bdeggleston commented on code in PR #49: URL: https://github.com/apache/cassandra-accord/pull/49#discussion_r1228460292
########## accord-core/src/main/java/accord/impl/AbstractFetchCoordinator.java: ########## @@ -0,0 +1,288 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package accord.impl; + +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import javax.annotation.Nullable; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import accord.api.Data; +import accord.api.DataStore; +import accord.coordinate.FetchCoordinator; +import accord.local.CommandStore; +import accord.local.Node; +import accord.local.Status; +import accord.messages.Callback; +import accord.messages.MessageType; +import accord.messages.ReadData; +import accord.messages.WaitAndReadData; +import accord.primitives.PartialDeps; +import accord.primitives.PartialTxn; +import accord.primitives.Ranges; +import accord.primitives.SyncPoint; +import accord.primitives.Timestamp; +import accord.primitives.TxnId; +import accord.utils.Invariants; +import accord.utils.async.AsyncChains; +import accord.utils.async.AsyncResult; +import accord.utils.async.AsyncResults; + +import static accord.primitives.Routables.Slice.Minimal; + +public abstract class AbstractFetchCoordinator extends FetchCoordinator +{ + private static final Logger logger = LoggerFactory.getLogger(AbstractFetchCoordinator.class); + + static class FetchResult extends AsyncResults.SettableResult<Ranges> implements DataStore.FetchResult + { + final AbstractFetchCoordinator coordinator; + + FetchResult(AbstractFetchCoordinator coordinator) + { + this.coordinator = coordinator; + } + + @Override + public void abort(Ranges abort) + { + coordinator.abort(abort); + } + } + + static class Key + { + final Node.Id id; + final Ranges ranges; + + Key(Node.Id id, Ranges ranges) + { + this.id = id; + this.ranges = ranges; + } + + @Override + public int hashCode() + { + return id.hashCode() + ranges.hashCode(); + } + + @Override + public boolean equals(Object obj) + { + if (this == obj) return true; + if (!(obj instanceof Key)) return false; + Key that = (Key) obj; + return id.equals(that.id) && ranges.equals(that.ranges); + } + } + + final DataStore.FetchRanges fetchRanges; + final CommandStore commandStore; + final Map<Key, DataStore.StartingRangeFetch> inflight = new HashMap<>(); + final FetchResult result = new FetchResult(this); + final List<AsyncResult<Void>> persisting = new ArrayList<>(); + + protected AbstractFetchCoordinator(Node node, Ranges ranges, SyncPoint syncPoint, DataStore.FetchRanges fetchRanges, CommandStore commandStore) + { + super(node, ranges, syncPoint, fetchRanges); + this.fetchRanges = fetchRanges; + this.commandStore = commandStore; + } + + protected abstract PartialTxn rangeReadTxn(Ranges ranges); + + protected abstract void onReadOk(Node.Id from, CommandStore commandStore, Data data, Ranges ranges); + + @Override + public void contact(Node.Id to, Ranges ranges) + { + Key key = new Key(to, ranges); + inflight.put(key, starting(to, ranges)); + Ranges ownedRanges = ownedRangesForNode(to); + Invariants.checkArgument(ownedRanges.containsAll(ranges)); + PartialDeps partialDeps = syncPoint.waitFor.slice(ownedRanges, ranges); + node.send(to, new FetchRequest(syncPoint.sourceEpoch(), syncPoint.syncId, ranges, partialDeps, rangeReadTxn(ranges)), new Callback<ReadData.ReadReply>() + { + @Override + public void onSuccess(Node.Id from, ReadData.ReadReply reply) + { + if (!reply.isOk()) + { + fail(to, new RuntimeException(reply.toString())); + inflight.remove(key).cancel(); + switch ((ReadData.ReadNack) reply) + { + default: throw new AssertionError("Unhandled enum: " + reply); + case Invalid: + case Redundant: + case NotCommitted: + throw new AssertionError(String.format("Unexpected reply: %s", reply)); + case Error: + // TODO (required): ensure errors are propagated to coordinators and can be logged + } + return; + } + + FetchResponse ok = (FetchResponse) reply; + Ranges received; + if (ok.unavailable != null) + { + unavailable(to, ok.unavailable); + if (ok.data == null) + { + inflight.remove(key).cancel(); + return; + } + received = ranges.difference(ok.unavailable); + } + else + { + received = ranges; + } + + // TODO (now): make sure it works if invoked in either order + inflight.remove(key).started(ok.maxApplied); + onReadOk(to, commandStore, ok.data, received); + // received must be invoked after submitting the persistence future, as it triggers onDone + // which creates a ReducingFuture over {@code persisting} + } + + @Override + public void onFailure(Node.Id from, Throwable failure) + { + inflight.remove(key).cancel(); + fail(from, failure); + } + + @Override + public void onCallbackFailure(Node.Id from, Throwable failure) + { + // TODO (soon) + logger.error("Fetch coordination failure from " + from, failure); + } + }); + } + + @Override + protected synchronized void success(Node.Id to, Ranges ranges) + { + super.success(to, ranges); + } + + @Override + protected synchronized void fail(Node.Id to, Ranges ranges, Throwable failure) + { + super.fail(to, ranges, failure); + } + + public FetchResult result() + { + return result; + } + + @Override + protected void onDone(Ranges success, Throwable failure) + { + if (success.isEmpty()) result.setFailure(failure); + else if (persisting.isEmpty()) result.setSuccess(Ranges.EMPTY); + else AsyncChains.reduce(persisting, (a, b) -> null) + .begin((s, f) -> { + if (f == null) result.setSuccess(ranges); + else result.setFailure(f); + }); + } + + @Override + public void start() + { + super.start(); + } + + void abort(Ranges abort) Review Comment: I'd rather leave it since it has a todo and is meant to be implemented later -- This is an automated message from the Apache Git Service. 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