opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/CompositeDataTreeCohort.java

   1 /*
   2  * Copyright (c) 2016 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
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import akka.actor.Status;
  12 import akka.actor.Status.Failure;
  13 import akka.dispatch.ExecutionContexts;
  14 import akka.dispatch.Futures;
  15 import akka.dispatch.Recover;
  16 import akka.japi.Function;
  17 import akka.pattern.Patterns;
  18 import akka.util.Timeout;
  19 import com.google.common.base.Preconditions;
  20 import com.google.common.base.Throwables;
  21 import com.google.common.collect.Iterables;
  22 import java.util.Collection;
  23 import java.util.Iterator;
  24 import java.util.concurrent.ExecutionException;
  25 import java.util.concurrent.TimeoutException;
  26 import org.opendaylight.controller.cluster.datastore.DataTreeCohortActor.CanCommit;
  27 import org.opendaylight.controller.cluster.datastore.DataTreeCohortActor.Success;
  28 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateTip;
  29 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  30 import scala.concurrent.Await;
  31 import scala.concurrent.Future;
  32
  33 /**
  34  *
  35  * Composite cohort, which coordinates multiple user-provided cohorts as if it was only one cohort.
  36  *
  37  * It tracks current operation and list of cohorts which successfuly finished previous phase in
  38  * case, if abort is necessary to invoke it only on cohort steps which are still active.
  39  *
  40  */
  41 class CompositeDataTreeCohort {
  42
  43     private enum State {
  44         /**
  45          * Cohorts are idle, no messages were sent.
  46          */
  47         IDLE,
  48         /**
  49          * CanCommit message was sent to all participating cohorts.
  50          */
  51         CAN_COMMIT_SENT,
  52         /**
  53          * Successful canCommit responses were received from every participating cohort.
  54          */
  55         CAN_COMMIT_SUCCESSFUL,
  56         /**
  57          * PreCommit message was sent to all participating cohorts.
  58          */
  59         PRE_COMMIT_SENT,
  60         /**
  61          * Successful preCommit responses were received from every participating cohort.
  62          */
  63         PRE_COMMIT_SUCCESSFUL,
  64         /**
  65          * Commit message was send to all participating cohorts.
  66          */
  67         COMMIT_SENT,
  68         /**
  69          * Successful commit responses were received from all participating cohorts.
  70          */
  71         COMMITED,
  72         /**
  73          * Some of cohorts responsed back with unsuccessful message.
  74          *
  75          */
  76         FAILED,
  77         /**
  78          *
  79          * Abort message was send to all cohorts which responded with success previously.
  80          *
  81          */
  82         ABORTED
  83     }
  84
  85     protected static final Recover<Object> EXCEPTION_TO_MESSAGE = new Recover<Object>() {
  86         @Override
  87         public Failure recover(Throwable error) throws Throwable {
  88             return new Failure(error);
  89         }
  90     };
  91
  92
  93     private final DataTreeCohortActorRegistry registry;
  94     private final String txId;
  95     private final SchemaContext schema;
  96     private final Timeout timeout;
  97     private Iterable<Success> successfulFromPrevious;
  98     private State state = State.IDLE;
  99
 100     CompositeDataTreeCohort(DataTreeCohortActorRegistry registry, String txId, SchemaContext schema, Timeout timeout) {
 101         this.registry = Preconditions.checkNotNull(registry);
 102         this.txId = Preconditions.checkNotNull(txId);
 103         this.schema = Preconditions.checkNotNull(schema);
 104         this.timeout = Preconditions.checkNotNull(timeout);
 105     }
 106
 107     void canCommit(DataTreeCandidateTip tip) throws ExecutionException, TimeoutException {
 108         Collection<CanCommit> messages = registry.createCanCommitMessages(txId, tip, schema);
 109         // FIXME: Optimize empty collection list with pre-created futures, containing success.
 110         Future<Iterable<Object>> canCommitsFuture =
 111                 Futures.traverse(messages, new Function<CanCommit, Future<Object>>() {
 112                     @Override
 113                     public Future<Object> apply(CanCommit input) {
 114                         return Patterns.ask(input.getCohort(), input, timeout).recover(EXCEPTION_TO_MESSAGE,
 115                                 ExecutionContexts.global());
 116                     }
 117                 }, ExecutionContexts.global());
 118         changeStateFrom(State.IDLE, State.CAN_COMMIT_SENT);
 119         processResponses(canCommitsFuture, State.CAN_COMMIT_SENT, State.CAN_COMMIT_SUCCESSFUL);
 120     }
 121
 122     void preCommit() throws ExecutionException, TimeoutException {
 123         Preconditions.checkState(successfulFromPrevious != null);
 124         Future<Iterable<Object>> preCommitFutures = sendMesageToSuccessful(new DataTreeCohortActor.PreCommit(txId));
 125         changeStateFrom(State.CAN_COMMIT_SUCCESSFUL, State.PRE_COMMIT_SENT);
 126         processResponses(preCommitFutures, State.PRE_COMMIT_SENT, State.PRE_COMMIT_SUCCESSFUL);
 127     }
 128
 129     void commit() throws ExecutionException, TimeoutException {
 130         Preconditions.checkState(successfulFromPrevious != null);
 131         Future<Iterable<Object>> commitsFuture = sendMesageToSuccessful(new DataTreeCohortActor.Commit(txId));
 132         changeStateFrom(State.PRE_COMMIT_SUCCESSFUL, State.COMMIT_SENT);
 133         processResponses(commitsFuture, State.COMMIT_SENT, State.COMMITED);
 134     }
 135
 136     void abort() throws TimeoutException {
 137         if (successfulFromPrevious != null) {
 138             sendMesageToSuccessful(new DataTreeCohortActor.Abort(txId));
 139         }
 140     }
 141
 142     private Future<Iterable<Object>> sendMesageToSuccessful(final Object message) {
 143         return Futures.traverse(successfulFromPrevious, new Function<DataTreeCohortActor.Success, Future<Object>>() {
 144
 145             @Override
 146             public Future<Object> apply(DataTreeCohortActor.Success cohortResponse) throws Exception {
 147                 return Patterns.ask(cohortResponse.getCohort(), message, timeout);
 148             }
 149
 150         }, ExecutionContexts.global());
 151     }
 152
 153     private void processResponses(Future<Iterable<Object>> resultsFuture, State currentState, State afterState)
 154             throws TimeoutException, ExecutionException {
 155         final Iterable<Object> results;
 156         try {
 157             results = Await.result(resultsFuture, timeout.duration());
 158         } catch (Exception e) {
 159             successfulFromPrevious = null;
 160             Throwables.propagateIfInstanceOf(e, TimeoutException.class);
 161             throw Throwables.propagate(e);
 162         }
 163         Iterable<Failure> failed = Iterables.filter(results, Status.Failure.class);
 164         Iterable<Success> successful = Iterables.filter(results, DataTreeCohortActor.Success.class);
 165         successfulFromPrevious = successful;
 166         if (!Iterables.isEmpty(failed)) {
 167             changeStateFrom(currentState, State.FAILED);
 168             Iterator<Failure> it = failed.iterator();
 169             Throwable firstEx = it.next().cause();
 170             while (it.hasNext()) {
 171                 firstEx.addSuppressed(it.next().cause());
 172             }
 173             Throwables.propagateIfPossible(firstEx, ExecutionException.class);
 174             Throwables.propagateIfPossible(firstEx, TimeoutException.class);
 175             throw Throwables.propagate(firstEx);
 176         }
 177         changeStateFrom(currentState, afterState);
 178     }
 179
 180     void changeStateFrom(State expected, State followup) {
 181         Preconditions.checkState(state == expected);
 182         state = followup;
 183     }
 184 }