haclog

haclog(Happy Async C Log) is a plain C asynchronous log library. The main goal of this library is to make the writing time of log front-end(log producer thread) as small as possible.

Build

It's easy to build this project with CMake, the typical workflow starts with:

mkdir build
cd build
cmake ..

If you want to compile and run unit tests and benchmark, run run_test_and_benchmark.sh (in Windows, run_test_and_benchmark.bat)

Usage samples

hello

#include <stdlib.h>
#include "haclog/haclog.h"

void add_console_handler()
{
	static haclog_console_handler_t handler;
	memset(&handler, 0, sizeof(handler));
	if (haclog_console_handler_init(&handler, 1) != 0) {
		fprintf(stderr, "failed init console handler");
		exit(EXIT_FAILURE);
	}

	haclog_handler_set_level((haclog_handler_t *)&handler, HACLOG_LEVEL_INFO);
	haclog_context_add_handler((haclog_handler_t *)&handler);
}

int main()
{
	// add console handler
	add_console_handler();

	// run haclog backend
	haclog_backend_run();

	// initialize thread context
	haclog_thread_context_init();

	HACLOG_INFO("Hello World");

	double pi = 3.14159265359;
	HACLOG_DEBUG("π = %.5f", pi);

	// cleanup thread context
	haclog_thread_context_init();

	return 0;
}

Use haclog_context_add_handler, you can add different log handler into context, built-in support handler is as follows
- haclog_console_handler_t: output to console(stdout/stderr)
- haclog_file_handler_t: output to file
- haclog_file_rotate_handler_t: output to file and rotate according to file size
- haclog_file_time_rot_handler_t: output to file and rotate according to time
After add handler, call haclog_backend_run to run log backend
In each thread, before write log, call haclog_thread_context_init to initialize haclog thread context
When thread exit, call haclog_thread_context_init to cleanup haclog thread context

NOTE: in haclog, the format string in each log must be a string literal, When using C++, the compiler will help the user to automatically detect it; when using C, the user needs to gurantee this by self

/* Bad!!! Don't do that, format string must be a string literal */
// char *fmt_str = NULL;
// int v = rand();
// if (v % 2 == 0) {
// 	fmt_str = "%d is even";
// } else {
// 	fmt_str = "%d is odd";
// }
// HACLOG_FATAL(fmt_str, v);

file handler

void add_file_handler()
{
	static haclog_file_handler_t handler;
	memset(&handler, 0, sizeof(handler));
	if (haclog_file_handler_init(&handler, "logs/hello.log", "w") != 0) {
		fprintf(stderr, "failed init file handler");
		exit(EXIT_FAILURE);
	}
	haclog_handler_set_level((haclog_handler_t *)&handler, HACLOG_LEVEL_DEBUG);
	haclog_context_add_handler((haclog_handler_t *)&handler);
}

rotate file handler

void add_file_rotate_handler()
{
	static haclog_file_rotate_handler_t handler;
	memset(&handler, 0, sizeof(handler));
	if (haclog_file_rotate_handler_init(&handler, "logs/hello.rot.log", 128 * 1024 * 1024, 5) != 0) {
		fprintf(stderr, "failed init file handler");
		exit(EXIT_FAILURE);
	}
	haclog_handler_set_level((haclog_handler_t *)&handler, HACLOG_LEVEL_DEBUG);
	haclog_context_add_handler((haclog_handler_t *)&handler);
}

time rotate file handler

void add_file_time_rot_handler()
{
	static haclog_file_time_rot_handler_t handler;
	memset(&handler, 0, sizeof(handler));
	if (haclog_file_time_rotate_handler_init( &handler, "logs/hello.time_rot.log", HACLOG_TIME_ROTATE_UNIT_DAY, 2, 0) != 0) {
		fprintf(stderr, "failed init file time rotate handler");
		exit(EXIT_FAILURE);
	}
	haclog_handler_set_level((haclog_handler_t *)&handler, HACLOG_LEVEL_DEBUG);
	haclog_context_add_handler((haclog_handler_t *)&handler);
}

Customize log format

By default, detailed log information will be printed in the following pattern:
${level}|${UTC+0 datetime}|${file & line number}|${function}|${thread id}

User can Customize log meta format

int my_write_meta(struct haclog_handler *handler, haclog_meta_info_t *meta)
{
	const char *level = haclog_level_to_str(meta->loc->level);
	return handler->writev(handler, "%s|%llu.%lu ", level,
						   (unsigned long long)meta->ts.tv_sec,
						   (unsigned long)meta->ts.tv_nsec);
}

...

haclog_handler_set_fn_write_meta((haclog_handler_t *)&handler, my_write_meta);
haclog_context_add_handler((haclog_handler_t *)&handler);

Set Bytes Buffer size

haclog_context_set_bytes_buf_size(2 * 1024 * 1024);

Set max length of one log line

haclog_context_set_msg_buf_size(2048);

migzone / haclog