From BCCD 3.0

Revision as of 21:56, 19 March 2017

Introduction

This document describes the build process for BCCD. The legacy process describes the old build_livecd.pl script; the improved process will describe the replacement for it.

Legacy process

The legacy process is driven by the bin/build_livecd.pl script in SVN. This script turns 8 years old on April 14, 2015 and, while functional, represents a much more rudimentary time for BCCD, both in terms of the distribution support and the team's (mainly Skylar's) software development knowledge.

The purpose of this section will be to document this legacy process comprehensively, and take inventory of its deficiencies so as to create the improved process.

Relationship with Bccd.pm

build_livecd.pl makes heavy use of Bccd.pm. Bccd.pm itself has a number of deficiencies itself:

• Poor error-handling - it will either log or die, when current best-practice for Perl is to throw an exception by returning undef, and catch in eval
• Excessively large methods
• Poor logging - logging should be built-in rather than requiring use of if/else
• Global filehandles - these should be scoped scalars
• Too many methods - should be broken up into multiple classes w/ inheritance

Legacy process details

The legacy process has the following stages:

• Configuration:
1. Parse the YAML configuration file in the workspace into a hash reference
2. Override configuration keys via command line option
• Debmirror - set the local debian mirror host so that we don't overload Earlham's Internet connection
• Hard coded settings - a large block of hard-coded settings

Legacy process deficiencies

• Tests are integrated with the build, making test-driven development difficult/impossible
• Error reporting is inconsistent
• Object orientation implementation gets in the way, some things might be better implemented as a simple library, with OO where appropriate
  • Object orientation might be useful for some things, e.g. handling networking configuration for multiple NICs
• Some architecture-specific actions are hard-coded into the build
  • Would be nice to support other architectures like ARM

Improved process

See also: the talk page

Build stages

The improved process is a Make-/Jenkins-driven pipeline consisting of the following stages:

debootstrap

Artifact 

target/debootstrap.tar.bz2

Make target 

target/debootstrap.tar.bz2

Triggers 

debootstrap-bccd

Produces the artifact by running the bin/prepare_debootstrap script.

fpm

Artifact 

target/bccd.noarch.deb, build/etc/bccd-revision

Make target 

target/bccd.noarch.deb

Triggers 

debootstrap-bccd

Generates bccd.noarch.deb using rpm and the checked-out files in the src directory.

debootstrap-bccd

Dependencies 

target/debootstrap.tar.bz2, build/etc/bccd-revision

Artifact 

target/debootstrap-bccd.tar.bz2

Make target 

target/debootstrap-bccd.tar.bz2

Triggers 

iso

Unpacks target/debootstrap.tar.bz2, runs bin/bccd_install_pkgs within it, and then creates target/debootstrap-bccd.tar.bz2

NOTE: Both the debootstrap and fpm will trigger this target. debootstrap only has to be run when updating the OS, while fpm needs to be run when the BCCD package is updated.

iso

Dependencies 

target/bccd.noarch.deb, build/etc/bccd-revision, target/debootstrap-bccd.tar.bz2

Make target 

target/bccd.amd64.iso

Unpacks debootstra-bccd.tar.bz2, installs target/bccd.noarch.deb within, then produces a filesystem.squashfs artifact, and finally an ISO image containing the squashfs.