BuildBot

Using BuildBot can be useful to automate OpenXT builds.

Let's assume you're running a 32bits installation of Debian Squeeze, which is the recommended configuration for building OpenXT.
Installing BuildBot is as easy as "apt-get install buildbot". The Squeeze version is quite outdated, but it does the job.

BuildBot works in 2 parts, the slave(s) that build, and the master that control the slave(s).
In the following, I'm describing a setup with just one master and one slave, both on the same machine.

Disclaimer: everything here is done in a pretty dummy way, there's a lot of room for improvement.

Creating the master and the slave

The configuration happens in /var/lib/buildbot for the master/slave configuration, and in /etc/default/buildbot for the deamon configuration.
To get started, "cd /var/lib/buildbot" as root (or as buildbot, after enabling its shell), and create a master and a slave:

# buildbot create-master master
# cd master
# mv master.cfg.sample master.cfg
# cd ..
# buildbot create-slave slave 127.0.0.1:9989 slave password
# cd master

Configuring the master

master.cfg is the main BuildBot file. That's where you define projects, steps and schedulers. Here's some modifications I made to it:

Renaming the "BuildSlave" from "bot1name" to "slave", and changing the password from "bot1passwd" to "password".
Disable the scheduler by commenting out the c['schedulers'].append line(s).

Fix the factory steps (the scripts are detailed in the "Creating the build scripts" section):

f1.addStep(Compile(command=["bash", "-e", "./fetch.sh"], name="Fetch", description="Fetch", descriptionDone="Fetched"))
f1.addStep(Compile(command=["bash", "-e", "./clean.sh"], name="Clean", description="Clean", descriptionDone="Cleaned"))
f1.addStep(Compile(command=["bash", "-e", "./build.sh"], name="Build", description="Build", descriptionDone="Built"))
f1.addStep(Compile(command=["bash", "-e", "./copy.sh"],  name="Copy",  description="Copy",  descriptionDone="Copied"))

In b1, the builder, fix the name ("openxt") the slavename ("slave"), and the builddir ("/home/buildbot")
Set allowForce=true, as described in a comment
Fix the project name and URL

Configuring the initscript

Below is the content of my /etc/default/buildbot

initscript

# buildbots to manage
# add a new set of variables for each buildbot to start

BB_NUMBER[0]=0          # index for the other values; negative disables the bot
BB_NAME[0]="master"     # short name printed on startup / stop
BB_USER[0]="buildbot"       # user to run as
BB_BASEDIR[0]="/var/lib/buildbot/master"        # basedir argument to buildbot (absolute path)
BB_OPTIONS[0]=""        # buildbot options
BB_PREFIXCMD[0]=""      # prefix command, i.e. nice, linux32, dchroot

BB_NUMBER[1]=1                  # index for the other values; negative disables the bot
BB_NAME[1]="slave"              # short name printed on startup / stop
BB_USER[1]="buildbot"           # user to run as
BB_BASEDIR[1]="/var/lib/buildbot/slave"                # basedir argument to buildbot (absolute path)
BB_OPTIONS[1]=""                # buildbot options
BB_PREFIXCMD[1]=""              # prefix command, i.e. nice, linux32, dchroot

Creating the build scripts

In /home/buildbot/build, I created the scripts corresponding to the steps added to the factory:

clean.sh

#!/bin/bash

umask 0022
rm -rf build
mkdir build

That removes the whole build tree and create an empty folder for the new build.
If the previous build finished, or at least lasted for a while, this step could take more than 60 minutes...

One way to speed this up which is left out here for clarity is to put the build on a filesystem on a block device which is unmounted, reformatted and mounted for each build.

fetch.sh

#!/bin/bash

for i in git/*.git; do
    echo "Fetching `basename $i`..."
    cd $i
    git fetch --all
    cd - > /dev/null
done