Here’s another short one this week…
I first learned about Linux::Inotify2 from a posting on acme’s blog. It’s a neat interface to the Linux Inotify system, which itself is basically a way of being informed whenever things happen in the file-system.
I was able to make use of this almost immediately– I took the sample script from acme’s post and made a few adjustments, then used it to look at the libraries that Image::Size loads during start-up. Turns out that there were a couple of them that didn’t need to be loaded until/unless needed, and once I saw this I was able to move them around and speed up the compile-time phase of the module.
This module has some great potential for monitoring, measuring, etc. I’m toying with a graphical version of acme’s script that I can have running during test suite runs, to get a better idea of other places I can improve things.
Check out the module, and check out acme’s original post on the subject, too!Tags: CPAN, module-monday, Perl
RT #52662: Fix requirement specification for XML::LibXML.
Today, a short one as I’m short on time. But I wasn’t able to do a PMM last week, and I’d hate to skip it two weeks in a row, so…
Say hello to File::Tail. A simple concept, but a very, very useful one. Ever run the *NIX “tail -f <file>” command? Yeah, it’s pretty much just like that. Only in Perl, so it’s actually more flexible. Much more.
You can use it in a very simple manner, to read from files that are continuously updating. You can control how often and to what degree it adjusts the wait-interval it uses when polling the underlying file to check for changes. You can also tie a file-handle to it. You can do things like select-polling across several such handles or objects, to read in a non-blocking way from multiple tail’d files at once. It even comes bundled with two sample scripts showing it in action.
Check it out!Tags: CPAN, module-monday, Perl
- t/01_pod.t (deleted)
- t/02_pod_coverage.t (deleted)
- t/03_meta.t (deleted)
- t/04_minimumversion.t (deleted)
- t/05_critic.t (deleted)
- xt/01_pod.t (added)
- xt/02_pod_coverage.t (added)
- xt/03_meta.t (added)
- xt/04_minimumversion.t (added)
- xt/05_critic.t (added)
RT #49406: Make Base64 data-type allow zero-length data.
RT #50013: Restore backwards-compatibility for projects that use RPC::XML::Parser directly.
RT #50143: Incorrectly called server_fault() as if it were a coderef.
- lib/RPC/XML/Parser/XMLLibXML.pm (added)
- t/21_xml_libxml.t (added)
- t/40_server_xmllibxml.t (added)
Perl seems to always lead the language-pack in terms of Advent Calendars each year. Here are a few that I know of, that I’m following daily:
Go forth and, errr, advent…Tags: Perl
I’ve been interested in the Chart::Clicker package for a while, and today it came up in a series of Twitter messages in my #perl search. So that seemed like a sign that it would be a good pick for this week’s feature.
Chart::Clicker is a mature, very feature-rich charting package that comes with a cookbook and many examples (the code for the examples is available on GitHub). There’s also a tutorial POD in the distribution. It does pie charts, line graphs, bar graphs, area graphs, stacked bar or area or line graphs, points, bubbles, or candlestick-style charts. In short, it makes pretty pictures in Perl:
The above is just one of the images shown as examples of what Chart::Clicker can do.
The module bases its rendering on Graphics::Primitive, specifically Graphics::Primitive::Driver::Cairo. This means it can render the chart in any format Cairo supports; PNG, PDF, even SVG among others. The internal object-model is based on Moose, which leads to keeping potentially-duplicate code to a minimum. Using the package is about as complex as you need your graph to be: a simple graph with a single set of data can be created in just 5 lines of code or so, while some of the examples are much more complicated scripts.
I’m surprised to see (according to CPANTS) that this module is not a component in any other packages’ lists of dependencies. It would seem to me to be a logical bit of functionality to integrate into a Catalyst view, or any stats package. I won’t be surprised if this changes in the near future, as (hopefully) more people start using the package.Tags: CPAN, module-monday, Perl
It looks as though I have some “competition” for my CPAN Twitter bot (@cpan_linked). The last few days I’ve been seeing posts from @cpanlive in my Perl search-column (I use Seesmic Desktop, with a permanent column for searches on “#perl“). This seems to be pretty much identical in intent to my bot, with some differences. I’ll cover those and what I think of them:
Where I do URL-shortening (currently through TinyURL due to some down-time with Metamark, though I think they’re back up now), @cpanlive doesn’t. I believe that if the status message were to exceed 140 characters, Twitter would notice this and scan the message for URLs to shorten automatically. In the end, I suppose it’s a matter of taste– with @cpanlive you’ll see the actual URL the majority of the time.
I usually provide two links, the second being to the “Changes” (Changes, ChangeLog, etc.) file, or the README if I can’t find a change-log. @cpanlive provides just the main link. I also include the author’s name. This goes back to the use of URL-shortening– I’m careful to keep my status under 140 characters, but having pre-shortened the links gives me more room to play with.
I don’t use any hash-tags, currently. @cpanlive uses both “#Perl” and “#CPAN”. On the one hand, I probably wouldn’t have even known about this if it weren’t for the tagging, as I wouldn’t have seen it otherwise. On the other hand, this puts a lot of data from a single bot into the #perl search-stream. Most people know to follow a given bot if they want CPAN stream updates, and would prefer to not have them cluttering up #perl.
That said, I am considering adding #CPAN to the updates that @cpan_linked puts out, as well as the re-write that I’m (slowly) working on. I think that such data is more useful to users searching on #CPAN than those searching on #Perl.
Speed and Pacing
When @cpan_linked gets a cluster of several CPAN updates at once, it tries to spread them out over the next period between polls of search.cpan.org‘s RDF feed. Currently, I poll it every 15 minutes, so if I get 5 new items to post they get posted roughly 3 minutes apart. It looks like @cpanlive doesn’t do anything like this, as the updates seem be in “clumps”, which is what I was trying to avoid. Again, a matter of taste. I didn’t want the bot to suddenly spew 10-20 updates into my Twitter stream, pushing everything else “below the fold” as it were. Other followers might not care one way or the other.
Something I’ve noticed, though, is that @cpanlive seems to be about an hour or so behind @cpan_linked, on average. I assume that they’re polling the RDF source hourly, rather than the 15-minute interval I use.
Well, there’s no “conclusion” here, really. I mean, it’s not like I have an exclusive license to relay CPAN releases to Twitter. If such an exclusive right existed, it wouldn’t be mine in the first place! I do wonder about the reason for doing it over again, though it may just be someone’s project for learning how to use the Net::Twitter modules. It does push me to get cracking on my re-write, though, as I have other features planned that should make it even more useful.Tags: CPAN, Perl, Twitter
What I like most about this is that it scratches a particular itch I often have when writing long-lived DB code: I get tired of always pinging the database through the handle, to make sure the connection is still there before attempting any new operation. On this point alone, DBIx::Connector is worth installing.
Fortunately, that wasn’t the only itch he was scratching, when he wrote it, so it does a lot more than just simplify persistent connections. It’s fork- and thread-safe, handles transactions and save-points (nested, no less), and does it all while letting you choose when/if the database gets pinged, and what happens when the connection is no longer active.CPAN, databases, module-monday, Perl