Improve logging around transaction lifecycle
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / LeaderFrontendState.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 package org.opendaylight.controller.cluster.datastore;
9
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;
17 import java.util.Map;
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;
38
39 /**
40  * Frontend state as observed by the shard leader. This class is responsible for tracking generations and sequencing
41  * in the frontend/backend conversation.
42  *
43  * @author Robert Varga
44  */
45 @NotThreadSafe
46 final class LeaderFrontendState implements Identifiable<ClientIdentifier> {
47     private static final Logger LOG = LoggerFactory.getLogger(LeaderFrontendState.class);
48
49     // Histories which have not been purged
50     private final Map<LocalHistoryIdentifier, LocalFrontendHistory> localHistories;
51
52     // RangeSet performs automatic merging, hence we keep minimal state tracking information
53     private final RangeSet<UnsignedLong> purgedHistories;
54
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;
60
61     private long expectedTxSequence;
62     private Long lastSeenHistory = null;
63
64     // TODO: explicit failover notification
65     //       Record the ActorRef for the originating actor and when we switch to being a leader send a notification
66     //       to the frontend client -- that way it can immediately start sending requests
67
68     // TODO: add statistics:
69     // - number of requests processed
70     // - number of histories processed
71     // - per-RequestException throw counters
72
73     LeaderFrontendState(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree) {
74         this(persistenceId, clientId, tree, TreeRangeSet.create(), StandaloneFrontendHistory.create(persistenceId,
75             clientId, tree), new HashMap<>());
76     }
77
78     LeaderFrontendState(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree,
79         final RangeSet<UnsignedLong> purgedHistories, final AbstractFrontendHistory standaloneHistory,
80         final Map<LocalHistoryIdentifier, LocalFrontendHistory> localHistories) {
81         this.persistenceId = Preconditions.checkNotNull(persistenceId);
82         this.clientId = Preconditions.checkNotNull(clientId);
83         this.tree = Preconditions.checkNotNull(tree);
84         this.purgedHistories = Preconditions.checkNotNull(purgedHistories);
85         this.standaloneHistory = Preconditions.checkNotNull(standaloneHistory);
86         this.localHistories = Preconditions.checkNotNull(localHistories);
87     }
88
89     @Override
90     public ClientIdentifier getIdentifier() {
91         return clientId;
92     }
93
94     private void checkRequestSequence(final RequestEnvelope envelope) throws OutOfOrderRequestException {
95         if (expectedTxSequence != envelope.getTxSequence()) {
96             throw new OutOfOrderRequestException(expectedTxSequence);
97         }
98     }
99
100     private void expectNextRequest() {
101         expectedTxSequence++;
102     }
103
104     @Nullable LocalHistorySuccess handleLocalHistoryRequest(final LocalHistoryRequest<?> request,
105             final RequestEnvelope envelope, final long now) throws RequestException {
106         checkRequestSequence(envelope);
107
108         try {
109             if (request instanceof CreateLocalHistoryRequest) {
110                 return handleCreateHistory((CreateLocalHistoryRequest) request);
111             } else if (request instanceof DestroyLocalHistoryRequest) {
112                 return handleDestroyHistory((DestroyLocalHistoryRequest) request, envelope, now);
113             } else if (request instanceof PurgeLocalHistoryRequest) {
114                 return handlePurgeHistory((PurgeLocalHistoryRequest)request, envelope, now);
115             } else {
116                 LOG.warn("{}: rejecting unsupported request {}", persistenceId, request);
117                 throw new UnsupportedRequestException(request);
118             }
119         } finally {
120             expectNextRequest();
121         }
122     }
123
124     private LocalHistorySuccess handleCreateHistory(final CreateLocalHistoryRequest request) throws RequestException {
125         final LocalHistoryIdentifier id = request.getTarget();
126         final AbstractFrontendHistory existing = localHistories.get(id);
127         if (existing != null) {
128             // History already exists: report success
129             LOG.debug("{}: history {} already exists", persistenceId, id);
130             return new LocalHistorySuccess(id, request.getSequence());
131         }
132
133         // We have not found the history. Before we create it we need to check history ID sequencing so that we do not
134         // end up resurrecting a purged history.
135         if (purgedHistories.contains(UnsignedLong.fromLongBits(id.getHistoryId()))) {
136             LOG.debug("{}: rejecting purged request {}", persistenceId, request);
137             throw new DeadHistoryException(lastSeenHistory.longValue());
138         }
139
140         // Update last history we have seen
141         if (lastSeenHistory == null || Long.compareUnsigned(lastSeenHistory, id.getHistoryId()) < 0) {
142             lastSeenHistory = id.getHistoryId();
143         }
144
145         localHistories.put(id, LocalFrontendHistory.create(persistenceId, tree, id));
146         LOG.debug("{}: created history {}", persistenceId, id);
147         return new LocalHistorySuccess(id, request.getSequence());
148     }
149
150     private LocalHistorySuccess handleDestroyHistory(final DestroyLocalHistoryRequest request,
151             final RequestEnvelope envelope, final long now)
152             throws RequestException {
153         final LocalHistoryIdentifier id = request.getTarget();
154         final LocalFrontendHistory existing = localHistories.get(id);
155         if (existing == null) {
156             // History does not exist: report success
157             LOG.debug("{}: history {} does not exist, nothing to destroy", persistenceId, id);
158             return new LocalHistorySuccess(id, request.getSequence());
159         }
160
161         existing.destroy(request.getSequence(), envelope, now);
162         return null;
163     }
164
165     private LocalHistorySuccess handlePurgeHistory(final PurgeLocalHistoryRequest request,
166             final RequestEnvelope envelope, final long now) throws RequestException {
167         final LocalHistoryIdentifier id = request.getTarget();
168         final LocalFrontendHistory existing = localHistories.remove(id);
169         if (existing == null) {
170             LOG.debug("{}: history {} has already been purged", persistenceId, id);
171             return new LocalHistorySuccess(id, request.getSequence());
172         }
173
174         LOG.debug("{}: purging history {}", persistenceId, id);
175         purgedHistories.add(Range.singleton(UnsignedLong.fromLongBits(id.getHistoryId())));
176         existing.purge(request.getSequence(), envelope, now);
177         return null;
178     }
179
180     @Nullable TransactionSuccess<?> handleTransactionRequest(final TransactionRequest<?> request,
181             final RequestEnvelope envelope, final long now) throws RequestException {
182         checkRequestSequence(envelope);
183
184         try {
185             final LocalHistoryIdentifier lhId = request.getTarget().getHistoryId();
186             final AbstractFrontendHistory history;
187
188             if (lhId.getHistoryId() != 0) {
189                 history = localHistories.get(lhId);
190                 if (history == null) {
191                     LOG.debug("{}: rejecting unknown history request {}", persistenceId, request);
192                     throw new UnknownHistoryException(lastSeenHistory);
193                 }
194             } else {
195                 history = standaloneHistory;
196             }
197
198             return history.handleTransactionRequest(request, envelope, now);
199         } finally {
200             expectNextRequest();
201         }
202     }
203
204     void reconnect() {
205         expectedTxSequence = 0;
206     }
207
208     void retire() {
209         // FIXME: flush all state
210     }
211
212     @Override
213     public String toString() {
214         return MoreObjects.toStringHelper(LeaderFrontendState.class).add("clientId", clientId)
215                 .add("purgedHistories", purgedHistories).toString();
216     }
217 }

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