summaryrefslogtreecommitdiff
path: root/src/mongo/db/repl/member_state.h
blob: 5486e2deebd48c124fa2f399df82e94749042f95 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
 *    Copyright (C) 2010 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

/** replica set member */

#pragma once

#include <ostream>
#include <string>
#include <type_traits>

#include "mongo/base/error_codes.h"
#include "mongo/base/static_assert.h"
#include "mongo/base/status_with.h"
#include "mongo/util/mongoutils/str.h"

namespace mongo {
namespace repl {


/*
    RS_STARTUP    serving still starting up, or still trying to initiate the set
    RS_PRIMARY    this server thinks it is primary
    RS_SECONDARY  this server thinks it is a secondary (slave mode)
    RS_RECOVERING recovering/resyncing; after recovery usually auto-transitions to secondary
    RS_STARTUP2   loaded config, still determining who is primary

    State -> integer mappings are reserved forever.  Do not change them or delete them, except
    to update RS_MAX when introducing new states.
*/
struct MemberState {
    enum MS {
        RS_STARTUP = 0,
        RS_PRIMARY = 1,
        RS_SECONDARY = 2,
        RS_RECOVERING = 3,
        RS_STARTUP2 = 5,
        RS_UNKNOWN = 6, /* remote node not yet reached */
        RS_ARBITER = 7,
        RS_DOWN = 8, /* node not reachable for a report */
        RS_ROLLBACK = 9,
        RS_REMOVED = 10, /* node removed from replica set */
        RS_MAX = 10
    } s;

    template <typename T>
    static StatusWith<MemberState> create(T t) {
        MONGO_STATIC_ASSERT_MSG(std::is_integral<T>::value, "T must be an integral type");
        using UnderlyingType = std::underlying_type<MS>::type;
        if (std::is_signed<T>::value && (t < 0))
            return {ErrorCodes::BadValue, str::stream() << "MemberState cannot be negative"};
        auto asUnderlying = static_cast<UnderlyingType>(t);
        if (asUnderlying > RS_MAX)
            return {ErrorCodes::BadValue, str::stream() << "Unrecognized numerical state"};
        return {static_cast<MemberState>(asUnderlying)};
    }

    MemberState(MS ms = RS_UNKNOWN) : s(ms) {}
    explicit MemberState(int ms) : s((MS)ms) {}

    bool startup() const {
        return s == RS_STARTUP;
    }
    bool primary() const {
        return s == RS_PRIMARY;
    }
    bool secondary() const {
        return s == RS_SECONDARY;
    }
    bool recovering() const {
        return s == RS_RECOVERING;
    }
    bool startup2() const {
        return s == RS_STARTUP2;
    }
    bool rollback() const {
        return s == RS_ROLLBACK;
    }
    bool readable() const {
        return s == RS_PRIMARY || s == RS_SECONDARY;
    }
    bool removed() const {
        return s == RS_REMOVED;
    }
    bool arbiter() const {
        return s == RS_ARBITER;
    }

    std::string toString() const;

    bool operator==(const MemberState& r) const {
        return s == r.s;
    }
    bool operator!=(const MemberState& r) const {
        return s != r.s;
    }
};

inline std::string MemberState::toString() const {
    switch (s) {
        case RS_STARTUP:
            return "STARTUP";
        case RS_PRIMARY:
            return "PRIMARY";
        case RS_SECONDARY:
            return "SECONDARY";
        case RS_RECOVERING:
            return "RECOVERING";
        case RS_STARTUP2:
            return "STARTUP2";
        case RS_ARBITER:
            return "ARBITER";
        case RS_DOWN:
            return "DOWN";
        case RS_ROLLBACK:
            return "ROLLBACK";
        case RS_UNKNOWN:
            return "UNKNOWN";
        case RS_REMOVED:
            return "REMOVED";
    }
    return "";
}

/**
 * Insertion operator for MemberState. Formats member state for output stream.
 * For testing only.
 */
inline std::ostream& operator<<(std::ostream& os, const MemberState& state) {
    return os << state.toString();
}

}  // namespace repl
}  // namespace mongo