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.FutureCallback;
  11 import com.google.common.util.concurrent.Futures;
  12 import com.google.common.util.concurrent.ListenableFuture;
  13 import com.google.common.util.concurrent.MoreExecutors;
  14 import com.google.common.util.concurrent.ThreadFactoryBuilder;
  15 import java.util.ArrayList;
  16 import java.util.HashMap;
  17 import java.util.Iterator;
  18 import java.util.List;
  19 import java.util.Map;
  20 import java.util.concurrent.BlockingQueue;
  21 import java.util.concurrent.ExecutorService;
  22 import java.util.concurrent.Executors;
  23 import java.util.concurrent.LinkedBlockingQueue;
  24 import java.util.concurrent.ThreadFactory;
  25 import org.checkerframework.checker.lock.qual.GuardedBy;
  26 import org.opendaylight.controller.md.sal.binding.api.BindingTransactionChain;
  27 import org.opendaylight.controller.md.sal.binding.api.DataBroker;
  28 import org.opendaylight.controller.md.sal.binding.api.ReadWriteTransaction;
  29 import org.opendaylight.controller.md.sal.common.api.data.AsyncTransaction;
  30 import org.opendaylight.controller.md.sal.common.api.data.TransactionChain;
  31 import org.opendaylight.controller.md.sal.common.api.data.TransactionChainListener;
  32 import org.slf4j.Logger;
  33 import org.slf4j.LoggerFactory;
  34
  35 /*  TODO:
  36  * Copied over as-is from southbound plugin. Good candidate to be common
  37  * when refactoring code.
  38  */
  39 public class TransactionInvokerImpl implements TransactionInvoker,TransactionChainListener, Runnable, AutoCloseable,
  40         Thread.UncaughtExceptionHandler {
  41     private static final Logger LOG = LoggerFactory.getLogger(TransactionInvokerImpl.class);
  42     private static final int QUEUE_SIZE = 10000;
  43
  44     private final DataBroker db;
  45     private final BlockingQueue<TransactionCommand> inputQueue = new LinkedBlockingQueue<>(QUEUE_SIZE);
  46     private final BlockingQueue<AsyncTransaction<?, ?>> failedTransactionQueue = new LinkedBlockingQueue<>(QUEUE_SIZE);
  47     private final ExecutorService executor;
  48
  49     @GuardedBy("this")
  50     private final Map<ReadWriteTransaction,TransactionCommand> transactionToCommand = new HashMap<>();
  51     @GuardedBy("this")
  52     private final List<ReadWriteTransaction> pendingTransactions = new ArrayList<>();
  53
  54     private BindingTransactionChain chain;
  55     //This is made volatile as it is accessed from uncaught exception handler thread also
  56     private volatile ReadWriteTransaction transactionInFlight = null;
  57     private Iterator<TransactionCommand> commandIterator = null;
  58
  59     public TransactionInvokerImpl(final DataBroker db) {
  60         this.db = db;
  61         this.chain = db.createTransactionChain(this);
  62         ThreadFactory threadFact = new ThreadFactoryBuilder().setNameFormat("transaction-invoker-impl-%d")
  63                 .setUncaughtExceptionHandler(this).build();
  64         executor = Executors.newSingleThreadExecutor(threadFact);
  65         //Using the execute method here so that un caught exception handler gets triggered upon exception.
  66         //The other way to do it is using submit method and wait on the future to catch any exceptions
  67         executor.execute(this);
  68     }
  69
  70     @Override
  71     public void invoke(final TransactionCommand command) {
  72         // TODO what do we do if queue is full?
  73         if (!inputQueue.offer(command)) {
  74             LOG.error("inputQueue is full (size: {}) - could not offer {}", inputQueue.size(), command);
  75         }
  76     }
  77
  78     @Override
  79     public void onTransactionChainFailed(final TransactionChain<?, ?> txChain,
  80             final AsyncTransaction<?, ?> transaction, final Throwable cause) {
  81         offerFailedTransaction(transaction);
  82     }
  83
  84     @Override
  85     public void onTransactionChainSuccessful(final TransactionChain<?, ?> txChain) {
  86         // NO OP
  87     }
  88
  89     @Override
  90     public void run() {
  91         while (true) {
  92             final List<TransactionCommand> commands;
  93             try {
  94                 commands = extractCommands();
  95             } catch (InterruptedException e) {
  96                 LOG.warn("Extracting commands was interrupted.", e);
  97                 continue;
  98             }
  99             commandIterator = commands.iterator();
 100             try {
 101                 while (commandIterator.hasNext()) {
 102                     TransactionCommand command = commandIterator.next();
 103                     synchronized (this) {
 104                         final ReadWriteTransaction transaction = chain.newReadWriteTransaction();
 105                         transactionInFlight = transaction;
 106                         recordPendingTransaction(command, transaction);
 107                         command.execute(transaction);
 108                         ListenableFuture<Void> ft = transaction.submit();
 109                         command.setTransactionResultFuture(ft);
 110                         Futures.addCallback(ft, new FutureCallback<Void>() {
 111                             @Override
 112                             public void onSuccess(final Void result) {
 113                                 forgetSuccessfulTransaction(transaction);
 114                             }
 115
 116                             @Override
 117                             public void onFailure(final Throwable throwable) {
 118                                 // NOOP - handled by failure of transaction chain
 119                             }
 120                         }, MoreExecutors.directExecutor());
 121                     }
 122                 }
 123                 transactionInFlight = null;
 124             } catch (IllegalStateException e) {
 125                 if (transactionInFlight != null) {
 126                     // TODO: This method should distinguish exceptions on which the command should be
 127                     // retried from exceptions on which the command should NOT be retried.
 128                     // Then it should retry only the commands which should be retried, otherwise
 129                     // this method will retry commands which will never be successful forever.
 130                     offerFailedTransaction(transactionInFlight);
 131                 }
 132                 transactionInFlight = null;
 133                 LOG.warn("Failed to process an update notification from OVS.", e);
 134             }
 135         }
 136     }
 137
 138     private void offerFailedTransaction(final AsyncTransaction<?, ?> transaction) {
 139         if (!failedTransactionQueue.offer(transaction)) {
 140             LOG.warn("failedTransactionQueue is full (size: {})", failedTransactionQueue.size());
 141         }
 142     }
 143
 144     private List<TransactionCommand> extractResubmitCommands() {
 145         List<TransactionCommand> commands = new ArrayList<>();
 146         synchronized (this) {
 147             AsyncTransaction<?, ?> transaction = failedTransactionQueue.poll();
 148             if (transaction != null) {
 149                 int index = pendingTransactions.lastIndexOf(transaction);
 150                 //This logic needs to be revisited. Is it ok to resubmit these things again ?
 151                 //are these operations idempotent ?
 152                 //Does the transaction chain execute n+1th if nth one threw error ?
 153                 List<ReadWriteTransaction> transactions =
 154                         pendingTransactions.subList(index, pendingTransactions.size() - 1);
 155                 for (ReadWriteTransaction tx: transactions) {
 156                     commands.add(transactionToCommand.get(tx));
 157                 }
 158                 resetTransactionQueue();
 159             }
 160         }
 161         if (commandIterator != null) {
 162             while (commandIterator.hasNext()) {
 163                 commands.add(commandIterator.next());
 164             }
 165         }
 166         return commands;
 167     }
 168
 169     private void resetTransactionQueue() {
 170         chain.close();
 171         chain = db.createTransactionChain(this);
 172         pendingTransactions.clear();
 173         transactionToCommand.clear();
 174         failedTransactionQueue.clear();
 175     }
 176
 177     synchronized void forgetSuccessfulTransaction(final ReadWriteTransaction transaction) {
 178         pendingTransactions.remove(transaction);
 179         transactionToCommand.remove(transaction);
 180     }
 181
 182     private synchronized void recordPendingTransaction(final TransactionCommand command,
 183             final ReadWriteTransaction transaction) {
 184         transactionToCommand.put(transaction, command);
 185         pendingTransactions.add(transaction);
 186     }
 187
 188     private List<TransactionCommand> extractCommands() throws InterruptedException {
 189         List<TransactionCommand> commands = extractResubmitCommands();
 190         if (!commands.isEmpty() && inputQueue.isEmpty()) {
 191             //we got some commands to be executed let us not sit and wait on empty queue
 192             return commands;
 193         }
 194         //pull commands from queue if not empty , otherwise wait for commands to be placed in queue.
 195         commands.addAll(extractCommandsFromQueue());
 196         return commands;
 197     }
 198
 199     private List<TransactionCommand> extractCommandsFromQueue() throws InterruptedException {
 200         List<TransactionCommand> result = new ArrayList<>();
 201         TransactionCommand command = inputQueue.take();
 202         result.add(command);
 203         inputQueue.drainTo(result);
 204         return result;
 205     }
 206
 207     @Override
 208     public void close() throws Exception {
 209         this.chain.close();
 210         this.executor.shutdown();
 211     }
 212
 213     @Override
 214     public void uncaughtException(final Thread thread, final Throwable ex) {
 215         LOG.error("Failed to execute hwvtep transact command, re-submitting the transaction again", ex);
 216         if (transactionInFlight != null) {
 217             offerFailedTransaction(transactionInFlight);
 218         }
 219         transactionInFlight = null;
 220         executor.execute(this);
 221     }
 222 }