Parsing external config file

ybiC has asked for the wisdom of the Perl Monks concerning the following question:

I'm cleaning up an old script with newfound knowledge. Part of this cleanup is to move user-modified parameters to an external file.

&CONFEXT is supposed to populate $timeout, @targets, and @command from the file ciscoconf.conf. As the Dumps show, CONFINT isn't fetching all the info into the appropriate arrays. I think my "push" syntax is good, and suspect my control structure is *not*. Would any wise monk(s) care to show me the error of my ways?

ciscoconf.pl - the script itself
- CONFINT - *working* function that reads config parameters from within script itself
- CONFEXT - *broken* function that tries to read same config parameters from external config file
ciscoconf.conf - external config file
ciscoconfint.dump - Data::Dumper output from CONFINT
ciscoconfext.dump - Data::Dumper output from CONFEXT

Hopefully relevant sections of code follow:
    tired groggy and quite loopy,
    Don
    striving for Perl Adept
    (it's pronounced "why-bick")

######################################################################
+###
# Begin small slice of ciscoconf.pl
use Data::Dumper;                       #only for testing
use vars qw(
            $section
            $timeout @timeout
            $target @targets
            $command @commands
            );

my $conf    = 'ciscoconf.conf';          # list of target devices and 
+commands
my $tmp     = 'ciscoconf.tmp';
my $log     = 'ciscoconf.log';

#&CONFINT();
&CONFEXT();
----------------------------------------------------------------------
+---
sub CONFINT {
    $timeout = '15';
    @targets = ('192.168.1.27','172.16.0.138' );
    @commands = (
        'sho clo',
        'set leng 0',
        'term leng 0',
        'sho clo',
        'disa',
        );
    open (DUMP, "> ciscoconfint.dump")  or die "Error opening ciscocon
+fint.dump for write: $!";
    print DUMP Dumper(@timeout), "\n";
    print DUMP Dumper(@targets), "\n";
    print DUMP Dumper(@commands), "\n";
    close (DUMP)  or die "Error closing ciscoconfint.dump after write:
+ $!";
    }
----------------------------------------------------------------------
+---
sub CONFEXT {
    open (CONF, "<$conf")  or die "Error opening $conf for read: $!";
    while (<CONF>) {
        next if /^#/ or /^s.*$/ or /^!/; # ignore comment lines
        chomp;
        if (/^\[([^\]]+)\]/) {
            $section = $1;
            next;
            }
        else {
            if ($section =~ /timeout/i) {
                push @timeout,$_;
                }
            if ($section =~ /targets/i) {
                push @targets,$_;
                }
            if ($section =~ /commands/i) {
                push @commands,$_;
                }
            }
        }
    close (CONF)  or die "  ciscoconf.pl: Error closing $conf after re
+ad: $!";
    open (DUMP, "> ciscoconfext.dump")  or die "Error opening ciscocon
+fext.dump for write: $!";
    print DUMP Dumper(@timeout), "\n";
    print DUMP Dumper(@targets), "\n";
    print DUMP Dumper(@commands), "\n";
    close (DUMP)  or die "Error closing ciscoconfext.dump after write:
+ $!";

    }
# End small slice of ciscoconf.pl
######################################################################
+###
# begin ciscoconf.conf
[Timeout]
15

[Targets]
192.168.1.27
172.16.0.138

[Commands]
sho clo
set leng 0
term leng 0
disa
sho clo
# end ciscoconf.conf
######################################################################
+###
# begin ciscoconfext.dump
$VAR1 = 15;
$VAR2 = '';

$VAR1 = '192.168.1.27';
$VAR2 = '172.16.0.138';
$VAR3 = '';

$VAR1 = 'term leng 0';
$VAR2 = 'disa';
# end ciscoconfext.dump
######################################################################
+###
# begin ciscoconfint.dump
$VAR1 = 15;

$VAR1 = '192.168.1.27';
$VAR2 = '172.16.0.138';

$VAR1 = 'sho clo';
$VAR2 = 'set leng 0';
$VAR3 = 'term leng 0';
$VAR4 = 'sho clo';
$VAR5 = 'disa';
# end ciscoconfint.dump
######################################################################
+###
[download]

Comment on Parsing external config file Download Code

Replies are listed 'Best First'.
Re: Parsing external config file by mirod (Canon) on Jan 21, 2001 at 14:57 UTC
Your problems come from this line: `next if /^#/ or /^s.$/ or /^!/; # ignore comment lines` and more precisely from the `/^s.$/` part. There you ignore all lines starting with 's' as comments, hence the missing commands (`sho clo`, `set leng 0'` and `sho clo` again. On the other hand empty (all space) lines are happily processed, hence the extra empty items in your lists I think you meant `/^\s*$/`, at least it works with it!	[reply] [d/l]
Re: (2): Parsing external config file (s/^s/^\\s/) by ybiC (Prior) on Jan 21, 2001 at 15:39 UTC
Bullseye, mirod - that was it exactly. Thanks a bunch! cheers, Don striving for Perl Adept (it's pronounced "why-bick")	[reply]
Re: Parsing external config file by BoredByPolitics (Scribe) on Jan 21, 2001 at 18:17 UTC
Not an answer to your question, but I would really recommend you investigate the AppConfig module. Makes changing/adding parameters at a later date extremely easy. It also handles both config files and commandline options. Pete	[reply]
Re: (2) Parsing external config file (variable interpolation in config file?) by ybiC (Prior) on Jan 21, 2001 at 19:34 UTC
Thanks for the suggestion, BBP. I was going to do that very thing a while back, and researched as many config file parsers as I could find. A new twist has cropped up though. It would simplify things a lot if I could include variable names for new passwords and community strings in the external config file. Not the passwords themselves, mind you (the script prompts for and retains them in RAM). I believe the term is "variable interpolation". Do you know if AppConfig would allow that? Or should I look at something like `do`ing Perl code as a config file? Ideally, it would go something like this, like templating I suppose: `[SetPass] conf t enable pass $newen line con 0 pass $newpass login line aux0 pass $newpass login line vty 0 4 pass $newpass login` [download] cheers, Don striving for Perl Adept (it's pronounced "why-bick") Update: Hmmm... that sounds very interesting BoredByPolitics. /me wanders off to take a look...	[reply] [d/l]
Re: Re: (2) Parsing external config file (variable interpolation in config file?) by BoredByPolitics (Scribe) on Jan 21, 2001 at 20:22 UTC
Yes! You can define 4 types of config variable - Boolean ("varname!") Scalar ("varname=s") Array ("varname=@") Hash ("varname=%") So your line `enable pass $newen` would be best handled as a hash, which would be called `enable`. `[section]` has the effect of prefixing the varname with the section name, so `login` would become `SetPass_login`. Multiple assignments to the same array or hash add further elements. Both environment varibles, and those previously defined in the config file, can be expanded as values. Take a look at the pods for AppConfig::State and AppConfig::File for more details. Overall I'm very impressed with this module - it has definately saved me alot of time with the program I'm currently writing. Pete	[reply] [d/l] [select]


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