotRetry);
1166     }
1167 
1168     protected synchronized void markClosed(IOException e) {
1169       if (shouldCloseConnection.compareAndSet(false, true)) {
1170         closeException = e;
1171         notifyAll();
1172       }
1173     }
1174 
1175     /* Cleanup all calls and mark them as done */
1176     protected void cleanupCalls() {
1177       cleanupCalls(0);
1178     }
1179 
1180     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NN_NAKED_NOTIFY",
1181       justification="Notify because timedout")
1182     protected void cleanupCalls(long rpcTimeout) {
1183       Iterator<Entry<Integer, Call>> itor = calls.entrySet().iterator();
1184       while (itor.hasNext()) {
1185         Call c = itor.next().getValue();
1186         long waitTime = System.currentTimeMillis() - c.getStartTime();
1187         if (waitTime >= rpcTimeout) {
1188           if (this.closeException == null) {
1189             // There may be no exception in the case that there are many calls
1190             // being multiplexed over this connection and these are succeeding
1191             // fine while this Call object is taking a long time to finish
1192             // over on the server; e.g. I just asked the regionserver to bulk
1193             // open 3k regions or its a big fat multiput into a heavily-loaded
1194             // server (Perhaps this only happens at the extremes?)
1195             this.closeException = new CallTimeoutException("Call id=" + c.id +
1196               ", waitTime=" + waitTime + ", rpcTimetout=" + rpcTimeout);
1197           }
1198           c.setException(this.closeException);
1199           synchronized (c) {
1200             c.notifyAll();
1201           }
1202           itor.remove();
1203         } else {
1204           break;
1205         }
1206       }
1207       try {
1208         if (!calls.isEmpty()) {
1209           Call firstCall = calls.get(calls.firstKey());
1210           long maxWaitTime = System.currentTimeMillis() - firstCall.getStartTime();
1211           if (maxWaitTime < rpcTimeout) {
1212             rpcTimeout -= maxWaitTime;
1213           }
1214         }
1215         if (!shouldCloseConnection.get()) {
1216           closeException = null;
1217           setSocketTimeout(socket, (int) rpcTimeout);
1218         }
1219       } catch (SocketException e) {
1220         LOG.debug("Couldn't lower timeout, which may result in longer than expected calls");
1221       }
1222     }
1223   }
1224 
1225   @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="IS2_INCONSISTENT_SYNC",
1226     justification="Presume sync not needed setting socket timeout")
1227   private static void setSocketTimeout(final Socket socket, final int rpcTimeout)
1228   throws java.net.SocketException {
1229     if (socket == null) return;
1230     socket.setSoTimeout(rpcTimeout);
1231   }
1232 
1233   /**
1234    * Client-side call timeout
1235    */
1236   @SuppressWarnings("serial")
1237   @InterfaceAudience.Public
1238   @InterfaceStability.Evolving
1239   public static class CallTimeoutException extends IOException {
1240     public CallTimeoutException(final String msg) {
1241       super(msg);
1242     }
1243   }
1244 
1245   /**
1246    * Construct an IPC cluster client whose values are of the {@link Message} class.
1247    * @param conf configuration
1248    * @param clusterId
1249    * @param factory socket factory
1250    */
1251   RpcClient(Configuration conf, String clusterId, SocketFactory factory) {
1252     this(conf, clusterId, factory, null);
1253   }
1254 
1255   /**
1256    * Construct an IPC cluster client whose values are of the {@link Message} class.
1257    * @param conf configuration
1258    * @param clusterId
1259    * @param factory socket factory
1260    * @param localAddr client socket bind address
1261    */
1262   RpcClient(Configuration conf, String clusterId, SocketFactory factory, SocketAddress localAddr) {
1263     this.maxIdleTime = conf.getInt("hbase.ipc.client.connection.maxidletime", 10000); //10s
1264     this.maxRetries = conf.getInt("hbase.ipc.client.connect.max.retries", 0);
1265     this.failureSleep = conf.getLong(HConstants.HBASE_CLIENT_PAUSE,
1266         HConstants.DEFAULT_HBASE_CLIENT_PAUSE);
1267     this.tcpNoDelay = conf.getBoolean("hbase.ipc.client.tcpnodelay", true);
1268     this.tcpKeepAlive = conf.getBoolean("hbase.ipc.client.tcpkeepalive", true);
1269     this.pingInterval = getPingInterval(conf);
1270     this.ipcUtil = new IPCUtil(conf);
1271     this.conf = conf;
1272     this.codec = getCodec();
1273     this.compressor = getCompressor(conf);
1274     this.socketFactory = factory;
1275     this.clusterId = clusterId != null ? clusterId : HConstants.CLUSTER_ID_DEFAULT;
1276     this.connections = new PoolMap<ConnectionId, Connection>(getPoolType(conf), getPoolSize(conf));
1277     this.failedServers = new FailedServers(conf);
1278     this.fallbackAllowed = conf.getBoolean(IPC_CLIENT_FALLBACK_TO_SIMPLE_AUTH_ALLOWED_KEY,
1279         IPC_CLIENT_FALLBACK_TO_SIMPLE_AUTH_ALLOWED_DEFAULT);
1280     this.localAddr = localAddr;
1281     this.userProvider = UserProvider.instantiate(conf);
1282     // login the server principal (if using secure Hadoop)
1283     if (LOG.isDebugEnabled()) {
1284       LOG.debug("Codec=" + this.codec + ", compressor=" + this.compressor +
1285         ", tcpKeepAlive=" + this.tcpKeepAlive +
1286         ", tcpNoDelay=" + this.tcpNoDelay +
1287         ", maxIdleTime=" + this.maxIdleTime +
1288         ", maxRetries=" + this.maxRetries +
1289         ", fallbackAllowed=" + this.fallbackAllowed +
1290         ", ping interval=" + this.pingInterval + "ms" +
1291         ", bind address=" + (this.localAddr != null ? this.localAddr : "null"));
1292     }
1293   }
1294 
1295   /**
1296    * Construct an IPC client for the cluster <code>clusterId</code> with the default SocketFactory
1297    * @param conf configuration
1298    * @param clusterId
1299    */
1300   public RpcClient(Configuration conf, String clusterId) {
1301     this(conf, clusterId, NetUtils.getDefaultSocketFactory(conf), null);
1302   }
1303 
1304   /**
1305    * Construct an IPC client for the cluster <code>clusterId</code> with the default SocketFactory
1306    * @param conf configuration
1307    * @param clusterId
1308    * @param localAddr client socket bind address.
1309    */
1310   public RpcClient(Configuration conf, String clusterId, SocketAddress localAddr) {
1311     this(conf, clusterId, NetUtils.getDefaultSocketFactory(conf), localAddr);
1312   }
1313 
1314   /**
1315    * Encapsulate the ugly casting and RuntimeException conversion in private method.
1316    * @return Codec to use on this client.
1317    */
1318   Codec getCodec() {
1319     // For NO CODEC, "hbase.client.rpc.codec" must be configured with empty string AND
1320     // "hbase.client.default.rpc.codec" also -- because default is to do cell block encoding.
1321     String className = conf.get(HConstants.RPC_CODEC_CONF_KEY, getDefaultCodec(this.conf));
1322     if (className == null || className.length() == 0) return null;
1323     try {
1324       return (Codec)Class.forName(className).newInstance();
1325     } catch (Exception e) {
1326       throw new RuntimeException("Failed getting codec " + className, e);
1327     }
1328   }
1329 
1330   @VisibleForTesting
1331   public static String getDefaultCodec(final Configuration c) {
1332     // If "hbase.client.default.rpc.codec" is empty string -- you can't set it to null because
1333     // Configuration will complain -- then no default codec (and we'll pb everything).  Else
1334     // default is KeyValueCodec
1335     return c.get("hbase.client.default.rpc.codec", KeyValueCodec.class.getCanonicalName());
1336   }
1337 
1338   /**
1339    * Encapsulate the ugly casting and RuntimeException conversion in private method.
1340    * @param conf
1341    * @return The compressor to use on this client.
1342    */
1343   private static CompressionCodec getCompressor(final Configuration conf) {
1344     String className = conf.get("hbase.client.rpc.compressor", null);
1345     if (className == null || className.isEmpty()) return null;
1346     try {
1347         return (CompressionCodec)Class.forName(className).newInstance();
1348     } catch (Exception e) {
1349       throw new RuntimeException("Failed getting compressor " + className, e);
1350     }
1351   }
1352 
1353   /**
1354    * Return the pool type specified in the configuration, which must be set to
1355    * either {@link PoolType#RoundRobin} or {@link PoolType#ThreadLocal},
1356    * otherwise default to the former.
1357    *
1358    * For applications with many user threads, use a small round-robin pool. For
1359    * applications with few user threads, you may want to try using a
1360    * thread-local pool. In any case, the number of {@link RpcClient} instances
1361    * should not exceed the operating system's hard limit on the number of
1362    * connections.
1363    *
1364    * @param config configuration
1365    * @return either a {@link PoolType#RoundRobin} or
1366    *         {@link PoolType#ThreadLocal}
1367    */
1368   protected static PoolType getPoolType(Configuration config) {
1369     return PoolType.valueOf(config.get(HConstants.HBASE_CLIENT_IPC_POOL_TYPE),
1370         PoolType.RoundRobin, PoolType.ThreadLocal);
1371   }
1372 
1373   /**
1374    * Return the pool size specified in the configuration, which is applicable only if
1375    * the pool type is {@link PoolType#RoundRobin}.
1376    *
1377    * @param config
1378    * @return the maximum pool size
1379    */
1380   protected static int getPoolSize(Configuration config) {
1381     return config.getInt(HConstants.HBASE_CLIENT_IPC_POOL_SIZE, 1);
1382   }
1383 
1384   /** Return the socket factory of this client
1385    *
1386    * @return this client's socket factory
1387    */
1388   SocketFactory getSocketFactory() {
1389     return socketFactory;
1390   }
1391 
1392   /** Stop all threads related to this client.  No further calls may be made
1393    * using this client. */
1394   public void stop() {
1395     if (LOG.isDebugEnabled()) LOG.debug("Stopping rpc client");
1396     if (!running.compareAndSet(true, false)) return;
1397 
1398     // wake up all connections
1399     synchronized (connections) {
1400       for (Connection conn : connections.values()) {
1401         conn.interrupt();
1402       }
1403     }
1404 
1405     // wait until all connections are closed
1406     while (!connections.isEmpty()) {
1407       try {
1408         Thread.sleep(100);
1409       } catch (InterruptedException ignored) {
1410       }
1411     }
1412   }
1413 
1414   Pair<Message, CellScanner> call(MethodDescriptor md, Message param, CellScanner cells,
1415       Message returnType, User ticket, InetSocketAddress addr, int rpcTimeout)
1416   throws InterruptedException, IOException {
1417     return call(md, param, cells, returnType, ticket, addr, rpcTimeout, HConstants.NORMAL_QOS);
1418   }
1419 
1420   /** Make a call, passing <code>param</code>, to the IPC server running at
1421    * <code>address</code> which is servicing the <code>protocol</code> protocol,
1422    * with the <code>ticket</code> credentials, returning the value.
1423    * Throws exceptions if there are network problems or if the remote code
1424    * threw an exception.
1425    * @param md
1426    * @param param
1427    * @param cells
1428    * @param addr
1429    * @param returnType
1430    * @param ticket Be careful which ticket you pass. A new user will mean a new Connection.
1431    *          {@link UserProvider#getCurrent()} makes a new instance of User each time so will be a
1432    *          new Connection each time.
1433    * @param rpcTimeout
1434    * @return A pair with the Message response and the Cell data (if any).
1435    * @throws InterruptedException
1436    * @throws IOException
1437    */
1438   Pair<Message, CellScanner> call(MethodDescriptor md, Message param, CellScanner cells,
1439       Message returnType, User ticket, InetSocketAddress addr,
1440       int rpcTimeout, int priority)
1441   throws InterruptedException, IOException {
1442     Call call = new Call(md, param, cells, returnType);
1443     Connection connection =
1444       getConnection(ticket, call, addr, rpcTimeout, this.codec, this.compressor);
1445     connection.writeRequest(call, priority);                 // send the parameter
1446 
1447     //noinspection SynchronizationOnLocalVariableOrMethodParameter
1448     synchronized (call) {
1449       while (!call.done) {
1450         if (connection.shouldCloseConnection.get()) {
1451           throw new IOException("Unexpected closed connection");
1452         }
1453         call.wait(1000);                       // wait for the result
1454       }
1455 
1456       if (call.error != null) {
1457         if (call.error instanceof RemoteException) {
1458           call.error.fillInStackTrace();
1459           throw call.error;
1460         }
1461         // local exception
1462         throw wrapException(addr, call.error);
1463       }
1464       return new Pair<Message, CellScanner>(call.response, call.cells);
1465     }
1466   }
1467 
1468   /**
1469    * Take an IOException and the address we were trying to connect to
1470    * and return an IOException with the input exception as the cause.
1471    * The new exception provides the stack trace of the place where
1472    * the exception is thrown and some extra diagnostics information.
1473    * If the exception is ConnectException or SocketTimeoutException,
1474    * return a new one of the same type; Otherwise return an IOException.
1475    *
1476    * @param addr target address
1477    * @param exception the relevant exception
1478    * @return an exception to throw
1479    */
1480   protected IOException wrapException(InetSocketAddress addr,
1481                                          IOException exception) {
1482     if (exception instanceof ConnectException) {
1483       //connection refused; include the host:port in the error
1484       return (ConnectException)new ConnectException(
1485          "Call to " + addr + " failed on connection exception: " + exception).initCause(exception);
1486     } else if (exception instanceof SocketTimeoutException) {
1487       return (SocketTimeoutException)new SocketTimeoutException("Call to " + addr +
1488         " failed because " + exception).initCause(exception);
1489     } else {
1490       return (IOException)new IOException("Call to " + addr + " failed on local exception: " +
1491         exception).initCause(exception);
1492     }
1493   }
1494 
1495   /**
1496    * Interrupt the connections to the given ip:port server. This should be called if the server
1497    *  is known as actually dead. This will not prevent current operation to be retried, and,
1498    *  depending on their own behavior, they may retry on the same server. This can be a feature,
1499    *  for example at startup. In any case, they're likely to get connection refused (if the
1500    *  process died) or no route to host: i.e. there next retries should be faster and with a
1501    *  safe exception.
1502    */
1503   public void cancelConnections(String hostname, int port, IOException ioe) {
1504     synchronized (connections) {
1505       for (Connection connection : connections.values()) {
1506         if (connection.isAlive() &&
1507             connection.getRemoteAddress().getPort() == port &&
1508             connection.getRemoteAddress().getHostName().equals(hostname)) {
1509           LOG.info("The server on " + hostname + ":" + port +
1510               " is dead - stopping the connection " + connection.remoteId);
1511           connection.closeConnection();
1512           // We could do a connection.interrupt(), but it's safer not to do it, as the
1513           //  interrupted exception behavior is not defined nor enforced enough.
1514         }
1515       }
1516     }
1517   }
1518 
1519   /* Get a connection from the pool, or create a new one and add it to the
1520    * pool.  Connections to a given host/port are reused. */
1521   protected Connection getConnection(User ticket, Call call, InetSocketAddress addr,
1522       int rpcTimeout, final Codec codec, final CompressionCodec compressor)
1523   throws IOException, InterruptedException {
1524     if (!running.get()) throw new StoppedRpcClientException();
1525     Connection connection;
1526     ConnectionId remoteId =
1527       new ConnectionId(ticket, call.md.getService().getName(), addr, rpcTimeout);
1528     synchronized (connections) {
1529       connection = connections.get(remoteId);
1530       if (connection == null) {
1531         connection = createConnection(remoteId, this.codec, this.compressor);
1532         connections.put(remoteId, connection);
1533       }
1534     }
1535     connection.addCall(call);
1536 
1537     //we don't invoke the method below inside "synchronized (connections)"
1538     //block above. The reason for that is if the server happens to be slow,
1539     //it will take longer to establish a connection and that will slow the
1540     //entire system down.
1541     //Moreover, if the connection is currently created, there will be many threads
1542     // waiting here; as setupIOstreams is synchronized. If the connection fails with a
1543     // timeout, they will all fail simultaneously. This is checked in setupIOstreams.
1544     connection.setupIOstreams();
1545     return connection;
1546   }
1547 
1548   /**
1549    * This class holds the address and the user ticket, etc. The client connections
1550    * to servers are uniquely identified by <remoteAddress, ticket, serviceName, rpcTimeout>
1551    */
1552   protected static class ConnectionId {
1553     final InetSocketAddress address;
1554     final User ticket;
1555     final int rpcTimeout;
1556     private static final int PRIME = 16777619;
1557     final String serviceName;
1558 
1559     ConnectionId(User ticket,
1560         String serviceName,
1561         InetSocketAddress address,
1562         int rpcTimeout) {
1563       this.address = address;
1564       this.ticket = ticket;
1565       this.rpcTimeout = rpcTimeout;
1566       this.serviceName = serviceName;
1567     }
1568 
1569     String getServiceName() {
1570       return this.serviceName;
1571     }
1572 
1573     InetSocketAddress getAddress() {
1574       return address;
1575     }
1576 
1577     User getTicket() {
1578       return ticket;
1579     }
1580 
1581     @Override
1582     public String toString() {
1583       return this.address.toString() + "/" + this.serviceName + "/" + this.ticket + "/" +
1584         this.rpcTimeout;
1585     }
1586 
1587     @Override
1588     public boolean equals(Object obj) {
1589      if (obj instanceof ConnectionId) {
1590        ConnectionId id = (ConnectionId) obj;
1591        return address.equals(id.address) &&
1592               ((ticket != null && ticket.equals(id.ticket)) ||
1593                (ticket == id.ticket)) && rpcTimeout == id.rpcTimeout &&
1594                this.serviceName == id.serviceName;
1595      }
1596      return false;
1597     }
1598 
1599     @Override  // simply use the default Object#hashcode() ?
1600     public int hashCode() {
1601       int hashcode = (address.hashCode() +
1602         PRIME * (PRIME * this.serviceName.hashCode() ^
1603         (ticket == null ? 0 : ticket.hashCode()) )) ^
1604         rpcTimeout;
1605       return hashcode;
1606     }
1607   }
1608 
1609   public static void setRpcTimeout(int t) {
1610     rpcTimeout.set(t);
1611   }
1612 
1613   public static int getRpcTimeout() {
1614     return rpcTimeout.get();
1615   }
1616 
1617   /**
1618    * Returns the lower of the thread-local RPC time from {@link #setRpcTimeout(int)} and the given
1619    * default timeout.
1620    */
1621   public static int getRpcTimeout(int defaultTimeout) {
1622     return Math.min(defaultTimeout, rpcTimeout.get());
1623   }
1624 
1625   public static void resetRpcTimeout() {
1626     rpcTimeout.remove();
1627   }
1628 
1629   /**
1630    * Make a blocking call. Throws exceptions if there are network problems or if the remote code
1631    * threw an exception.
1632    * @param md
1633    * @param controller
1634    * @param param
1635    * @param returnType
1636    * @param isa
1637    * @param ticket Be careful which ticket you pass. A new user will mean a new Connection.
1638    *          {@link UserProvider#getCurrent()} makes a new instance of User each time so will be a
1639    *          new Connection each time.
1640    * @param rpcTimeout
1641    * @return A pair with the Message response and the Cell data (if any).
1642    * @throws InterruptedException
1643    * @throws IOException
1644    */
1645   Message callBlockingMethod(MethodDescriptor md, RpcController controller,
1646       Message param, Message returnType, final User ticket, final InetSocketAddress isa,
1647       final int rpcTimeout)
1648   throws ServiceException {
1649     long startTime = 0;
1650     if (LOG.isTraceEnabled()) {
1651       startTime = System.currentTimeMillis();
1652     }
1653     PayloadCarryingRpcController pcrc = (PayloadCarryingRpcController)controller;
1654     CellScanner cells = null;
1655     if (pcrc != null) {
1656       cells = pcrc.cellScanner();
1657       // Clear it here so we don't by mistake try and these cells processing results.
1658       pcrc.setCellScanner(null);
1659     }
1660     Pair<Message, CellScanner> val = null;
1661     try {
1662       val = call(md, param, cells, returnType, ticket, isa, rpcTimeout,
1663         pcrc != null? pcrc.getPriority(): HConstants.NORMAL_QOS);
1664       if (pcrc != null) {
1665         // Shove the results into controller so can be carried across the proxy/pb service void.
1666         if (val.getSecond() != null) pcrc.setCellScanner(val.getSecond());
1667       } else if (val.getSecond() != null) {
1668         throw new ServiceException("Client dropping data on the floor!");
1669       }
1670 
1671       if (LOG.isTraceEnabled()) {
1672         long callTime = System.currentTimeMillis() - startTime;
1673         if (LOG.isTraceEnabled()) {
1674           LOG.trace("Call: " + md.getName() + ", callTime: " + callTime + "ms");
1675         }
1676       }
1677       return val.getFirst();
1678     } catch (Throwable e) {
1679       throw new ServiceException(e);
1680     }
1681   }
1682 
1683   /**
1684    * Creates a "channel" that can be used by a blocking protobuf service.  Useful setting up
1685    * protobuf blocking stubs.
1686    * @param sn
1687    * @param ticket
1688    * @param rpcTimeout
1689    * @return A blocking rpc channel that goes via this rpc client instance.
1690    */
1691   public BlockingRpcChannel createBlockingRpcChannel(final ServerName sn,
1692       final User ticket, final int rpcTimeout) {
1693     return new BlockingRpcChannelImplementation(this, sn, ticket, rpcTimeout);
1694   }
1695 
1696   /**
1697    * Blocking rpc channel that goes via hbase rpc.
1698    */
1699   // Public so can be subclassed for tests.
1700   public static class BlockingRpcChannelImplementation implements BlockingRpcChannel {
1701     private final InetSocketAddress isa;
1702     private volatile RpcClient rpcClient;
1703     private final int rpcTimeout;
1704     private final User ticket;
1705 
1706     protected BlockingRpcChannelImplementation(final RpcClient rpcClient, final ServerName sn,
1707         final User ticket, final int rpcTimeout) {
1708       this.isa = new InetSocketAddress(sn.getHostname(), sn.getPort());
1709       this.rpcClient = rpcClient;
1710       // Set the rpc timeout to be the minimum of configured timeout and whatever the current
1711       // thread local setting is.
1712       this.rpcTimeout = getRpcTimeout(rpcTimeout);
1713       this.ticket = ticket;
1714     }
1715 
1716     @Override
1717     public Message callBlockingMethod(MethodDescriptor md, RpcController controller,
1718         Message param, Message returnType)
1719     throws ServiceException {
1720       return this.rpcClient.callBlockingMethod(md, controller, param, returnType, this.ticket,
1721         this.isa, this.rpcTimeout);
1722     }
1723   }
1724 }