log_buffer.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include "rocksdb/env.h"
#include "util/arena.h"
#include "util/autovector.h"
#include "port/sys_time.h"
#include <ctime>
namespace rocksdb {
class Logger;
// A class to buffer info log entries and flush them in the end.
class LogBuffer {
public:
// log_level: the log level for all the logs
// info_log: logger to write the logs to
LogBuffer(const InfoLogLevel log_level, Logger* info_log);
// Add a log entry to the buffer. Use default max_log_size.
// max_log_size indicates maximize log size, including some metadata.
void AddLogToBuffer(size_t max_log_size, const char* format, va_list ap);
size_t IsEmpty() const { return logs_.empty(); }
// Flush all buffered log to the info log.
void FlushBufferToLog();
private:
// One log entry with its timestamp
struct BufferedLog {
struct timeval now_tv; // Timestamp of the log
char message[1]; // Beginning of log message
};
const InfoLogLevel log_level_;
Logger* info_log_;
Arena arena_;
autovector<BufferedLog*> logs_;
};
// Add log to the LogBuffer for a delayed info logging. It can be used when
// we want to add some logs inside a mutex.
// max_log_size indicates maximize log size, including some metadata.
extern void LogToBuffer(LogBuffer* log_buffer, size_t max_log_size,
const char* format, ...);
// Same as previous function, but with default max log size.
extern void LogToBuffer(LogBuffer* log_buffer, const char* format, ...);
} // namespace rocksdb