// // Copyright(c) 2015 Gabi Melman. // Distributed under the MIT License (http://opensource.org/licenses/MIT) // spdlog usage example #include #include void load_levels_example(); void stdout_logger_example(); void basic_example(); void rotating_example(); void daily_example(); void callback_example(); void async_example(); void binary_example(); void vector_example(); void stopwatch_example(); void trace_example(); void multi_sink_example(); void user_defined_example(); void err_handler_example(); void syslog_example(); void udp_example(); void custom_flags_example(); void file_events_example(); void replace_default_logger_example(); #include "spdlog/spdlog.h" #include "spdlog/cfg/env.h" // support for loading levels from the environment variable #include "spdlog/fmt/ostr.h" // support for user defined types int main(int, char *[]) { // Log levels can be loaded from argv/env using "SPDLOG_LEVEL" load_levels_example(); spdlog::info("Welcome to spdlog version {}.{}.{} !", SPDLOG_VER_MAJOR, SPDLOG_VER_MINOR, SPDLOG_VER_PATCH); spdlog::warn("Easy padding in numbers like {:08d}", 12); spdlog::critical("Support for int: {0:d}; hex: {0:x}; oct: {0:o}; bin: {0:b}", 42); spdlog::info("Support for floats {:03.2f}", 1.23456); spdlog::info("Positional args are {1} {0}..", "too", "supported"); spdlog::info("{:>8} aligned, {:<8} aligned", "right", "left"); // Runtime log levels spdlog::set_level(spdlog::level::info); // Set global log level to info spdlog::debug("This message should not be displayed!"); spdlog::set_level(spdlog::level::trace); // Set specific logger's log level spdlog::debug("This message should be displayed.."); // Customize msg format for all loggers spdlog::set_pattern("[%H:%M:%S %z] [%^%L%$] [thread %t] %v"); spdlog::info("This an info message with custom format"); spdlog::set_pattern("%+"); // back to default format spdlog::set_level(spdlog::level::info); // Backtrace support // Loggers can store in a ring buffer all messages (including debug/trace) for later inspection. // When needed, call dump_backtrace() to see what happened: spdlog::enable_backtrace(10); // create ring buffer with capacity of 10 messages for (int i = 0; i < 100; i++) { spdlog::debug("Backtrace message {}", i); // not logged.. } // e.g. if some error happened: spdlog::dump_backtrace(); // log them now! try { stdout_logger_example(); basic_example(); rotating_example(); daily_example(); callback_example(); async_example(); binary_example(); vector_example(); multi_sink_example(); user_defined_example(); err_handler_example(); trace_example(); stopwatch_example(); udp_example(); custom_flags_example(); file_events_example(); replace_default_logger_example(); // Flush all *registered* loggers using a worker thread every 3 seconds. // note: registered loggers *must* be thread safe for this to work correctly! spdlog::flush_every(std::chrono::seconds(3)); // Apply some function on all registered loggers spdlog::apply_all([&](std::shared_ptr l) { l->info("End of example."); }); // Release all spdlog resources, and drop all loggers in the registry. // This is optional (only mandatory if using windows + async log). spdlog::shutdown(); } // Exceptions will only be thrown upon failed logger or sink construction (not during logging). catch (const spdlog::spdlog_ex &ex) { std::printf("Log initialization failed: %s\n", ex.what()); return 1; } } #include "spdlog/sinks/stdout_color_sinks.h" // or #include "spdlog/sinks/stdout_sinks.h" if no colors needed. void stdout_logger_example() { // Create color multi threaded logger. auto console = spdlog::stdout_color_mt("console"); // or for stderr: // auto console = spdlog::stderr_color_mt("error-logger"); } #include "spdlog/sinks/basic_file_sink.h" void basic_example() { // Create basic file logger (not rotated). auto my_logger = spdlog::basic_logger_mt("file_logger", "logs/basic-log.txt", true); } #include "spdlog/sinks/rotating_file_sink.h" void rotating_example() { // Create a file rotating logger with 5mb size max and 3 rotated files. auto rotating_logger = spdlog::rotating_logger_mt("some_logger_name", "logs/rotating.txt", 1048576 * 5, 3); } #include "spdlog/sinks/daily_file_sink.h" void daily_example() { // Create a daily logger - a new file is created every day on 2:30am. auto daily_logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30); } #include "spdlog/sinks/callback_sink.h" void callback_example() { // Create the logger auto logger = spdlog::callback_logger_mt("custom_callback_logger", [](const spdlog::details::log_msg &/*msg*/) { // do what you need to do with msg }); } #include "spdlog/cfg/env.h" void load_levels_example() { // Set the log level to "info" and mylogger to "trace": // SPDLOG_LEVEL=info,mylogger=trace && ./example 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(args, argv); } #include "spdlog/async.h" void async_example() { // Default thread pool settings can be modified *before* creating the async logger: // spdlog::init_thread_pool(32768, 1); // queue with max 32k items 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"); for (int i = 1; i < 101; ++i) { async_file->info("Async message #{}", i); } } // Log binary data as hex. // Many types of std::container types can be used. // Iterator ranges are supported too. // 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. #include "spdlog/fmt/bin_to_hex.h" void binary_example() { std::vector buf(80); for (int i = 0; i < 80; i++) { buf.push_back(static_cast(i & 0xff)); } spdlog::info("Binary example: {}", spdlog::to_hex(buf)); spdlog::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)); // logger->info("hexdump style: {:a}", spdlog::to_hex(buf)); // logger->info("hexdump style, 20 chars per line {:a}", spdlog::to_hex(buf, 20)); } // Log a vector of numbers #ifndef SPDLOG_USE_STD_FORMAT # include "spdlog/fmt/ranges.h" void vector_example() { std::vector vec = {1, 2, 3}; spdlog::info("Vector example: {}", vec); } #else void vector_example() {} #endif // ! DSPDLOG_USE_STD_FORMAT // Compile time log levels. // define SPDLOG_ACTIVE_LEVEL to required level (e.g. SPDLOG_LEVEL_TRACE) void trace_example() { // trace from default logger SPDLOG_TRACE("Some trace message.. {} ,{}", 1, 3.23); // debug from default logger SPDLOG_DEBUG("Some debug message.. {} ,{}", 1, 3.23); // trace from logger object auto logger = spdlog::get("file_logger"); SPDLOG_LOGGER_TRACE(logger, "another trace message"); } // stopwatch example #include "spdlog/stopwatch.h" #include void stopwatch_example() { spdlog::stopwatch sw; std::this_thread::sleep_for(std::chrono::milliseconds(123)); spdlog::info("Stopwatch: {} seconds", sw); } #include "spdlog/sinks/udp_sink.h" void udp_example() { spdlog::sinks::udp_sink_config cfg("127.0.0.1", 11091); auto my_logger = spdlog::udp_logger_mt("udplog", cfg); my_logger->set_level(spdlog::level::debug); my_logger->info("hello world"); } // A logger with multiple sinks (stdout and file) - each with a different format and log level. 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"); } // User defined types logging struct my_type { int i = 0; explicit my_type(int i) : i(i){}; }; #ifndef SPDLOG_USE_STD_FORMAT // when using fmtlib template<> struct fmt::formatter : fmt::formatter { auto format(my_type my, format_context &ctx) -> decltype(ctx.out()) { return format_to(ctx.out(), "[my_type i={}]", my.i); } }; #else // when using std::format template<> struct std::formatter : std::formatter { auto format(my_type my, format_context &ctx) -> decltype(ctx.out()) { return format_to(ctx.out(), "[my_type i={}]", my.i); } }; #endif void user_defined_example() { spdlog::info("user defined type: {}", my_type(14)); } // Custom error handler. Will be triggered on log failure. void err_handler_example() { // can be set globally or per logger(logger->set_error_handler(..)) spdlog::set_error_handler([](const std::string &msg) { printf("*** Custom log error handler: %s ***\n", msg.c_str()); }); } // syslog example (linux/osx/freebsd) #ifndef _WIN32 # 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."); } #endif // Android example. #if defined(__ANDROID__) # 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."); } #endif // Log patterns can contain custom flags. // this will add custom 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() { using spdlog::details::make_unique; // for pre c++14 auto formatter = make_unique(); formatter->add_flag('*').set_pattern("[%n] [%*] [%^%l%$] %v"); // set the new formatter using spdlog::set_formatter(formatter) or logger->set_formatter(formatter) // spdlog::set_formatter(std::move(formatter)); } 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) { spdlog::info("After opening {}", filename); fputs("After opening\n", fstream); }; handlers.before_close = [](spdlog::filename_t filename, std::FILE *fstream) { spdlog::info("Before closing {}", filename); fputs("Before closing\n", fstream); }; handlers.after_close = [](spdlog::filename_t filename) { spdlog::info("After closing {}", filename); }; auto file_sink = std::make_shared("logs/events-sample.txt", true, handlers); spdlog::logger my_logger("some_logger", file_sink); my_logger.info("Some log line"); } void replace_default_logger_example() { // store the old logger so we don't break other examples. auto old_logger = spdlog::default_logger(); auto new_logger = spdlog::basic_logger_mt("new_default_logger", "logs/new-default-log.txt", true); spdlog::set_default_logger(new_logger); spdlog::set_level(spdlog::level::info); spdlog::debug("This message should not be displayed!"); spdlog::set_level(spdlog::level::trace); spdlog::debug("This message should be displayed.."); spdlog::set_default_logger(old_logger); }