Recently I wanted to build a .deb package for an internal IBM application I was writing so that users could easily install it and also so we could distribute them through some internal repositories. This proved a bit harder than I expected so this is a quick summary of how I ended up doing it. Note that your requirements might be entirely different!
The first thing to do is to create the files required by the packaging process. I discovered that the dh_make command can create a load of sample files that can be used as part of this process. To do this, create a directory in the format [package-name]-[version] (e.g. my-great-app-1.0) and run dh_make from within it (I specified ’s’ for single binary when prompted). This will create a load of sample files in a ‘debian’ subdirectory. Delete any of these you don’t need (which is probably most of them); I kept the following:
compat – no idea why I needed this but things don’t work properly later if I don’t
control – the details of the package you are creating (see the specification for all configuration options)
dirs – the list of directories in which your app will install files (e.g. /usr/bin, /usr/share/pyshared/my-great-app, /usr/share/applications)
README.Debian – the README for your app
rules – a MakeFile with instructions for how to create the package (for my Python app the important bit here was in the ‘install’ section; here I created a $(CURDIR)/debian/my-great-app subdirectory and copied all files into it as if it were /, e.g. binary to $(CURDIR)/debian/my-great-app/usr/bin/my-great-app)
Once I’d created all those files and put them in my-great-app/packaging/debian and my source in my-great-app/src I created a simple build script my-great-app/bin/build. This looked something like the following:
cd ../build
sudo rm -rf my-great-app*
mkdir -p my-great-app-$VERSION
cp -u ../src/*.py ../src/*.desktop ../src/*.ico ../packaging/my-great-app my-great-app-$VERSION
tar -czf my-great-app-$VERSION.orig.tar.gz my-great-app-$VERSION/
cd my-great-app-$VERSION
mkdir debian
cp -u ../../packaging/debian/* debian/
gksu dpkg-buildpackage
This should create you a my-great-app_1.0-1_all.deb and the my-great-app_1.0-1_i386.changes, my-great-app_1.0-1.dsc and my-great-app_1.0-1.tar.gz files your repository maintainer might want.
A really useful video I found for helping me fill in the contents of the debian control files (and getting me through the whole process) was here. Definitely worth checking out if you need to do this yourself.
On Wednesday we had the pleasure of Richard Hughes joining us at Hursley to talk about PackageKit. I’ve heard of it but never quite bothered finding out any more than the name but having gone to the presentation I’m pretty glad. PackageKit is (yet another) attempt at making software updating/installation easier on Linux. There are many existing tools for this already but PackageKit seems to be particularly interesting because it’s not actually trying to replace anything; it works with and makes use of the existing tools whilst providing some real value on top. Below is a very quick summary of Richard’s presentation.
Existing stuff
Good packaging formats
Depency solvers, downloaders and UIs bolted on
Can’t have automatic updates (needs password authentication)
Can’t use fast-user switching (lock out install applications/databases)
Errors/warnings in English only and really confusing to average user
Installation is done by package names not application names (many to many relationships)
Can power down during update – bit dangerous!
PackageKit implementation
The ‘glue’
Integrates with existing tools (including dependency mangement etc)
Improves authentication (uses PolicyKit – fine grained control)
System activited daemon (only running when you need it)
Only need to write simple integration between tools and PackageKit (doesn’t even need to be complete and done for most tools already) plus thin UI
Uses DBUS (two layers – one for full control, one “just do it”)
Applications can integrate directly (e.g. install clipart from openoffice)
Installation/update by application not package (users know what it is they’re installing!)
Doesn’t allow shutdown during installs
PackageKit project
Easy to contribute (git with anonymous access – merged to release daily)
Rapid development (roughly one minor release per month)
Shipped with Fedora 9 (and others)
Strong interest from OpenMOKO, Ubuntu (and others)
I’ve installed an old-ish release on my Ubuntu machine (straight from the repositories) and it looks pretty good. Definitely gonna pay attention to this project, it looks like a big step in the right direction.
Recently I’ve been putting together a Web application for a research project. I decided it was about time I really looked properly into REST so my Web interfaces are better structured. I won’t go into all the benefits here, you can read for yourself. Suffice to say it seems like a good approach to take.
This is quite a long article and you might only be interested in some of it so here are the sections:
For my BSL level 3 course I have a variety of OpenOffice documents for different forms etc which make up the portfolio. I wanted a way to merge these into a single document but they each had different margins and all sorts; this meant doing it within OpenOffice was proving to be a pain. My solution was to write a quick shell script to convert each document into PDF and then merge the multiple PDFs. The script looks something like the following:
# convert to pdf unoconv -f pdf myfile1.odt myfile2.odt ...
# merge pdfs pdftk myfile1.pdf myfile2.pdf ...
# remove individual pdf documents
rm myfile1.pdf myfile2.pdf ...
A handy little hack to generate my entire portfolio.
I received an IBM Thanks! award recently from Darren for helping out with the Feel Good Inc. Extreme Blue project. One of the choices was a ‘Recycled Office Pack’ which sounded interesting and so I thought I’d go for that:
All items say things like ‘made from recycled paper and card’, ‘using sustainable timber’ etc.
A simple thing but one that made me feel quite virtuous. I’ve written a very very simple script that turns off the screen whenever I lock the computer. Should save some energy every time I go to a meeting or off for a cuppa.
For anyone interested, it’s a Perl script which watches for the D-Bus signals from gnome-screensaver. Code is as follows:
my $cmd = "dbus-monitor --session \"type='signal',interface='org.gnome.ScreenSaver',member='SessionIdleChanged'\"";
open (IN, "$cmd |");
while () {
if (m/^\s+boolean true/) {
system('/etc/acpi/screenblank.sh')
}
}
Note that it relies you running Linux, using GNOME and there being a screen blanking script ‘/etc/acpi/screenblank.sh‘ (which in turn executes ‘/usr/share/acpi-support/screenblank‘ for every display). Not too much to ask I’m sure
Just a warning: I’m now going into sales-pitch mode. I do not work for the One Account but I think it’s brilliant (well, brilliant for me, I take no responsibility if you listen to me and end up huge great hole of debt). Having said that, I could get some money if you sign up and say I recommended you but that’s not the point of this post. Really it isn’t. That *would* be nice though…
The One Account is one of those ‘offset everything you own against your mortgage’ type accounts. This means that you merge your mortgage, savings and current accounts in a single pot so any money you have is constantly offset against your mortgage. This means the actual amount of money you’re borrowing at any one time is less that it otherwise would be and hence you pay less in interest. Ok… sounds interesting but what does that actually mean? Well, it gives you a variety of options but the most important one for me is that you can pay of your mortgage in a much shorter time period.
We signed up for the One Account at the beginning of this year and set the ambitious aim of paying our (not insignificant) mortgage off in 4 years instead of the usual 20-25. What?! 4 years? Are you freakin’ crazy I hear you say? [Well you might not be saying that but it makes this post far more interesting for me if I imagine you are so I'll pretend.] We didn’t pluck the 4 year figure out of thin air; the One Account website has a handy Mortgage Shrinker you can use as a guide. The following graph gives you an idea how this works:
As you can see, salary comes in every now and then which reduces how me we owe to the bank and then this amount slowly increases as we spend money before the next salary payment. More importantly, the amount it increases to each time is lower than the previous amount, i.e. the mortgage is getting smaller.
So half a year in, how’s it looking? Pretty darn good actually. Amazingly, that ability to offset your salary payments against your mortgage until you spend them, plus the ability to effectively pay off bits of your mortgage constantly has left us in pretty good shape. We are entirely on track to pay the thing off in 4 years, if not sooner.
P.S. Worth noting that just because you can pay off loads of your mortgage quickly, doesn’t mean you can’t spend it too. Effectively you could end up only having paid off interest after 20 years and no capital, or pay off £20k and then blow it on a new car or something. Only a good idea if you have some self-control over your finances!
I went on a brief trip to Toronto a few weeks ago and a friend of mine asked for recommendations on things to do. Here are mine – please make add any comments/suggestions Things to do
CN Tower: tallest building in the world and some fantastic views, try and go when it’s quiet though as there’s not much space to move around
Toronto Eaton Centre: a large shopping mall that feels quite impressive and plenty of shops to wander round
St. Lawrence Market: a really fun and interesting market with all kinds of food
I recently hit this snag when working with Dojo. Basically I wanted to set the checked status of a checkbox on a webpage programmatically. Simple you might think? Apparently not as easy as it should be.
Interaction with checkboxes has changed slightly in Dojo 1.1 (apparently) but myCheckbox.setValue(true) should be valid. When calling dojo.byId('my-checkbox-id').setValue(true), I was getting an error saying the method didn’t exist. The object was definitely the checkbox as I could determine the correct checked state from that object (myCheckbox.checked) so I was very confused. I then remembered another way to access objects with Dojo is using the HTML attribute ‘jsId‘. This creates a global javascript variable referring to that object in the DOM. So I set something like jsId='myCheckbox' and then called myCheckbox.setValue(true) and it worked!
Very odd behaviour. I can only guess that the javascript object created by Dojo using jsId and dojo.byId() is a different bit of code and creates an object pointing to the DOM checkbox object in a different way. Very strange but at least there’s the workaround above…
Ok, so that’s definitely not true but I try. Although he often has interpreters coming into the office, I regularly act as a backup interpreter for Ben for small meetings etc. The other day however, his interpreter had an accident and Ben was supposed to be giving a talk in the auditorium at Hursley where we work. Can you guess what happened next?
So I stood up to the challenge and tried to interpret Ben’s talk to the audience. It was a very strange experience as I’d never really interpreted from BSL to English apart from in small groups, or even seen it done very often – most interpreters I see are from English to BSL for Ben’s benefit. I wasn’t sure how well it went as knew I didn’t manage to get everything across, my language was quite simple compared to what Ben was trying to articulate, and I did swap from the 1st person (the correct method where I pretend to be Ben) to the 3rd a couple of times. However, a few people (including Ben himself) were extremely generous with their praise which was fantastic to hear (e.g. here, here, here and here).
Following that talk I was full of confidence and so then happily interpreted for Ben at the next one (someone else on stage, English to BSL). Definitely got a rush that day, very exciting. Maybe I’ll do more of this in the future…
P.S. I know I’ve done more signed versions of BSL-related posts in the past but I’m finding it quite hard to find the time to do it. Writing is much quicker for me and to then translate I need to get a camera, work out what I want so sign, how to translate etc. Maybe it would be better to start with a BSL version and translate that to English instead. I’ll have a think about it and see what I can do.
