--config files don't support quoted values

[Maciej Dobrzanski]

It seems that when columns-regex is set through a config file, pt-diskstat loses the outermost parts of the regular expression. Examples:

(garfield:~) macko% cat ~/.pt-diskstats.conf
group-by=all
columns-regex='rd_s|rd_avgkb|rd_rt|rd_cnc|wr_s|wr_avgkb|wr_rt|wr_cnc|busy|qtime'
(garfield:~) macko% pt-diskstats --devices-regex='sda$' 2012_06_13_11_42_48-diskstats | head -2
  #ts device rd_cnc rd_rt wr_s wr_cnc wr_rt busy
  1.0 sda 2.2 12.6 0.0 0.0 0.0 100%
^C

(garfield:~) macko% cat ~/.pt-diskstats.conf
group-by=all
columns-regex='rd_s|rd_avgkb|rd_rt|rd_cnc|wr_s|wr_avgkb|wr_rt|wr_cnc|busy|qtime|'
(garfield:~) macko% pt-diskstats --devices-regex='sda$' 2012_06_13_11_42_48-diskstats | head -2
  #ts device rd_cnc rd_rt wr_s wr_cnc wr_rt busy qtime
  1.0 sda 2.2 12.6 0.0 0.0 0.0 100% 13.5
^C

(garfield:~) macko% cat ~/.pt-diskstats.conf
group-by=all
columns-regex='rd_s|rd_avgkb|rd_rt|rd_cnc|wr_s|wr_avgkb|wr_rt|wr_cnc|busy|qtime|stime'
(garfield:~) macko% pt-diskstats --devices-regex='sda$' 2012_06_13_11_42_48-diskstats | head -2
  #ts device rd_cnc rd_rt wr_s wr_cnc wr_rt busy qtime
  1.0 sda 2.2 12.6 0.0 0.0 0.0 100% 13.5
^C

(garfield:~) macko% cat ~/.pt-diskstats.conf
group-by=all
columns-regex='rd_s|rd_avgkb|rd_rt|rd_cnc|wr_s|wr_avgkb|wr_rt|wr_cnc|busy|qtime|stime|whatever'
(garfield:~) macko% pt-diskstats --devices-regex='sda$' 2012_06_13_11_42_48-diskstats | head -2
  #ts device rd_cnc rd_rt wr_s wr_cnc wr_rt busy qtime stime
  1.0 sda 2.2 12.6 0.0 0.0 0.0 100% 13.5 5.7

In every case 'rd_s' as well as the last column listed is missing in the output. This does not happen when columns-regex is specified in the command line.

[Baron Schwartz (baron-xaprb)]

The problem is that the quotes enclosing the option are considered to be part of the value itself. The real bug here is that we don't support leading or trailing whitespace, which could be considered a feature, not a bug. We'd need to understand quotes in order to do that. As it is, quotes are just characters after the = sign, nothing more.

I'll mark this as a documentation bug and we can fix it in the man page that applies to option parsing.

[Baron Schwartz (baron-xaprb)]

The offending code snippet in OptionParser.pm, which trims leading and trailing whitespace but doesn't understand quotes:

1139 sub _read_config_file {
1140 my ( $self, $filename ) = @_;
1141 open my $fh, "<", $filename or die "Cannot open $1142 my @args;
1143 my $prefix = '--';
1144 my $parse = 1;
1145
1146 LINE:
1147 while ( my $line = <$fh> ) {
1148 chomp $line;
1149 # Skip comments and empty lines
1150 next LINE if $line =~ m/^\s*(?:\#|\;|$)/;
1151 # Remove inline comments
1152 $line =~ s/\s+#.*$//g;
1153 # Remove whitespace
1154 $line =~ s/^\s+|\s+$//g;

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-991