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Writing commandlets with parameters in Perl


Summary: I've noticed a strange behaviour (in WFA 4.0 and 4.1) when writing a Perl commandlet. Although I define the parameters correctly (I think), they are not passed to the perl code properly unless I actually craft a Powershell param() equivalent and use that to discover the parameters.


Take this simple example:


use strict;
use warnings;
use Getopt::Long;
use WFAUtil;
use Data::Dumper;

my $wfa_util = WFAUtil->new();

my $success = 'true';
  "success:s" => \$success
) or die 'Illegal command parameters\n';

$wfa_util->sendLog('INFO', 'Success: ' . $success);

I define a parameter "success" as a boolean on the "Parameters Definition" tab and the "Parameters Mapping" tab is populated automatically. Now when I run this commandlet, I always get "Success: true" despite what value I select on the test. Diving into the perl specifics, it looks like the parameter is passed only after a '--' argument which causes GetOptions to ignore the parameter.



The only way to get aroud this seems to be to define a minimal PowerShell script which can be used to discover the same parameter (i.e. the config tabs look exactly the same as before after the discovery):

param (
  [parameter (Mandatory=$False, HelpMessage="None")]

And then suddenly the Perl code works as expected.



Now, maybe I missed something obvious and this is not a bug which is why I post it here before opening up a ticket with support. Any ideas anyone?


Re: Writing commandlets with parameters in Perl




'Discover Parameters' is not available for Perl commands. You would need to manually add parameters in 'Parameter Definitions' tab. 


You code looks fine and it works fine at my end with WFA too.


Export your command in .dar file and post here. lets see if that gives any clue.







If this post resolved your issue, help others by selecting ACCEPT AS SOLUTION or adding a KUDO.

Re: Writing commandlets with parameters in Perl


Thanks for looking into this. And I've found the problem as well. Why not write your first ever post based on a rookie mistake, kinda makes sense ...


I was about to recreate the commad one more time in order to export to dar as you requested. This is when I finally realized my mistake. When adding the parameters manually, you press "Add Parameter" to add a blank line. I then double (!) clicked the name column of that blank line to fill it in -- not realizing that a double click will put the cursor behind a single space character. So I ended up adding a parameter called " success" rather than "success" everytime which obviously cannot work.


Apologies for the rookie mistake, but at least posting here helped me solve my personal problem. Yay for the community.


Maybe there are technical reasons for putting in the single space character for new parameters - if not, it might make sense to remove it in future versions to avoid my mistake?





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