Spyced

I'm reading the prerelease of the Scala book , since I'm working for a heavily Java-invested organization now and programming in Java feels like running a race with cement shoes. Politically, Jython doesn't seem like an option; Scala might be an easier sell. Here's some of my impressions going through the book. Scala is a decent scripting language [updated this section thanks to comments from anonymous, Jörn, and Eric.] Here's how you can loop through each line in a file: Python: import sys for line in open(sys.argv[0]): print line Scala: import scala.io.Source Source.fromFile(args(0)).getLines.foreach(println) The scala interpreter also has a REPL , which is nice for experimenting. This article has more examples of basic scripting in scala. Getters and setters One thing I despise in Java is the huge amount of wasted lines of code dedicated to getFoo and setFoo methods. Sure, your IDE can autogenerate thes...

My father got a ps3 for Christmas, but ran into some problems getting it on his wireless network. The first one was "connection error 80130128" after configuring it to use DHCP. I couldn't google anything useful about this; just a few other hapless victims asking if anyone had any ideas. Fortunately Dad had his laptop there too and noticed Windows complaining that two machines on the network were both using the same IP. So, over the phone, I walked him through setting up the ps3 with a static address: on his laptop, run -> cmd ipconfig Read the "gateway" ip. Put that into his browser to go to his router's admin page Find the DHCP settings for his router to see what range of IPs it hands out; pick one outside that range Set up the ps3 with that IP, the router IP as primary dns, and an opendns server as secondary This made the connection test happy. But when he tried to go to the playstation store, it gave a DNS error. If he repeated the connection te...

If you want to run a multi-petabyte storage system then you don't want to do it with Raid 5 or Raid 6 ; with modern disks' ~3% per year failure rate , that's 300 a year when you have 10000 disks and the odds start to get pretty good (relatively speaking) that you'll face permanent data loss at some point when you lose a third disk from an array while two are rebuilding. And of course monitoring and replacing disks in lots of small arrays is manpower-intensive, which to investors translates as "expensive." You probably don't want to go with triplication , either; disks are cheap, but not so cheap that you want to triple your hardware costs unnecessarily. While storing multiple copies of frequently used data is good, all your data probably isn't "frequently used." What is the solution? As it turns out, Raid is actually a special case of Reed-Solomon encoding , which lets you specify any degree of redundancy you want. You can be safer th...

About three years ago (so pre-Mozy and definitely pre-Mac Mozy) my brother had his powerbook hard disk die. As in, not just mostly dead -- it would not power up. It had a lot of stuff on it that he didn't want to lose, but he felt like the usual suspects who charge $1k to $2k for data recovery were a rip off. So he hung onto the disk in case a cheaper option came along. Then just recently when I saw some people on a local linux group mailing list recommend utah data rescue I suggested to my brother that he give it a try. UTDR starts at "only" $300. UTDR did indeed recover the data, although they charged $100 extra for this one. Mac fee? Tricky hw problem? I don't know. But it was still a lot cheaper than the other companies I googled for fixing a physically dead drive. (As opposed to a corrupt partition table or something where the hardware itself was okay.) At least, the ones that actually give you a price up front rather than hiding behind "reques...

I had to install subversion on a couple HP-UX boxes. Fortunately, there's an HP-UX software archive out there with precompiled versions of lots of software. Unfortunately, dependency resolution is like the bad old days of 1997: entirely manual. And there's fifteen or so dependencies for subversion. So, I wrote a script to parse the dependencies and download the packages automatically. It requires Python -- which you can install from the archive with just the Python package and the Db package -- and BeautifulSoup, which you can google for. Usage is hpuxinstaller <archive package url> <package name> [e.g., hpuxinstaller http://hpux.cs.utah.edu/hppd/hpux/Development/Tools/subversion-1.4.4/ subversion] [wait for packages to download] gunzip *.gz [paste in conveniently given swinstall commands] Here is the script: #!/usr/local/bin/python import urlparse, urllib2, sys, os from subprocess import Popen, PIPE from BeautifulSoup import BeautifulSoup required = {...

I left backup service provider Mozy about three months ago, and yesterday they were acquired by EMC as rumored by techcrunch earlier. The cool thing about startups is they pretty much have to hire people who are totally not qualified to do awesome things and let them try. There's no way Amazon would have hired me to write S3, but that's what I did for Mozy. Mozy was the third startup I've been a part of, and the first to amount to anything. I was employee number #3 and saw it grow from sharing a single rented office to 50 employees in two years. With people who didn't think it was strange to wear a tie to work. Trippy. Unfortunately I'm not there to witness the final stage of being assimilated by the Borg firsthand, but I hear that's not really any more fun than it sounds so perhaps it's just as well. Nice work, guys.

Wing IDE version 3 has been released . The list of new features is a little underwhelming. Multi-threaded debugging and the unit testing tool (only supporting unittest -- does anyone still use that old module anymore?) are nice but I don't see myself paying to upgrade from 2.1 yet. Now if they could get the GUI to keep up with my typing in Windows, I'd pay for that... I guess this is a sign that Python IDEs are nearing maturity; Komodo 4 didn't have any earth-shaking new features either, at least as far as Python was concerned. (Personally I think someone should start supporting django/genshi/mako templates already. Maybe in 3.1, guys?) Following ActiveState's lead , Wingware has also released a completely free version, Wing IDE 101. The main difference is that where the most essential feature Komodo Edit leaves out as an incentive to upgrade is debugging, Wing IDE 101 includes the debugger but omits code completion. Wingware also continues to offer the low-c...

I went to the BYU CS alumni dinner tonight. At one point they briefly put everyone's name and position on a projector, one at a time. (At five seconds apiece it wasn't as tedious as it sounds.) When it was my turn, it announced "Jonathan Ellis, System Administrator." What the hell? It turns out that when I RSVP'd I said I was a "python kung-fu master & sysadmin of last resort." (In the sense that, if you really can't find a better sysadmin, I know enough to be dangerous.) Don't bother trying to be clever around bureaucrats.

The first Utah Open Source Conference finished today. I heard that they had close to 300 attendees -- not bad at all for a freshman effort. I reprised presentations that I've given before, on SQLAlchemy and distributed source control. My slides are on the presentations page (although if you've seen my slides from either before, there's not much new there -- I got lucky, SA 0.4 isn't stable yet so I stuck with 0.3.10). I had to work Friday so I missed a lot of presentations, but of the one I saw my favorite was on Ganglia , which I hadn't heard of before but which looks quite useful for anyone running a bunch of servers that takes uptime and qos seriously. (This was actually Brad Nicholes's third presentation of the conference -- he must have been busy!) Afterwards I went to the board games BoF and played Mag Blast. Fun little game.

Since Adam Barr replied to my post on his book , I'd like to elaborate a little on what I said. Adam wrote, [F]or me, "knowing" Python means you understand how slices work, the difference between a list and a tuple, the syntax for defining a dictionary, that indenting thing you do for blocks, and all that. It's not about knowing that there is a sort() function. In Python, reinventing sort and split is like a C programmer starting a project by writing his own malloc. It just isn't something you see very often. Similarly, I just don't think you can credibly argue that a C programmer who doesn't know how to use malloc really knows C. At some level, libraries do matter. On the other hand, I wouldn't claim that you must know all eleventy jillion methods that the Java library exposes in one way or another to say you know Java. What is the middle ground here? I think the answer is something along the lines of, "you have to get enough practi...

Update: an anonymous commenter pointed out that yes, there is a (much!) better way to do this with svnadmin load --parent-dir, which is covered in the docs under "repository migration." All I can say in my defense is that it wasn't something google thought pertinent. So, for google's benefit: how to merge subversion repositories . Thanks for the pointer, anonymous! I needed to merge team A's svn repository into team B's. I wanted to preserve the history of team A's commits as much as reasonably possible. I would have thought that someone had written a tool to do this, but I couldn't find one, so I wrote this. (Of course, now that I'm posting this, I fully expect someone to point me to a better, pre-existing implementation that I missed.) The approach is to take a working copy of repository B, add a directory for A's code, and for each revision in A's repository, apply that to the working copy and commit it. This would be easy if...

I picked up a copy of Adam Barr's Find the Bug , which is a cool concept for a book. (5 languages, 50 programs, 50 bugs; see if you can spot them.) I found the bug in the first program, in C, then skipped to the Python chapter. The first two programs were not too bad, as pedagogical exercises go (although iterating through substrings instead of a.startswith(b) in the 2nd was painful). The third, though, was "Alphabetize words," 25 sloc to perform the equivalent of def alphabetize(buffer): L = buffer.split(' ') L.sort() return L ... doing everything about the hardest way possible. Now, it's pretty hard to introduce a non-obvious bug into my version of this function, so it wouldn't be appropriate for Mr. Barr's book when written this way. But the right thing to do is to make the task more difficult, not dumb Python down to the level of C! It's very very painful to read Python written like that. (Actually it's painful to read a...

http://utahpython.org/jellis/sa-tutorial-oscon.pdf Also the code snippets: http://utahpython.org/jellis/test_tables.py http://utahpython.org/jellis/test_code.py This is what I'll be using in my tutorial tomorrow. Update: I forgot to "svn up" on my web server. So now the final version is up.

After I complained that python.org could use a PEP rss feed , David Goodger invited me to volunteer to write one. So I did. (With Martin v. Löwis doing the integration with the site build script. Thanks Martin!) The feed is live at http://www.python.org/dev/peps/peps.rss .

I've been trying Opera 9.2 for a week, and I'm pleased with it enough that it's going to continue to be my main browser. The main selling points for me are MDI weirdness is mostly hidden now, I hated earlier Opera UIs 20-30% less memory use; even after poking about in the guts of about:config to force FF's memory cache to the same 10MB that I gave Opera (which exposes this option right in the UI), Opera consistently uses less memory for the same workload. (Without adding this option to FF, it would max out around 400MB instead of 150MB.) feels snappier; opera seems quicker to start rendering something useful on slow-loading sites like 1up.com, although total render time is about the same. It's also instantaneous to open a new tab, which consistently takes around 1s on FF after I've been using it a while. I open and close tabs frequently. UI takes up less space: I know it's possible to re-skin FF, but I'd have to google it to find out how. Opera m...

About two years ago I reported the bug sys.excepthook doesn't work in threads . Then just recently someone asked in #utahpython if I had a workaround. Here it is (also added as a comment to the bug report) -- all we do is monkeypatch Thread.run to run the excepthook manually if there is an uncaught exception: def install_thread_excepthook(): """ Workaround for sys.excepthook thread bug (https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1230540&group_id=5470). Call once from __main__ before creating any threads. If using psyco, call psyco.cannotcompile(threading.Thread.run) since this replaces a new-style class method. """ import sys, threading run_old = threading.Thread.run def run(*args, **kwargs): try: run_old(*args, **kwargs) except (KeyboardInterrupt, SystemExit): raise except: sys.excepthook(*sys.exc_info()) threading...

A couple months ago, I migrated my text rpg Carnage Blender to a new server, with Ubuntu 6.06 on the new box. For an unknown reason, ftstrpnm on the new box wouldn't generate the pngs I used in my captchas. It was easier to just check in the images from the old machine into the my svn repository than debug this, so I did. The downside was that my working copy on my Windows laptop stopped being able to update from the repository. It would get to "words/con.png," and error out. Google, for once, didn't turn up anything useful. Today I got motivated. I tried all kinds of ways to get this to work. A new checkout had the same problem on Windows, but on Linux worked fine. The svn command line client for windows didn't work any better than Tortoise -- instead of "Error: Can't open file '...words\.svn\text-base\con.png.svn-base': Access is denied", it barfed con.png to stdout, and died. This was a clue, but I didn't realize that until...

I found out from Brett Cannon's blog that an abstract base clase (ABC) PEP has been accepted. I don't like this PEP. It's a very big (and more important, inelegant) change to Python's style. But my real complaint is that as big as this change is, and as much as I try to stay current with Python (subscribing to 30+ blogs) I didn't have a chance to get involved in the discussion until after the PEP was already approved. Python is big enough now that there should be some mechanism for feedback from the community before the priesthood of python-dev writes something in stone. Currently, if you want to know about PEPs before they are approved, you have to subscribe to both python-dev and python-3000 (which isn't linked from either the mailing lists page or the dev page , btw). I really don't care about the vast majority of these lists' traffic but PEPs, at least some of them, are important. If the python-dev summaries ever got updated this might be...

It's really surprisingly difficult for someone who has been programming for a long time to write about programming at a level appropriate for real beginners. The first time I taught a class full of beginners at Neumont, I tried to take things as slow as possible. Then I spent the next week covering the material from the first day even slower. So when the UGIC asked me to recommend a book to get for the participants in the Introduction to Python, I looked at all the ones I could find, but they all either assumed too much existing knowledge or covered material that would just confuse a beginner. Often both. But then Michael Bernstein pointed me to Python for Dummies . If you're looking to teach beginners, or you're a beginner yourself, Python for Dummies is by far the best option. There's a few sections that are strikingly inappropriate for a book at its level (new-style classes!?) but it's still much, much better than any of the other books on the market in ...

Here are the slides from my introduction to python at the UGIC conference today. This presentation was meant for people with little to no programming experience. So I deliberately kept it pretty basic, and in fact in 90 minutes we only covered up to about slide 20 in the pdf. I also added an exercise before moving on to slide 10. ("Read 3 integers into a list, and print the sum.") There were 17? people there (which was the room's capacity), so it was very nice to have Kevin Bell also answering questions individually during the exercises.