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

I am using Perl CLI Framework to write some script. Now I want to pass the variable from the control module to the sub-command module. I have tried to set the variable as the global variable in the control module but the sub-command module still cannot get the variable. It is even not able to share the global variable in the same module. There are some error messages when executing the script: 
[root@old]# perl pc --ip=dsfa --device dsfasdf on
Use of uninitialized value $Power::Control::data in concatenation (.) 
+or string at Power/Control.pm line 63.

 The globla data is 
Use of uninitialized value $Power::Control::data in concatenation (.) 
+or string at Power/Control.pm line 75.

 The data from parent is  

 The device name is dsfasdf

 The ip address is dsfa

 This is the command on

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Here is the script pc: 
    #! /usr/bin/perl
    
    use strict;
    use warnings;
    use Power::Control;
    
    use lib 'lib';
    
    # ---- EXECUTION ----
    Power::Control->run(); # Launch command

[download]
Here is the Power/Control.pm: 
    package Power::Control;
    use base qw( CLI::Framework );
    
    use strict;
    use warnings;
    
    sub usage_text {
        qq{
        $0 [--verbose|v]:
    
        OPTIONS:
            --verbose -v:   be vebose
    
        ARGUMENTS (subcommands):
            on:         power on the device
            off:        power off the device
            reboot:     reboot the device
            version:    show PDU version
            status:     show PDU status
            sysstat:    show PDU sysstatus
        }
    }
    
    sub option_spec {
        [ 'device|d=s'     => 'device name' ],
        [ 'ip=s'           => 'ip address' ],
        [ 'user|u=s'       => 'user name' ],
        [ 'password|p=s'   => 'password' ],
        [ 'interval|i=s'   => 'interval' ],
        [ 'brand|b=s'      => 'brand' ],
        [ 'community|c=s'  => 'community' ],
        [ 'version|v=s'    => 'version' ],
    }
    
    sub command_map {
        on      => 'Power::Control::Command::On',
        off     => 'Power::Control::Command::Off',
        reboot  => 'Power::Control::Command::Reboot',
        version => 'Power::Control::Command::Version',
        status  => 'Power::Control::Command::Status',
        sysstat => 'Power::Control::Command::Sysstat',
    }
    
    sub command_alias {
        r   => 'reboot',
        v   => 'version',
        st  => 'status',
        sys => 'sysstat',
    }
    
    our $opts;
    our $self;
    our $data;
    
    sub init {
        ($self, $opts) = @_;
    
        $data = $opts->{'ip'};
        print "\n The device name is $opts->{'device'}\n";
        print "\n The ip address is $data\n";
    }
    
    print "\n The globla data is $data\n";
    1;
    
    # ---- COMMAND: On ----
    package Power::Control::Command::On;
    use base qw( CLI::Framework::Command );
    
    use strict;
    use warnings;
    use Power::Control;
    use Data::Dumper;
    
    print "\n The data from parent is $data \n";
    
    sub usage_text {
        q{
        on [--d=<device name>: Power on the device
        }
    }
    
    #sub option_spec {
    #    [ 'device|d=s@'   => 'device name'  ],
    #}
    
    sub run {
    
        print "\n This is the command on\n";
    }
    1;

[download]

Replies are listed 'Best First'.
Re: How to share the global variables between two modules by using Perl CLI Framework?
by Preceptor (Deacon) on Jun 12, 2013 at 19:39 UTC
    At risk of missing the point of the question you're asking - have you had a look at the module 'Exporter'? It's ... well, it's basically geared up to exporting (and importing) variables from modules.

    Anyway, that aside - the reason you get those to errors, is because the module 'runs' when you import it. The print statements on like 63 and 75 aren't encapsulated within a subroutine, so they run at the same time as you import the module - which is before the 'init' subroutine is called.

    You will get the same error with a blank script that just has the 'use' lines in it, I think. 

    #!/usr/bin/perl

use strict;
use warnings;

package testfish;

sub sub_to_do_something
{
  print "Doing something \n";
}

print "FISH\n";
1;

    [download]
    And script: 
    #!/usr/bin/perl

use strict;
use warnings;
use testfish;

print "Not done anything with the module yet\n";
&testfish::sub_to_do_something();

    [download]
    Gives an output of: 
    FISH
Not done anything with the module yet
Doing something

    [download]
    Which is more or less the same as you're doing with that 'print' line in your modules. Init hasn't been called yet. (I assume it's something that CLI::Framework requires and uses later).
[reply]
[d/l]
[select]
Re: How to share the global variables between two modules by using Perl CLI Framework?
by Anonymous Monk on Jun 13, 2013 at 00:19 UTC
[reply]

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