Linux/c++ 日志轮换方案

发布于 2024-07-12 04:51:58 字数 576 浏览 5 评论 0原文

我有一个记录器系统，它基本上是一种以线程安全的方式将数据写入 std::clog 的奇特方式。

我还将 std::clog 重定向到这样的文件：

int main() {
    std::ofstream logfile(config::logname, std::ios::app);
    std::streambuf *const old_buffer = std::clog.rdbuf(logfile.rdbuf());

    // .. the guts of the application

    std::clog.rdbuf(old_buffer);
}

这很好用...但是，我的应用程序还生成大量日志。我想知道正确轮换日志文件的好方法是什么。有没有一种安全的方法可以通过 cron 任务切换文件？我猜不会。

我能想到的唯一肯定有效的方法是，如果我让应用程序本身打开一个新文件，并将 clog 的 rdbuf 重定向到该文件，同时保留日志互斥体。但这感觉像是一个廉价的解决方案，我需要检查一下是否需要经常轮换日志才能使其有效。必须有更好的方法。

原文

I have a logger system which basically is a fancy way of writing my data to std::clog in a thread safe way.

I also, redirect std::clog to a file like this:

int main() {
    std::ofstream logfile(config::logname, std::ios::app);
    std::streambuf *const old_buffer = std::clog.rdbuf(logfile.rdbuf());

    // .. the guts of the application

    std::clog.rdbuf(old_buffer);
}

This works great... however, my application also produces a very large amount of logs. I was wondering what would be a good way to properly rotate my log files. Is there a safe way to switch out the file via a cron task? I would guess no.

The only thing I can think of that would definitely work is if I had the application itself open a new file, and redirect the rdbuf of clog to that while holding the logging mutex. But that feels like a cheap solution, and I would need to check so see if it is time to rotate logs fairly often for it to be effective. There has got to be a better way.

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小鸟爱天空丶 2024-07-19 04:51:58

您可以使用 /etc/logrotate.conf 和/或 /etc/logrotate.d/ 中配置的内置日志轮换方法 - 通常让 logrotate 向您的应用程序发送 SIGUSR1 作为关闭并重新打开所有应用程序的信号日志文件。

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幽蝶幻影 2024-07-19 04:51:58

或者只使用 syslog 而不是您的自定义日志记录方案，并且日志无论如何都会由 logrotate 轮换。 -- 取决于它的配置方式，但在大多数桌面/服务器系统上，它已经设置为轮换它们。

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绝不服输 2024-07-19 04:51:58

您可以使用类似于以下内容的内容，并以任何方式将日志文件移走（logrotate、cron 脚本等）（提供 Cish 示例，应该很容易转换）

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

void logworker()
{
    ino_t inode = 0;
    FILE *logfile;

    logfile = fopen(logfilename, "a+");
    while(running)
    {
        struct stat mystat;

        if (stat(logfilename, &mystat)!=0 || mystat.st_ino != inode)
        {
            logfile = freopen(logfilename, "a+", logfile);
            inode = mystat.st_ino;
        }

        while (stuff_in_buffer)
        {
            fwrite(); /* etc */
        }
        fflush(logfile);

        /* sleep until something interesting happens */
    }
}

移动后写入文件是安全的，所以不需要额外小心

You can use something similar to the following, and move the log file away whichever way (logrotate, cron script, etc.) (providing Cish sample, should be easily convertible)

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

void logworker()
{
    ino_t inode = 0;
    FILE *logfile;

    logfile = fopen(logfilename, "a+");
    while(running)
    {
        struct stat mystat;

        if (stat(logfilename, &mystat)!=0 || mystat.st_ino != inode)
        {
            logfile = freopen(logfilename, "a+", logfile);
            inode = mystat.st_ino;
        }

        while (stuff_in_buffer)
        {
            fwrite(); /* etc */
        }
        fflush(logfile);

        /* sleep until something interesting happens */
    }
}

It is safe to write to a file after it has been moved, so there's no need for extra caution

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