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.
haclog supports multiple build tools
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)
meson setup build
meson compile -C build
#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);
// NOTE: assert false will crash when build type is debug
int actual = 1;
int expect = 1;
HACLOG_ASSERT_MSG(actual == expect,
"actual: %d, expect: %d", actual, expect);
// NOTE: fatal level log will crash when build type is debug
if (actual != expect) {
HACLOG_FATAL("actual != expect, crash when debug");
}
// cleanup thread context
haclog_thread_context_init();
return 0;
}
- Use
haclog_context_add_handler, you can add different log handler into context, built-in supporthandleris as followshaclog_console_handler_t: output to console(stdout/stderr)haclog_file_handler_t: output to filehaclog_file_rotate_handler_t: output to file and rotate according to file sizehaclog_file_time_rot_handler_t: output to file and rotate according to time
- After add
handler, callhaclog_backend_runto run log backend - In each thread, before write log, call
haclog_thread_context_initto initializehaclogthread context - When thread exit, call
haclog_thread_context_initto cleanuphaclogthread 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);
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);
}
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);
}
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);
}
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);
haclog_context_set_bytes_buf_size(2 * 1024 * 1024);
haclog_context_set_msg_buf_size(2048);