Hello Monks,

I am working to develop a software distribution that will be run by several users in my environment. In order this this application to function correctly, I must have the ability to dynamically install CPAN modules when found not to be present within the current PERL installation. I have the logic down; however, I am still having issues...

Logic:
1.) Test if module is currently installed with eval "require <module>";
2.) If module is not installed, install it...

Part two is where I am having problems. I have tried both the command line for cpan (cpan -I <module>) as well as the install function of CPAN::Shell (CPAN::Shell->install(<module>)). Unfortunately every time I run this script it tells me the latest version of the specific module is already installed; however, it most certainly is not. Take the example of Bone::Easy. When I run: CPAN::Shell->install("Bone::Easy"); or `cpan -I Bone::Easy`; I get the message that I already have the latest version. If I then, go on to attempt to use this module (using: require Bone::Easy;), I am met with this module not being installed.

Can anyone help me to better understand what may be going on here. I am certain I am missing something and would really appreciate the help.

Here is a copy of the script I am using to test this procedure...

use CPAN;
use CPAN::Shell;

BEGIN
{
    my @Required_Modules    =    ("LWP::UserAgent","HTTP::Request::Com
+mon","common::sense","Silly::Werder","Bone::Easy");
    my @Installed_Modules    =    ();
    my @Needed_Modules        =    ();
    my @NotInstalled_Modules=    ();
    my @Die_If_Missing        =    ("LWP::UserAgent","HTTP::Request::C
+ommon","common::sense","Silly::Werder","Bone::Easy");
    foreach (@Required_Modules)
    {
        #Eval require * for each module required.
        eval "require ($_)";
        #See from output if module is not already installed - if so, t
+hen add to list of modules needing install.
        if ($@ =~ m/^Can\'t locate/){push(@Needed_Modules,$_)}
        #If modules appears to already be installed, add to list of mo
+dules installed.
        else {push(@Installed_Modules,$_)}
    }
    #For each entry on list of modules needing to be installed:
    foreach (@Needed_Modules)
    {
        #Attempt to install module using cpan
        #my $CPAN_Install    =    `cpan -I $_`;
        #print $CPAN_Install;
        CPAN::Shell->install($_);
        #Parse CPAN output
        my @CPAN_Error    =    split("\n",$CPAN_Install);
        #push module to list of installed modules unless there was a C
+PAN error.
        push(@Installed_Modules,$_) unless $CPAN_Error[$#CPAN_Error] =
+~ m/^>\(error\): Skipping/;
        #push module to list of modules note installed if there was a 
+CPAN error.
        push(@NotInstalled_Modules,$_) if $CPAN_Error[$#CPAN_Error] =~
+ m/^>\(error\): Skipping/;
    }
    foreach(@Installed_Modules){print ("$_\n")}
    foreach(@NotInstalled_Modules){print ("$_\n")}
    <STDIN>;
    foreach(@NotInstalled_Modules)
    {
        my $Missing_Module    =    $_;
        foreach(@Die_If_Missing)
        {
            die("Could not find / instal critical module!") if $Missin
+g_Module eq $_;
        }
    }
    <STDIN>;
}

PickupLine();

sub PickupLine
{
    require Bone::Easy;
    print pickup;
}

[download]
Best,
Bry

In reply to Installing CPAN Modules within BEGIN of PERL Script by GhostCode

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