Re: Plan B for log rotation support: borrow Apache code

Here are the log scripts posted by Andrew Sullivan and Peter E.

---------------------------------------------------------------------------

Tom Lane wrote:
> Peter Eisentraut  writes:
> > Or we could take the one I posted, which does exactly the same thing as
> > Apache's (at least about a year ago, not sure where the APR plays in
> > nowadays), thus shortcircuiting that porting effort.
> 
> I'd forgotten that one.  Where is it again?
> 
> 			regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
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> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
#!/usr/local/bin/perl
#
#pglog-rotator
#Copyright (c) Liberty RMS 2001-2003
#This file may be distributed under the same terms as PostgreSQL
#This file comes with NO WARRANTY WHATSOEVER
#
#

use IPC::Open3;
use IO::Handle;

$err_log_file='/path/to/logs/stderr_pg.log';
$out_log_file='/path/to/logs/stdout_pg.log';

#### log size in MBytes
$size_limit=1;

#### rotate nn files
$max_logs=7;

#### postgres cmd
# it is best if you set $PGDATA
# and use the $PATH to call just postmaster.
# That makes the output of 'ps -auxww' more valuable
$command = 'postmaster';


#######
sub HUP_SIGNAL {
	($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime(time);
	$gmtime = sprintf ("%.2d/%.2d/%.4d %.2d:%.2d:%.2d: ",  $mon+1, $mday, 1900+$year, $hour, $min, $sec);
        print "$gmtime: SIGHUP received. Ignored.\n";
}
$SIG{HUP} = \&HUP_SIGNAL;


open(LOG, ">>$err_log_file");
autoflush LOG 1;
open(OUT_LOG, ">>$out_log_file");
autoflush OUT_LOG 1;

$cnt = $max_logs;
$size_limit=$size_limit * 1024 * 1024;

### postgres 7.1.3 writes to stderr in any debug_level (0 to 16)
sub read_stderr
{
    while()
    {
	($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size, $atime,$mtime,$ctime,$blksize,$blocks) = stat($err_log_file);
	if ( $size > $size_limit ) {
		close LOG;

		while ($cnt > 0) {
			$old_log=sprintf("%s.%s", $err_log_file, $cnt);
			$new_log=sprintf("%s.%s", $err_log_file, $cnt-1);
			rename $new_log, $old_log;
			$cnt--;
		}
		rename $err_log_file, $new_log;
		$cnt = $max_logs;
		open(LOG, ">>$err_log_file");
	}
	($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime(time);
	$gmtime = sprintf ("%.2d/%.2d/%.4d %.2d:%.2d:%.2d: ",  $mon+1, $mday, 1900+$year, $hour, $min, $sec);
	print LOG "$gmtime $_";
    }

}

### postgres 7.1.3 writes to stdout in debug_level 3 to 16
sub read_stdout
{
    while()
    {
	($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size, $atime,$mtime,$ctime,$blksize,$blocks) = stat($out_log_file);
	if ( $size > $size_limit ) {
		close OUT_LOG;

		while ($cnt > 0) {
			$old_log=sprintf("%s.%s", $out_log_file, $cnt);
			$new_log=sprintf("%s.%s", $out_log_file, $cnt-1);
			rename $new_log, $old_log;
			$cnt--;
		}
		rename $out_log_file, $new_log;
		$cnt = $max_logs;
		open(OUT_LOG, ">>$out_log_file");
	}
	($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime(time);
	$gmtime = sprintf ("%.2d/%.2d/%.4d %.2d:%.2d:%.2d: ",  $mon+1, $mday, 1900+$year, $hour, $min, $sec);
	print OUT_LOG "$gmtime $_";
    }

}


$pid = open3(\*WTRFH, \*RDRFH, \*ERRFH, $command);

printf "postmaster [$pid] started: ";

print "$command\n";
print "STDERR log file: $err_log_file\n";
print "STDOUT log file: $out_log_file\n";
printf ("size limit: %.3f MBytes, ", $size_limit / 1024 / 1024); 
print "max logs: $max_logs\n";


# read stdout from postmaster
if (fork() == 0) {	## this is the child
	read_stdout();
	exit(0);
}

read_stderr();

printf "postmaster [$pid] killed.\n\n";

#include "c.h"

#include 
#include 
#include 
#include 
#include 
#include 

#include "pqsignal.h"

volatile static int hangup_flag = 0;


static void
signalhandler(SIGNAL_ARGS)
{
	hangup_flag = 1;
}


#define BUF_SIZE 8192
#define MAX_ERRORS 200

#define MAX_ERRORS_CHECK() do { errcount++; if (max_errors > 0 && errcount >= max_errors) exit(2); } while(0)

int
main(int argc, char *argv[])
{
	const char *filename;
	int fd = -1;
	static char buf[BUF_SIZE];
	unsigned int errcount = 0;
	unsigned int max_errors = MAX_ERRORS;

	if (argc != 2)
	{
		fprintf(stderr, "%s: missing required argument\n", argv[0]);
		fprintf(stderr, "Try '%s --help' for more information.\n", argv[0]);
		exit(1);
	}

	if (strcmp(argv[1], "--help")==0)
	{
		printf("this should be a help message...\n");
		exit(0);
	}

	filename = argv[1];

	fd = open(filename, O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND, 0666);
	if (fd < 0)
	{
		fprintf(stderr, "%s: could not open file %s: %s\n",
				argv[0], filename, strerror(errno));
		exit(1);
	}

	pqsignal(SIGUSR1, signalhandler);

	for (;;)
	{
		int read_bytes;
		int written_bytes;
		char * buf_ptr;

		read_bytes = read(0, buf, sizeof(buf));
		if (read_bytes < 0)
		{
			if (errno == EINTR)
				continue;
			else
			{
				fprintf(stderr, "*** %s: read error from %s: %s\n",
						argv[0], filename, strerror(errno));
				MAX_ERRORS_CHECK();
			}
		}
		if (read_bytes == 0)
		{
			/* end of file, postmaster exited? */
			close(fd);
			exit(0);
		}

		if (hangup_flag)
		{
			int fdnew;

			fdnew = open(filename, O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND, 0666);
			if (fdnew < 0)
			{
				fprintf(stderr, "*** %s: could not open new output file %s: %s\n",
					   argv[0], filename, strerror(errno));
				MAX_ERRORS_CHECK();
			}
			else
			{
				close(fd);
				fd = fdnew;
			}
			hangup_flag = 0;
		}

		buf_ptr = buf;
		do
		{
			written_bytes = write(fd, buf_ptr, read_bytes);
			if (written_bytes < 0)
			{
				if (errno == EINTR)
					continue;
				fprintf(stderr, "*** %s: could not write to file %s: %s\n",
						argv[0], filename, strerror(errno));
				MAX_ERRORS_CHECK();

				break;
			}
			if (written_bytes < read_bytes)
			{
				buf_ptr += written_bytes;
				read_bytes -= written_bytes;
				continue;
			}
			break;
		} while(1);
	}

	return 127;
}