# spdlog **Repository Path**: shubulan/spdlog ## Basic Information - **Project Name**: spdlog - **Description**: spdlog spdlog spdlog - **Primary Language**: C++ - **License**: MIT - **Default Branch**: v1.x - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 4 - **Created**: 2022-05-29 - **Last Updated**: 2024-06-02 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # spdlog 非常高效，仅需要头文件，也可以编译运行。C++日志库。[![Build Status](https://app.travis-ci.com/gabime/spdlog.svg?branch=v1.x)](https://app.travis-ci.com/gabime/spdlog)  [![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true&branch=v1.x)](https://ci.appveyor.com/project/gabime/spdlog) [![Release](https://img.shields.io/github/release/gabime/spdlog.svg)](https://github.com/gabime/spdlog/releases/latest) ## 安装 #### 仅使用头文件 把头文件目录 [folder](https://github.com/gabime/spdlog/tree/v1.x/include/spdlog) 拷贝到你的项目构建目录，然后使用C++11编译器. #### 静态库版本 (推荐 - 编译更快) ```console $ git clone https://github.com/gabime/spdlog.git $ cd spdlog && mkdir build && cd build $ cmake .. && make -j ``` 看一个使用样例 [CMakeLists.txt](https://github.com/gabime/spdlog/blob/v1.x/example/CMakeLists.txt) 来学习如何使用 ## 平台 * Linux, FreeBSD, OpenBSD, Solaris, AIX * Windows (msvc 2013+, cygwin) * macOS (clang 3.5+) * Android ## 包管理工具: * Debian: `sudo apt install libspdlog-dev` * Homebrew: `brew install spdlog` * MacPorts: `sudo port install spdlog` * FreeBSD: `pkg install spdlog` * Fedora: `dnf install spdlog` * Gentoo: `emerge dev-libs/spdlog` * Arch Linux: `pacman -S spdlog` * vcpkg: `vcpkg install spdlog` * conan: `spdlog/[>=1.4.1]` * conda: `conda install -c conda-forge spdlog` * build2: ```depends: spdlog ^1.8.2``` ## 特点 * 非常高效 (see [benchmarks](#benchmarks) below). * 仅需要头文件或者也支持编译 * 支持富文本格式，使用了非常优秀的格式化库[fmt](https://github.com/fmtlib/fmt). * 异步输出 (可选) * 定制格式[Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting). * 支持单线程和多线程. * 多种输出目标: * 循环日志文件. * 每日日志文件. * 控制台输出 (支持颜色). * 系统日志. * 窗口时间日志. * 窗口调试 (```OutputDebugString(..)```). * 容易拓展到定制的日志文件 [extendable](https://github.com/gabime/spdlog/wiki/4.-Sinks#implementing-your-own-sink) * 日志过滤 - 日志级别可以在运行时和编译时修改 * 支持从运行时参数或者环境变量中载入日志级别 * [Backtrace](#backtrace-support) 函数调用栈支持 - 存储debug消息在环形缓冲区，根据需要再输出 ## 使用案例 #### 基本使用 ```c++ #include "spdlog/spdlog.h" int main() { // 直接输出字符串 spdlog::info("Welcome to spdlog!"); // 支持多种格式化模板 // 参数化 spdlog::error("Some error message with arg: {}", 1); // 高级参数 spdlog::warn("Easy padding in numbers like {:08d}", 12); // 特殊参数: 多种格式 spdlog::critical("Support for int: {0:d}; hex: {0:x}; oct: {0:o}; bin: {0:b}", 42); // 浮点数 spdlog::info("Support for floats {:03.2f}", 1.23456); // 定制顺序 spdlog::info("Positional args are {1} {0}..", "too", "supported"); // 排版格式 spdlog::info("{:<30}", "left aligned"); //运行时log等级 spdlog::set_level(spdlog::level::debug); // Set global log level to debug spdlog::debug("This message should be displayed.."); // 改变日志格式change log pattern spdlog::set_pattern("[%H:%M:%S %z] [%n] [%^---%L---%$] [thread %t] %v"); // Compile time log levels // 编译时设置日志级别 // define SPDLOG_ACTIVE_LEVEL to desired level SPDLOG_TRACE("Some trace message with param {}", 42); SPDLOG_DEBUG("Some debug message"); } ``` --- #### 创建标准输出/错误输出对象Create stdout/stderr logger object ```c++ #include "spdlog/spdlog.h" #include "spdlog/sinks/stdout_color_sinks.h" void stdout_example() { // create color multi threaded logger // 创建对象 auto console = spdlog::stdout_color_mt("console"); auto err_logger = spdlog::stderr_color_mt("stderr"); // 获取全局注册对象 spdlog::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name)"); } ``` --- #### 基本文件日志 Basic file logger ```c++ #include "spdlog/sinks/basic_file_sink.h" void basic_logfile_example() { // 打开文件可能会遇到异常，研究里面处理 try { auto logger = spdlog::basic_logger_mt("basic_logger", "logs/basic-log.txt"); } catch (const spdlog::spdlog_ex &ex) { std::cout << "Log init failed: " << ex.what() << std::endl; } } ``` --- #### 循环文件日志Rotating files ```c++ #include "spdlog/sinks/rotating_file_sink.h" void rotating_example() { // Create a file rotating logger with 5mb size max and 3 rotated files // 三个循环文件 每个文件 1048576 * 5 auto max_size = 1048576 * 5; auto max_files = 3; auto logger = spdlog::rotating_logger_mt("some_logger_name", "logs/rotating.txt", max_size, max_files); } ``` --- #### 每日日志Daily files ```c++ #include "spdlog/sinks/daily_file_sink.h" void daily_example() { // Create a daily logger - a new file is created every day on 2:30am // 每天2.30创建一个日志文件 auto logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30); } ``` --- #### 函数调用栈信息Backtrace support ```c++ // Debug messages can be stored in a ring buffer instead of being logged immediately. // debug消息被存在循环缓冲中，不会立即输出 // This is useful in order to display debug logs only when really needed (e.g. when error happens). // 当真正需要时才显示日志 // When needed, call dump_backtrace() to see them. spdlog::enable_backtrace(32); // Store the latest 32 messages in a buffer. Older messages will be dropped. // or my_logger->enable_backtrace(32).. for(int i = 0; i < 100; i++) { spdlog::debug("Backtrace message {}", i); // not logged yet.. } // e.g. if some error happened: spdlog::dump_backtrace(); // log them now! show the last 32 messages // or my_logger->dump_backtrace(32).. ``` --- #### 周期性刷新 Periodic flush ```c++ // 每3s刷新所有注册的logger // 只有在logger线程安全时才能使用, 以mt结尾的loggers是线程安全的 spdlog::flush_every(std::chrono::seconds(3)); ``` --- #### Stopwatch ```c++ // Stopwatch support for spdlog // 随时打印时间戳，方便统计代码效率 #include "spdlog/stopwatch.h" void stopwatch_example() { spdlog::stopwatch sw; spdlog::debug("Elapsed {}", sw); spdlog::debug("Elapsed {:.3}", sw); } ``` --- #### 以16进制输出二进制数据Log binary data in hex ```c++ // many types of std::container types can be used. // 可以使用很多类型的std char容器 // ranges are supported too. // 范围也支持 // format flags: // {:X} - print in uppercase. // {:s} - don't separate each byte with space. // {:p} - don't print the position on each line start. // {:n} - don't split the output to lines. // {:a} - show ASCII if :n is not set. #include "spdlog/fmt/bin_to_hex.h" void binary_example() { auto console = spdlog::get("console"); std::array buf; console->info("Binary example: {}", spdlog::to_hex(buf)); console->info("Another binary example:{:n}", spdlog::to_hex(std::begin(buf), std::begin(buf) + 10)); // more examples: // logger->info("uppercase: {:X}", spdlog::to_hex(buf)); // logger->info("uppercase, no delimiters: {:Xs}", spdlog::to_hex(buf)); // logger->info("uppercase, no delimiters, no position info: {:Xsp}", spdlog::to_hex(buf)); } ``` --- #### 多目标（sinks）日志Logger with multi sinks - each with different format and log level ```c++ // create logger with 2 targets with different log levels and formats. // 创建一个logger 有两个输出目标，并且有不同的日志输出等级 // the console will show only warnings or errors, while the file will log all. // 控制台只会输出warnings和errors，文件会输出全部 void multi_sink_example() { auto console_sink = std::make_shared(); console_sink->set_level(spdlog::level::warn); console_sink->set_pattern("[multi_sink_example] [%^%l%$] %v"); auto file_sink = std::make_shared("logs/multisink.txt", true); file_sink->set_level(spdlog::level::trace); spdlog::logger logger("multi_sink", {console_sink, file_sink}); logger.set_level(spdlog::level::debug); logger.warn("this should appear in both console and file"); logger.info("this message should not appear in the console, only in the file"); } ``` --- #### 异步日志Asynchronous logging ```c++ #include "spdlog/async.h" #include "spdlog/sinks/basic_file_sink.h" void async_example() { // default thread pool settings can be modified *before* creating the async logger: // spdlog::init_thread_pool(8192, 1); // queue with 8k items and 1 backing thread. auto async_file = spdlog::basic_logger_mt("async_file_logger", "logs/async_log.txt"); // alternatively: // auto async_file = spdlog::create_async("async_file_logger", "logs/async_log.txt"); } ``` --- #### Asynchronous logger with multi sinks ```c++ #include "spdlog/sinks/stdout_color_sinks.h" #include "spdlog/sinks/rotating_file_sink.h" void multi_sink_example2() { spdlog::init_thread_pool(8192, 1); auto stdout_sink = std::make_shared(); auto rotating_sink = std::make_shared("mylog.txt", 1024*1024*10, 3); std::vector sinks {stdout_sink, rotating_sink}; auto logger = std::make_shared("loggername", sinks.begin(), sinks.end(), spdlog::thread_pool(), spdlog::async_overflow_policy::block); spdlog::register_logger(logger); } ``` --- #### 用户定义的类型User defined types ```c++ // user defined types logging by implementing operator<< #include "spdlog/fmt/ostr.h" // must be included struct my_type { int i; // 模板，既支持标准库，又支持自定义"<<"符号重载的流 template friend OStream &operator<<(OStream &os, const my_type &c) { return os << "[my_type i=" << c.i << "]"; } }; void user_defined_example() { spdlog::get("console")->info("user defined type: {}", my_type{14}); } ``` --- #### 用户定义的flag.User defined flags in the log pattern ```c++ // Log patterns can contain custom flags. // the following example will add new flag '%*' - which will be bound to a instance. #include "spdlog/pattern_formatter.h" class my_formatter_flag : public spdlog::custom_flag_formatter { public: void format(const spdlog::details::log_msg &, const std::tm &, spdlog::memory_buf_t &dest) override { std::string some_txt = "custom-flag"; dest.append(some_txt.data(), some_txt.data() + some_txt.size()); } std::unique_ptr clone() const override { return spdlog::details::make_unique(); } }; void custom_flags_example() { auto formatter = std::make_unique(); formatter->add_flag('*').set_pattern("[%n] [%*] [%^%l%$] %v"); spdlog::set_formatter(std::move(formatter)); } ``` --- #### 定制的错误处理器Custom error handler ```c++ void err_handler_example() { // can be set globally or per logger(logger->set_error_handler(..)) spdlog::set_error_handler([](const std::string &msg) { spdlog::get("console")->error("*** LOGGER ERROR ***: {}", msg); }); spdlog::get("console")->info("some invalid message to trigger an error {}{}{}{}", 3); } ``` --- #### 系统日志syslog ```c++ #include "spdlog/sinks/syslog_sink.h" void syslog_example() { std::string ident = "spdlog-example"; auto syslog_logger = spdlog::syslog_logger_mt("syslog", ident, LOG_PID); syslog_logger->warn("This is warning that will end up in syslog."); } ``` --- #### android示例, Android example ```c++ #include "spdlog/sinks/android_sink.h" void android_example() { std::string tag = "spdlog-android"; auto android_logger = spdlog::android_logger_mt("android", tag); android_logger->critical("Use \"adb shell logcat\" to view this message."); } ``` --- #### 从环境变量中载入日志级别Load log levels from env variable or from argv ```c++ #include "spdlog/cfg/env.h" int main (int argc, char *argv[]) { spdlog::cfg::load_env_levels(); // or from command line: // ./example SPDLOG_LEVEL=info,mylogger=trace // #include "spdlog/cfg/argv.h" // for loading levels from argv // spdlog::cfg::load_argv_levels(argc, argv); } ``` So then you can: ```console $ export SPDLOG_LEVEL=info,mylogger=trace $ ./example ``` --- #### 日志文件打开与关闭时间处理Log file open/close event handlers ```c++ // You can get callbacks from spdlog before/after log file has been opened or closed. // This is useful for cleanup procedures or for adding someting the start/end of the log files. void file_events_example() { // pass the spdlog::file_event_handlers to file sinks for open/close log file notifications spdlog::file_event_handlers handlers; handlers.before_open = [](spdlog::filename_t filename) { spdlog::info("Before opening {}", filename); }; handlers.after_open = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("After opening\n", fstream); }; handlers.before_close = [](spdlog::filename_t filename, std::FILE *fstream) { fputs("Before closing\n", fstream); }; handlers.after_close = [](spdlog::filename_t filename) { spdlog::info("After closing {}", filename); }; auto my_logger = spdlog::basic_logger_st("some_logger", "logs/events-sample.txt", true, handlers); } ``` --- #### 替换默认的logger.Replace the Default Logger ```c++ void replace_default_logger_example() { auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/new-default-log.txt", true); spdlog::set_default_logger(new_logger); spdlog::info("new logger log message"); } ``` --- ## 测试数据Benchmarks Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz #### Synchronous mode ``` [info] ************************************************************** [info] Single thread, 1,000,000 iterations [info] ************************************************************** [info] basic_st Elapsed: 0.17 secs 5,777,626/sec [info] rotating_st Elapsed: 0.18 secs 5,475,894/sec [info] daily_st Elapsed: 0.20 secs 5,062,659/sec [info] empty_logger Elapsed: 0.07 secs 14,127,300/sec [info] ************************************************************** [info] C-string (400 bytes). Single thread, 1,000,000 iterations [info] ************************************************************** [info] basic_st Elapsed: 0.41 secs 2,412,483/sec [info] rotating_st Elapsed: 0.72 secs 1,389,196/sec [info] daily_st Elapsed: 0.42 secs 2,393,298/sec [info] null_st Elapsed: 0.04 secs 27,446,957/sec [info] ************************************************************** [info] 10 threads, competing over the same logger object, 1,000,000 iterations [info] ************************************************************** [info] basic_mt Elapsed: 0.60 secs 1,659,613/sec [info] rotating_mt Elapsed: 0.62 secs 1,612,493/sec [info] daily_mt Elapsed: 0.61 secs 1,638,305/sec [info] null_mt Elapsed: 0.16 secs 6,272,758/sec ``` #### Asynchronous mode ``` [info] ------------------------------------------------- [info] Messages : 1,000,000 [info] Threads : 10 [info] Queue : 8,192 slots [info] Queue memory : 8,192 x 272 = 2,176 KB [info] ------------------------------------------------- [info] [info] ********************************* [info] Queue Overflow Policy: block [info] ********************************* [info] Elapsed: 1.70784 secs 585,535/sec [info] Elapsed: 1.69805 secs 588,910/sec [info] Elapsed: 1.7026 secs 587,337/sec [info] [info] ********************************* [info] Queue Overflow Policy: overrun [info] ********************************* [info] Elapsed: 0.372816 secs 2,682,285/sec [info] Elapsed: 0.379758 secs 2,633,255/sec [info] Elapsed: 0.373532 secs 2,677,147/sec ``` ## Documentation Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages. --- Thanks to [JetBrains](https://www.jetbrains.com/?from=spdlog) for donating product licenses to help develop **spdlog**