1 /*
2 * Copyright (C) 2016, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.internal.ketch;
45
46 import static org.eclipse.jgit.internal.ketch.KetchReplica.State.OFFLINE;
47
48 import java.util.ArrayList;
49 import java.util.Collection;
50 import java.util.Collections;
51 import java.util.List;
52
53 import org.eclipse.jgit.annotations.Nullable;
54 import org.eclipse.jgit.lib.ObjectId;
55
56 /** A snapshot of a leader and its view of the world. */
57 public class LeaderSnapshot {
58 final List<ReplicaSnapshot> replicas = new ArrayList<>();
59 KetchLeader.State state;
60 long term;
61 LogIndex headIndex;
62 LogIndex committedIndex;
63 boolean idle;
64
65 LeaderSnapshot() {
66 }
67
68 /** @return unmodifiable view of configured replicas. */
69 public Collection<ReplicaSnapshot> getReplicas() {
70 return Collections.unmodifiableList(replicas);
71 }
72
73 /** @return current state of the leader. */
74 public KetchLeader.State getState() {
75 return state;
76 }
77
78 /**
79 * @return {@code true} if the leader is not running a round to reach
80 * consensus, and has no rounds queued.
81 */
82 public boolean isIdle() {
83 return idle;
84 }
85
86 /**
87 * @return term of this leader. Valid only if {@link #getState()} is
88 * currently {@link KetchLeader.State#LEADER}.
89 */
90 public long getTerm() {
91 return term;
92 }
93
94 /**
95 * @return end of the leader's log; null if leader hasn't started up enough
96 * to begin its own election.
97 */
98 @Nullable
99 public LogIndex getHead() {
100 return headIndex;
101 }
102
103 /**
104 * @return state the leader knows is committed on a majority of participant
105 * replicas. Null until the leader instance has committed a log
106 * index within its own term.
107 */
108 @Nullable
109 public LogIndex getCommitted() {
110 return committedIndex;
111 }
112
113 @Override
114 public String toString() {
115 StringBuilder s = new StringBuilder();
116 s.append(isIdle() ? "IDLE" : "RUNNING"); //$NON-NLS-1$ //$NON-NLS-2$
117 s.append(" state ").append(getState()); //$NON-NLS-1$
118 if (getTerm() > 0) {
119 s.append(" term ").append(getTerm()); //$NON-NLS-1$
120 }
121 s.append('\n');
122 s.append(String.format(
123 "%-10s %12s %12s\n", //$NON-NLS-1$
124 "Replica", "Accepted", "Committed")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
125 s.append("------------------------------------\n"); //$NON-NLS-1$
126 debug(s, "(leader)", getHead(), getCommitted()); //$NON-NLS-1$
127 s.append('\n');
128 for (ReplicaSnapshot r : getReplicas()) {
129 debug(s, r);
130 s.append('\n');
131 }
132 s.append('\n');
133 return s.toString();
134 }
135
136 private static void debug(StringBuilder b, ReplicaSnapshot s) {
137 KetchReplica replica = s.getReplica();
138 debug(b, replica.getName(), s.getAccepted(), s.getCommitted());
139 b.append(String.format(" %-8s %s", //$NON-NLS-1$
140 replica.getParticipation(), s.getState()));
141 if (s.getState() == OFFLINE) {
142 String err = s.getErrorMessage();
143 if (err != null) {
144 b.append(" (").append(err).append(')'); //$NON-NLS-1$
145 }
146 }
147 }
148
149 private static void debug(StringBuilder s, String name,
150 ObjectId accepted, ObjectId committed) {
151 s.append(String.format(
152 "%-10s %-12s %-12s", //$NON-NLS-1$
153 name, str(accepted), str(committed)));
154 }
155
156 static String str(ObjectId c) {
157 if (c instanceof LogIndex) {
158 return ((LogIndex) c).describeForLog();
159 } else if (c != null) {
160 return c.abbreviate(8).name();
161 }
162 return "-"; //$NON-NLS-1$
163 }
164 }