hwvtepsouthbound/hwvtepsouthbound-impl/src/main/java/org/opendaylight/ovsdb/hwvtepsouthbound/transactions/md/TransactionInvokerImpl.java

   1 /*
   2  * Copyright (c) 2015, 2017 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.ovsdb.hwvtepsouthbound.transactions.md;
   9
  10 import com.google.common.util.concurrent.FluentFuture;
  11 import com.google.common.util.concurrent.FutureCallback;
  12 import com.google.common.util.concurrent.MoreExecutors;
  13 import com.google.common.util.concurrent.ThreadFactoryBuilder;
  14 import java.util.ArrayList;
  15 import java.util.HashMap;
  16 import java.util.Iterator;
  17 import java.util.List;
  18 import java.util.Map;
  19 import java.util.concurrent.BlockingQueue;
  20 import java.util.concurrent.ExecutorService;
  21 import java.util.concurrent.Executors;
  22 import java.util.concurrent.LinkedBlockingQueue;
  23 import java.util.concurrent.ThreadFactory;
  24 import org.checkerframework.checker.lock.qual.GuardedBy;
  25 import org.opendaylight.mdsal.binding.api.DataBroker;
  26 import org.opendaylight.mdsal.binding.api.ReadWriteTransaction;
  27 import org.opendaylight.mdsal.binding.api.Transaction;
  28 import org.opendaylight.mdsal.binding.api.TransactionChain;
  29 import org.opendaylight.mdsal.binding.api.TransactionChainListener;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32
  33 /*  TODO:
  34  * Copied over as-is from southbound plugin. Good candidate to be common
  35  * when refactoring code.
  36  */
  37 public class TransactionInvokerImpl implements TransactionInvoker,TransactionChainListener, Runnable, AutoCloseable,
  38         Thread.UncaughtExceptionHandler {
  39     private static final Logger LOG = LoggerFactory.getLogger(TransactionInvokerImpl.class);
  40     private static final int QUEUE_SIZE = 10000;
  41
  42     private final DataBroker db;
  43     private final BlockingQueue<TransactionCommand> inputQueue = new LinkedBlockingQueue<>(QUEUE_SIZE);
  44     private final BlockingQueue<Transaction> failedTransactionQueue = new LinkedBlockingQueue<>(QUEUE_SIZE);
  45     private final ExecutorService executor;
  46
  47     @GuardedBy("this")
  48     private final Map<ReadWriteTransaction,TransactionCommand> transactionToCommand = new HashMap<>();
  49     @GuardedBy("this")
  50     private final List<ReadWriteTransaction> pendingTransactions = new ArrayList<>();
  51
  52     private TransactionChain chain;
  53     //This is made volatile as it is accessed from uncaught exception handler thread also
  54     private volatile ReadWriteTransaction transactionInFlight = null;
  55     private Iterator<TransactionCommand> commandIterator = null;
  56
  57     public TransactionInvokerImpl(final DataBroker db) {
  58         this.db = db;
  59         this.chain = db.createTransactionChain(this);
  60         ThreadFactory threadFact = new ThreadFactoryBuilder().setNameFormat("transaction-invoker-impl-%d")
  61                 .setUncaughtExceptionHandler(this).build();
  62         executor = Executors.newSingleThreadExecutor(threadFact);
  63         //Using the execute method here so that un caught exception handler gets triggered upon exception.
  64         //The other way to do it is using submit method and wait on the future to catch any exceptions
  65         executor.execute(this);
  66     }
  67
  68     @Override
  69     public void invoke(final TransactionCommand command) {
  70         // TODO what do we do if queue is full?
  71         if (!inputQueue.offer(command)) {
  72             LOG.error("inputQueue is full (size: {}) - could not offer {}", inputQueue.size(), command);
  73         }
  74     }
  75
  76     @Override
  77     public void onTransactionChainFailed(final TransactionChain txChain,
  78             final Transaction transaction, final Throwable cause) {
  79         offerFailedTransaction(transaction);
  80     }
  81
  82     @Override
  83     public void onTransactionChainSuccessful(final TransactionChain txChain) {
  84         // NO OP
  85     }
  86
  87     @Override
  88     public void run() {
  89         while (true) {
  90             final List<TransactionCommand> commands;
  91             try {
  92                 commands = extractCommands();
  93             } catch (InterruptedException e) {
  94                 LOG.warn("Extracting commands was interrupted.", e);
  95                 continue;
  96             }
  97             commandIterator = commands.iterator();
  98             try {
  99                 while (commandIterator.hasNext()) {
 100                     executeCommand(commandIterator.next());
 101                 }
 102                 transactionInFlight = null;
 103             } catch (IllegalStateException e) {
 104                 if (transactionInFlight != null) {
 105                     // TODO: This method should distinguish exceptions on which the command should be
 106                     // retried from exceptions on which the command should NOT be retried.
 107                     // Then it should retry only the commands which should be retried, otherwise
 108                     // this method will retry commands which will never be successful forever.
 109                     offerFailedTransaction(transactionInFlight);
 110                 }
 111                 transactionInFlight = null;
 112                 LOG.warn("Failed to process an update notification from OVS.", e);
 113             }
 114         }
 115     }
 116
 117     private synchronized void executeCommand(final TransactionCommand command) {
 118         final ReadWriteTransaction transaction = chain.newReadWriteTransaction();
 119         transactionInFlight = transaction;
 120         recordPendingTransaction(command, transaction);
 121         command.execute(transaction);
 122         FluentFuture<?> ft = transaction.commit();
 123         command.setTransactionResultFuture(ft);
 124         ft.addCallback(new FutureCallback<Object>() {
 125             @Override
 126             public void onSuccess(final Object result) {
 127                 forgetSuccessfulTransaction(transaction);
 128             }
 129
 130             @Override
 131             public void onFailure(final Throwable throwable) {
 132                 // NOOP - handled by failure of transaction chain
 133             }
 134         }, MoreExecutors.directExecutor());
 135     }
 136
 137     private void offerFailedTransaction(final Transaction transaction) {
 138         if (!failedTransactionQueue.offer(transaction)) {
 139             LOG.warn("failedTransactionQueue is full (size: {})", failedTransactionQueue.size());
 140         }
 141     }
 142
 143     private List<TransactionCommand> extractResubmitCommands() {
 144         List<TransactionCommand> commands = new ArrayList<>();
 145         synchronized (this) {
 146             Transaction transaction = failedTransactionQueue.poll();
 147             if (transaction != null) {
 148                 int index = pendingTransactions.lastIndexOf(transaction);
 149                 //This logic needs to be revisited. Is it ok to resubmit these things again ?
 150                 //are these operations idempotent ?
 151                 //Does the transaction chain execute n+1th if nth one threw error ?
 152                 List<ReadWriteTransaction> transactions =
 153                         pendingTransactions.subList(index, pendingTransactions.size() - 1);
 154                 for (ReadWriteTransaction tx: transactions) {
 155                     commands.add(transactionToCommand.get(tx));
 156                 }
 157                 resetTransactionQueue();
 158             }
 159         }
 160         if (commandIterator != null) {
 161             while (commandIterator.hasNext()) {
 162                 commands.add(commandIterator.next());
 163             }
 164         }
 165         return commands;
 166     }
 167
 168     private void resetTransactionQueue() {
 169         chain.close();
 170         chain = db.createTransactionChain(this);
 171         pendingTransactions.clear();
 172         transactionToCommand.clear();
 173         failedTransactionQueue.clear();
 174     }
 175
 176     synchronized void forgetSuccessfulTransaction(final ReadWriteTransaction transaction) {
 177         pendingTransactions.remove(transaction);
 178         transactionToCommand.remove(transaction);
 179     }
 180
 181     private synchronized void recordPendingTransaction(final TransactionCommand command,
 182             final ReadWriteTransaction transaction) {
 183         transactionToCommand.put(transaction, command);
 184         pendingTransactions.add(transaction);
 185     }
 186
 187     private List<TransactionCommand> extractCommands() throws InterruptedException {
 188         List<TransactionCommand> commands = extractResubmitCommands();
 189         if (!commands.isEmpty() && inputQueue.isEmpty()) {
 190             //we got some commands to be executed let us not sit and wait on empty queue
 191             return commands;
 192         }
 193         //pull commands from queue if not empty , otherwise wait for commands to be placed in queue.
 194         commands.addAll(extractCommandsFromQueue());
 195         return commands;
 196     }
 197
 198     private List<TransactionCommand> extractCommandsFromQueue() throws InterruptedException {
 199         List<TransactionCommand> result = new ArrayList<>();
 200         TransactionCommand command = inputQueue.take();
 201         result.add(command);
 202         inputQueue.drainTo(result);
 203         return result;
 204     }
 205
 206     @Override
 207     public void close() throws Exception {
 208         this.chain.close();
 209         this.executor.shutdown();
 210     }
 211
 212     @Override
 213     public void uncaughtException(final Thread thread, final Throwable ex) {
 214         LOG.error("Failed to execute hwvtep transact command, re-submitting the transaction again", ex);
 215         if (transactionInFlight != null) {
 216             offerFailedTransaction(transactionInFlight);
 217         }
 218         transactionInFlight = null;
 219         executor.execute(this);
 220     }
 221 }