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                     executeCommand(commandIterator.next());
 103                 }
 104                 transactionInFlight = null;
 105             } catch (IllegalStateException e) {
 106                 if (transactionInFlight != null) {
 107                     // TODO: This method should distinguish exceptions on which the command should be
 108                     // retried from exceptions on which the command should NOT be retried.
 109                     // Then it should retry only the commands which should be retried, otherwise
 110                     // this method will retry commands which will never be successful forever.
 111                     offerFailedTransaction(transactionInFlight);
 112                 }
 113                 transactionInFlight = null;
 114                 LOG.warn("Failed to process an update notification from OVS.", e);
 115             }
 116         }
 117     }
 118
 119     private synchronized void executeCommand(final TransactionCommand command) {
 120         final ReadWriteTransaction transaction = chain.newReadWriteTransaction();
 121         transactionInFlight = transaction;
 122         recordPendingTransaction(command, transaction);
 123         command.execute(transaction);
 124         ListenableFuture<Void> ft = transaction.submit();
 125         command.setTransactionResultFuture(ft);
 126         Futures.addCallback(ft, new FutureCallback<Void>() {
 127             @Override
 128             public void onSuccess(final Void result) {
 129                 forgetSuccessfulTransaction(transaction);
 130             }
 131
 132             @Override
 133             public void onFailure(final Throwable throwable) {
 134                 // NOOP - handled by failure of transaction chain
 135             }
 136         }, MoreExecutors.directExecutor());
 137     }
 138
 139     private void offerFailedTransaction(final AsyncTransaction<?, ?> transaction) {
 140         if (!failedTransactionQueue.offer(transaction)) {
 141             LOG.warn("failedTransactionQueue is full (size: {})", failedTransactionQueue.size());
 142         }
 143     }
 144
 145     private List<TransactionCommand> extractResubmitCommands() {
 146         List<TransactionCommand> commands = new ArrayList<>();
 147         synchronized (this) {
 148             AsyncTransaction<?, ?> transaction = failedTransactionQueue.poll();
 149             if (transaction != null) {
 150                 int index = pendingTransactions.lastIndexOf(transaction);
 151                 //This logic needs to be revisited. Is it ok to resubmit these things again ?
 152                 //are these operations idempotent ?
 153                 //Does the transaction chain execute n+1th if nth one threw error ?
 154                 List<ReadWriteTransaction> transactions =
 155                         pendingTransactions.subList(index, pendingTransactions.size() - 1);
 156                 for (ReadWriteTransaction tx: transactions) {
 157                     commands.add(transactionToCommand.get(tx));
 158                 }
 159                 resetTransactionQueue();
 160             }
 161         }
 162         if (commandIterator != null) {
 163             while (commandIterator.hasNext()) {
 164                 commands.add(commandIterator.next());
 165             }
 166         }
 167         return commands;
 168     }
 169
 170     private void resetTransactionQueue() {
 171         chain.close();
 172         chain = db.createTransactionChain(this);
 173         pendingTransactions.clear();
 174         transactionToCommand.clear();
 175         failedTransactionQueue.clear();
 176     }
 177
 178     synchronized void forgetSuccessfulTransaction(final ReadWriteTransaction transaction) {
 179         pendingTransactions.remove(transaction);
 180         transactionToCommand.remove(transaction);
 181     }
 182
 183     private synchronized void recordPendingTransaction(final TransactionCommand command,
 184             final ReadWriteTransaction transaction) {
 185         transactionToCommand.put(transaction, command);
 186         pendingTransactions.add(transaction);
 187     }
 188
 189     private List<TransactionCommand> extractCommands() throws InterruptedException {
 190         List<TransactionCommand> commands = extractResubmitCommands();
 191         if (!commands.isEmpty() && inputQueue.isEmpty()) {
 192             //we got some commands to be executed let us not sit and wait on empty queue
 193             return commands;
 194         }
 195         //pull commands from queue if not empty , otherwise wait for commands to be placed in queue.
 196         commands.addAll(extractCommandsFromQueue());
 197         return commands;
 198     }
 199
 200     private List<TransactionCommand> extractCommandsFromQueue() throws InterruptedException {
 201         List<TransactionCommand> result = new ArrayList<>();
 202         TransactionCommand command = inputQueue.take();
 203         result.add(command);
 204         inputQueue.drainTo(result);
 205         return result;
 206     }
 207
 208     @Override
 209     public void close() throws Exception {
 210         this.chain.close();
 211         this.executor.shutdown();
 212     }
 213
 214     @Override
 215     public void uncaughtException(final Thread thread, final Throwable ex) {
 216         LOG.error("Failed to execute hwvtep transact command, re-submitting the transaction again", ex);
 217         if (transactionInFlight != null) {
 218             offerFailedTransaction(transactionInFlight);
 219         }
 220         transactionInFlight = null;
 221         executor.execute(this);
 222     }
 223 }