svn merging on OSX

I don't always use svn as a version control system with which I'll need to merge branches, but when I do, I use fmdiff.

$ brew install fmdiff

One minor annoyance - fmmerge (used for interactive conflict resolution) doesn't work. The number of arguments passed to the script has changed since it was first written. I patched it locally, but it still didn't work. FileMerge was launched, I could edit files, etc; but it kept saying that the merge needed resolving. Instead, I just postpone all merge conflicts during the merge, and then use fmresolve and svn resolve to resolve any individual merge conflicts.

[1] I like to branch by feature typically, but occasionally, branch by VCS is used.

Installing Graphite on OSX (Snow Leopard)

This wasn't entirely straightforward, so in the hope that it's useful for others:

python on Snow Leopard doesn't seem to come with the development headers, so we need to address that, since pycairo needs them.

$ brew install python

• edit the PATH to have /usr/local/share/python at the start
• open a new shell to recognise the new PATH
• install cairo as per http://stackoverflow.com/questions/6886578/how-to-install-pycairo-1-10-on-mac-osx-with-default-python
• I do --use-gcc since it doesn't work with LLVM / LLVM-based GCC.

$ brew install cairo --use-gcc
$ wget http://cairographics.org/releases/py2cairo-1.10.0.tar.bz2
$ tar xjf py2cairo-1.10.0.tar.bz2
$ pushd py2cairo-1.10.0
$ emacs wscript
$ export CC=/usr/bin/gcc
$ export PKG_CONFIG_PATH=/usr/local/Cellar/cairo/1.10.2/lib/pkgconfig/
$ python waf configure
$ python waf build
$ python waf install 

Now install python dependencies

$ pip install django
$ pip install django-tagging
$ pip install twisted
$ pushd path/to/graphite/
$ pushd whisper
$ python setup.py install
$ popd
$ pushd carbon
$ python setup.py install
$ popd 
$ python check-dependencies.py
$ python setup.py install
$ pushd /opt/graphite/webapp
$ export PYTHON_PATH=${PYTHON_PATH}:/opt/graphite/webapp
$ pushd graphite
$ python manage.py syncdb 

Grabbed this file and put it in /opt/graphite/bin. That means I don't need to setup apache httpd locally.

$ wget https://raw.github.com/tmm1/graphite/d0f76a659f4f2dea67f19902002710f601f534aa/bin/run-graphite-devel-server.py
$ python /opt/graphite/bin/carbon-cache.py start
$ python /opt/graphite/bin/run-graphite-devel-server.py /opt/graphite 

Browse to http://localhost:8080/ and I have a graphite webapp running

$ python path/to/graphite/examples/example-client.py 

I now have a script putting data into graphite. Might want to tweak local_settings.py (make it Europe/London, for example), and conf/carbon.conf to have reasonable retention periods / file sizes for the whisper data files.

Related links:

• http://stackoverflow.com/questions/7138076/installing-graphite-on-os-x-lion-how-to-configure-apache2
• http://stackoverflow.com/questions/1811783/how-do-you-install-pycairo-on-mac-os-x
• http://stackoverflow.com/questions/6886578/how-to-install-pycairo-1-10-on-mac-osx-with-default-python
  

Objective-C concurrency issues

Disclaimer - I've not shipped Java Swing / SWT apps. I'm a server guy where markup is the UI. Consequently, I don't have in-depth knowledge of Java to compare against. I'm aware of SwingUtilities.invokeLater(Runnable) but otherwise just assume I'm clueless about Swing.

First rule of GUI programming - don't block the main thread.

Second rule of GUI programming - don't block the main thread, etc.

Quantifying this, you have a device running at a refresh rate of 60Hz. So you if you do anything in the main thread, you need it to complete in under 16ms, or your UI will not be smooth and responsive.

In Java, I would normally look at Executors, Callables, Runnables and related APIs to do things off the main thread. In Objective-C, we have NSOperationQueue and NSOperation. Learn, use and love them. In particular, don't do what I did and start porting java.util.concurrent classes to Objective-C. I wrote a CountdownLatch, which was very nice and taught me about various low-level concurrency primitives. Unfortunately it was completely the wrong solution for the language. What I should have done was to use [NSOperation addDependency:] to chain tasks together.

Capturing Mobile Network Traffic On OS X

Recently had to audit an app to ensure that it wasn't leaking any unwanted details over the network. This was an iPhone app, but the same process can be used for Android, etc.

1. Ensure Macbook Pro is plugged into Ethernet.
2. Open System Preferences
3. Internet & Wireless | Sharing (in Snow Leopard).
4. Click Internet Sharing.
5. From Ethernet
6. On Airport
7. Close System Preferences
8. Click Airport
9. Select Create Network...
10. On the phone, open the WiFi controls and connect to the network that you've just created.
11. Run Wireshark.
12. Start capturing traffic on the wireless card.
13. Check stuff is using SSL that should be, etc.

mod_python in apache on OS X with Homebrew

Recently had to install mod_python to test something for a customer. It needed some nudging, so including it here. Snow Leopard, Homebrew and default httpd.

Objective-C for Java Developers

I'm coming from an Eclipse on Ubuntu background, but this is equally applicable for IDEA on Windows. What are the equivalents for iPhone development?

Java	iPhone	Notes
JUnit (unit testing framework)	?	It is possible to use TDD for Swing apps, although I've been predominantly a server-side guy with client stuff happening in the browser for quite a while now. Cucumber with iPhone looks worth exploring...
Hudson (continuous integration tool)	?	On my first iPhone app, it rapidly became apparent how easy it was for people to do bad merges and delete classes from the Xcode project file / strings from the UTF-16 l14n Localizable.strings file. You can argue that people should take more care; yeah, that'll fix it. git bisect is great, but a tool that builds on each commit is better.

iMac - Guide for Linux Users

Got a MacBook Pro recently at work, for doing more iPhone stuff. I've long admired Macs as hardware, but haven't ever owned one due to an irrational distrust of Steve Jobs. Oh well, lots of friends recommend them and have told me it's the best computing experience going. I'm expecting a learning curve, but here goes:

1. Go through basic setup for my user account. No friction so far apart from the keyboard. I know which keys to check when I'm installing a Linux, so I do the same. SHIFT+2 and SHIFT+' give me @". WTF? Need to remap certain stuff; that's not the British English layout I'm used to; none of my other computers are Macs and I have 10 years of muscle memory when it comes to typing. I'll come back to fixing that. First off, Apple | System Preferences | Keyboard | Modifier Keys and sort out Caps Lock and CTRL, for good emacs usage.


2. Where's a bloody terminal? Spend 5 minutes learning the nuances of the trackpad (I'm used to a nipple) and then drag one out of Applications | Utilities onto the Dock.


3. Good, ssh is available. Copy my SSH keys and config off the Dell laptop running Ubuntu 9.10. Test all ssh stuff and grin like a maniac.


4. Right, best install any system updates before I start configuring the arse off it. For a Unix, Mac OS X seems to need a lot of restarts for simple stuff like iTunes updates.


5. WTF!? Nothing like aptitude? That seems like a glaring omission. What are my options? Googling seems to point to Macports, Fink and Homebrew as the available options.


6. IRC client - download Colloquy and start talking to real people about their experiences.


7. After that very small skewed sample, decide to go with Macports for now with an intention to properly evaluate Homebrew Real Soon Now.


8. Install git with git-svn support. $ sudo port install git-core +svn gitX


9. Checkout my github stuff. Git is missing something - completion!


10. $ sudo port install bash_completion
    $ curl -o git "http://repo.or.cz/w/git.git/blob_plain/HEAD:/contrib/completion/git-completion.bash"
    $ sudo mv git /opt/local/etc/bash_completion.d/


11. Download the behemoth that is Xcode from the Apple Developer site and start checking out Objective-C

That'll do as a minimally usable system for now. Hardware-wise, it's a delight. Being able to watch all of InfoQ content without the teething problems that I always seem to have on Ubuntu is just a major relief - I've got a lot of stuff in delicious tagged from there that I've never managed to watch, so I can start getting through that backlog as well.