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PAR::Tutorial(3) User Contributed Perl Documentation PAR::Tutorial(3) NAME PAR::Tutorial - Cross-Platform Packaging and Deployment with PAR SYNOPSIS This is a tutorial on PAR, first appeared at the 7th Perl Conference. The HTML version of this tutorial is available online as <http://search.cpan.org/perldoc?PAR::Tutorial> DESCRIPTION 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(...)'" • How do we know which modules are needed? • New versions of CPAN modules may break "sshnuke.pl" • A2: Install Perl & "tar zxf my_perllib.tgz" • Possibly overwriting existing modules; not cross-platform at all • A3: Use the executable generated by "perlcc sshnuke.pl" • Impossible to debug; "perlcc" usually does not work anyway PAR, the Perl Archive Toolkit • Do what JAR (Java Archive) does for Perl • Aggregates modules, scripts and other files into a Zip file • Easy to generate, update and extract • Version consistency: solves forward-compatibility problems • Developed by community: "par@perl.org" • PAR files can be packed into self-contained scripts • Automatically scans perl script for dependencies • Bundles all necessary 3rd-party modules with it • Requires only core Perl to run on the target machine • PAR also comes with "pp", the Perl Packager: % pp -o sshnuke.exe sshnuke.pl # stand-alone executable! 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: • "-b" bundles non-core modules needed by "PAR.pm": % par.pl -b -O./foo.pl foo.par # self-contained script • "-B" bundles core modules in addition to "-b": % parl -B -O./foo.exe foo.par # self-contained binary 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 • Also supports "gcc"-style long options: % pp --gui --verbose --output=out.exe src.pl • 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 • However, XS modules are specific to Perl version and platform • Multiple versions of a XS module can co-exist in a PAR file • 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 • Index of all files inside PAR • Can be parsed with "ExtUtils::Manifest" • META.yml • Dependency, license, runtime options • Can be parsed with "YAML" • SIGNATURE • OpenPGP-signed digital signature • Can be parsed and verified with "Module::Signature" Advantages over perlcc, PerlApp and Perl2exe • This is not meant to be a flame • All three maintainers have contributed to PAR directly; I'm grateful • perlcc • "The code generated in this way is not guaranteed to work... Use for production purposes is strongly discouraged." (from perldoc perlcc) • Guaranteed to not work is more like it • PerlApp / Perl2exe • Expensive: Need to pay for each upgrade • Non-portable: Only available for limited platforms • Proprietary: Cannot extend its features or fix bugs • Obfuscated: Vendor and black-hats can see your code, but you can't • Inflexible: Does not work with existing Perl installations 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 • Supported by "Module::Build", "ExtUtils::MakeMaker", "Module::Install" • 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 • Supported by "Module::Signature", "CPANPLUS" and "Module::Build" • A typical "SIGNATURE" looks like this: -----BEGIN PGP SIGNED MESSAGE-----Hash: MESSAGE----Hash: Hash: SHA1 SHA1 8a014cd6d0f6775552a01d1e6354a69eb6826046 AUTHORS ... -----BEGIN PGP SIGNATURE-----... SIGNATURE----... ... -----END PGP SIGNATURE-----• 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 • Similar to Java's "Web Application Archive" (WAR) files • Works with mod_perl 1.x or 2.x • A complete web application inside a ".par" file • Apache configuration, static files, Perl modules... • Supports Static, Registry and PerlRun handlers • Can also load all PARs under a directory • 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" • Download only if modified • Safe for offline use after the first time • May use "SIGNATURE" to prevent DNS-spoofing • Makes large-scale deployment a breeze • Upgrades from a central location • No installers needed Code Obfuscation • Also known as source-hiding techniques • It is not encryption • Offered by PerlApp, Perl2Exe, Stunnix... • Usually easy to defeat • Take optree dump from memory, feed to "B::Deparse" • If you just want to stop a casual "grep", "deflate" already works • PAR now supports pluggable input filters with "pp -f" • Bundled examples: Bleach, PodStrip and PatchContent • True encryption using "Crypt::*" • Or even _product activation_ over the internet • 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"? • Some toolkits (notably Tk) autoloads modules without "use" or "require" • Hence "pp" and "Module::ScanDeps" may fail to detect them • Tk problems mostly fixed by now, but other toolkits may still break • You can work around it with "pp -M" or an explicit "require" • Or better, send a short test-case to "par@perl.org" so we can fix it Precompiled CPAN distributions • Installing XS extensions from CPAN was difficult • Some platforms do not come with a compiler (Win32, MacOSX...) • Some headers or libraries may be missing • PAR.pm itself used to suffer from both problems • ...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 • Of course, you still need to type "make par" and upload the precompiled package • PAR users can also install it directly with "parl -i" Platform-specific Tips • Win32 and other icon-savvy platforms • Needs 3rd-party tools to add icons to "pp"-generated executables • PE Header manipulation in Perl -- volunteers wanted! • Linux and other libc-based platforms • Try to avoid running "pp" on a bleeding-edge version of the OS • Older versions with an earlier libc won't work with new ones • Solaris and other zlib-lacking platforms (but not Win32) • You need a static-linked "Compress::Zlib" before installing PAR • In the future, PAR may depend on "Compress::Zlib::Static" instead • Any platform with limited bandwidth or disk space • Use UPX to minimize the executable size Thank you! • Additional resources • Mailing list: "par@perl.org" • Subscribe: Send a blank email to "par-subscribe@perl.org" • List archive: <http://nntp.x.perl.org/group/perl.par> • PAR::Intro: <http://search.cpan.org/dist/PAR/lib/PAR/Intro.pod> • Apache::PAR: http://search.cpan.org/dist/Apache-PAR/ <http://search .cpan.org/dist/Apache- PAR /> • Module::Install: http://search.cpan.org/dist/Module-Install/ <http://search.cpan.org/dist/Module-Install/> • Any questions? Bonus Slides: PAR Internals Overview of PAR.pm's Implementation • Here begins the scary part • Grues, Dragons and Jabberwocks abound... • You are going to learn weird things about Perl internals • PAR invokes four areas of Perl arcana: • @INC code references • On-the-fly source filtering • Overriding "DynaLoader::bootstrap()" to handle XS modules • Making self-bootstrapping binary executables • The first two only works on 5.6 or later • DynaLoader and %INC are there since Perl 5 was born • PAR currently needs 5.6, but a 5.005 port is possible Code References in @INC • On 1999-07-19, Ken Fox submitted a patch to P5P • To _enable using remote modules_ by putting hooks in @INC • It's accepted to come in Perl 5.6, but undocumented until 5.8 • Type "perldoc -f require" to read the nitty-gritty details • 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! • It turns out that @INC hooks can return two values • The first is still the file handle • The second is a code reference for line-by-line source filtering! • 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 • They cannot be loaded as part of a zip file, so we extract them out • Must intercept DynaLoader's library-finding process • Module names are passed to "bootstrap" for XS loading • During the process, it calls "dl_findfile" to locate the file • So we install pre-hooks around both functions • Our "_bootstrap" just checks if the library is in PARs • If yes, extract it to a "File::Temp" temp file • The file will be automatically cleaned up when the program ends • It then pass the arguments to the original "bootstrap" • Finally, our "dl_findfile" intercepts known filenames and return it Anatomy of a Self-Contained PAR executable • The par script ($0) itself • May be in plain-text or native executable format • Any number of embedded files • Typically used to bootstrap PAR's various dependencies • Each section begins with the magic string "FILE" • Length of filename in pack('N') format and the filename (auto/.../) • File length in pack('N') and the file's content (not compressed) • One PAR file • Just a regular zip file with the magic string "PK\003\004" • Ending section • A pack('N') number of the total length of FILE and PAR sections • Finally, there must be a 8-bytes magic string: "\012PAR.pm\012" Self-Bootstrapping Tricks • All we can expect is a working perl interpreter • The self-contained script *must not* use any modules at all • But to process PAR files, we need XS modules like Compress::Zlib • Answer: bundle all modules + libraries used by PAR.pm • That's what the "FILE" section in the previous slide is for • Load modules to memory, and write object files to disk • Then use a local @INC hook to load them on demand • Minimizing the amount of temporary files • First, try to load PerlIO::scalar and File::Temp • Set up an END hook to unlink all temp files up to this point • Load other bundled files, and look in the compressed PAR section • This can be much easier with a pure-perl "inflate()"; patches welcome! Thank you (again)! • Any questions, please? SEE ALSO PAR, pp, par.pl, parl ex::lib::zip, Acme::use::strict::with::pride App::Packer, Apache::PAR, CPANPLUS, Module::Install AUTHORS Audrey Tang <cpan@audreyt.org> <http://par.perl.org/> is the official PAR website. You can write to the mailing list at <par@perl.org>, or send an empty mail to <par-subscribe@perl.org> to participate in the discussion. Please submit bug reports to <bug-par@rt.cpan.org>. COPYRIGHT Copyright 2003, 2004, 2005, 2006 by Audrey Tang <cpan@audreyt.org>. This document is free documentation; you can redistribute it and/or modify it under the same terms as Perl itself. See <http://www.perl.com/perl/misc/Artistic.html> perl v5.12.5 2010-02-02 PAR::Tutorial(3) |
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