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Evangelizing Test-Driven Development

By Ethan Rowe
June 2, 2007

I read Practices of an Agile Developer shortly after it was published, and I got pretty fired up about many ideas in it, with particular interest in test-driven development. From that point I did progressively more with testing in my day-to-day work, but everything changed for me once I went all-out and literally employed “test-driven development” for a minor project where I once wouldn’t have worried about testing at all.

If you’re not familiar with the principle, it basically boils down to this: When you are developing something, write the tests first.

I originally greeted this idea with skepticism, or viewed it as unrealistic. It also struck me as overkill for small projects. However, as I’ve been writing more tests, and finally came around to writing tests first, it’s really demonstrated its value to me. I’ll list an abstract set of benefits, and then provide a hopefully-not-too-tedious example.

Benefits

1. Cleaner interfaces

In order to test something, you test its interfaces. Which means you think through how the interface would really need to work from the user’s perspective. Of course, one should always plan a clean interface, …

USPS changes the Web Tools Rate Calculator API

By Dan Collis-Puro
May 14, 2007

End Point offers integration with online shipping APIs to provide “live lookups” of rates.

Advantages of “live lookups”:

• Current rates
• Includes additional costs such as fuel surcharges
• No manual maintenance of rate tables

Disadvantages of “live lookups”:

• Dependent on the availability and performance of the rate service
• Planning, programming and rolling out API changes

CH CH CH CH CHANGES!

Speaking of changes, the USPS has changed shipping rates as of May 14, 2007 (non-tech-friendly details here). The changes include updates to rates, package attributes and shipping methods. These changes impact the XML-based Web Tools Rate Calculator, in some cases breaking lookups altogether. As of press time, the USPS hasn’t documented the changes to the API. Broken lookups appear to be confined mostly to international shipping.

Many of the changes represent a simplification and restructuring of international shipping methods, detailed here. This tweaking of international shipping methods is definitely an improvement — there were too many confusing options before. Unfortunately, these tweaks aren’t backwards compatible — meaning nearly all …

Creating a PL/Perl RPM linked against a custom Perl build

By Jon Jensen
March 7, 2007

We sometimes have to install a custom Perl build without thread support, and to have some specific versions of CPAN modules, and we don’t want to affect the standard distribution Perl that lives in /usr/bin/perl and /usr/lib/perl5. We use standard PGDG RPMs to install PostgreSQL. We also like PL/Perl, and want PL/Perl to link against our custom Perl build.

It’s easy to achieve this with a small patch to the source RPM spec file:

--- postgresql-8.2.spec.before  2007-02-15 11:52:53.000000000 -0700
+++ postgresql-8.2.spec 2007-02-15 12:02:35.000000000 -0700
@@ -306,6 +306,7 @@
 %endif
 %if %plperl
        --with-perl \
+       --with-libraries=/usr/local/lib/perl5/5.8.7/i386-linux/CORE/libperl.so \
 %endif
 %if %plpython
        --with-python \

After applying that patch (adjusted for your own custom Perl build, of course), rebuild the RPM, and install the postgresql-plperl (as of PostgreSQL 8.2) or postgresql-pl (8.1 and earlier) RPM. With a service postgresql restart, you’re ready to go.

New edition of The Book of JavaScript reviewed

By Jeff Boes
February 21, 2007

The Book of JavaScript (2nd edition) is a new and comprehensive introduction to the JavaScript language presented in an entertaining, practical format. I have significant practical experience with JavaScript, so I do not consider myself in the target audience for this book; however, I still found much of it useful so it will remain as a valuable reference on my bookshelf.

My full review of the book was just published at OS News.

Interchange 5.4.2 released

By Jon Jensen
February 7, 2007

Today a new version on the Interchange 5.4 stable branch was released. This was primarily a bugfix release, as documented in the release notes summary.

Greg Sabino Mullane’s PostgreSQL tips and how-to articles

By Jon Jensen
January 15, 2007

End Point engineer Greg Sabino Mullane is a prolific writer of PostgreSQL tips, suggestions, and how-to articles in his Planet PostgreSQL blog. Some posts involve emergency procedures to diagnose and fix an ailing database, while others are helpful recipes developers can use. The strengths and weaknesses of various approaches are compared, and there are lots of neat things to learn along the way.

Here’s my list of favorites from those Greg has posted since last March, in reverse chronological order:

• Turning a table into a queue
• Reindexing the PostgreSQL system tables
• Viewing nearby rows
• Finding multi-column keys
• In-database email address validation without reinventing the wheel
• Making a copy of a unique row
• Finding the median of a table using PL/Perl
• Finding the value closest to the average using PL/Perl
• Getting random rows from a database table
• Scripting with psql
• The million table challenge

Enjoy!

Hardware Monitoring with Nagios on OpenBSD

By Jon Jensen
January 4, 2007

At End Point we use Nagios and its remote client, NRPE, to monitor servers we manage and alert us to any problems. Aside from the usual monitoring of remote accessibility of services such as a website, database, SSH, etc., it’s very helpful to have monitoring of memory usage, disk space, number of processes, and CPU load.

In this detailed article Dan Collis-Puro shows how to go even further and monitor the CPU and case temperature, and fan speeds, to alert administrators to hardware failures so they can be remedied before they become catastrophic.

YAPC::NA 2006 Conference Report

By Brian J. Miller
July 11, 2006

End Pointers Jon Jensen and I, along with 450-500 other Perl enthusiasts, descended on the campus of IIT, the Illinois Institute of Technology in Chicago, for three days at the end of June for the annual North American edition of what is affectionately known by the Perl community as Yet Another Perl Conference (YAPC).

This year’s conference had three main focuses covered by four tracks of talks: Web 2.0 (as the hypesters like to call it), software development methodology improvements, and Perl 6 – the future of the language. Participants and speakers had a range of experience with Perl and varied backgrounds, from experts working for the Perl Foundation on the forefront of Perl 6 development to beginners finding out how best to implement their first assignment.

Perl 6, while not immediately practical for daily use at this time, is advancing the language at the heart of most of End Point’s development. Perl 6 represents advancements in language design that will likely bring Perl back to the forefront of dynamic language syntax and research. But Perl 5 remains in the practical lead it’s long held, with the amazingly wide-ranging and useful CPAN, and it is …