Jonathan's Pancheria: Category technical

The Mainstream realizes SOA is going the way of WS-*

Jonathan Altman — Mon, 11 Aug 2008 19:21:00 +0000

So I disagree with the way the argument in this post is framed, but I am glad to see the “mainstream” tech press realizing there’s a better way to get to SOA:

A growing number of companies are finding that lower-visibility Web-oriented architecture (WOA) developments, spawned through grassroots movements, are a better route to the service-oriented architecture. WOA, like SOA, is an architectural approach to system design, though WOA is resource-oriented rather than service-oriented. What’s the difference? While the core SOA design unit is a reusable service that fulfills a distinct business function, resource-oriented services are more limited and data-focused.

SOA and WOA work at different layers of abstraction. SOA is a system-level architectural style that tries to implement new business capabilities so that they can be consumed by many applications. WOA is an interface-level architectural style that focuses on the means by which these service capabilities are exposed to consumers. Governance, quality of service, security, and management are of equal importance, whether the functionality is being delivered via SOA or WOA.

I think the delineation between SOA design units as a service fulfilling a distinct business function and WOA as a resource-oriented service being more limited and data-focused is so much dissembling for SOA being an attempt to force a top-down, waterfall-based model on what services you offer in your architecture versus an iterative or even agile strategy of building the individual services and then gluing them together.

I think SOA was also overblown in the framework for tying them together, which is the root of this problem, and leads to the conclusion I made up above. Put a bunch of webservices out there that handle orthogonal responsibilities, make it easy to access them (personally, preferably with easy HTTP/POX or a light SOAP layer), rather than a huge management stack that services have to a priori fit into, with the up-front design and overhead that comes with it.

Good point about any Web Services != RPC

Jonathan Altman — Fri, 25 Jul 2008 15:44:34 +0000

So ordinarily, this post would have gone up as a link in del.icio.us, but the interesting part of it is actually a single quote that flows in the article but is not the main point. So I will just crib the interesting part here. It is worth reading the entire post as it is interesting, but what I want to call out is:

bq.IMO the real underlying problem is that as long as programmers expect to write a class and flip a switch to get a service or one or more RESTful resources then we have nothing really but RPC masquerading as something else. Both resource and service advocates would be well-off in trying to move the developer community to get past the “class is all I need” stage. If REST is successful in getting developers to get their hands dirty more power to it.

...And we shall call it NetBlub

Jonathan Altman — Wed, 02 Jul 2008 06:07:00 +0000

Paul Graham first wrote about a strawman hypothetical programming language blub that examined the constraints that people who choose to stay firmly embedded in only one language seem to impose upon themselves and their programming capabilities and creativity.

Steve Vinoski, who has been writing a bunch about some of the failures of RPC-style distributed systems technologies (and should know, having been involved in CORBA), I think just extended the theme to distributed systems programming here.

Running Rails Apps on a Nokia N810

Jonathan Altman — Wed, 13 Feb 2008 05:28:00 +0000

Goaded on by requests for screenshots of Tracks running on my n810, I decided to instead document to the best of my recollection what I did to get Tracks and Instiki running on my n810.

1. Preface: Why?

2. Screenshots

3. Prerequisites

4. Tracks and Instiki

5. Wrapping Up

DISCLAIMER: I am going to show you how to do some things that can probably badly mess up your device if you get them wrong, and maybe even if you follow these instructions to the letter. I do not promise that these instructions are even complete or accurate anymore; I am nearly positive the instructions below are incomplete regarding what to install. You follow these instructions at your OWN RISK. This worked for me, it may or may not work for you, with or without additional steps. I did this about 3 months ago and was not taking good notes because I figured over time apt packages would catch up and this would not be necessary to repeat. If you follow and you get warnings you need to install additional stuff to continue, you should probably assume that is correct.

Preface: Why?

So one of the main reasons I actually got a Nokia n810 internet table (Linux/gnome-based tablet) was because:

It had a keyboard
It ran Linux and was reasonably powerful enough to possibly run some interesting things
It might let me replace my horrible system of “engineering notebook” plus wiki on my personal laptop plus complete lack of organizational system for keeping track of tasks with a single device that could provide all of that in a small, portable package

To get this, however, I was going to have to be able to install 2 Rails apps that I liked:

Instiki, for wiki
Tracks, for GTD (Getting Things Done) task management

I pre-ordered my n810 directly from Nokia (with a very nice discount) before it was available, and received mine I think within the first week of its being generally available in the United States. So to preface this description of how I got things working, I did all this in late November, 2007. Some packages may have moved around, and there may be better ways to do things than what I had to do. But Chinook (OS2008) ported packages were fairly slim at that time.

I should also point out that I was not interested in developing Rails apps on this machine, just installing and using them. Once I got things to an acceptable level of “done” for me, I did not investigate some pecularities further. So some things that you will not have after this are:

The ruby gem system is not installed. I did get it installed, but could not get it to actually read the gem catalog, so I see no reason to describe how to install it. Could it be made to work? Don’t know and I don’t care for my purposes on this box. I have gem working lots of other places on different chip architectures, but the n810 was not a target I needed it working on at this time
I did absolutely no investigation on how to have Rails apps start when you boot up the n810. I have a shell script I use to start my apps, and anybody who wants to take that to the next level and get this autostarted, please document it and I will gladly use it. But my shell script works for me since I reboot the thing maybe once every 3 weeks
This does not get you the Rails gem installed anywhere in your site_ruby, nor ActiveRecord, nor anything else. Most packaged Rails apps seem to freeze their Rails install into railsapp/vendor anyway these days, so installing a pre-packaged app works just fine. So my instructions may not work for some Rails apps, and it certainly won’t work for you to start making your own new Rails app on your n810

Screenshots

So without further ado, as a tease, here are screenshots of Tracks running on my n810. As you can see by the lateness of many actions, I have been better about getting Tracks set up than in actually having it improve my personal organization!

”

The Tracks “Home” view. David Allen would be appalled!

Adding an action. Notice that the Ajax calendar works just fine.

Prerequisites

These are the steps to take to get the basics set up on your n810 to even put a Rails app like Tracks or Instiki on it.

Turn on Red Pill Mode

I am not sure this is strictly necessary, but I had it on while I was doing this,and I suspect it’s necessary. This is the first but not the last dangerous part of these instructions. Instructions on doing so, and what it does for you, are on the Maemo wiki here

Libsqlite3-0

libsqlite3-0 appears to already be installed, so there is nothing to do. But you might want to confirm in the Application manager that it is already installed.

Install Ruby and Ruby Sqlite3 Bindings

~~-I got the packages from http://maemo.rubyx.co.uk/ruby-maemo/ however the site appears to have been down for a while now.~~- The ruby packages I installed appear to now live at http://gplsystems.com/apt/dists/chinook/main/binary-armel/Packages (thank you friend and coworker who wishes to remain anonymous). The packages I installed, which I recall all coming from there, were:

libruby1.8
libruby1.8-dev (not sure it’s necessary, but I grabbed it)
ruby1.8 (1.8.6-p110-1)
ruby1.8-libxml (I don’t think it’s necessary, but I do a lot of stuff with XML)
ruby1.8-maemo (again, not sure it’s necessary)
ruby1.8-sdl (nearly positive I did not need this)
ruby1.8-sqlite3 – definitely required

I found and installed rubygems from somewhere, but I could never get it to do anything but hang trying to update catalog. Both Instiki and Tracks releases ship “complete” so there’s no gems needed, so I skipped this.

Add the Maemo Repository to Application Manager

Add the maemo stable repository at http://repository.maemo.org/. When you are done, the apt.sources line ends up looking like “deb http://repository.maemo.org/ chinook free non-free” for those of you that like to look at the raw apt package configuration files.

I also added the Maemo extras repository and maemo-hackers.org repository

Install p7Zip, gcc, make and some needed Libs

Since rubygems didn’t work for me, I decided to install mongrel from source. You need gcc, and I think make. You also need something to unpack tar/zip archives, and at the time the only maemo package I could find was p7zip. These are in the maemo repository/repositories you added earlier. I have

p7zip 4.42.maemo-1
make 3.80-9osso
gcc 3.4.4
libc6-dev if you don’t already have it

There may have been some other pieces needed too.

Download and Install Mongrel

Webrick runs on the n810, for values of run equal to a geriatric snail. You will not be happy with a Rails app running under webrick. Mongrel is, while not exactly instantaneous, at least responsive enough to run an AJAX-y Rails app.

Download the mongrel source tarball from http://mongrel.rubyforge.org/. 1.1.1 was the latest at the time but they are on 1.1.3 as of February 5, 2008. Untar to a directory (using p7zip). Then do ruby setup.rb which should configure, build, and install mongrel. You should now have /usr/bin/mongrel_rails.

Tracks and Instiki

Where to Install

You will be installing Tracks and Instiki from source tarballs or zipfiles. After you download them, you will need to unpack them somewhere, using p7zip. I put them on my removable media card, which is /media/mmc1 because I was concerned about the GPS/mapping software filling up the fixed 2GB memory card /media/mmc2. If you plan to swap out memory cards often that might be a bad decision for you, but I am happy with it.

Tracks

Download a Tracks tarball/zipfile. I used Tracks 1.043 which was the latest “release” drop on their site, but I am sure you could grab trunk out of the Tracks source repository and turn that into a tarball too
Untar/unzip the source archive and cd to the top directory of Tracks. In my case that was /media/mmc1/tracks-1.043. You may lay it down differently, but if so remember to alter your paths throughout the rest of these instructions appropriately.
cd into the tracks directory you just unpacked
Make sure that the database.yml in the config subdir is set up the way you like. I left mine using db/filename.db as it shipped
Now the moment of truth: start up Tracks. From the main directory you could do ruby script/server just to test (it might start up webrick instead of mongrel, for values of might equal to probably). If it starts up without error, point your web browser at your Tracks instance: http://localhost:3000/
Once you have it up and running, you can stop Tracks with ctrl-c
Now try mongrel. /usr/bin/ruby /usr/bin/mongrel_rails start -c /media/mmc1/tracks-1.043 -e production -a 127.0.0.1 -p 3000 is what I use in my environment. You might need to adjust the path after -c to match how you laid down Tracks. It should start up, and you should be able to point your web browser at it. If so, go ahead and stop Tracks by typing ctrl-c.

Congratulations, you’ve installed Tracks on your n810!

Instiki

Download Instiki 0.12.0 (or newer if it exists and you want it). I would avoid earlier versions of Instiki that use Madeleine for persistence. 0.12.0 uses sqlite3 for persistence, and that seems safer than using Madeleine on the n810
Untar the source archive and cd to the top directory of Tracks. In my case that was /media/mmc1/instiki-0.12.0. You may lay it down differently, but if so remember to alter your paths throughout the rest of these instructions appropriately.
cd into the instiki directory you just unpacked
Make sure that the database.yml in the config subdir is set up the way you like. I left mine using db/filename.db as it shipped
Now the moment of truth: start up Instiki. From the main directory you could do ruby script/server just to test (it might start up webrick instead of mongrel, for values of might equal to probably). If it starts up without error, point your web browser at your Instiki instance: http://localhost:2500/
Once you have it up and running, you can stop Tracks with ctrl-c
Now try mongrel. /usr/bin/ruby /usr/bin/mongrel_rails start -c /media/mmc1/instiki-0.12.0 -e production -a 127.0.0.1 -p 2500 is what I use in my environment. You might need to adjust the path after -c to match how you laid down Instiki. It should start up, and you should be able to point your web browser at it. If so, go ahead and stop Instiki by typing ctrl-c.

Congratulations, you have installed Instiki on your n810.

Wrapping Up

Now that you have Tracks and/or Instiki up and running, what next? I left my apps running on their default ports of 3000 and 2500, but you could run them on different ports if you chose. I saw no reason to do that, nor to find a webserver to proxy them to so they are off the “main” webserver. That’s just overhead the n810 really does not need.

Starting up Rails Apps

Once I was happy with my install, I made myself a little shell script to fire them both off. When I boot up, I start up an XTerm and fire off the script. Here are its contents (sorry for the iframe, it was easier):

Stopping Rails Apps

The easiest way I stop both my apps if I need to, like if I want to hook up the USB cable or otherwise want to make sure the Rails apps shut down cleanly, I just issue a killall ruby and that kills the mongrel processes given how I start them. Before you just do that, make sure you know what ruby processes are running on your n810 and that you’re ok to kill them all.

Note that it can take a good few seconds, from 15-20 up to maybe 30, for all the Rails apps to respond to the kill signal. Just be patient. I also highly recommend aliasing ps -ef | grep in the shell to pgrep because inputting the pipe symbol on an n810 is fairly cumbersome.

Switch (back)

Jonathan Altman — Sun, 25 Nov 2007 19:20:00 +0000

Well, after 12 years I have switched (back) to Macs.

My first computer was an original 128k Mac, one of the very first ones. My mouse actually had a 5-digit serial number, IIRC. I gave up in 1995 swearing I would never buy another Mac:

I bought a Powerbook Duo 210-possibly the worst Mac ever engineered- right when it came out, shortly before Steve Jobs cut the price in half, and then shortly after that discontinued it. And no, he didn’t give me any funny money to go spend in his stores after he did it
The various unixes, which is how I made my living at the time, all had reasonable PC-based implementations that were free and open source. Linux was viable, and FreeBSD 2.2 was a really nice, stable OS
The Mac just did not have interesting software that I wanted to play with, and I could run systems I could get paid to play with on x86 pc hardware
Oh yeah, did I mention the turd of a computer that the Powerbook Duo 210 was?

The Good

So why the switch back? It comes down to things Just Working. I’ve been using various Linux distros, most recently Ubuntu, at home for a while. I will continue to run Ubuntu on my home laptop. But for a computer for the rest of the family to use, and for certain things for me, the Mac is just easier:

It is just about as easy to manage software on the Mac as on Ubuntu. I am convinced that the debian apt system (or possibly similar like yum or rpms) are the way to go for maintaining systems. But Apple’s installation system has so far been very easy to work with to get things on here.

Most importantly, once software and drivers are installed, the hardware and software Just Works

As a quick example, I installed the iSync plugin for my Nokia N95. I then used the iMac’s bluetooth wizard to connect to the phone, it found it and paired properly (no extra credit, most things do these days), but then iSync popped up and within 10 minutes of starting I had downloaded the plugin, installed it, connected my phone, and synced my phone into iCal and the address book

*Unix-y goodness. I like being able to pop into a shell and do things, and having rsync and friends around is nice

The Bad

So everybody touts the awesome OSX GUI. But here’s the deal, much of it is still the best that 1983 has to offer.

The single menu bar at the top of the screen that switches as you change apps has got to go. I have had the computer running less than a day and I’ve already thought I’ve closed an app about 20 times only to remember that closing the last window…closes the last window. It is too hard to get into and out of apps
I’m not thrilled about the dock showing both open and available apps. I would prefer one list of open apps and another of apps I frequently use to click on. I know there is a visual indicator of what’s open or not, but my dock is cluttered because I am used to using a strip of icons for apps I start frequently

Overall

Overall, I am happy with the switch back, but I think I’m jaded enough not to become too much of an Apple fan boy. There are too many usability nits left in the OS from 20 years ago.

I’m using firefox and thunderbird for mail because at the base of it I want an OS to run my apps on top off, and I like that I have the same apps on Windows, linux, and OSX.

Finally, I am sure I have said something in here to anger Mac, Windows, and Linux/Debian/Ubuntu fans everywhere. Remember, this is my choice. I use all 3 OSes now every day (Windows at work, Ubuntu on my personal machine, and OSX on the family computer). I use what works for me out of each of them, and none of them does exactly what I want for every single thing. Linux->Debian->Ubuntu and OSX each have their strong points, and I like each for what they can do. But each has downsides too. Remember, this is all IMHO, with the emphasis on my and opinion. You are free to have yours, and have them not be the same as mine.

Initial Lockdown of a Joyent Accelerator

Jonathan Altman — Fri, 25 May 2007 04:37:00 +0000

Here are some quick steps I did to do initial lockdown of a freshly created Joyent Accelerator:

Change passwords

Sign in as admin via secure shell to the default account, change its password
su to root and change the root password
Go into virtualmin->webmin->Webmin Users->Click on the admin user. Then set Password Authentication to Unix Authentication in the dropdown box, like in this screenshot: Hit the Save button at the bottom of the page. After you do this, you will have to log back in to webmin. Alternately, you could just set the password to be the same as the one you used for the admin user you secure shell’ed in, if you are worried about webmin having access to the Solaris password authentication system. But then you also have to worry about keeping the passwords in sync.

Shut off unnecessary services

Disable apache: I am not ready to run a webserver yet, so I shut off apache by su’ing to root and running # svcadm disable cswapache2
Make postfix only accept mail from localhost: Webmin->Server->Postfix Configuration->General. Set the text box on “Network interfaces for receiving mail” to localhost, like in this image: then save. Then stop and restart postfix

When I was done, my netstat -a -f inet display showed only the following listening ports:

*.s s h: s s h daemon
*.10000: webmin
localhost.smtp: smtp, but can only be accessed via localhost
localhost.3306: mysql daemon

IT versus software development

Jonathan Altman — Tue, 03 Oct 2006 20:38:00 +0000

Having worked at some places with what I would call “restrictive access policies” regarding internet sites and ports that can be accessed, as well as the software and configuration of computers issued to employees, I am led to the following question for companies that develop software:

If you do not trust your software developers with their own computer, how can you trust them to write the software products you sell?

If you are worried about me setting up my own printers, or installing software on my computer, or where I browse, then how can you trust the commercial software that I write for you? Sure, there are criminal penalties for the latter, but are you saying that the only way I will behave in a lawful manner is under pain of imprisonment?

Sound Bite for Rest/non-object serialization web services

Jonathan Altman — Mon, 02 Oct 2006 02:17:00 +0000

I have posted several times about it, made a bunch of different arguments, and anybody who has talked to me about web services has heard me try and make the argument not to force a web service to be the serialized transfer of object artifacts. But here’s the summary in a nice single sentence from the post CommonRESTquestions:

REST can be seen a documented-oriented subset of Object-Orientation. It deliberately reduces the expressiveness of Objects down to the capabilities of resources to ensure compatability and interoperability between components of the architecture.

The rest of that paragraph goes on to say

Object-Orientation allows too great a scope of variation for internet-scale software systems such as the world-wide-web to develop, and doesn’t evolve well as demands on the feature set change. REST is Object-Orientation that works between agencies, between opposing interests. For that you need to make compromises rather than doing things your own way.

So there you go, someone said in a paragraph exactly what it has taken me 2 years to try and say.

Font hinting in Ubuntu

Jonathan Altman — Fri, 09 Jun 2006 14:39:00 +0000

Courtesy of Sean McGrath, who found it elsewhere.

Put this in .fonts.conf in your home directory:


<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <match target="font">
    <edit name="autohint" mode="assign">
      <bool>true</bool>
    </edit>
  </match>
</fontconfig>

SOA for managers

Jonathan Altman — Mon, 06 Feb 2006 17:21:00 +0000

Finally, a description of good web service/SOA design that even pointy haired bosses can understand :-)

The graphics are designed to make it clear to non-technical users how to go about designing the boundaries of your web services/SOA!