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Subject: Re: [PORTS] Logging (was Re: [GENERAL] PostgreSQL 7.0-2 RPMset
From: Palle Girgensohn <girgen@partitur.se>
Date: Mon, 22 May 2000 17:02:37 +0200
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Tom Lane wrote:
>
> Lamar Owen <lamar.owen@wgcr.org> writes:
> > The real problem with redirecting the postmaster output is the issue
> > of log rolling, which is impossible to do in the 'classic'
> > stderr/stdout redirect UNLESS you throw down postmaster when rolling
> > the log (unless you know a trick I don't).
I think I do ;-) read on...
> Yes. I think ultimately we will have to do some logging support code of
> our own to make this work the way we want. My thought at the moment is
> there's nothing wrong with logging to stderr, as long as there's some
> code somewhere that periodically closes stderr and reopens it to a new
> log file. There needn't be a lot of code involved, we just need a
> well-thought-out spec for how it should work. Comments anyone?
>
> regards, tom lane
I really enjoy using apache's rotatelogs program. stderr is
redirected through a pipe to a very small and robust C program,
rotatelogs, that takes as arguments number of seconds between
log rotates and the log filename. Logs are rotated every
argv[2] seconds. The rotatelogs program takes care of closing
and reopening, and nothing has to done from the application,
just start postmaster with '2>&1 | rotatelogs ...' at the end,
and log to stderr.
Also, BSD license! :)
For reference, I enclose the program as an attachment; it's
less than 100 lines. Also, here's the man page:
Name
rotatelogs - rotate Apache logs without having to kill
the
server
Synopsis
rotatelogs logfile rotationtime
Description
rotatelogs is a simple program for use in conjunction
with
Apache's piped logfile feature which can be used
like
this:
TransferLog "|rotatelogs
/path/to/logs/access_log
86400"
This creates the files /path/to/logs/access_log.nnnn
where
nnnn is the system time at which the log nominally
starts
(this time will always be a multiple of the rotation
time,
so you can synchronize cron scripts with it). At the
end
of each rotation time (here after 24 hours) a new log
is
started.
Options
logfile
The path plus basename of the logfile. The
suffix
.nnnn is automatically added.
rotationtime
The rotation time in seconds.
See Also
httpd(8)
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/*
* Simple program to rotate Apache logs without having to kill the server.
*
* Contributed by Ben Laurie <ben@algroup.co.uk>
*
* 12 Mar 1996
*/
#define BUFSIZE 65536
#define MAX_PATH 1024
#include "ap_config.h"
#include <time.h>
#include <errno.h>
#include <fcntl.h>
int main (int argc, char **argv)
{
char buf[BUFSIZE], buf2[MAX_PATH];
time_t tLogEnd = 0;
time_t tRotation;
int nLogFD = -1;
int nRead;
char *szLogRoot;
if (argc != 3) {
fprintf(stderr,
"%s <logfile> <rotation time in seconds>\n\n",
argv[0]);
#ifdef OS2
fprintf(stderr,
"Add this:\n\nTransferLog \"|%s.exe /some/where 86400\"\n\n",
argv[0]);
#else
fprintf(stderr,
"Add this:\n\nTransferLog \"|%s /some/where 86400\"\n\n",
argv[0]);
#endif
fprintf(stderr,
"to httpd.conf. The generated name will be /some/where.nnnn "
"where nnnn is the\nsystem time at which the log nominally "
"starts (N.B. this time will always be a\nmultiple of the "
"rotation time, so you can synchronize cron scripts with it).\n"
"At the end of each rotation time a new log is started.\n");
exit(1);
}
szLogRoot = argv[1];
tRotation = atoi(argv[2]);
if (tRotation <= 0) {
fprintf(stderr, "Rotation time must be > 0\n");
exit(6);
}
for (;;) {
nRead = read(0, buf, sizeof buf);
if (nRead == 0)
exit(3);
if (nRead < 0)
if (errno != EINTR)
exit(4);
if (nLogFD >= 0 && (time(NULL) >= tLogEnd || nRead < 0)) {
close(nLogFD);
nLogFD = -1;
}
if (nLogFD < 0) {
time_t tLogStart = (time(NULL) / tRotation) * tRotation;
sprintf(buf2, "%s.%010d", szLogRoot, (int) tLogStart);
tLogEnd = tLogStart + tRotation;
nLogFD = open(buf2, O_WRONLY | O_CREAT | O_APPEND, 0666);
if (nLogFD < 0) {
perror(buf2);
exit(2);
}
}
if (write(nLogFD, buf, nRead) != nRead) {
perror(buf2);
exit(5);
}
}
}
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