Debugging Perl Komodo IDE only

Tutorial

Komodo can debug Perl programs locally or remotely, including debugging in CGI and mod_perl environments. The instructions below describe how to configure Komodo and Perl for debugging. For general information about using the Komodo debugger, see Komodo Debugger Functions.

Debugger commands can be accessed from the Debug menu, by shortcut keys, or from the Debug Toolbar. For a summary of debugger commands, see the Debugger Command List.

Configuring the Perl Debugger

To specify which Perl interpreter Komodo uses to debug and run Perl programs:

  1. On the Edit menu, click Preferences.
  2. In the Preferences dialog box under Languages, click Perl. Komodo searches for Perl interpreters on your system and displays them in the drop-down list.
  3. If the preferred interpreter is in this list, click to select it. If not, click Browse to locate it.
  4. Click OK.

To start a local Perl debugging session:

On the Debug menu or Debug Toolbar, click Go/Continue or Step In to invoke the debugging session. See Komodo Debugger Functions for full instructions on using Komodo's debugging functionality.

Startng a Komodo debugging session with perl -d

You may wish to use the Komodo debugger when working at the command line instead of using perl's built-in debugger. To do this, configure the environment variables described in Debugging Perl Remotely on your local machine using localhost as the hostname. Running the comand 'perl -d' will start a debugging session in Komodo.

Enabling "Break Now"

By default, the Break Now function is disabled for Perl debugging because some programs and modules (e.g. LWP and WWW::Mechanize) are not compatible with asynchronous breaking.

To enable Break Now, include the setting 'async=1' in the PERLDB_OPTS environment variable. This can be done in Komodo's Environment preferences (Edit|Preferences...|Environment).

Debugging Perl Remotely

When debugging a Perl program remotely, the program is executed on the remote system and the debug output is sent to Komodo. Komodo controls the debugging session (e.g. stepping and breakpoints) once the session starts on the remote system.

Perl remote debugging works on any system that can run the version of perl5db.pl distributed with Komodo. ActivePerl and most other distributions of Perl (version 5.6 or greater) will work.

Note: If you have the ActiveState Perl Development Kit (PDK) installed, follow the instructions for PDK users to disable the PDK debugger before continuing.

To debug Perl programs remotely:

Step One: Configure the Remote Machine

  1. Copy Komodo's perl debugger and its associated libraries to the remote machine by copying the entire dbgp/perllib sub-directory of the Komodo installation to the new machine, or download a package from the Komodo Remote Debugging page.

    Note: Do not copy perl5db.pl to the standard "lib" directory of the Perl installation on the remote machine, as this will overwrite the standard perl5db.pl file.


  2. On the remote machine, set the PERL5LIB environment variable to the location of the new perl5db.pl and its libraries. For example, if the remote machine is running Windows and perllib directory was copied to C:\misc\perllib, set the variable as follows:
    set PERL5LIB=C:\misc\perllib

    For example, if the remote machine is running Linux or Mac OS X and perllib was copied to the /home/me/perl/komodo_perl_debugging directory, set the variable as follows:

    export PERL5LIB=/home/me/perl/komodo_perl_debugging/perllib
  3. On the remote machine, set the PERLDB_OPTS and DBGP_IDEKEY variables. This tells the Perl interpreter on the remote machine where to connect to Komodo or the DBGP Proxy and how to identify itself.

    PERLDB_OPTS=RemotePort=<hostname>:<port>
    DBGP_IDEKEY=<ide_key>
    

    For example:

    Windows 2000, NT, XP

    set PERLDB_OPTS=RemotePort=127.0.0.1:9000
    set DBGP_IDEKEY=jdoe
    

    Windows Me

    Use the MSCONFIG utility (Start|Run|MSCONFIG). Select the Environment tab, and create a new variable with the Variable Name of PERLDB_OPTS, and the Variable Value of RemotePort=127.0.0.1:9000.

    Linux and Mac OS X Systems

    export PERLDB_OPTS="RemotePort=127.0.0.1:9000"
    export DBGP_IDEKEY="jdoe"
    

    Note: As with local debugging, the Break Now function is disabled by default. To enable this button and functionality, add the option 'async=1' to the PERLDB_OPTS environment variable. For example, on Windows:

    set PERLDB_OPTS=RemotePort=127.0.0.1:9000 async=1
    

Step Two: Listen for Debugger Connections

In Komodo, on the Debug menu, click Listen for Debugger Connections.

Step Three: Start the Perl Program on the Remote Machine

Start the debugging process using the "-d" flag:

perl -d program_name.pl

A Perl Debug tab is displayed in Komodo.

Step Four: Debug the Perl Program using Komodo

Click Step In, or Go/Continue to run to the first breakpoint. See Komodo Debugger Functions for full instructions on using Komodo's debugging functionality.

Disabling and Enabling the Perl Dev Kit (PDK) Debugger

If you have installed the ActiveState Perl Development Kit (PDK) on the remote machine, the system may be configured to use the PDK debugger when a Perl debug session (perl -d) is launched. To use Komodo's debugger, disable the PDK debugger on the remote machine first. If necessary, you can re-enable the PDK debugger on the remote machine later.

Disabling the PDK Debugger on the Remote Machine

To disable the PDK debugger on the remote machine, perform one of the following procedures:

Option 1:

At the command shell, enter the following command:

Windows

set PERL5DB=BEGIN { require 'perl5db.pl'; }
set PERLDB_OPTS=

Linux

export PERLDB_OPTS=

To re-enable the PDK debugger, set the PERL5DB variable to an empty string.

Option 2: (Windows)

  1. Open System Properties:

These changes take effect in new Command Prompt windows. To re-enable the PDK debugger, delete the PERL5DB variable, and change the PERLDB_OPTS variable back to it's original value.

Configuring Perl for CGI Debugging

Debugging CGI programs on live production servers can seriously impair performance. We recommend using a test server for CGI debugging. Instructions for configuring Microsoft IIS and Apache servers are shown below; for other web servers, use these examples and the web server software documentation as a guide for modifying the server environment.

The settings and paths listed are examples only. Substitute these with the specific paths, hostnames and port numbers of your server as necessary

Configuring a Microsoft IIS Web Server

Configuring an Apache Web Server

Ensure that Perl CGI scripts are operating correctly on the Apache server before proceeding with CGI debugger configuration. If you are running Apache under Windows, disable the ScriptInterpreterSource registry in the httpd.conf file. Use a stand-alone Perl interpreter for remote debugging.

Starting a CGI Debugging Session

After the configuration is complete, debug programs as follows:

Debugging mod_perl

Debugging mod_perl handlers is similar to debugging any Perl program remotely (see Debugging Perl Remotely to familiarize yourself with the terminology). Debugging mod_perl is different in that you'll typically invoke the code indirectly with a web browser, and that the Perl code is running inside an Apache web server.

To configure Komodo debugging in mod_perl:

  1. Copy the entire dbgp/perllib sub-directory of the Komodo installation to a convenient directory on the server, or download and unpack the Perl Remote Debugging package from the Komodo Remote Debugging page. If you are running Apache on your local workstation, you can use Komodo's copy directly (e.g. <Komodo-install-dir>/lib/support/dbgp/perllib ) for the following steps. Note: Do not copy perl5db.pl to the standard "lib" directory of the Perl installation on the remote machine, as this will overwrite the standard perl5db.pl file.

  2. In the directory containing perl5db.pl, create a new directory called Apache. For example:
    $ cd Komodo/lib/support/dbgp/perllib
    $ mkdir Apache
    
  3. Create a symlink or shortcut to perl5db.pl within the new Apache directory. For example:
    $ cd Apache
    $ ln -s ../perl5db.pl .
    
  4. Install the Apache::DB perl module on the server:
    $ cpan Apache::DB
    
  5. Add the following snippet to your httpd.conf file (replace "/path/to/dbgp/perllib" with the full path to the directory containing perl5db.pl):
    <Perl> 
      use ModPerl::Registry;
      use lib qw(/path/to/dbgp/perllib);
      $ENV{PERLDB_OPTS} = "RemotePort=localhost:9000 LogFile=stderr";
      use Apache::DB ();
      Apache::DB->init;
    </Perl> 
    

    Make sure that RemotePort is set to the hostname and port Komodo using to listen for debugger connections (see the PERLDB_OPTS setting in the "Configure the Remote Machine" section of Debugging Perl Remotely).

  6. You will probably already have a <Location> section in httpd.conf (or apache.conf) for your perl scripts. Add the following line to that section:
    PerlFixupHandler Apache::DB
    

    For example:

    <Location /perl-bin> 
      SetHandler perl-script
      PerlHandler ModPerl::Registry
      Options +ExecCGI
      PerlOptions +ParseHeaders
      PerlFixupHandler Apache::DB
    </Location>
    
  7. Restart Apache in debug mode (e.g. apache -X), and open the page you wish to debug in a browser.