BCS Meeting 26th July 2012 on the Isle of Man

I’ll be giving a talk about agile development on the 26th July 2012, in Douglas on the Isle of Man – more details here: http://www.bcs.org.im/2012/07/agile-masterclass-xp-scrum-and-lean-startups-july-26th/

 

Upgrading PEAR if Guzzle install fails

I had a problem with the PEAR installer with the Guzzle package (a generally excellent PHP HTTP framework).

A channel discover would give the following error:

root@ip-10-56-47-23:~# pear channel-discover guzzlephp.org/pear
 Discovering channel guzzlephp.org/pear over http:// failed with message: channel-add: Cannot open "http://guzzlephp.org/pear/channel.xml" (File http://guzzlephp.org:80/pear/channel.xml not valid (received: HTTP/1.1 404 Not Found
 ))
 Trying to discover channel guzzlephp.org/pear over https:// instead
 Discovery of channel "guzzlephp.org/pear" failed (channel-add: Cannot open "https://guzzlephp.org/pear/channel.xml" (Connection to `guzzlephp.org:443' failed: Connection refused))

Strangely, I could fetch the channel.xml file manually and add the channel. But even then, the install would fail (with similar messages about 404 errors).

The solution seemed to be upgrading PEAR – I was running version 1.9.0 (check it with “pear -V”), so I upgraded it:

root@ip-10-56-47-23:~# pear upgrade pear

after which I had version 1.9.4. Then I tried the channel discover again, with much better results:

root@ip-10-56-47-23:~# pear channel-discover guzzlephp.org/pearAdding Channel "guzzlephp.org/pear" succeeded
 Discovery of channel "guzzlephp.org/pear" succeeded

 

Using Jenkins to run remote deployment scripts over SSH

We use Jenkins to deploy code to multiple servers, so that we can manage builds and deployments from the same (even better if you’re using the Jenkins IRC plugin).

The deployment is done by a parameterized build job, where the parameter is the version of the project that we want to deploy. The job will run remote commands over ssh on servers that you’ve defined in the Jenkins configuration. Those commands will pull down a version of our code, unpack it, and run the rest of the install steps.

 

First you’ll need to install the Publish over SSH Plugin, which will allow files to be transferred to your servers and remote commands to be run.

Set up the SSH key for remote access of your target servers, in the Manage Jenkins page:

and setup the definitions for each of the servers that you want to deploy to:

Then in the configuration for the new deployment job you’ve set up, you’ll use the “Send files or execute commands over SSH before the build starts” settings in the “Build Environment” section to remotely execute a script to carry out the install steps on each remote server:

Notice that the build parameter “$version” is available to the Exec command that gets remotely executed – other Jenkins environment variables will also be available (e.g. $BUILD_NUMBER, $JOB_NAME etc).

Use the “Add Server” button to add more target servers, with the same Exec command.

Now you can deploy your project (or run any other remote scripts) by running the build job and specifying a version number.

 

Building github branches with Jenkins

We usually work on several parallel branches of a repo on github, and we wanted to be able to build and test any branch on demand.

So we set up a parameterised job in Jenkins that will take the name of a branch and run the build process.

As for all github builds, you need to have installed the git plugin first (https://wiki.jenkins-ci.org/display/JENKINS/Git+Plugin) and set up your github globals in the Jenkins settings:

 

 

 

Then set up a parameterized build job with the repo as the GitHub project and with “branch” as the parameter to be specified:

and in the Source Code Management section, add the parameter to the “Branches to build”:

Don’t specify any build triggers – you’ll probably just want to run this on-demand against specific branches, rather than every time there’s a push to the repo (which is what happens by default).

Now you can build any branch just by giving the branch name as the required parameter when the job is started.

 

 

 

Importing a project into github

We’re moving our development projects into github, so we wanted to get a copy of the code (checked out of Subversion) into a new project in github.

Here are the steps (assumes that you’ve set up your ssh keys correctly, according to e.g. http://help.github.com/linux-set-up-git/)

Setup the git globals:

$ git config --global user.name "Julian Higman"
$ git config --global user.email "jh @ kasabi.com"

Create the new project, add a README file, and connect it to the github remote project:

$ mkdir my-new-project
$ cd my-new-project/
$ git init
$ touch README
$ git add README
$ git commit -m "First commit"
$ git remote add origin git@github.com:kasabi/my-new-project.git
$ git push -u origin master

Now copy in the project source files, excluding svn files and other project config files:

$ cd ..
$ rsync -r --exclude=.svn --exclude=.buildpath --exclude=.project --exclude=.git my-old-project/ my-new-project/

Then add the new files, commit them, and push to the remote repo:

$ cd my-new-project/
$ git add -A
$ git status
$ git commit -m "added project files"
$ git push

 

 

Using Drush Make while ftp.drupal.org is down

The Drush Make utility downloads modules from ftp.drupal.org during the build – but the ftp.drupal.org site is currently down, which means Drush Make won’t work (and so our continuous integration has ground to a halt).

There’s a fix for general Drush usage here: http://contrib.linalis.com/content/continuer-dutiliser-drush-quand-ftpdrupalorg-est-down

That fix changes the download url to use drupal.org (which is working) instead of ftp.drupal.org (which isn’t).

Unfortunately Drush Make uses it’s own download functions, so this doesn’t help.. Here’s my (very similar) hack to get the Drush Make downloads working..

Change line 367 in drush_make.drush.inc to the following:

'url'  => str_replace('ftp.', '', $release['file']),

(The file should be somewhere like /usr/share/drush/commands/drush_make)

And don’t forget to remove the hack when ftp.drupal.org comes back..

Enable trackpad coasting in Ubuntu 10.04

I like the way trackpad edge-scrolling allows you to “coast” (start scrolling with the edge of the trackpad, then release it, and the scrolling continues until you tap the trackpad again).

It’s not enabled by default on Ubuntu 10.04, but here’s how to turn it on (put it in a startup script):

xinput set-prop –type=float “AlpsPS/2 ALPS DualPoint TouchPad” “Synaptics Coasting Speed” 1

PHP 5.3.0 and the “global” keyword

This had me stumped for a while – using some 3rd party code with PHP 5.3.0, the “global” keyword didn’t seem to work any more (references to the supposedly “global” variable from within functions always gave NULL)..

You have to declare the variable as “global” before setting it in the outer scope – then it works again.

So, this used to work (but doesn’t under PHP 5.3.0) :

$util = new Utility();
global $util;
function show() {
    global $util;
    echo "$util->version";
}
but if you swap the lines of the declaration of $utils, then it does work under PHP 5.3.0 :
global $util;
$util = new Utility();
function show() {
    global $util;
    echo "$util->version";
}

Installing Ruby Active Record on Ubuntu 10.04

I had to jump through a few hoops..

I tried the obvious “sudo gem install activerecord”, but it gave an error – it needs to install the i18n gem, but that needs rubygems version >= 1.3.6, and I had rubygems 1.3.5.

So I had to upgrade  rubygems first, which would normally be :

sudo gem update --system

but that reports that it’s been disabled on Debian, and directs you to use apt-get instead (which doesn’t have a better version). So I had to use the gem-updater gem:

sudo gem install rubygems-update
sudo update_rubygems
after which I had rubygems 1.3.7. Then I could get active record:
sudo gem install activerecord

I still needed to get the mysql gem installed, which in turn needed the libmysql-dev stuff installed

sudo apt-get install libmysqlclient15-dev
sudo gem install mysql

Ubuntu and CloudInit on Amazon EC2

Alestic and Canonical have released new Ubuntu AMIs for EC2 – the EBS version in the eu-west-1 region has AMI ID “ami-38bf954c”, and the source is “099720109477/ebs/ubuntu-images/ubuntu-lucid-10.04-i386-server-20100827″.

Ubuntu images support CloudInit, which runs scripts on startup to allow you to configure the server (set up ssh keys, update the repos etc). There’s a load of different ways to specify what should get run (see https://help.ubuntu.com/community/CloudInit for full details).

One of the simplest is just to give it a script in the User Data, like this:

#!/bin/sh
echo "Hello World.  The time is now $(date -R)!" | tee /root/output.txt
EOF

It runs as the root user, so you can do pretty much anything you want to configure the box.