On Deploying Perl Applications

% sshnuke.pl 10.2.2.2 -rootpw="Z1ON0101"
Perl v5.6.1 required--this is only v5.6.0, stopped at sshnuke.pl line 1.
BEGIN failed--compilation aborted at sshnuke.pl line 1.

• Q: "Help! I can't run your program!"
• A1: Install Perl & "perl -MCPAN -e'install(...)'"

•

A2: Install Perl & "tar zxf my_perllib.tgz"

•

A3: Use the executable generated by "perlcc sshnuke.pl"

PAR, the Perl Archive Toolkit

•

Do what JAR (Java Archive) does for Perl

•

PAR files can be packed into self-contained scripts

Simple Packaging

• PAR files are just Zip files with modules in it
• Any Zip tools can generate them:

  % zip foo.par Hello.pm World.pm        # pack two modules
  % zip -r bar.par lib/          # grab all modules in lib/
  

• To load modules from PAR files:

  use PAR;
  use lib "foo.par";             # the .par part is optional
  use Hello;
  

• This also works:

  use PAR "/home/mylibs/*.par";  # put all of them into @INC
  use Hello;
  

PAR Loaders

• Use "par.pl" to run files inside a PAR archive:

  % par.pl foo.par               # looks for 'main.pl' by default
  % par.pl foo.par test.pl       # runs script/test.pl in foo.par
  

• Same thing, with the stand-alone "parl" or "parl.exe":

  % parl foo.par                 # no perl or PAR.pm needed!
  % parl foo.par test.pl         # ditto
  

• The PAR loader can prepend itself to a PAR file:

Dependency Scanning

• Recursively scan dependencies with "scandeps.pl":

  % scandeps.pl sshnuke.pl
  # Legend: [C]ore [X]ternal [S]ubmodule [?]NotOnCPAN
  'Crypt::SSLeay'       => '0', #  X   #
  'Net::HTTP'           => '0', #      #
  'Crypt::SSLeay::X509' => '0', # S    # Crypt::SSLeay
  'Net::HTTP::Methods'  => '0', # S    # Net::HTTP
  'Compress::Zlib'      => '0', #  X   # Net::HTTP::Methods
  

• Scan an one-liner, list all involved files:

  % scandeps.pl -V -e "use Dynaloader;"
  ...
  # auto/DynaLoader/dl_findfile.al [autoload]
  # auto/DynaLoader/extralibs.ld [autoload]
  # auto/File/Glob/Glob.bs [data]
  # auto/File/Glob/Glob.so [shared]
  ...
  

Perl Packager: "pp"

• Combines scanning, zipping and loader-embedding:

  % pp -o out.exe src.pl         # self-contained .exe
  % out.exe                      # runs anywhere on the same OS
  

• Bundle additional modules:

  % pp -o out.exe -M CGI src.pl  # pack CGI + its dependencies, too
  

• Pack one-liners:

  % pp -o out.exe -e 'print "Hi!"'   # turns one-liner into executable
  

• Generate PAR files instead of executables:

  % pp -p src.pl                 # makes 'source.par'
  % pp -B -p src.pl              # include core modules
  

How it works

•

Command-line options are almost identical to "perlcc"'s

• Small initial overhead; no runtime overhead
• Dependencies are POD-stripped before packing
• Loads modules directly into memory on demand
• Shared libraries (DLLs) are extracted with File::Temp
• Works on Perl 5.6.0 or above
• Tested on Win32 (VC++ and MinGW), FreeBSD, NetBSD, Linux, MacOSX, Cygwin, AIX, Solaris, HP-UX, Tru64...

Aggregating multiple programs

• A common question:

  > I have used pp to make several standalone applications which work
  > great, the only problem is that for each executable that I make, I am
  > assuming the parl.exe is somehow bundled into the resulting exe.
  

• The obvious workaround:

  You can ship parl.exe by itself, along with .par files built
  by "pp -p", and run those PAR files by associating them to parl.exe.
  

• On platforms that have "ln", there is a better solution:

  % pp --output=a.out a.pl b.pl  # two scripts in one!
  % ln a.out b.out               # symlink also works
  % ./a.out                      # runs a.pl
  % ./b.out                      # runs b.pl
  

Cross-platform Packages

• Of course, there is no cross-platform binary format
• Pure-perl PAR packages are cross-platform by default

• Suppose we need "out.par" on both Win32 and Finix:

  C:\> pp --multiarch --output=out.par src.pl
  ...copy src.pl and out.par to a Finix machine...
  % pp --multiarch --output=out.par src.pl
  

• Now it works on both platforms:

  % parl out.par                 # runs src.pl
  % perl -MPAR=out.par -e '...'  # uses modules inside out.par
  

The Anatomy of a PAR file

• Modules can reside in several directories:

  /                      # casual packaging only
  /lib/                  # standard location
  /arch/                 # for creating from blib/ 
  /i386-freebsd/         # i.e. $Config{archname}
  /5.8.0/                # i.e. Perl version number
  /5.8.0/i386-freebsd/   # combination of the two above
  

• Scripts are stored in one of the two locations:

  /                      # casual packaging only
  /script/               # standard location
  

• Shared libraries may be architecture- or perl-version-specific:

  /shlib/(5.8.0/)?(i386-freebsd/)?
  

• PAR files may recursively contain other PAR files:

  /par/(5.8.0/)?(i386-freebsd/)?
  

Special files

•

MANIFEST

•

META.yml

•

SIGNATURE

Advantages over perlcc, PerlApp and Perl2exe

•

This is not meant to be a flame

•

perlcc

•

PerlApp / Perl2exe

MANIFEST: Best viewed with Mozilla

• The URL of "MANIFEST" inside "/home/autrijus/foo.par":

  jar:file:///home/autrijus/foo.par!/MANIFEST
  

• Open it in a Gecko browser (e.g. Netscape 6+) with Javascript enabled:
• No needed to unzip anything; just click on files to view them

META.yml: Metadata galore

•

Static, machine-readable distribution metadata

• A typical "pp"-generated "META.yml" looks like this:

  build_requires: {}
  conflicts: {}
  dist_name: out.par
  distribution_type: par
  dynamic_config: 0
  generated_by: 'Perl Packager version 0.03'
  license: unknown
  par:
    clean: 0
    signature: ''
    verbatim: 0
    version: 0.68
  

• The "par:" settings controls its runtime behavior

SIGNATURE: Signing and verifying packages

•

OpenPGP clear-signed manifest with SHA1 digests

• A typical "SIGNATURE" looks like this:

  -----BEGIN PGP SIGNED MESSAGE-----
  Hash: SHA1
  SHA1 8a014cd6d0f6775552a01d1e6354a69eb6826046 AUTHORS
  ...
  -----BEGIN PGP SIGNATURE-----
  ...
  -----END PGP SIGNATURE-----
  

• Use "pp" and "cpansign" to work with signatures:

  % pp -s -o foo.par bar.pl      # make and sign foo.par from bar.pl
  % cpansign -s foo.par  # sign this PAR file
  % cpansign -v foo.par  # verify this PAR file
  

Perl Servlets with Apache::PAR

•

Framework for self-contained Web applications

•

A complete web application inside a ".par" file

•

One additional special file: "web.conf"

Alias /myapp/cgi-perl/ ##PARFILE##/
<Location /myapp/cgi-perl>
    Options +ExecCGI
    SetHandler perl-script
    PerlHandler Apache::PAR::Registry
</Location>

Hon Dah, A-par-che!

• First, make a "hondah.par" from an one-liner:

  # use the "web.conf" from the previous slide
  % pp -p -o hondah.par -e 'print "Hon Dah!\n"' \
       --add web.conf
  % chmod a+x hondah.par
  

• Add this to "httpd.conf", then restart apache:

  <IfDefine MODPERL2>
  PerlModule Apache2
  </IfDefine>
  PerlAddVar PARInclude /home/autrijus/hondah.par
  PerlModule Apache::PAR
  

• Test it out:

  % GET http://localhost/myapp/cgi-perl/main.pl
  Hon Dah!
  

• Instant one-liner web application that works!

On-demand library fetching

• With LWP installed, your can use remote PAR files:

  use PAR;
  use lib 'http://aut.dyndns.org/par/DBI-latest.par';
  use DBI;    # always up to date!
  

• Modules are now cached under $ENV{PAR_GLOBAL_TEMP}
• Auto-updates with "LWP::Simple::mirror"

•

Makes large-scale deployment a breeze

Code Obfuscation

•

Also known as source-hiding techniques

•

Usually easy to defeat

•

PAR now supports pluggable input filters with "pp -f"

•

Alternatively, just keep core logic in your server and use RPC

Accessing packed files

• To get the host archive from a packed program:

  my $zip = PAR::par_handle($0); # an Archive::Zip object
  my $content = $zip->contents('MANIFEST');
  

• Same thing, but with read_file():

  my $content = PAR::read_file('MANIFEST');
  

• Loaded PAR files are stored in %PAR::LibCache:

  use PAR '/home/mylibs/*.par';
  while (my ($filename, $zip) = each %PAR::LibCache) {
      print "[$filename - MANIFEST]\n";
      print $zip->contents('MANIFEST');
  }
  

Packing GUI applications

• GUI toolkits often need to link with shared libraries:

  # search for libncurses under library paths and pack it
  % pp -l ncurses curses_app.pl  # same for Tk, Wx, Gtk, Qt...
  

• Use "pp --gui" on Win32 to eliminate the console window:

  # pack 'src.pl' into a console-less 'out.exe' (Win32 only)
  % pp --gui -o out.exe src.pl
  

• "Can't locate Foo/Widget/Bar.pm in @INC"?

Precompiled CPAN distributions

•

Installing XS extensions from CPAN was difficult

• ...but not anymore -- "Module::Install" to the rescue!

  # same old Makefile.PL, with a few changes
  use inc::Module::Install;      # was "use ExtUtils::MakeMaker;"
  WriteMakefile( ... );          # same as the original
  check_nmake();                 # make sure the user have nmake
  par_base('AUTRIJUS');          # your CPAN ID or a URL
  fetch_par() unless can_cc();   # use precompiled PAR only if necessary
  

• Users will not notice anything, except now it works

Thank you!

•

Additional resources

•

Any questions?

Overview of PAR.pm's Implementation

•

Here begins the scary part

•

PAR invokes four areas of Perl arcana:

•

The first two only works on 5.6 or later

Code References in @INC

•

On 1999-07-19, Ken Fox submitted a patch to P5P

• Coderefs in @INC may return a fh, or undef to 'pass':

  push @INC, sub {
      my ($coderef, $filename) = @_;  # $coderef is \&my_sub
      open my $fh, "wget ftp://example.com/$filename |";
      return $fh;        # using remote modules, indeed!
  };
  

• Perl 5.8 let you open a file handle to a string, so we just use that:

  open my $fh, '<', \($zip->memberNamed($filename)->contents);
  return $fh;
  

• But Perl 5.6 does not have that, and I don't want to use temp files...

Source Filtering without Filter::* Modules

•

... Undocumented features to the rescue!

•

This is how "Acme::use::strict::with::pride" works:

# Force all modules used to use strict and warnings
open my $fh, "<", $filename or return;
my @lines = ("use strict; use warnings;\n", "#line 1 \"$full\"\n");
return ($fh, sub {
    return 0 unless @lines;    
    push @lines, $_; $_ = shift @lines; return length $_;
});

Source Filtering without Filter::* Modules (cont.)

• But we don't really have a filehandle for anything
• Another undocumented feature saves the day!
• We can actually omit the first return value altogether:

  # Return all contents line-by-line from the file inside PAR
  my @lines = split(
      /(?<=\n)/,
      $zip->memberNamed($filename)->contents
  );
  return (sub {
      $_ = shift(@lines);
      return length $_;
  });
  

Overriding DynaLoader::bootstrap

•

XS modules have dynamically loaded libraries

•

Module names are passed to "bootstrap" for XS loading

•

Our "_bootstrap" just checks if the library is in PARs

Anatomy of a Self-Contained PAR executable

•

The par script ($0) itself

•

Any number of embedded files

•

One PAR file

•

Ending section

Self-Bootstrapping Tricks

•

All we can expect is a working perl interpreter

•

Answer: bundle all modules + libraries used by PAR.pm

•

Minimizing the amount of temporary files

Thank you (again)!

•

Any questions, please?