summaryrefslogtreecommitdiff
path: root/src/mongo/db/repl/oplogreader.h
blob: 10abc5800871915f3ba8d9ae485a1c2475e43c4a (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
/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    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 Server Side 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.
 */


#pragma once

#include "mongo/client/dbclient_connection.h"
#include "mongo/client/dbclient_cursor.h"
#include "mongo/util/net/hostandport.h"

namespace mongo {
namespace repl {

/**
 * Authenticates conn using the server's cluster-membership credentials.
 *
 * Returns true on successful authentication.
 */
bool replAuthenticate(DBClientBase* conn);

/* started abstracting out the querying of the primary/master's oplog
   still fairly awkward but a start.
*/

class OplogReader {
private:
    std::shared_ptr<DBClientConnection> _conn;
    std::shared_ptr<DBClientCursor> cursor;
    int _tailingQueryOptions;

    // If _conn was actively connected, _host represents the current HostAndPort of the
    // connection.
    HostAndPort _host;

public:
    OplogReader();
    ~OplogReader() {}
    void resetCursor() {
        cursor.reset();
    }
    void resetConnection() {
        cursor.reset();
        _conn.reset();
        _host = HostAndPort();
    }
    DBClientConnection* conn() {
        return _conn.get();
    }
    BSONObj findOne(const char* ns, const Query& q) {
        return conn()->findOne(ns, q, 0, QueryOption_SlaveOk);
    }
    BSONObj findOneByUUID(const std::string& db, UUID uuid, const BSONObj& filter) {
        // Note that the findOneByUUID() function of DBClient passes SlaveOK to the client.
        BSONObj foundDoc;
        std::tie(foundDoc, std::ignore) = conn()->findOneByUUID(db, uuid, filter);
        return foundDoc;
    }

    /* SO_TIMEOUT (send/recv time out) for our DBClientConnections */
    static const Seconds kSocketTimeout;

    /* ok to call if already connected */
    bool connect(const HostAndPort& host);

    void tailCheck();

    bool haveCursor() {
        return cursor.get() != 0;
    }

    void tailingQuery(const char* ns, const BSONObj& query);

    bool more() {
        uassert(15910, "Doesn't have cursor for reading oplog", cursor.get());
        return cursor->more();
    }

    bool moreInCurrentBatch() {
        uassert(15911, "Doesn't have cursor for reading oplog", cursor.get());
        return cursor->moreInCurrentBatch();
    }

    BSONObj nextSafe() {
        return cursor->nextSafe();
    }
};

}  // namespace repl
}  // namespace mongo