Category Archives: Software Development

Software Development

WordPress 2.1 Released

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The WordPress team has announced the release of version 2.1 of their WordPress blogging software on Monday. A list of the changes can be found in the release announcement.

Sure, this is old news (by internet time standards) but I just got around to getting caught up. I’ve upgraded the site and the process was absolutely painless. All of my current plugins worked as far as I can tell.

For those who have a bit of trepidation over upgrades and the compatibility of plugins, I can tell you that my installation, with over 17 plugins active, seems to be working fine after the upgrade this morning after a total upgrade time of around 15 minutes including backups of my installation directory and database. As usual, the upgrade instructions are available on the WordPress site.

The WordPress team is planning its next release, Version 2.2, around the April 23 timeframe.

I haven’t had a great deal of time this morning to play around, but it does seem that the site runs just a tad bit faster then it did under the previous version.

Studying Up On Ruby

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Photo by rbieber

I’ve been focusing on Ruby a lot over the past 3 days (Rails specifically). What a great environment to work in!

This was taken about a month ago. I’ve been doing quite a bit of reading and experimenting with Rails and I have to say, I love it. While I’m still at the stage of figuring out “how” to do things, once you do it you get why its done that way. That can’t be said for many environments.

Denying Spammers

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I’ve been having a real problem with the site being hit hard by spammers lately. Consequently, I have turned comments off on most of the articles on the site at this point.

Due to the implementation of SPAM Karma 2 and Akismet, none of the comment spam actually made it to the blog. I was pretty amazed at how thoroughly these two pieces of software have filtered the incoming comments.

However, the comments not making it to the blog doesn’t mean that the spammers haven’t done any real damage. Twice now I’ve come home to find my comments disabled by my provider, due to basically a Denial of Service attack being executed on the site by these morons.

I found a great page at the WordPress Codex on Combatting Comment Spam. I would encourage anyone currently dealing with this problem to check out this page. I will be implementing some of these ideas one by one over the coming weeks to see how much they help.

I’ll let you know of the success I have. In the meantime, if you aren’t running Spam Karma, I would encourage you to go take a look at it and its corresponding Akismet plugin. The combination of both has been highly effective in this corner of the web.

Practical Subversion – Second Edition

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I received a free copy of Practical Subversion, Second Edition by Daniel Berlin and Garrett Rooney on Friday from their publishers, Apress.

I had reviewed the first edition before it was released and had found it to be an excellent companion to “Version Control with Subversion” (C. Michael Pilato, Ben Collins-Sussman, Brian W. Fitzpatrick), mostly due to its coverage of the Subversion API’s – which I had not seen covered in any real depth in any other book.

I have to say, the authors have outdone themselves with the Second Edition. The book is extremely well written for varying levels of Subversion experience. The beginner will find a very easy to understand introduction to using Subversion in the first two chapters, giving a really great tutorial on how to use the tool along with explanations of many of the concepts embodied in the implementation of the tool, such as locking vs. non-locking systems, properties (from file to revision properties), the basic workflow involved in using version control, and how to use the various commands, from checking out, to using svn blame (or ‘praise’ as I learned from the book is an alias for the command) to find the origin of a change in the system.

Thats just the first two chapters. As the book goes on the reader will learn about repository administration, the differences between the BDB and FSFS file systems, using Apache and Apache modules to squeeze additional functionality into the system, migrating from other version control systems such as CVS and Perforce and third party tools that work with Subversion (such as ViewVC, emacs, etc). The book also covers maintaining vendor branches, and contains a very good chapter on Version Control Best Practices. You then have, from my memory anyway, a greatly expanded chapter on using the Subversion API.

Practical Subversion, Second Edition does a really good job of covering information at many skill levels in an extremely accessible way. This book will definitely be one of those that I would put on the shelf at work as we continue to move people into more advanced roles in the management of our repositories – as there’s really nothing the book doesn’t cover.

I’ve been a user of Subversion for a very long time (I think I started around version 0.19 or so) and as I perused the book last night I walked away with some new distinctions about how we were using the tool and changes I could make to make administration and maintenance easier. That says a lot.

Congratulations to Garrett and Daniel on a fine piece of work. Hopefully the next edition will cover some of the newer features of 1.4, specifically the svnsync tool.

WordPress 2.0.5 Released

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The folks on the WordPress team have released version 2.0.5 of the WordPress Blogging Application. This release includes around 50 bug fixes one of which was a missing index on the posts table. I just upgraded and the site performs much better now. I had always thought that the site ran a tad bit slower after the 2.0 upgrade, but for some reason I just figured 2.0 was doing so much more than the 1.x versions. Didn’t even think of looking at table indexes.

Mark Jaquith has also put together his list of change files and corresponding archives containing only the changes from 2.0.4 to 2.0.5, along with a patch file to upgrade your stuff directly. I opted to download from the WordPress site.

In any event, according to the release announcement, there are some security fixes in this release as well. As I do with every release of WordPress that contains security release, I am reminding you not to be lazy and get your site upgraded as soon as you can. The performance improvements alone are worth it.

Now … off to see if they fixed that “posting from Flickr mangling CSS thing” …

Building Subversion on The Mac and using Ecto for Blogging

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I finally upgraded my Subversion installation on my MacIntosh to the 1.4 version. I was waiting for the “official” packages to come out so that I could just install it, but in looking at the different places recommended by the downloads page, these distributions haven’t been updated since early 1.3 releases.

I’ve had a goal to keep my Mac somewhat pristine. I decided thats not really practical. There are a lot of things that I use that I just like having built from scratch, so that I’m on the most current software and not dependent on someone else’s schedule. Subversion is one of those tools.

One thing I was shocked at was how quickly and seamlessly the build happened on the Mac. These MacBooks are pretty fast machines. I think it took a total of roughly 20 minutes (if that) to build, run tests, and install. The build on the Mac is definitely the fastest configure/check/install cycle I’ve gone through in the many installations of Subversion that I have performed over the years.

I tell you, the more I’m on the Mac, the more I like it. I haven’t run into anything that I’ve found irritating.

Its all good.

This is also the first post I am writing using a trial version of Ecto. I have to say, this application is pretty impressive too. They have both a Mac and a Windows version. I like it much better than blogging in WordPress directly – and at $17.95 a copy, its practically a no brainer to purchase.

Don’t get me wrong, I’m going to milk the 21 day trial, but it feels like this application is a pretty good fit for me.

Upgrading Subversion to 1.4

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This weekend I finally bit the bullet and upgraded our production Subversion server to 1.4. The upgrade was painless, after the usual running of autogen.sh on the Neon libraries that for some reason are necessary when building on the Solaris 9 environment. I also had some weird test failures that wound up being caused by hook scripts being called on the test repositories. For some reason, Python couldn’t find one of the standard libraries, even though I had set my path and library path in my environment. A quick Google search later and all tests passed.

We have been running Subversion with the Berkeley 2.2 back-end since May of 2004, when the Subversion team first released 1.0. We’ve done a few upgrades since then, when I found the time, but wound up getting as far as 1.2.3 and my time to actually do the upgrades never really materialized. Part of that had to do with some pretty large projects that were going on that I didn’t want to interrupt the teams with an upgrade.

So yesterday, finally, I did the upgrade to 1.4. As part of the upgrade, I decided to dump and load the repositories (11 of them) to take advantage of the new SVN Diff format that 1.4 brings to the table. As part of that, I also decided to abandon the Berkeley back-end in favor of the FSFS file system.

The dumps and loads took quite a long time, about sixteen hours. However, the results were worth it. After all was said and done, we saw a reduction in server disk space usage of about 46.8%.

Not bad guys!

As I had mentioned in a previous post, one of the motivators for this upgrade were the working copy improvements, which according to the release notes, should cut down on inode usage on machines running the client. In our environment, we have about 20 people all working on the same machine (in their home directories) and we have had problems with inode max-outs in the past. Again, I’ll have to reserve judgement on these changes until we see the results, but this is one of the things that motivated me to bite the bullet and take a Saturday to do the upgrades.

The other big motivation for me, especially after yesterday was this statement from the FSFS document referenced above:

An FSFS repository can be backed up with standard backup software.
Since old revision files don’t change, incremental backups with
standard backup software are efficient. (See “Note: Backups” for
caveats.)

(BDB repositories can be backed up using “svnadmin hotcopy” and can be
backed up incrementally using “svnadmin dump”. FSFS just makes it
easier.)

Aside from normal system backups done nightly by the admin team, our nightly backups have also consisted of doing nightly dumps of all of the repositories so that, in the event that the repository server goes down, we can just load the repository on another machine (you can never have too many backups – in my opinion). The wake up call from yesterday is that it takes much longer to reload a repository on Solaris 9 than it does on the Linux work-group server I have sitting here that I did all of my original testing on a few years ago. What I thought would be a trivial load (3 hours was the estimate that I had in my head) wound up being 5-6 times that on the 2×2 Solaris box at work. It will be nice to be able to rely on the nightly system backups for these now — and perhaps just a quick tarring of the existing repository structure for quick backups (using hotcopy), rather than the dump / load process we have planned to use up until now. I’ve just never been comfortable for some reason with the Berkeley backend and backups outside of repository dumps.

Finally, I’m really looking forward to playing around with svnsync to set up a shadow fail-over repository in the event of an outage. This was something I threw on a wish list back in 2004, and I’m excited to see a tool to synchronize a “stand by repository” included in this release. There apparently is not much documentation on this new feature yet, but this article should be a good starting point.

Thanks to the Subversion team for another great release of their software. As anyone who reads this blog with any regularity knows, this is one of those pieces of software that I continuously receive value from and cannot say enough about.

Now I’m off to search for more svnsync documentation …

Subversion 1.4 Released

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The Subversion team has released version 1.4 of its popular version control software. You can check out the release notes over at the official site get the the details, but here’s a summary of the changes, pulled directly from the aforementioned release notes:

  • svnsync, a new repository mirroring tool
  • Huge working-copy performance improvements
  • Support for BerkeleyDB 4.4 and its “auto recovery” feature
  • Size improvements to the binary delta algorithm
  • A handful of new command switches
  • Many improved APIs
  • More than 40 new bugfixes

I was going to post about this yesterday, but I wanted to make sure I had the software built and installed here at the Labs before throwing the link out there. The upgrade went relatively well. Since I still use Berkeley DB for some of the repositories here, I build my own software to minimize the amount of dumping / loading I have to do. Currently I am still running Berkely DB 4.2. Referencing this during the build allowed me to avoid some problems people have reported using pre-packaged distributions that upgrade Berkeley DB for you, rendering your repository useless. Building my own also allows me to get the software without waiting for the binary distributions to become available.

One note on the upgrade. I’ve been a little lax in upgrading my Apache server (also custom built) and was running version 2.0.48 or so. The new release requires an up to date version of the apr libraries, so this also forced me to upgrade Apache to 2.0.59. Overall, the upgrade was painless.

As mentioned above, this release also includes the svnsync tool, which is a repository mirroring tool. From what I’ve read so far, the destination mirror must remain read only – there is no synchronization between two duplicate repositories (at least from the limited reading material I’ve found around so far), so this release by no means invalidates the SVK tool. Nevertheless, the working copy improvements and the mirroring capability shows that the team is still on the right track.

Also noted in the release notes:

… the new working copy format allows the client to more quickly search a working copy, detect file modifications, manage property metadata, and deal with large files. The overall disk footprint is smaller as well, with fewer inodes being used. Additionally, a number of long standing bugs related to merging and copying have been fixed.

I’m going to reserve judgement on these improvements until I get the Solaris boxes at work upgraded. The working copies are really an Achilles heel on Solaris environments, where 20 or so developers use one machine to do all development. We’ve had a number of inode-maxouts over the last year or so. When I get these machines upgraded, I’ll post a follow up on the performance on Solaris.

One other enhancement I’m glad to see, the diff and merge commands now support a -c option which you can use to merge one revision between branches. This allows you to avoid using a revision range for a simple one revision merge. This should simplify things a bit …

Subversion is still, overall, the best version control tool I’ve worked with thus far (and I’ve worked with quite a few of them). Kudos to the team on the new release. I like what I see so far …