bin/logcmd

   1 #!/usr/bin/perl -w
   2 ##------------------------------------------------------------------------##
   3 ##  File:
   4 ##      $Id: logcmd,v 1.1 2002/10/01 22:49:46 ehood Exp $
   5 ##  Author:
   6 ##      Earl Hood       earl@earlhood.com
   7 ##  Description:
   8 ##      Program to log the output of a program.
   9 ##      POD at __END__.
  10 ##------------------------------------------------------------------------##
  11 ##    Copyright (C) 2002   Earl Hood, earl@earlhood.com
  12 ##
  13 ##    This program is free software; you can redistribute it and/or modify
  14 ##    it under the terms of the GNU General Public License as published by
  15 ##    the Free Software Foundation; either version 2 of the License, or
  16 ##    (at your option) any later version.
  17 ##
  18 ##    This program is distributed in the hope that it will be useful,
  19 ##    but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ##    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ##    GNU General Public License for more details.
  22 ##
  23 ##    You should have received a copy of the GNU General Public License
  24 ##    along with this program; if not, write to the Free Software
  25 ##    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  26 ##    02111-1307, USA
  27 ##------------------------------------------------------------------------##
  28
  29 package Devtools::locmd;
  30
  31 use strict;
  32 use Getopt::Long;
  33 use POSIX;
  34
  35 my $our_name = 'logcmd';
  36 my @cmd = ( );
  37 my $cmd_name = "";
  38 my $time_fmt = '%Y-%m-%d %H:%M:%S';
  39
  40 my $first_time = 1;
  41 my $log_file = '-';
  42 my $log_fh;
  43 my $child_pid;
  44
  45 MAIN: {
  46   my @mailto   = ( );
  47   my ($help, $man);
  48
  49   GetOptions(
  50     'log=s'       => \$log_file,
  51     'mailto=s@'   => \@mailto,  # not implemented, yet
  52     'time-fmt=s'  => \$time_fmt,
  53
  54     'help'        => \$help,
  55     'man'         => \$man,
  56   ) || die qq/ERROR: Use -help for usage information\n/;
  57   usage(1, 0)  if ($help);
  58   usage(2, 0)  if ($man);
  59
  60   if (!@ARGV) {
  61     die qq/ERROR: No command specified\n/;
  62   }
  63   ($cmd_name = $ARGV[0]) =~ s/.*\///;
  64   @cmd = @ARGV;
  65
  66   $child_pid = open(CMD, "-|");
  67   if ($child_pid) {   # parent
  68     {
  69       local @SIG{'PIPE','TERM','INT'} = (sub {
  70         log_line($our_name, $$, "Caught signal: SIG$_[0]\n");
  71       }) x 3;
  72
  73       while (<CMD>) {
  74         log_line($cmd_name, $child_pid, $_);
  75       }
  76     }
  77     if (!close(CMD)) {
  78       log_line($our_name, $$, qq/Non-zero exit for [$child_pid]: $?\n/);
  79     }
  80     log_close();
  81
  82   } else {      # child
  83     open(STDERR, '>&STDOUT');
  84     exec(@cmd) || die qq/ERROR: Cannot exec "@cmd": $!\n/;
  85   }
  86
  87 } # End: MAIN
  88
  89 ##=========================================================================##
  90
  91 sub format_time {
  92   POSIX::strftime($time_fmt, localtime);
  93 }
  94
  95 sub log_line  {
  96   my $label = shift;
  97   my $pid   = shift;
  98   my $line  = shift;
  99   my $have_newline = $line =~ /\n\Z/;
 100   my $eol = ($have_newline) ? "" : "\n";
 101   if ($first_time) {
 102     $first_time = 0;
 103     log_open($log_file);
 104     print $log_fh join('', '[',format_time(),']',' [',$$,'] ',$our_name,': ',
 105                            "Command: [$child_pid] @cmd\n");
 106   }
 107   print $log_fh join('', '[',format_time(),']',' [',$pid,'] ',$label,': ',
 108                           $line,$eol);
 109 }
 110
 111 sub log_open {
 112   my $file = shift;
 113   if (!defined($file) || $file eq '-') {
 114     $log_fh = \*STDOUT;
 115   } else {
 116     open(LOG, ">>$file") ||
 117         die qq/ERROR: Unable to open "$file" for appending: $!\n/;
 118     $log_fh = \*LOG;
 119   }
 120 }
 121
 122 sub log_close {
 123   if (!$first_time) {
 124     if ($log_fh != \*STDOUT) {
 125       close($log_fh) ||
 126           warn qq/Warning: Problem closing log file: $!\n/;
 127     }
 128   }
 129 }
 130
 131 sub usage {
 132   require Pod::Usage;
 133   my $verbose   = shift || 0;
 134   my $exit_code = shift;
 135
 136   if ($verbose == 0) {
 137     Pod::Usage::pod2usage(-verbose => $verbose);
 138   } else {
 139     my $pager = $ENV{'PAGER'} || 'more';
 140     local(*PAGER);
 141     my $fh = (-t STDOUT && open(PAGER, "|$pager")) ? \*PAGER : \*STDOUT;
 142     Pod::Usage::pod2usage(-verbose => $verbose,
 143                           -output  => $fh);
 144     close(PAGER)  if ($fh == \*PAGER);
 145   }
 146   defined($exit_code) && exit($exit_code);
 147 }
 148
 149 ##=========================================================================##
 150 __END__
 151
 152 =head1 NAME
 153
 154 logcmd - Log the output of a program.
 155
 156 =head1 SYNOPSIS
 157
 158   logcmd [options] -- <command> [command-args ...]
 159
 160 =head1 DESCRIPTION
 161
 162 B<logcmd> logs the output of a program.  This program is useful
 163 for logging program output for programs that do not have a built-in
 164 logging facility.
 165
 166 Typical usage is to use B<logcmd> in crontabs to log any command
 167 output to a file instead of mail automatically being sent to the
 168 crontab owner.
 169
 170 When invoking B<logcmd>, you B<must> use "C<-->" to separate the
 171 B<logcmd> and its options from the command you are invoking.  For
 172 example,
 173
 174   logcmd -log out.log -- some-cmd arg1 arg2 arg3
 175
 176 This tells B<logcmd> to run "C<some-cmd arg1 arg2 arg3>" and have
 177 any output goto C<out.log>.
 178
 179 Each line logged will be preceded by a timestamp, the process ID, and
 180 the name of the command.  Also, before the first log message for a command
 181 is printed, B<logcmd> will print out a line giving the full command-line
 182 of the command invoked.  Example:
 183
 184   [2002-07-30 14:52:13] [25392] logcmd: Command: [25393] mhonarc -quiet -out out /var/archiver/mail
 185   [2002-07-30 14:52:13] [25393] mhonarc:
 186   [2002-07-30 14:52:13] [25393] mhonarc: Warning: Unrecognized character set: utf-8
 187   [2002-07-30 14:52:13] [25393] mhonarc:          Message-Id: <1022714308.2028.1.camel@xxx.xxx.xxx>
 188   [2002-07-30 14:52:13] [25393] mhonarc:          Message Number: 00367
 189   [2002-07-30 14:52:13] [25393] mhonarc:
 190   [2002-07-30 14:52:13] [25393] mhonarc: Warning: Unrecognized character set: utf-8
 191   [2002-07-30 14:52:13] [25393] mhonarc:          Message-Id: <1022716087.2028.3.camel@xxx.xxx.xxx>
 192   [2002-07-30 14:52:13] [25393] mhonarc:          Message Number: 00368
 193   [2002-07-30 14:52:14] [25393] mhonarc:
 194   [2002-07-30 14:52:14] [25393] mhonarc: Warning: Unrecognized character set: utf-8
 195   [2002-07-30 14:52:14] [25393] mhonarc:          Message-Id: <1024365245.9394.0.camel@xxx.xxx.xxx>
 196   [2002-07-30 14:52:14] [25393] mhonarc:          Message Number: 00398
 197
 198
 199 =head1 OPTIONS
 200
 201 =over
 202
 203 =item C<-help>
 204
 205 Display SYNOPSIS and OPTIONS sections.
 206
 207 =item C<-log> I<pathname>
 208
 209 Command output will be logged to I<pathname>.  If this option is
 210 not specified, then standard out is used.
 211
 212 =item C<-man>
 213
 214 Display manpage.
 215
 216 =item C<-time-fmt> I<fmt>
 217
 218 Date/time format to use when printing time before each logged line.
 219 The format string should be in C<strftime>(3) format.  If this
 220 option is not specified, then "C<%Y-%m-%d %H:%M:%S>" is used.
 221
 222 =item C<-->
 223
 224 Terminate option processing for B<logcmd>.  Any arguments after
 225 C<--> comprise the command that B<logcmd> should execute.
 226
 227 =back
 228
 229 =head1 EXAMPLES
 230
 231 The following is an example crontab entries of a user that has
 232 any output of commands goto a personal log file:
 233
 234   0 2 * * * logcmd -log $HOME/log/cron.log -- $HOME/bin/clean_account
 235   0 3 * * * logcmd -log $HOME/log/cron.log -- $HOME/bin/pack_mail
 236
 237 =head1 LIMITATIONS
 238
 239 =over
 240
 241 =item *
 242
 243 B<logcmd> performs no file locking on the log file specified.  To help
 244 minimize that a single output line to the log does not get broken up
 245 due to multiple writers, the entire line is dumped in a single call
 246 to Perl's C<print> operator.
 247
 248 =back
 249
 250 =head1 DEPENDENCIES
 251
 252 C<Getopt::Long>, C<POSIX>.
 253
 254 =head1 AUTHOR
 255
 256 Earl Hood, earl@earlhood.com
 257
 258 This program comes with ABSOLUTELY NO WARRANTY and may be copied only
 259 under the terms of the GNU General Public License.
 260
 261 =cut
 262