2 * Copyright (c) 2016, 2017 Cisco Systems, Inc. and others. All rights reserved.
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
8 package org.opendaylight.controller.cluster.datastore;
10 import com.google.common.base.MoreObjects;
11 import com.google.common.base.Preconditions;
12 import com.google.common.base.Verify;
13 import java.util.ArrayDeque;
14 import java.util.Optional;
15 import java.util.Queue;
16 import javax.annotation.Nullable;
17 import javax.annotation.concurrent.NotThreadSafe;
18 import org.opendaylight.controller.cluster.access.commands.IncrementTransactionSequenceRequest;
19 import org.opendaylight.controller.cluster.access.commands.IncrementTransactionSequenceSuccess;
20 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
21 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
22 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
23 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
24 import org.opendaylight.controller.cluster.access.concepts.RequestException;
25 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
26 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
27 import org.opendaylight.yangtools.concepts.Identifiable;
28 import org.slf4j.Logger;
29 import org.slf4j.LoggerFactory;
32 * Frontend common transaction state as observed by the shard leader.
34 * @author Robert Varga
37 abstract class FrontendTransaction implements Identifiable<TransactionIdentifier> {
38 private static final Logger LOG = LoggerFactory.getLogger(FrontendTransaction.class);
40 private final AbstractFrontendHistory history;
41 private final TransactionIdentifier id;
44 * It is possible that after we process a request and send a response that response gets lost and the client
45 * initiates a retry. Since subsequent requests can mutate transaction state we need to retain the response until
46 * it is acknowledged by the client.
48 private final Queue<Object> replayQueue = new ArrayDeque<>();
49 private long firstReplaySequence;
50 private Long lastPurgedSequence;
51 private long expectedSequence;
53 private RequestException previousFailure;
55 FrontendTransaction(final AbstractFrontendHistory history, final TransactionIdentifier id) {
56 this.history = Preconditions.checkNotNull(history);
57 this.id = Preconditions.checkNotNull(id);
61 public final TransactionIdentifier getIdentifier() {
65 final AbstractFrontendHistory history() {
69 final String persistenceId() {
70 return history().persistenceId();
73 final java.util.Optional<TransactionSuccess<?>> replaySequence(final long sequence) throws RequestException {
74 // Fast path check: if the requested sequence is the next request, bail early
75 if (expectedSequence == sequence) {
76 return java.util.Optional.empty();
79 // Check sequencing: we do not need to bother with future requests
80 if (Long.compareUnsigned(expectedSequence, sequence) < 0) {
81 throw new OutOfOrderRequestException(expectedSequence);
84 // Sanity check: if we have purged sequences, this has to be newer
85 if (lastPurgedSequence != null && Long.compareUnsigned(lastPurgedSequence.longValue(), sequence) >= 0) {
86 // Client has sent a request sequence, which has already been purged. This is a hard error, which should
87 // never occur. Throwing an IllegalArgumentException will cause it to be wrapped in a
88 // RuntimeRequestException (which is not retriable) and report it back to the client.
89 throw new IllegalArgumentException(String.format("Invalid purged sequence %s (last purged is %s)",
90 sequence, lastPurgedSequence));
93 // At this point we have established that the requested sequence lies in the open interval
94 // (lastPurgedSequence, expectedSequence). That does not actually mean we have a response, as the commit
95 // machinery is asynchronous, hence a reply may be in the works and not available.
97 long replaySequence = firstReplaySequence;
98 for (Object replay : replayQueue) {
99 if (replaySequence == sequence) {
100 if (replay instanceof RequestException) {
101 throw (RequestException) replay;
104 Verify.verify(replay instanceof TransactionSuccess);
105 return Optional.of((TransactionSuccess<?>) replay);
112 return java.util.Optional.empty();
115 final void purgeSequencesUpTo(final long sequence) {
116 // FIXME: implement this
118 lastPurgedSequence = sequence;
121 // Request order has already been checked by caller and replaySequence()
122 @SuppressWarnings("checkstyle:IllegalCatch")
124 final TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
125 final long now) throws RequestException {
126 if (request instanceof IncrementTransactionSequenceRequest) {
127 final IncrementTransactionSequenceRequest incr = (IncrementTransactionSequenceRequest) request;
128 expectedSequence += incr.getIncrement();
130 return recordSuccess(incr.getSequence(),
131 new IncrementTransactionSequenceSuccess(incr.getTarget(), incr.getSequence()));
134 if (previousFailure != null) {
135 LOG.debug("{}: Rejecting request {} due to previous failure", persistenceId(), request, previousFailure);
136 throw previousFailure;
140 return doHandleRequest(request, envelope, now);
141 } catch (RuntimeException e) {
143 * The request failed to process, we should not attempt to ever
144 * apply it again. Furthermore we cannot accept any further requests
145 * from this connection, simply because the transaction state is
148 LOG.debug("{}: Request {} failed to process", persistenceId(), request, e);
149 previousFailure = new RuntimeRequestException("Request " + request + " failed to process", e);
150 throw previousFailure;
155 abstract TransactionSuccess<?> doHandleRequest(TransactionRequest<?> request, RequestEnvelope envelope,
156 long now) throws RequestException;
158 abstract void retire();
160 private void recordResponse(final long sequence, final Object response) {
161 if (replayQueue.isEmpty()) {
162 firstReplaySequence = sequence;
164 replayQueue.add(response);
168 final <T extends TransactionSuccess<?>> T recordSuccess(final long sequence, final T success) {
169 recordResponse(sequence, success);
173 private long executionTime(final long startTime) {
174 return history.readTime() - startTime;
177 final void recordAndSendSuccess(final RequestEnvelope envelope, final long startTime,
178 final TransactionSuccess<?> success) {
179 recordResponse(success.getSequence(), success);
180 envelope.sendSuccess(success, executionTime(startTime));
183 final void recordAndSendFailure(final RequestEnvelope envelope, final long startTime,
184 final RuntimeRequestException failure) {
185 recordResponse(envelope.getMessage().getSequence(), failure);
186 envelope.sendFailure(failure, executionTime(startTime));
190 public final String toString() {
191 return MoreObjects.toStringHelper(this).omitNullValues().add("identifier", getIdentifier())
192 .add("expectedSequence", expectedSequence).add("firstReplaySequence", firstReplaySequence)
193 .add("lastPurgedSequence", lastPurgedSequence)