Is it possible to run multiple installs of Perl (in "containers") on one machine?
Reason is that I have different Perl-based server side web applications and wish to schedule updates to them independently.
For example, bugzilla upgrades seem to me to be very invasive, downloading all manner or module updates and lengthy, too (thereby increasing the chance of unpredictable behavior on other applications that depend on those modules, during the time that the upgrade is still partial).
I think it should be possible to run multiple independent server-side CGI Perl applications on one server, I'd rather not be told to separate them onto different machines - I think that's wasteful and I don't have that resource anyway.
Investigate PerlBrew and cpanm:
http://qa.celogeek.com/programming/perl/for/developer/overview
Edit, more info:
http://www.bryanesmith.com/documents/a2pm/perlbrew-june-14-2011.pdf
http://www.dagolden.com/index.php/1384/parallel-make-for-perlbrew/
http://www.perlbrew.pl/
It's easy to install and manage multiple perls. Simply install them in different places and use each perl's tools. I talk about this in The Effective Perler.
Some people suggest perlbrew without realizing that it doesn't really give you any benefit. It can download a perl, configure and install it, and switch around symbolic links to make one of those the default. It doesn't do anything magical, though.
Downloading and installing aren't a problem though. You've never needed root or sudo to do that, and if you do, you'll still need it for perlbrew. You can always install into any directory where you have permission. perlbrew doesn't get around that at all. From the source directory, you have two simple commands to run:
$./Configure -des -Dprefix=/where/you/want/to/install
$ make install
For you, that might mean Bugzilla gets its own perl:
$./Configure -des -Dprefix=/where/you/want/to/install/bugzilla-perl
$ make install
From there, you have a completely self-contained perl installation. When it matters to me which perl I use, I give the program the full path to it:
#!/where/you/want/to/install/bugzilla-perl/bin/perl
It's much easier to make these per-applications installations without perlbrew, which wants to do as much as it can for you, including deciding the directory name, which it prefers you didn't know at all.
perlbrew's main advantage is not the compilation and installation, but it's switch feature to let you make one perl the default. You probably don't want that feature though because you want bugzilla, CGI programs, and so on using only the perl you want them to use, not whatever default perl you last specified.
When you want to update the bugzilla-perl, just use it's tools, which already have adjusted shebang lines to find the right perl:
$ /where/you/want/to/install/bugzilla-perl/bin/cpan ...
I don't like all of those long paths, though, which is why I make links to them all. Then I can just call them with whatever naming scheme I decide, which might be:
$ bugzilla-cpan ...
There's never a question about which tool or version I'm using.
Related
I thought it would be a good idea in general to update all software on my computer regularly. Since CPAN modules are not managed by my package manager I figured I should do cpan -u every once in a while. It was only after executing this that I read the man page note on this:
-u Upgrade all installed modules. Blindly doing this can really break
things, so keep a backup.
Why should this break anything? And how should I keep my CPAN modules up to date otherwise; do I need to keep track of all manually installed modules (cpan doesn't seem to do this) and only update those regularly? How about the dependencies of my manually installed modules?
Why did cpan -u upgrade stuff for ~15min even though I haven't installed a single CPAN module?
Can I revert the cpan -u? Is it enough to delete ~/.cpan for this?
Why should this break anything?
It shouldn't, but complex systems are complex and sometimes things do break (e.g. if a module is updated with a non-backwards compatible change, or depends on a C library which has bugs which only show up in combination with specific dependencies).
And how should I keep my CPAN modules up to date otherwise;
Just keep backups in case things break.
Why did cpan -u upgrade stuff for ~15min even though I haven't installed a single CPAN module?
Perl is distributed with a large collection of modules, and other modules may have been installed by your distribution.
Can I revert the cpan -u?
You can overwrite it with the backup that the documentation recommended you take.
Is it enough to delete ~/.cpan for this?
No. That directory is used by the installer tool to cache data about available modules, to store source code, and to hold build artefacts. The installed files are written to your lib like any other library.
New or update code is new or updated bugs. I have the opposite view of Quentin: why would changing a bunch of stuff keep not break things? That's what I expect with most updates. However, the Perl 5 porters take great pains to test perl distributions against as much of CPAN as they can. That doesn't mean that your particular use of a module (and how you've worked around existing bugs) is stable.
Some modules that come with perl are also on CPAN. These are "dual-lived" modules and they might update from CPAN.
The cpan tool doesn't revert anything for you, but you can do what I do sometimes. Make your installation a git repo. Branch when you change it. Try the branch with your code. If anything goes wrong you can always switch back to master. You don't even need to commit the changes! Tools such as Pinto help you manage sets of Perl modules.
There are some other things to consider.
First, I recommend that you don't mess with the system perl. Let the system do that. If you want a fresher perl that you manage yourself, install a different one. You might like perlbrew for that (I don't, but that's no big deal).
You can screw up that one as much as you like and the system won't start doing weird things. Consider major changes like removing . from #INC and Deprecating unescaped left braces in regexes. Those were changes in perl but they broke some important things.
Second, you can configure cpan to install somewhere besides the system directories. The -I switch will use local::lib for you. Besides that, you can configure it manually.
I have a perl script that I've put together to do some monitoring and graphing.
It works nicely on my dev system, where I have carte-blanch to install my own modules from CPAN.
What I'm looking at doing is bundling it up to deploy onto another system. But here's the catch - this other system is 'standalone' and has no network connection. (And I have change control paperwork to fill in, indicating what I'm installing).
As a result, I'd really like a nice easy way to figure out:
- What modules my scripts are making use of. (Including dependencies)
- how to easily grab them (cpan get probably)
- Is there an easy way to tell what external binaries I'm using? (I'm using for sure ssh and rrdtool - the former is definitely installed, the latter probably not).
I have a few thoughts on how to do this, but it strikes me as something that should be smoother.
I may also need to deploy a new perl, so I'm pondering whether I'm better off 'installing' the modules with system perl (probably 5.8.8 on RHEL5), or just 'packaging' the whole thing in a directory of it's own with a standalone perl instance.
Use pp to package your script and all dependant modules and libraries into a stand alone executable.
pp -x yourscript.pl -o outputfilename
See the documentation for examples of how to link to external shared objects (etc) if required. With pp you don't need perl on the target system where outputfilename will run.
Revisiting this, as the need hasn't really gone away. I have moved towards using docker - this is an 'image' and 'container' system for app deployment, which amongst other things, allows you to 'package' an application.
You create a Dockerfile - which is analagous to a Makefile - that runs through the steps to install perl + dependencies (either via a package manager, or from CPAN).
Once it has, you have a self contained, runnable 'image' that you can clone and create an instance of (a "container" in docker parlance).
It's also quite useful - even if you don't then deploy via container - to figure out what the dependencies of this application/packages were. The version in the container has everything locally installed that it needed, because it was a clean build.
When you have a system where you can't control the Perl installation (and the install is a really, really old version of Perl like 5.8.8 which is missing many nice improvements like state variables, autodie, say, and switch), you should look into Perlbrew.
Perlbrew allows you to install a user version of Perl. (In fact, it allows you to install multiple versions of Perl), and allows you to switch between the Perlbrew install and the officially installed version. It makes doing everything in Perl much, much easier.
You will have freer access to install new Perl modules, and you can do that task yourself rather than wait for your IT department to do it for you.
I ended up using it on one of our systems where the primitive version of Perl just wasn't doing what my version of Perl did. I originally asked our IT to upgrade, but they really messed up the upgrade. After going back and forth, I simply asked if I could install Perlbrew.
Which is an important point. Always ask permission. A lot of time, the IT department is more than happy to oblige. They're not Perl people, and CPAN is a world they don't want to deal with. Being able to get out of having to answer your beck and call about installing this or that Perl module is a great relief.
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.
Being very new to Perl but not to dynamic languages, I'm a bit surprised at how not straight forward the manage of modules is.
Sure, cpan X does theoretically work, but I'm working on the same project from three different machines and OSs (at work, at home, testing in an external environment).
At work (Windows 7) I have problem using cpan because of our firewall that makes ftp unusable
At home (Mac OS X) it does work
In the external environment (Linux CentOs) it worked after hours because I don't have root access and I had to configure cpan to operate as a non-root user
I've tried on another server where I have an access. If the previous external environment is a VPS and so I have a shell access, this other one is a cheap shared hosting where I have no way to install new modules other than the ones pre-installed
At the moment I still can't install Template under Windows. I've seen that as an alternative I could compile it and I've also tried ActiveState's PPM but the module is not existent there.
Now, my perplexity is about Perl being a dynamic language. I've had all these kind of problems while working, for example, with C where I had to compile all the libraries for all the platform, but I thought that with Perl the approach would have been very similar to Python's or PHP's where in 90% of the cases copying the module in a directory and importing it simply works.
So, my question: if Perl's modules are written in Perl, why the copy/paste approach will not work? If some (or some part) of the modules have to be compiled, how to see in CPAN if a module is Perl-only or it relies upon compiled libraries? Isn't there a way to download the module (tar, zip...) and use cpan to deploy it? This would solve my problem under Windows.
Now, Perl is a dynamic language, but that doesn't imply that everything that people write is portable across platforms. That's not the fault of the language. It's not even the fault of the programmer. Some things, like Win32::OLE shouldn't work on Unix. :)
Other dynamic languages will have some of the same problems. If you have to compile C code, you won't be able to merely copy files to another machine. Some distributions configure the code slightly differently depending on your operating system, etc.
Even if you could copy files, you have to ensure that you copy all of the files that you need. Do you know everything that you need for a particular module? Remember, many of them have dependencies.
Most of the problems you're having aren't anything to do with the language. You're having trouble with the tools. If you want a zero conf CPAN tool that makes all the decisions for you, try cpanminus. It's mostly the same thing that you'd get out of cpan (although different code), but it makes all of the decisions for you. It doesn't run any of the distribution tests, and it installs into your user directory. When you need something that gives you control, come back to cpan.
In the external environment (Linux CentOs) it worked after hours because I don't have root access and I had to configure cpan to operate as a non-root user
This is one of those times when it helps to know The Trick. In this case local::lib, which lets you configure a non-root install area and all the ENV variables in about three minutes.
if perl's modules are written in perl, why the copy/past approach will not work?
Some are written in Pure Perl, but many are written partially in C (using Perl's XS API) for efficiency.
Sometimes you end up with situations like JSON::XS, JSON::PP and JSON::Any to autoselect the best one that is installed.
Isn't there a way to download the module (tar, zip...) and use cpan to deploy it?
The cpan program is all about getting things from the Internet. You can download the package (there will be a link along the lines of "Download: CGI.pm-3.49.tar.gz" on the right hand side of the CPAN page), untar it, then
perl Makefile.PL
make
make install
You would probably be better off configuring your cpan installation to use only HTTP sources (in the urllist config option). Possibly going to far as to create a mini CPAN mirror inside your network.
I need to install my Perl-based software on networked machines which aren't connected to the internet. Therefore, I would like to download specific versions and/or latest versions of the Perl modules and I would also like to know if there is an install procedure required for these modules.
Background:
The machines aren't connected to the internet for security reasons and its deemed unnecessary also.
I would place the downloaded modules on a machine that I call the 'install server' and it contains my Perl based software and would also contain the local copies of the Perl modules.
I call a machine that I want to install my Perl-based software on, the 'target machine', also not connected to the internet. There can be several target machines, each can run this software that I want to install. I log onto the target machine and run an install script which would connect to the install machine via the local network to obtain the Perl-based software and dependent Perl modules and installs them.
So I need to know:
How/Where to get specific versions of Perl modules, e.g. CGI.pm etc
How to install these Perl modules. Is it a case of just placing them in a directory somewhere, e.g. a library path and making sure that this directory path is in the #INC library path environmental variable, if it is not already?
I would prefer not to have to do anything like make install etc. as part of installing the modules. I would like to modules to be pre-compiled or prepared as necessary so it is as simple as possible to install them. I want to avoid additional dependencies like make and its configuration, and having to parse its output to check whether it was successful.
Please help me by asking the above specific questions as I am not able to change the concept of 'install machine' and 'target machine' which aren't connected to the internet - I have to provide a solution that works within this arrangement.
The usual way to solve "I want to install stuff from CPAN but without network" problems is to use a minicpan as David Dorward wrote in his answer. But since you're going one step further, saying that you'd rather not do any real installation on the client (target) machines at all, and that you want to use precompiled modules if possible, I urge you to check out PAR and specifically PAR::Repository (server) and PAR::Repository::Client.
Since this approach needs some research before you're up to speed, I wouldn't suggest it for "I just need Foo.pm" like problems. Once you're talking about a handful of dependencies and at least a handful of clients, then it becomes a more appropriate solution.
For an outline of how it works, check out the slides of my talk at YAPC::EU 2008. It also hints at solutions to the bootstrapping problem of making the PAR::Repository::Client module available on the clients (hint: PAR can generate self-contained executables).
You can create a MiniCPAN that has just the latest versions of everything from CPAN. You can insert additional, non-public modules into it with CPAN::Mini::Inject. If you need to greater control over versions (i.e. not choosing the latest versions), you might want to create a DPAN.
With any of these solutions, you can configure your CPAN client to pull from your local source. That could be a directory you know ahead of time or something that you figure out dynamically, like a CD or a thumb-drive. It's just a matter of setting up the configuration correctly.
You might be able to get away with creating operating-system packages for most of your work, but that still means you have to compile them at least the first time.
1) How/Where to get specific versions of Perl modules, e.g. CGI.pm etc
http://search.cpan.org/
If you don't want the latest version, you can get an earlier version by following the link in the breadcrumbs.
http://img.skitch.com/20091209-bu7kt3bj65374k7iijfnhrue2y.png
2) How to install these Perl modules. Is it a case of just placing them
in a directory somewhere, e.g. a library path and making sure that this
directory path is in the #INC library path environmental variable, if
it is not already?
That sometimes work, but you really should go through the perl Makefile.PL && make && make test && make install process.
Doing this would require that you manually chase all the dependencies though. You would probably be better off with something like minicpan.