2 * Copyright (c) 2016 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.collect.Range;
13 import com.google.common.collect.RangeSet;
14 import com.google.common.collect.TreeRangeSet;
15 import com.google.common.primitives.UnsignedLong;
16 import java.util.HashMap;
18 import javax.annotation.Nullable;
19 import javax.annotation.concurrent.NotThreadSafe;
20 import org.opendaylight.controller.cluster.access.commands.CreateLocalHistoryRequest;
21 import org.opendaylight.controller.cluster.access.commands.DeadHistoryException;
22 import org.opendaylight.controller.cluster.access.commands.DestroyLocalHistoryRequest;
23 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
24 import org.opendaylight.controller.cluster.access.commands.LocalHistorySuccess;
25 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
26 import org.opendaylight.controller.cluster.access.commands.PurgeLocalHistoryRequest;
27 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
28 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
29 import org.opendaylight.controller.cluster.access.commands.UnknownHistoryException;
30 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
31 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
32 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
33 import org.opendaylight.controller.cluster.access.concepts.RequestException;
34 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
35 import org.opendaylight.yangtools.concepts.Identifiable;
36 import org.slf4j.Logger;
37 import org.slf4j.LoggerFactory;
40 * Frontend state as observed by the shard leader. This class is responsible for tracking generations and sequencing
41 * in the frontend/backend conversation.
43 * @author Robert Varga
46 final class LeaderFrontendState implements Identifiable<ClientIdentifier> {
47 private static final Logger LOG = LoggerFactory.getLogger(LeaderFrontendState.class);
49 // Histories which have not been purged
50 private final Map<LocalHistoryIdentifier, LocalFrontendHistory> localHistories = new HashMap<>();
52 // RangeSet performs automatic merging, hence we keep minimal state tracking information
53 private final RangeSet<UnsignedLong> purgedHistories = TreeRangeSet.create();
55 // Used for all standalone transactions
56 private final AbstractFrontendHistory standaloneHistory;
57 private final ShardDataTree tree;
58 private final ClientIdentifier clientId;
59 private final String persistenceId;
61 private long expectedTxSequence;
62 private Long lastSeenHistory = null;
65 // TODO: explicit failover notification
66 // Record the ActorRef for the originating actor and when we switch to being a leader send a notification
67 // to the frontend client -- that way it can immediately start sending requests
69 // TODO: add statistics:
70 // - number of requests processed
71 // - number of histories processed
72 // - per-RequestException throw counters
74 LeaderFrontendState(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree) {
75 this.persistenceId = Preconditions.checkNotNull(persistenceId);
76 this.clientId = Preconditions.checkNotNull(clientId);
77 this.tree = Preconditions.checkNotNull(tree);
78 standaloneHistory = new StandaloneFrontendHistory(persistenceId, tree.ticker(), clientId, tree);
82 public ClientIdentifier getIdentifier() {
86 private void checkRequestSequence(final RequestEnvelope envelope) throws OutOfOrderRequestException {
87 if (expectedTxSequence != envelope.getTxSequence()) {
88 throw new OutOfOrderRequestException(expectedTxSequence);
92 private void expectNextRequest() {
96 @Nullable LocalHistorySuccess handleLocalHistoryRequest(final LocalHistoryRequest<?> request,
97 final RequestEnvelope envelope, final long now) throws RequestException {
98 checkRequestSequence(envelope);
101 if (request instanceof CreateLocalHistoryRequest) {
102 return handleCreateHistory((CreateLocalHistoryRequest) request);
103 } else if (request instanceof DestroyLocalHistoryRequest) {
104 return handleDestroyHistory((DestroyLocalHistoryRequest) request, now);
105 } else if (request instanceof PurgeLocalHistoryRequest) {
106 return handlePurgeHistory((PurgeLocalHistoryRequest)request, now);
108 throw new UnsupportedRequestException(request);
115 private LocalHistorySuccess handleCreateHistory(final CreateLocalHistoryRequest request) throws RequestException {
116 final LocalHistoryIdentifier id = request.getTarget();
117 final AbstractFrontendHistory existing = localHistories.get(id);
118 if (existing != null) {
119 // History already exists: report success
120 LOG.debug("{}: history {} already exists", persistenceId, id);
121 return new LocalHistorySuccess(id, request.getSequence());
124 // We have not found the history. Before we create it we need to check history ID sequencing so that we do not
125 // end up resurrecting a purged history.
126 if (purgedHistories.contains(UnsignedLong.fromLongBits(id.getHistoryId()))) {
127 LOG.debug("{}: rejecting purged request {}", persistenceId, request);
128 throw new DeadHistoryException(lastSeenHistory.longValue());
131 // Update last history we have seen
132 if (lastSeenHistory != null && Long.compareUnsigned(lastSeenHistory, id.getHistoryId()) < 0) {
133 lastSeenHistory = id.getHistoryId();
136 localHistories.put(id, new LocalFrontendHistory(persistenceId, tree.ticker(), tree.ensureTransactionChain(id)));
137 LOG.debug("{}: created history {}", persistenceId, id);
138 return new LocalHistorySuccess(id, request.getSequence());
141 private LocalHistorySuccess handleDestroyHistory(final DestroyLocalHistoryRequest request, final long now)
142 throws RequestException {
143 final LocalHistoryIdentifier id = request.getTarget();
144 final LocalFrontendHistory existing = localHistories.get(id);
145 if (existing == null) {
146 // History does not exist: report success
147 LOG.debug("{}: history {} does not exist, nothing to destroy", persistenceId, id);
148 return new LocalHistorySuccess(id, request.getSequence());
151 return existing.destroy(request.getSequence(), now);
154 private LocalHistorySuccess handlePurgeHistory(final PurgeLocalHistoryRequest request, final long now)
155 throws RequestException {
156 final LocalHistoryIdentifier id = request.getTarget();
157 final LocalFrontendHistory existing = localHistories.remove(id);
158 if (existing != null) {
159 purgedHistories.add(Range.singleton(UnsignedLong.fromLongBits(id.getHistoryId())));
161 if (!existing.isDestroyed()) {
162 LOG.warn("{}: purging undestroyed history {}", persistenceId, id);
163 existing.destroy(request.getSequence(), now);
166 // FIXME: record a PURGE tombstone in the journal
168 LOG.debug("{}: purged history {}", persistenceId, id);
170 LOG.debug("{}: history {} has already been purged", persistenceId, id);
173 return new LocalHistorySuccess(id, request.getSequence());
176 @Nullable TransactionSuccess<?> handleTransactionRequest(final TransactionRequest<?> request,
177 final RequestEnvelope envelope, final long now) throws RequestException {
178 checkRequestSequence(envelope);
181 final LocalHistoryIdentifier lhId = request.getTarget().getHistoryId();
182 final AbstractFrontendHistory history;
184 if (lhId.getHistoryId() != 0) {
185 history = localHistories.get(lhId);
186 if (history == null) {
187 LOG.debug("{}: rejecting unknown history request {}", persistenceId, request);
188 throw new UnknownHistoryException(lastSeenHistory);
191 history = standaloneHistory;
194 return history.handleTransactionRequest(request, envelope, now);
201 expectedTxSequence = 0;
205 // FIXME: flush all state
209 public String toString() {
210 return MoreObjects.toStringHelper(LeaderFrontendState.class).add("clientId", clientId)
211 .add("purgedHistories", purgedHistories).toString();