How do i figure out which dependences of a CPAN distribution require a compiler? - perl

I need to install a perl tool on a production server which has no compiler. I can install CPAN distributions fine via local::lib, but the lack of compiler means I have to ask the sysadmins to install further modules. Due to them having an average turnaround time of 1-2 weeks even for the most ridiculously simple tasks, the process of trying to install, asking them to install what's borked, trying to install again, etc. etc. is extremely painful.
So how can i figure out quickly which given dependencies of a dist require a c compiler, so i can just give them a list?

When you search for a module in CPAN at http://search.cpan.org, take a look at the far right side of the browser window. Over there you'll see a link called Dependencies. This is right below the link to download the module.
If you click on that link, it'll take you to http://deps.cpantesters.org which will show you the dependency tree for that module. For example, take a look at this one for File::Spec at http://deps.cpantesters.org/?module=File::Spec&perl=5.12.1&os=any+OS&pureperl=on&devperls=on.
It's not perfect, but it'll give you a good idea what modules you do need.
The best way is to use the cpan command or the ppm manager on Windows. These will automatically download the dependent modules.

Maybe you could just install all you need on a test server and then package the application along with its dependencies using PAR?

As David said, cpantesters tries to figure out if a module is "pure"..
their explanation on how they do this might be helpful ..
Or I guess you could just install the modules on a similar system and copy them over? Or is this against the "rules"? ;)

Figured out a solution:
Trace system calls with Technet ProcMon (for Windows) or strace on Linux, then run the test suite and filter the result for "/auto/". That way you'll see all dlls it tries to load and can work out the dists requiring a compiler from there.

Related

Giving Credit for Perl Module

I wrote a script for my company and I am using some libraries I obtained from CPAN. My manager wanted me to consolidate and remove the extra libraries - which is a little funny because I include them for the script to work.
A few notes:
I do not have root access on this server nor can I request access
To use CPAN modules w/o root I have them installed to my user directory
To allow other users to run my scripts I usually include a folder called 'libs' and inside of my script's directory and in the script I have: use 'libs'; at the top before I use my CPAN modules.
The only solution I have right now is to literally put the contents of the perl modules inside of my perl script. However I want to give credit where it is due and also not get in trouble for including opensource code w/o proper credit to its authors and organizations.
Therefore, how should I go about this? I am not trying to get away with anything.. I honestly want to go about doing this the right way.
All three modules say "licensed under the same terms as Perl itself" but I feel like it shouldn't be this easy.
I would also like to explore any other ideas too!
The modules are:
Text::Table
Text::Aligner
Term::ANSIColor
Is using PAR Packager an option for you? That would generate a standalone executable.
If the modules are pure Perl modules, you may be able to simply append the code (including those package statements) into your program. I'd also include the POD which would include the copyright statements and the names of the authors too. That should satisfy the Artistic License Requirement (but may not satisfy GNU licensing requirements).
Another possibility is to use Perlbrew which will allow you to install a user version of Perl on the system. This way, you can install CPAN modules without needing Administrative permission, and you can tell other users to use Perlbrew too.
I use it because I can install and switch between various versions of Perl which allows me to test my Perl scripts in various versions of Perl. I've also used it on our servers where I need a newer version of Perl or modules that weren't included in the standard release.
You need to get your IT approval before installing Perlbrew, but a lot of times they're relieved that they no longer have to be bothered with maintaining and installing CPAN modules for your use.
Interesting question & perspective. I don't understand what is against using libraries or modules, but I'll let your manager do the thinking ;-)
Regarding copyright, you're best to consult a lawyer if you want to be sure, but as far as I understand it, you can combine the work of others provided you retain the copyright notices. The combined work may not be covered by copyleft, so you may be able to use it commercially (i.e., distribute it without disclosing the source). But do check with a lawyer.
But, since you said you wanted to explore other ideas, App::Staticperl may be a solution? I do not have experience with it, but I tried it with a simple example and got a working executable.
App::Staticperl builds a stand-alone executable from the Perl interpreter with embedded CPAN modules. The steps I followed were roughly (you'll need to adapt, because obviously I couldn't test with your script):
latest version of App::Staticperl is 1.43: https://cpan.metacpan.org/authors/id/M/ML/MLEHMANN/App-Staticperl-1.43.tar.gz
either install the module via CPAN, or simply extract bin/staticperl from the tar - it's a standalone script
edit staticperl to change EMAIL and CPAN (optional, but you may want to change the CPAN mirror)
./staticperl install downloads and builds Perl; it ended with an error message on my box, but did produce a working Perl
./staticperl cpan enters an interactive CPAN prompt; install Text::Table, install Term::ANSIColor, and whatever else you need
./staticperl mkapp my_app --boot path/to/your/script -MText::Table -MText::Aligner -MTerm::ANSIColor
try the app: ./my_app - it will most likely fail with an error message about missing modules; repeat the previous step and include the missing modules in the -M flags
Good luck!
Can you reduce the unnecessary code (to satisfy your manager's concerns). Leave in tact the needed code in the file it came in - and give the author's credit within that module/package.
Eg: This was inspired (stolen) from Joe E Perl.

Install Perl modules that require customized options via CPAN

a few times I've come across modules that require custom flags when installing. For example, now I'm stuck at Net::ZooKeeper which requires --zookeeper-include and --zookeeper-lib set. Is there a way I can set these within the cpan shell? Or do I just need to build manually?
There's an easy way to "build manually" but still let CPAN handle finding the latest release, downloading, and unpacking for you -- at the cpan shell do look Net::ZooKeeper, or with cpanminus do cpanm --look Net::ZooKeeper, and it'll be fetched and unpacked and then you'll get a shell in the directory it was unpacked into, at which point you can do the usual perl Makefile.PL; make; make install dance with whatever options you like, and then exit. It's pretty simple and probably the fastest possible thing if this is something you only need to do very rarely.
On the other hand, if this is an automated or repetitive process, then go ahead and follow eugene y's advice and create a distroprefs file for the modules that need custom configuration, and deploy it wherever it's needed, and then however and wherever those modules are installed they'll be configured properly and not fail the build :)
See Configuration for individual distributions (Distroprefs) section in the CPAN reference.

How do I install deps for CPAN module without installing it?

This is a follow-up to my previous question about developing Perl applications. Let’s say I develop an application as a CPAN module using Module::Install. Now I upload the code to the production server, say using a git push, and I would like to install the application dependencies listed in Makefile.PL. If I simply run cpan ., the thing tries to install the application like a regular Perl module, ie. starts to copy the modules and documentation to standard Perl directories all over the system.
Is this the way it’s supposed to be? Do you install the application into the standard Perl directories? I am used to having my Perl applications in one directory with separate lib. Otherwise it seems I’d have to manage a lot of other things, like installing the resources somewhere on path etc. If I just want to install the deps declared in Makefile.PL and run the application tests to make sure everything works, what should I do?
(Is this documented somewhere? I mean, is there something like best practice for deploying and updating non-trivial Perl applications? Or is everybody doing this his own way?)
I might be misunderstanding, but I think what you're looking for is
perl Makefile.PL
make installdeps
If you are using Module::Install, you're really using ExtUtils::MakeMaker behind the scenes. You can use all of the MakeMaker features and the targets it provides. Although the documentation doesn't show every feature, there are some valuable things to be found in the generated Makefile.
However, MakeMaker is old news and most everyone has asked Santa Claus for it to disappear. If you want better control, including creating your own targets and process, Module::Build is orders of magnitude easier to work with as well as cross-platform (even if that just means not using a different make, gmake, or whatever on the same OS on different boxes). If you deviate from the normal, consumer-grade installation process, you're life will be easier without MakeMaker.
Some people appreciate the brevity of the Module::Install build file, but once constructed, you don't spend a lot of time messing with your build file so it's not that much of a real benefit. When the little benefit you get locks you into MakeMaker, it's not a win at all.
A 2014 update: Module::Build has now fallen out of favor and needs a maintainer. It never quite got to the point where people could use it to build and distribute XS modules. It was deprecated in Perl v5.19 although you can still get it from CPAN.
You could look at Module::ScanDeps to generate a list of dependent modules for installing. Or Par::Packer for packaging up the whole thing as an "app".

How can I install a specific version of a set of Perl modules?

I'm tasked with replicating a production environment to create many test/sit environments.
One of the things I need to do is build up Perl, with all the modules which have been installed (including internal and external modules) over the years. I could just use CPAN.pm autobundle, but this will result in the test environment having much newer versions of the external modules that production has.
What is the easiest/best way to get and install (a lot of) version specific Perl modules.
bdfoy has the best large scale solution, but if you just want to install a few modules you can ask the CPAN shell to install a specific distribution by referencing a path to a tarball (relative to the top of the CPAN tree).
cpan> install MSCHWERN/Test-Simple-0.62.tar.gz
Throw a URL to BackPAN into your URL list and you can install any older version.
cpan> o conf urllist push http://backpan.perl.org/
This is in the CPAN.pm FAQ under "how do I install a 'DEVELOPER RELEASE' of a module?"
cpan install App::cpanminus
cpanm Your::Module#1.23
(Carton, as referenced in other answers, uses cpanm underneath to resolve explicit version requirements.)
Make your own CPAN mirror with exactly what you want. Stratopan.com, a service, and Pinto, tools that's built on top of, can help you do that.
The CPAN tools only install the latest version of any distribution because PAUSE only indexes the latest version. However, you can create your own, private CPAN that has exactly the distributions that you want. Once you have your own CPAN mirror with only what you want, you point your CPAN tools at only that mirror so it only installs those versions. More on that in a minute.
Now, you want to have several versions of that. You can create as many mirrors as you like, and you can also put the mirrors in source control so you can check out any version of the mirror that you like.
Tools such as CPAN::Mini::Inject can help you set up your own CPAN. Check out my talks on Slideshare for the basic examples, and some of my videos on Vimeo for some of the demonstrations. Look at anything that has "CPAN" or "BackPAN" in the title. I think I might have some stuff about it in The Perl Review too, or should by the next issue. :)
Lately, I've been working on a program called dpan (for DarkPAN) that can look at random directories, find Perl distributions in them, and create the structure and index files that you need. You run dpan, you get a URL to point your CPAN client toward, and off you go. It's part of my MyCPAN-Indexer project, which is in Github. It's not quite ready for unsupervised public use because I mostly work with corporate clients to customize their setup. If you're interested in that, feel free to ask me questions though.
Also, I recently released CPAN::PackageDetails that can help you build the right index file. It's still a bit young too, but again, if you need something special, just ask.
[It's almost five years on and this is a well-asked and well-answered question that has had a lot of views. Since this page must still come up in Google searches, an update can't hurt.]
Carton is worth mentioning here. Carton is a relatively recent tool in the same style as App::cpanminus, App::cpanoutdated, perlbrew, et. al. The author (Miyagawa) calls it "alpha" quality, but even in its current state carton helps simplify the maintenance of multiple environments of version tuned modules across machines.
Pinto too is another recent tool relevant to some of the responses (in fact one of the respondents is a contributor).
Stratopan.com is another alternative. Stratopan provides private CPANs in the cloud. You can fill your Stratopan repository with specific versions of modules (and their dependencies) and then install them using the standard Perl tool chain. The repository changes only when you decide to change it, so you'll get always get the versions of the modules that you want.
Disclaimer: I operate Stratopan.
It seems that creating a cpanfile listing all your modules and desired versions (using the == <version> syntax to lock it to a specific release) could serve well here, too. That would mean using Carton or cpanm for installing the modules.
Doing this would have the benefit of being able to quickly/easily tweak the file to test upgrading specific modules in a dev or staging environment - something that a private CPAN mirror wouldn't let you do (without creating multiple mirrors).

What's the best system for installing a Perl web app?

It seems that most of the installers for Perl are centered around installing Perl modules, not applications. Things like ExtUtils::MakeMaker and Module::Build are very well suited for modules, but require some additional work for Web Apps.
Ideally it would be nice to be able to do the following after checking out the source from the repository:
Have missing dependencies detected
Download and install dependencies from CPAN
Run a command to "Build" the source into a final state (perform any source parsing or configuration necessary for the local environment).
Run a command to install the built files into the appropriate locations. Not only the perl modules, but also things like template (.tt) files, and CGI scripts, JS and image files that should be web-accessible.
Make sure proper permissions are set on installed files (and SELinux context if necessary).
Right now we have a system based on Module::Build that does most of this. The work was done by done by my co-worker who was learning to use Module::Build at the time, and we'd like some advice on generalizing our solution, since it's fairly app-specific right now. In particular, our system requires us to install dependencies by hand (although it does detect them).
Is there any particular system you've used that's been particularly successful? Do you have to write an installer based on Module::Build or ExtUtils::MakeMaker that's particular to your application, or is something more general available?
EDIT: To answer brian's questions below:
We can log into the machines
We do not have root access to the machines
The machines are all (ostensibly) identical builds of RHEL5 with SELinux enabled
Currently, the people installing the machines are only programmers from our group, and our source is not available to the general public. However, it's conceivable our source could eventually be installed on someone else's machines in our organization, to be installed by their programmers or systems people.
We install by checking out from the repository, though we'd like to have the option of using a distributed archive (see above).
The answer suggesting RPM is definitely a good one. Using your system's package manager can definitely make your life easier. However, it might mean you also need to package up a bunch of other Perl modules.
You might also take a look at Shipwright. This is a Perl-based tool for packaging up an app and all its Perl module dependencies. It's early days yet, but it looks promising.
As far as installing dependencies, it wouldn't be hard to simply package up a bunch of tarballs and then have you Module::Build-based solution install them. You should take a look at pip, which makes installing a module from a tarball quite trivial. You could package this with your code base and simply call it from your own installer to handle the deps.
I question whether relying on CPAN is a good idea. The CPAN shell always fetches the latest version of a distro, rather than a specific version. If you're interested in ensuring repeatable installs, it's not the right tool.
What are your limitations for installing web apps? Can you log into the machine? Are all of the machines running the same thing? Are the people installing the web apps co-workers or random people from the general public? Are the people installing this sysadmins, programmers, web managers, or something else? Do you install by distributed an archive or checking out from source control?
For most of my stuff, which involves sysadmins familiar with Perl installing in control environments, I just use MakeMaker. It's easy to get it to do all the things you listed if you know a little about MakeMaker. If you want to know more about that, ask a another question. ;) Module::Build is just as easy, though, and the way to go if you don't already like using MakeMaker.
Module::Build would be a good way to go to handle lots of different situations if the people are moderately clueful about the command line and installing software. You'll have a lot of flexibility with Module::Build, but also a bit more work. And, the cpan tool (which comes with Perl), can install from the current directory and handle dependencies for you. Just tell it to install the current directory:
$ cpan .
If you only have to install on a single platorm, you'll probably have an easier time making a package in the native format. You could even have Module::Build make that package for you so the developers have the flexibility of Module::Build, but the installers have the ease of the native process. Sticking with Module::Build also means that you could create different packages for different platforms from a single build tool.
If the people installing the web application really have no idea about command lines, CPAN, and other things, you'll probably want to use a packager and installer that doesn't scare them or make them think about what is going on, and can accurately report problems to you automatically.
As Dave points out, using a real CPAN mirror always gets you the latest version of a module, but you can also make your own "fake" CPAN mirror with exactly the distributions you want and have the normal CPAN tools install from that. For our customers, we make "CPAN on a CD" (although thumb drives are good now too). With a simple "run me" script everything gets installed in exactly the versions they need. See, for instance, my Making my own CPAN talk if you're interested in that. Again, consider the audience when you think about that. It's not something you'd hand to the general public.
Good luck, :)
I'd recommend seriously considering a package system such as RPM to do this. Even if you're running on Windows I'd consider RPM and cygwin to do the installation. You could even set up a yum or apt repository to deliver the packages to remote systems.
If you're looking for a general installer for customers running any number of OSes and distros, then the problem becomes much harder.
Take a look at PAR.
Jonathan Rockway as a small section on using this with Catalyst in his book.