Internal CPAN - what module - perl

I want to setup in-house CPAN for distributing our internal code.
So I was looking at CPAN::Mini as recommended here. But it looks there are other options as CPAN::Site, CPAN::Dark, Dist::Zilla ...
I'm little bit overwhelmed with all these options. What do people mostly use/ recommend?
What I need is a way to push internal modules to repository which can be accesses from several machines.

The quick answer is that you want to use CPAN::Mini to create a local mirror of all that is current on the CPAN, and then CPAN::Mini::Inject to add your own distributions to it.
The long answer is that it helps to understand how a CPAN mirror is constructed. Broadly speaking, it is simply a directory that contains two sub-directories.
The 'modules' directory contains in turn two files, 03modlist.data.gz, whose contents is ignored by modern CPAN clients but there's legacy code that assumes this file exists, so just copy it from an existing mirror. The other is 02packages.details.txt.gz, which I shall describe later.
The 'authors' directory contains a file '01mailrc.txt.gz' which is another relic of the past whose contents can be ignored, so just copy it from another mirror, and it contains the 'id' directory. This in turn contains sub-directories and distributions, whose names follow a pattern. For example, my PAUSE id is DCANTRELL, and one of my distributions is XML-Tiny-2.06.tar.gz, so that file lives at .../authors/id/D/DC/DCANTRELL/XML-Tiny-2.06.tar.gz.
The 02packages.details.txt.gz file is the index that maps module names to distributions, and this must be up to date for your mirror to work properly. It consists of a few header lines, which must be present and correct, followed by a blank line, followed by one line for each module. Those lines are three fields separated by spaces:
module name
module version
distribution filename
eg
XML::Tiny 2.06 D/DC/DCANTRELL/XML-Tiny-2.06.tar.gz
(you may also see .tgz, .zip, and a coupla others)
A distribution may appear in several lines, once for each module it contains. eg
XML::Tiny::DOM 1.1 D/DC/DCANTRELL/XML-Tiny-DOM-1.1.tar.gz
XML::Tiny::DOM::Element 1.1 D/DC/DCANTRELL/XML-Tiny-DOM-1.1.tar.gz
In a normal CPAN mirror, there may be several versions of a distribution, and several versions of a module - for example, the current version and a few older ones, or the current stable one and a dev one. The index file contains the most recent stable version. You can tell dev versions of distributions because they have an underscore in their version, or contain the string '-TRIAL'.
So, knowing all that, you can construct a CPAN-a-like that contains only your code. But using CPAN::Mini and CPAN::Mini::Inject to add your stuff to a "real" CPAN is less work.
Once you've created your CPAN-a-like, you can either expose it on HTTP and access it using any client as normal, or you could just have it in the filesystem and configure the CPAN client to access it using a file:/// URL.

You might also consider Pinto. Pinto allows you to curate your own stable CPAN repository, which can contain any number of both public and private distributions. Pinto also helps you to manage change as your dependencies evolve over time.

DrHyde gave a very nice answer to the question. But if you don't want to maintain a CPAN mirror, you can use MyCPAN::App::DPAN together with MyCPAN::Indexer.
Cave: Both distributions are under development. Not all combinations will work. What I use is the latest version of MyCPAN::App::DPAN on github (1.28_11) and MyCPAN::Indexer version 1.28_10 (later versions don't work with MyCPAN::App::DPAN).
MyCPAN::App::DPAN will create a CPAN-like directory structure on your local disk from the distributions you feed it. You will need to create a config file for it (say, .dpanrc):
# contents of .dpanrc
indexer_id Edward Baudrez <my.email.address#example.org>
dpan_dir /home/ebaudrez/rsync.net/dpan
merge_dirs /home/ebaudrez/rsync.net/dpan/dists
report_dir /home/ebaudrez/rsync.net/dpan/indexer_reports
Put your distribution tarballs in the directory merge_dirs (I think there's no reason that directory should reside under dpan_dir, but I'm too lazy to figure it out right now). Then call dpan:
dpan -f $HOME/.dpanrc
dpan will create a CPAN-like structure in dpan_dir (containing, in particular, authors and modules). This directory can then be used with cpanm (for instance):
cpanm --mirror $HOME/rsync.net/dpan --mirror http://search.cpan.org/CPAN
Note that I use real CPAN as fallback, because the DarkPAN is by definition incomplete. If you also happen to have a mini CPAN mirror, you can also use it here:
cpanm --mirror $HOME/rsync.net/dpan --mirror $HOME/mirrors/minicpan --mirror-only
Do note that, for this scheme to work, you will need to create distribution tarballs from your source code. I like and use Dist::Zilla, but note that you can also generate tarballs from Makefile.PL, so you definitely don't need to use Dist::Zilla. But it takes care of a lot of the details.
Creating a real distribution from your source code may seem like a lot of work, but Dist::Zilla helps lift the burden, and the transition to a real CPAN module, some day in the future ;-), is also simplified a lot when you already have a distribution.

Related

dpan does not find Perl module in package root

We use MyCPAN::App::DPAN (Version 1.28) just like in Question: How can I manage Perl module dependencies?
This works quite well in general. But we ran into troubles with some specific packages:
As expample DBD::Oracle does not have their main *.pm file in DBD-Oracle-1.27/lib/DBD/Oracle/Oracle.pm but in DBD-Oracle-1.27/Oracle.pm.
It seems that dpan does not find this *.pm file, since it is not listed in modules/02packages.details.txt.gz. Whereas DBD::Oracle::Object (other Perl-Module of this distribution, but located DBD-Oracle-1.27/lib/DBD/Oracle/) is listed there.
In dpan.conf we only have set the recommended values:
dpan_dir /some/dir
indexer_id Me
pause_full_name The Admin Team
pause_id TAT
system_id my system id
Other Packages with the same problem:
Apache::DB
Packages that work:
Crypt::Blowfish (no extra modules)
Math::Round (no extra modules)
XML::Twig (no "lib" dir, but extra modules)
Does someone have any tips/hints?
DPAN works by indexing the distributions and storing the results in a file in the indexer_reports directory. As a workaround until I can investigate your problem, you can just edit the report it created for the problem distributions. As long as you haven't set fresh_start in your configuration, it will use the cached report which you have edited to add the missing module.

Can I move a Perl installation from one computer to another computer?

I am trying to set up an application dependant on few Perl modules, but the server I am installing to, does not have Internet connection. I read about offline module installs via ppd files, however I would have to resolve all the dependencies one by one.. All the more tedious considering I don't have direct internet connection.
I am hoping to find a solution, where I install ActivePerl on my PC and install all the libraries that I want and then copy paste the directories to my server. If it is just a matter of fixing some environment variables, that would be fine. Just want to know the definitive list of variables to modify. Not sure whether it is mandatory to install the perl libraries on the computer in which it is intended to run? (One is 32 bit platform and other one is 64 bit, but the server is already running various 32 bit applications so I hope it is not a major problem) For best compatibility, I plan to install ActivePerl on both the systems and merge the library directories to be identical.
The answer was on Perl FAQ, my bad didn't go through it properly.
I copied the perl binary from one machine to another, but scripts don't work.
That's probably because you forgot libraries, or library paths differ.
You really should build the whole distribution on the machine it will
eventually live on, and then type "make install". Most other approaches
are doomed to failure.
One simple way to check that things are in the right place is to print
out the hard-coded #INC that perl looks through for libraries:
% perl -le 'print for #INC'
If this command lists any paths that don't exist on your system, then
you may need to move the appropriate libraries to these locations, or
create symbolic links, aliases, or shortcuts appropriately. #INC is also
printed as part of the output of
% perl -V
You might also want to check out "How do I keep my own module/library
directory?" in perlfaq8.
From this link
Occasionally, you will not be able to
use any of the methods to install
modules. This may be the case if you
are a particularly under-privileged
user - perhaps you are renting web
space on a server, where you are not
given rights to do anything.
It is possible, for some modules, to
install the module without compiling
anything, and so you can just drop the
file in place and have it work.
Without going into a lot of the
detail, some Perl modules contain a
portion written in some other language
(such as C or C++) and some are
written in just in Perl. It is the
latter type that this method will work
for. How will you know? Well, if there
are no files called something.c and
something.h in the package, chances
are that it is a module that contains
only Perl code.
In these cases, you can just unpack
the file, and then copy just the *.pm
files to a directory from which you
will run the modules. Two examples of
this should suffice to illustrate how
this is done.
IniConf.pm is a wonderful little
module that allows you to read
configuration information out of a
.ini-style config file. IniConf.pm is
written only in Perl, and has no C
portion. When you unpack the .tar.gz
file that you got from CPAN, you will
find several files in there, and one
of them is called IniConf.pm. This is
the only file that you are actually
interested in. Copy that file to the
directory where you have the Perl
programs that will be using this
module. You can then use the module as
you would if it was installed
``correctly,'' with just the line:
use IniConf;
Time::CTime is another very handy
module that lets you print times in
any format that strikes your fancy. It
is written just in Perl, without a C
component. You will install it just
the same way as you did with IniConf,
except that the file, called CTime.pm,
must be placed in a subdirectory
called Time. The colons, as well as
indicating an organization of modules,
also indicates a directory structure
on your file system.

How do I start a new Perl module distribution?

I'm trying to set up a large-ish project, written in Perl. The IBM MakeMaker tutorial has been very helpful so far, but I don't understand how to link all the modules into the main program. In my project root, I have MANIFEST, Makefile.PL, README, a bin directory, and a lib directory. In my bin directory, I have my main script (Main.pl). In the lib directory, I have each of my modules, divided up into their own respective directories (i.e. Utils::Util1 and Utils::Utils2 in the utils directory, etc). In each module directory, there is also a t directory, containing tests
My MANIFEST file has the following:
bin/Main.pl
lib/Utils/Util1.pm
lib/Utils/Util2.pm
lib/Utils/t/Utils1.t
lib/Utils/t/Utils2.t
Makefile.PL
MANIFEST
README
Makefile.PL is the following:
use ExtUtils::MakeMaker;
WriteMakefile(
'NAME'=>'Foo',
'VERSION_FROM'=>'bin/Main.pl',
'PREREQ_PM'=>{
"XML::Simple"=> 2.18}, #The libraries that we need and their
#minimum version numbers
'EXE_FILES' =>[("bin/Main.pl")]
);
After I make and run, the program crashes, complaining that it cannot find Utils::Util1, and when I run 'make test, it says no tests defined. Can anyone make any suggestions? I have never done a large scale project like this in perl, and I will need to add many more modules
If you are just starting to create Perl modules (which is also Perl's equivalent of a project), don't use Makemaker. Module::Build is the way to go, and it's now part of the standard library. Makemaker is for us old salts who haven't converted to Module::Build yet. :) I'll strike that now that Module::Build is unmaintained and out of favor; I still use MakeMaker.
You should never start off a Perl project by trying to create the structure yourself. It's too much work and you'll always forget something.
There's h2xs, a program that comes with perl and was supposed to be a tool to convert .h files into Perl's glue language XS. It works fine, but its advantage is that it comes with perl:
% h2xs -AXn Module::Name
Something like Module::Starter is a bit more sophisticated, although you have to get it from CPAN. It's the tool we use in Intermediate Perl because it's simple. It fills in some templates with your information:
% module-starter --author=... --email=... --module=...
If you are doing to do this quite a bit, you might then convert that to Distribution::Cooker so you can customize your files and contents. It's a dinky utility I wrote for myself so I could use my own templates.
% dist_cooker Module::Name
If you're really hard core, you might want Dist::Zilla, but that's more for people who already know what they are doing.
Might I also suggest module-starter? It'll automatically create a skeleton project which "Just Works". I learned what little I know about Perl modules organization by reading the generated skeleton files. It's all well-documented, and quite easy to use as a base for growing a larger project in. You can check out the getting-started docs to see what it gives you.
Running module-starter will give you a Perl distribution, consisting of a number of modules (use the command line option --module, such as:
module-starter --distro=Project --module=Project::Module::A,Project::Module::B [...]
to create multiple modules in a single distribution). It's then up to you whether you'd prefer to organize your project as a single distribution consisting of a number of modules working together, or as a number of distributions which can be released separately but which depend on each other (as configured in your Build or Makefile.PL file) to provide a complete system.
Try this structure:
bin/Main.pl
lib/Utils/Util1.pm
lib/Utils/Util2.pm
Makefile.PL
MANIFEST
README
t/Utils1.t
t/Utils2.t
As ysth said, make does not install your modules, it just builds them in a blib directory. (In your case it just copies them there, but if you had XS code, it would be compiled with a C compiler.) Use make install to install your modules for regular scripts to use.
If you want to run your script between make and make install, you can do:
perl -Mblib bin/Main.pl
The -Mblib instructs perl to temporarily add the appropriate directories to the search path, so you can try out an uninstalled module. (make test does that automatically.)
By default, tests are looked for in a top-level t directory (or a test.pl file, but that has some limitations, so should be avoided).
You say "After I make and run"...make puts things into a blib directory structure ready to be installed, but doesn't do anything special to make running a script access them. (make test is special; it does add appropriate paths from blib to perl's #INC to be able to run the tests.) You will need to do a "make install" to install the modules where your script will find them (or use a tool like PAR to package them together with your script).

How do I use rpm to update/replace existing files?

I have several applications that I wish to deploy using rpm. Some of the files in my application deployments override files from other deployed packages. Simply including the new files in the deployment package will cause rpm conflicts.
I am looking for the proper way to use rpm to update/replace already installed files.
I have already come up with a few solutions but nothing seems quite right.
Maintain custom versions of the rpms containing the original files.
This seems like a large amount of work for a relatively small reward even though it feels less like a hack than some of the other possible solutions.
Include the files in the rpm with another name and copy them over in the post section.
This would work but will mean littering the system with multiple copies of the files. Also it means additional maintenance in the rpm build spec for each file.
Use wget in the post section to replace the original files from some known server.
This is similar to the copy technique but the files wouldn't even live in the rpm. This might act like a nice central configuration authority though.
Deploy the files as new files, then use symlinks to override the originals.
This is also similar to the copy technique but with less clutter. The problem here is that some files don't behave well as symlinks.
To the best of my knowledge, RPM is not designed to permit updating / replacing existing files, so anything that you do is going to be a hack.
Of the options you list, I'd choose #1 as the least bad hack if the target systems are systems that I admin (as you say, it's more work but is the cleanest solution) and a combination of #2 and #4 (symlinks where possible, copies where not) if I'm creating the RPMs for others' systems (to avoid having to distribute a bunch of RPMs, but I'd make it very clear in the docs what I'm doing).
You haven't described which files need to be updated or replaced and how they need to be updated. Depending on the answers to those questions, you may have a couple of other options:
Many programs are designed to use a single default configuration file and also to grab configuration files from a .d subdirectory. For example, Apache uses /etc/httpd/conf/httpd.conf and /etc/httpd/conf.d/*.conf, so your RPMs could drop files under /etc/httpd/conf.d instead of modifying /etc/httpd/conf/httpd.conf. And if the files that you need to modify are config files that don't follow this pattern but could be made to, you can suggest to the package maintainers that they add this capability; this wouldn't help you immediately but would make future releases easier.
For command-line utilities like sendmail and lpr that can be provided by multiple packages, the alternatives system (see man alternatives) permits more than 1 RPM that provides these utilities to be installed side by side. Again, if the files that you need to modify are command-line utilities that don't follow this pattern but could be made to, you can suggest to the package maintainers that they add this capability.
Config file changes on systems that you administer are better managed through a tool like Cfengine or Puppet rather than through custom RPMs. I think that Red Hat favors Puppet.
If I were creating the RPMs for systems I don't administer, I'd consider using a third-party tool like Bitrock and dumping all of my stuff under /opt just so I wouldn't have to stomp on files installed by other admins' RPMs.
Edit (2019): Nowadays, Software Collections offers a useful alternative. You can create packages that install somewhere under /opt, and the Software Collections tools offer a standardized way for users to opt in to using those instead of whatever's normally installed under /usr. Red Hat uses this to distribute newer versions of tools for their otherwise stable and long-lived (i.e., older) Red Hat Enterprise Linux distributions.
You can also execute rpm -U --replacefiles --replacepkgs ..., which will give you what you want.
See here for more info on RPM %files directives:
http://www.rpm.org/max-rpm/s1-rpm-inside-files-list-directives.html
You can use the arguments from the %post and %pre sections in the RPM scriptlets to determine if you are installing, upgrading or removing packages.
If $1 is 0 - then we're removing old stuff. Targeting 0 packages installed.
If $1 is 1 - then we're installing new stuff. Targeting a total of 1 package to be installed.
If $1 is 2 or more - then we're upgrading this package and $1 represents the number of packages already installed.
These sections help with managing files among the versions.
Keep track of what you're doing between versions and consider what one might do if they were to skip a version or two.
Have consideration for these things and you should be good to go!

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).