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 #pragma once 32 33 #include "mongo/base/disallow_copying.h" 34 #include "mongo/db/concurrency/deferred_writer.h" 35 #include "mongo/db/service_context.h" 36 37 namespace mongo { 38 39 class HealthLogEntry; 40 41 /** 42 * The interface to the local healthlog. 43 * 44 * This class contains facilities for creating and asynchronously writing to the local healthlog 45 * collection. There should only be one instance of this class, initialized on startup and cleaned 46 * up on shutdown. 47 */ 48 class HealthLog { 49 MONGO_DISALLOW_COPYING(HealthLog); 50 51 public: 52 /** 53 * Required to use HealthLog as a ServiceContext decorator. 54 * 55 * Should not be used anywhere else. 56 */ 57 HealthLog(); 58 59 /** 60 * The maximum size of the in-memory buffer of health-log entries, in bytes. 61 */ 62 static const int64_t kMaxBufferSize = 25'000'000; 63 64 /** 65 * Start the worker thread writing the buffer to the collection. 66 */ 67 void startup(void); 68 69 /** 70 * Stop the worker thread. 71 */ 72 void shutdown(void); 73 74 /** 75 * The name of the collection. 76 */ 77 static const NamespaceString nss; 78 79 /** 80 * Get the current context's HealthLog. 81 */ 82 static HealthLog& get(ServiceContext* ctx); 83 static HealthLog& get(OperationContext* ctx); 84 85 /** 86 * Asynchronously insert the given entry. 87 * 88 * Return `false` iff there is no more space in the buffer. 89 */ 90 bool log(const HealthLogEntry& entry); 91 92 private: 93 DeferredWriter _writer; 94 }; 95 } 96