1
2 /**
3 * Copyright (C) 2018-present MongoDB, Inc.
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the Server Side Public License, version 1,
7 * as published by MongoDB, Inc.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * Server Side Public License for more details.
13 *
14 * You should have received a copy of the Server Side Public License
15 * along with this program. If not, see
16 * <http://www.mongodb.com/licensing/server-side-public-license>.
17 *
18 * As a special exception, the copyright holders give permission to link the
19 * code of portions of this program with the OpenSSL library under certain
20 * conditions as described in each individual source file and distribute
21 * linked combinations including the program with the OpenSSL library. You
22 * must comply with the Server Side Public License in all respects for
23 * all of the code used other than as permitted herein. If you modify file(s)
24 * with this exception, you may extend this exception to your version of the
25 * file(s), but you are not obligated to do so. If you do not wish to do so,
26 * delete this exception statement from your version. If you delete this
27 * exception statement from all source files in the program, then also delete
28 * it in the license file.
29 */
30
31 #include "mongo/platform/basic.h"
32
33 #include "mongo/db/keys_collection_cache_reader.h"
34
35 #include "mongo/db/keys_collection_client.h"
36 #include "mongo/db/keys_collection_document.h"
37 #include "mongo/util/mongoutils/str.h"
38
39 namespace mongo {
40
KeysCollectionCacheReader(std::string purpose,KeysCollectionClient * client)41 KeysCollectionCacheReader::KeysCollectionCacheReader(std::string purpose,
42 KeysCollectionClient* client)
43 : _purpose(std::move(purpose)), _client(client) {}
44
refresh(OperationContext * opCtx)45 StatusWith<KeysCollectionDocument> KeysCollectionCacheReader::refresh(OperationContext* opCtx) {
46 LogicalTime newerThanThis;
47
48 decltype(_cache)::size_type originalSize = 0;
49
50 {
51 stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
52 auto iter = _cache.crbegin();
53 if (iter != _cache.crend()) {
54 newerThanThis = iter->second.getExpiresAt();
55 }
56
57 originalSize = _cache.size();
58 }
59
60 auto refreshStatus = _client->getNewKeys(opCtx, _purpose, newerThanThis);
61
62 if (!refreshStatus.isOK()) {
63 return refreshStatus.getStatus();
64 }
65
66 auto& newKeys = refreshStatus.getValue();
67
68 stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
69 if (originalSize > _cache.size()) {
70 // _cache cleared while we getting the new keys, just return the newest key without
71 // touching the _cache so the next refresh will populate it properly.
72 // Note: newKeys are sorted.
73 if (!newKeys.empty()) {
74 return std::move(newKeys.back());
75 }
76 }
77
78 for (auto&& key : newKeys) {
79 _cache.emplace(std::make_pair(key.getExpiresAt(), std::move(key)));
80 }
81
82 if (_cache.empty()) {
83 return {ErrorCodes::KeyNotFound, "No keys found after refresh"};
84 }
85
86 return _cache.crbegin()->second;
87 }
88
getKeyById(long long keyId,const LogicalTime & forThisTime)89 StatusWith<KeysCollectionDocument> KeysCollectionCacheReader::getKeyById(
90 long long keyId, const LogicalTime& forThisTime) {
91 stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
92
93 for (auto iter = _cache.lower_bound(forThisTime); iter != _cache.cend(); ++iter) {
94 if (iter->second.getKeyId() == keyId) {
95 return iter->second;
96 }
97 }
98
99 return {ErrorCodes::KeyNotFound,
100 str::stream() << "Cache Reader No keys found for " << _purpose
101 << " that is valid for time: "
102 << forThisTime.toString()
103 << " with id: "
104 << keyId};
105 }
106
getKey(const LogicalTime & forThisTime)107 StatusWith<KeysCollectionDocument> KeysCollectionCacheReader::getKey(
108 const LogicalTime& forThisTime) {
109 stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
110
111 auto iter = _cache.upper_bound(forThisTime);
112
113 if (iter == _cache.cend()) {
114 return {ErrorCodes::KeyNotFound,
115 str::stream() << "No key found that is valid for " << forThisTime.toString()};
116 }
117
118 return iter->second;
119 }
120
resetCache()121 void KeysCollectionCacheReader::resetCache() {
122 // keys that read with non majority readConcern level can be rolled back.
123 if (!_client->supportsMajorityReads()) {
124 stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
125 _cache.clear();
126 }
127 }
128
129 } // namespace mongo
130