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嵌入式日志信息保存調(diào)試(ulog)
獲取
項目地址:https://github.com/rdpoor/ulog
uLog 為嵌入式微控制器或任何資源有限的系統(tǒng)提供結(jié)構(gòu)化的日志記錄機制。它繼承了流行的 Log4c
和 Log4j
平臺背后的一些概念,但開銷更低。
使用方法
將ulog
中的ulog.c
和ulog.h
文件移植進(jìn)入自己的工程。
- 打開使能ulog函數(shù)使能,在ulog.h中
#define ULOG_ENABLED
- 日志輸出等級
typedef enum {ULOG_TRACE_LEVEL=100,ULOG_DEBUG_LEVEL,ULOG_INFO_LEVEL,ULOG_WARNING_LEVEL,ULOG_ERROR_LEVEL,ULOG_CRITICAL_LEVEL,ULOG_ALWAYS_LEVEL
} ulog_level_t;
- main函數(shù)分析
記住一個點:自定義里面的等級A,只有我們使用的ULOG_XXX函數(shù)中XXX的等級 >= A 的時候,該函數(shù)才會被真正的執(zhí)行
#include <stdio.h>
#include <string.h>
#include "ulog.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>// 用戶自定義用于調(diào)試的函數(shù)函數(shù)
void my_console_logger(ulog_level_t severity, char *msg)
{printf("console: %s [%s]: %s\n","time", // user defined functionulog_level_name(severity),msg);
}
// 用戶自定義用于將日志存儲進(jìn)文件的函數(shù)
void my_file_logger(ulog_level_t severity, char *msg)
{int fd = open("file.txt",O_RWRD|O_CRATE,0655);printf(,"file: %s [%s]: %s\n","time", // user defined functionulog_level_name(severity),msg)close(fd);
}int main()
{int arg = 42;// ulog的初始化ULOG_INIT();// 訂閱my_console_logger函數(shù),給予相應(yīng)的等級為 ULOG_WARNING_LEVELULOG_SUBSCRIBE(my_console_logger, ULOG_WARNING_LEVEL);// 訂閱my_file_logger函數(shù),給予相應(yīng)的等級為 ULOG_DEBUG_LEVELULOG_SUBSCRIBE(my_file_logger, ULOG_DEBUG_LEVEL);// 只會執(zhí)行 my_file_logger的函數(shù),理由是 ULOG_WARNING_LEVEL > ULOG_INFO_LEVEL 的等級// 但是 ULOG_DEBUG_LEVEL < ULOG_INFO_LEVEL 的等級// 自定義函數(shù)相應(yīng)等級只有小于等于的時候才會執(zhí)行相應(yīng)的操作函數(shù)ULOG_INFO("Info, arg=%d", arg); // logs to file but not console// ULOG_WARNING_LEVEL > ULOG_DEBUG_LEVELULOG_CRITICAL("Critical, arg=%d", arg); // logs to file and console// 改變my_console_logger函數(shù)的操作等級為 ULOG_INFO_LEVELULOG_SUBSCRIBE(my_console_logger, ULOG_INFO_LEVEL);// 改變后兩個自定義函數(shù)的操作等級都小于等于 ULOG_INFO_LEVEL,所以兩個函數(shù)都會執(zhí)行ULOG_INFO("Info, arg=%d", arg); // logs to file and console// 取消 my_file_logger 函數(shù)的訂閱操作ULOG_UNSUBSCRIBE(my_file_logger);// 其中my_file_logger取消了,又 ULOG_INFO_LEVEL >= ULOG_INFO_LEVEL, 所以打印調(diào)試信息ULOG_INFO("Info, arg=%d", arg);
}
自定義日志函數(shù)編寫
- windows
char* get_timestamp()
{time_t ti_t;struct tm s_tm;time(&ti_t);localtime_s(&s_tm, &ti_t);char* time_chr = (char*)malloc(sizeof(char)*20);memset(time_chr,0,20);sprintf(time_chr, "%d-%d-%d %d:%d:%d",s_tm.tm_year + 1900, s_tm.tm_mon + 1, s_tm.tm_mday, s_tm.tm_hour, s_tm.tm_min, s_tm.tm_sec);return time_chr;
}void my_console_logger(ulog_level_t severity, const char* msg) {char *get_time = get_timestamp();printf("%s [%s]: %s\n",get_time, // user defined functionulog_level_name(severity),msg);free(get_time);
}
- linux
char *get_timestamp()
{time_t tt;struct tm *t;time(&tt);char *time_chr = (char *)malloc(sizeof(char) * 20);memset(time_chr, 0, 20);t = localtime(&tt);sprintf(time_chr, "%d-%d-%d %d:%d:%d", t->tm_year+1900,t->tm_mon + 1,t->tm_mday,(t->tm_hour + 15)%24,t->tm_min,t->tm_sec);return time_chr;
}void my_console_logger(ulog_level_t severity, const char *msg)
{char *get_time = get_timestamp();printf("%s [%s]: %s\n",get_time, // user defined functionulog_level_name(severity),msg);free(get_time);
}void my_file_logger(ulog_level_t severity, const char *msg)
{char *get_time = get_timestamp();FILE* fp = fopen("my_test.txt", "a+"); // 打開文件my_test.txt 這里文件可以跟改為時間fprintf(fp, "%s [%s]: %s\n",get_time, // user defined functionulog_level_name(severity),msg);free(get_time);
}
執(zhí)行后,文件中的內(nèi)容類似以下,這個格式是按照自己喜好在日志函數(shù)中自己編寫。
2023-4-18 20:23:14 [INFO]: Info, arg=42
2023-4-18 20:23:14 [CRITICAL]: main.c:67 arg=42
2023-4-18 20:23:14 [INFO]: main.c:66 arg=42
源碼分析
- ulog_message
#define ULOG_DEBUG(...) ulog_message(ULOG_DEBUG_LEVEL, __VA_ARGS__)
// 這里的...表示的是可變參數(shù) __VA_ARGS__ 這個也是對應(yīng)的表示可變參數(shù) 這里也可以改為
// #define ULOG_DEBUG(...) ulog_message(ULOG_DEBUG_LEVEL, const char* fmt, ...)void ulog_message(ulog_level_t severity, const char* fmt, ...) {// va_list 是一個字符指針,可以理解為指向當(dāng)前參數(shù)的一個指針,取參必須通過這個指針進(jìn)行va_list ap;int i;// 然后應(yīng)該對ap 進(jìn)行初始化,讓它指向可變參數(shù)表里面的第一個參數(shù),也就是const char* fmtva_start(ap, fmt);// 依次獲取ap的類型,并進(jìn)行sprintf函數(shù)類型功能組合成字符串,// 最大長度 ULOG_MAX_MESSAGE_LENGTH,超過會被截斷vsnprintf(s_message, ULOG_MAX_MESSAGE_LENGTH, fmt, ap);// 將這個 ap 指針關(guān)掉,以免發(fā)生危險va_end(ap);for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++) {// 函數(shù)是依次執(zhí)行的,那個函數(shù)先注冊,那個先運行if (s_subscribers[i].fn != NULL) {// 只有使用的輸出等級大于自定義函數(shù)等級的時候,就會執(zhí)行if (severity >= s_subscribers[i].threshold) {s_subscribers[i].fn(severity, s_message);}}}
}
- ulog_err_t
// 錯誤標(biāo)志枚舉
typedef enum {ULOG_ERR_NONE = 0,ULOG_ERR_SUBSCRIBERS_EXCEEDED,ULOG_ERR_NOT_SUBSCRIBED,
} ulog_err_t;
- ulog_subscribe、ulog_unsubscribe
// 執(zhí)行函數(shù)指針
typedef void (*ulog_function_t)(ulog_level_t severity, char* msg);
// 執(zhí)行結(jié)構(gòu)體
typedef struct {ulog_function_t fn;ulog_level_t threshold;
} subscriber_t;
// 執(zhí)行結(jié)構(gòu)體數(shù)組
#define ULOG_MAX_SUBSCRIBERS 6
static subscriber_t s_subscribers[ULOG_MAX_SUBSCRIBERS];// search the s_subscribers table to install or update fn
// 訂閱函數(shù),也就是將函數(shù)放入執(zhí)行結(jié)構(gòu)體數(shù)組中,并賦予相應(yīng)的輸出等級
ulog_err_t ulog_subscribe(ulog_function_t fn, ulog_level_t threshold) {int available_slot = -1;int i;for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++) {if (s_subscribers[i].fn == fn) {// 執(zhí)行結(jié)構(gòu)體數(shù)組已經(jīng)含有該執(zhí)行函數(shù),進(jìn)行更新即可// already subscribed: update threshold and return immediately.s_subscribers[i].threshold = threshold;return ULOG_ERR_NONE;}else if (s_subscribers[i].fn == NULL) {// found a free slot// 找到數(shù)組中最近的一個未使用的執(zhí)行結(jié)構(gòu)體,賦予標(biāo)志信息available_slot = i;}}// fn is not yet a subscriber. assign if possible.if (available_slot == -1) {// 執(zhí)行結(jié)構(gòu)體數(shù)組中已經(jīng)存儲滿return ULOG_ERR_SUBSCRIBERS_EXCEEDED;}// 將執(zhí)行函數(shù)信息,放入執(zhí)行結(jié)構(gòu)體數(shù)組s_subscribers[available_slot].fn = fn;s_subscribers[available_slot].threshold = threshold;return ULOG_ERR_NONE;
}// search the s_subscribers table to remove
// 取消訂閱,就是將該函數(shù)從執(zhí)行結(jié)構(gòu)體數(shù)組中刪除
ulog_err_t ulog_unsubscribe(ulog_function_t fn) {int i;for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++) {if (s_subscribers[i].fn == fn) {s_subscribers[i].fn = NULL; // mark as emptyreturn ULOG_ERR_NONE;}}return ULOG_ERR_NOT_SUBSCRIBED;
}
- ulog_level_name
// 獲取相應(yīng)的輸出等級字符串
const char* ulog_level_name(ulog_level_t severity) {switch (severity) {case ULOG_TRACE_LEVEL: return "TRACE";case ULOG_DEBUG_LEVEL: return "DEBUG";case ULOG_INFO_LEVEL: return "INFO";case ULOG_WARNING_LEVEL: return "WARNING";case ULOG_ERROR_LEVEL: return "ERROR";case ULOG_CRITICAL_LEVEL: return "CRITICAL";case ULOG_ALWAYS_LEVEL: return "ALWAYS";default: return "UNKNOWN";}
}