Continuous Integration for Ruby on Rails Ross Niemi ThoughtWorks, - - PowerPoint PPT Presentation

Continuous Integration for Ruby on Rails

Ross Niemi ThoughtWorks, Inc. Email: rniemi@thoughtworks.com Blog: http://rossniemi.wordpress.com March 12th, 2007

Agenda

• What is Continuous Integration (CI)?
• What CI tools are currently available for

Ruby and Ruby on Rails (RoR)?

• How do these tools compare?
• Demo
• Questions

Agile Software Development

• Agile Manifesto

– Individuals and interactions over processes and tools – Working software over comprehensive documentation – Customer collaboration over contract negotiation – Responding to change over following a plan

• Continuous Integration helps us to deliver

working software

Continuous Integration

• “… is a software development practice where

members of a team integrate their work frequently…”

• “Each integration is verified by an automated

build (including test) to detect integration errors as quickly as possible”

• Martin Fowler

Before we continue…

• It is important to note that Continuous Integration:

– IS NOT a tool or product – IT IS a practice or philosophy that a team has to buy into

• Recall: Individuals and interactions over processes and tools
• Tools can be used to help automate Continuous

Integration

• James Shore

“Continuous Integration is an Attitude, Not a Tool”

Early Days

• Check-in “token”

– Developer wanting to check in code into the repository must acquire the “token” – Only one person can check in at a time – The same person would then check out the code on a different machine and run the build in a clean environment – If the build “breaks”, the offender fixes it on their machine and tries the verification step again – Once the build passes, the “token” is returned so someone else could perform a check in – Very serial process, time consuming

Early Days

• Cron / Scheduler Jobs

– An attempt to automate the verification build – Schedule builds to happen during set times

• Nightly or Daily Builds (quiet times)
• Depending on the length of the build, you typically would

want to increase the build frequency

– The greater the time between scheduled builds

• The less useful the feedback from the build would be
• The more difficult debugging a broken build would be

Present Day

• CI Tools are responsible for orchestrating the

verification build

– Detects a change in the code repository – Update its working copy – Runs the build and executes tests – Notifies interested parties of success or failure

• The repetition of these steps is known as a build

cycle or build loop

• Typically implemented as a server / daemon

CI Tool Realizations

• By automating the verification build:

– The verification step is done for the committer automatically – Verification builds can be done more often

• For example, after every checkin

– The tool can notify the developer(s) of a broken or successful build as soon as the verification build finishes – Shorter verification build cycles means:

• The developer can check in code more often (XP)
• Faster feedback will lead to greater productive

Typical Architecture

CI for Ruby On Rails

• Jay Fields Poor Mans CI
• Continuous Builder
• Cerberus
• CruiseControl with CI_Reporter
• CruiseControl.rb

Jay Fields Poor Mans CI

• If using Subversion, use a post-commit hook

to fire off a build

• Pass a revision number as an argument

– Use number to create output directories for running build

• If on a Mac, use Growl to send a status

message to developer workstation

• http://jayfields.blogspot.com/2006/07/ruby-

continuous-integration.html

Continuous Builder

• Simple Rails plugin written by DHH
• Add a Subversion post-commit hook to build

the latest revision and notify the developer on success / failure by:

– Email – Campfire

• http://dev.rubyonrails.org/browser/plugins/con

tinuous_builder

Cerberus

• Designed to be a light-weight CI solution with

a small memory footprint

– Loaded into memory and executed only when needed

• Similar to previous approaches, but offers

support for managing multiple projects

– Command line – YML

• http://cerberus.rubyforge.org/

Commands

# Add application directory to monitor cerberus add directory APPLICATION_NAME=application RECIPIENTS=email address, … # Add application SVN repository to monitor cerberus add subversion_url APPLICATION_NAME=application RECIPIENTS=email address, … # List of active projects cerberus list # Build a single or all applications cerberus build application cerberus buildall # Command line help cerberus --help

Files and Directories

# Default home $CERBERUS_HOME=~/.cerberus # Server artifacts ~/.cerberus/config.yml ~/.cerberus/error.log # Project artifacts ~/.cerberus/config/application.yml ~/.cerberus/work/application /logs - timestamped build logs /Status.log - status of last build

Build Loop

• Cerberus will check if there were any

changes to application directory or Subversion repository

– Build only if there were

• Since build and buildall are one time shots,

you will either need to setup Cerberus with:

– Cron (polling) – Subversion post-commit hook (trigger)

CruiseControl

• The defacto standard for Continuous

Integration in the Java world

• CruiseControl 2.6 has direct support for Rake

– Leverage existing plugins

• Source Code Management (SCM) systems
• Publishers / Notifiers
• Using CI Reporter with CruiseControl will

allow for reporting on test failure

• http://cruisecontrol.sourceforge.net

Commands

cruise_dir/cruisecontrol.sh cruise_dir/cruisecontrol.bat

• Windows service now available

Files and Directories

# Server / Project configuration cruise_dir/config.xml # Project artifacts - can override locations cruise_dir/project.ser cruise_dir/projects/project cruise_dir/logs/project cruise_dir/artifacts/project

Configuration

• CruiseControl build projects are defined in

cruise_dir/config.xml

• Each build project has the following sections:

– Bootstrappers are operations done before the build takes place, regardless if a build is necessary or not – ModificationSet is scheduled to poll to see if change in the code repository occurred – Schedule is a reoccurring event used to perform a build provided that there are modifications – Publishers distribute the results of a build – Log is used to report on the build execution

CI Reporter

• Can use with existing CI solutions that

understand JUnit XML

– CruiseControl, Bamboo, etc.

• Support for Test::Unit or RSpec
• http://svn.caldersphere.net/svn/main/ci_

reporter/

Files and Directories

• Modify Rakefile

require 'rubygems' gem 'ci_reporter’ # use the following if using RSpec require 'ci/reporter/rake/rspec’ # use the following if using Test::Unit require 'ci/reporter/rake/test_unit’

• Make ci:setup:<rspec|testunit>

a dependency of your test tasks

CruiseControl.rb

• CruiseControl for Ruby and RoR
• Written from the ground up on Rails
• http://cruisecontrolrb.rubyforge.org/

Commands

# Start the web server ./cruise start [options ]

• -port=port
• -binding=ip
• -daemon
• -environment=test|development|production

# Add application SVN repository to monitor ./cruise add your_project --url subversion-url [--username username --password password] # Build your_project ./cruise build your_project [--trace ] # Command line help ./cruise help [command ]

Files and Directories

# Server artifacts cruise_dir/config/site_config.rb # Project artifacts cruise_dir/projects/your_project /work /build-rev /build.log /build_status.status /changeset.log /cruise_config.rb

Build Loop

• Assumption:

– Rails application built by Rake

• Alternatively:

– Use Rake to build other applications

• Ruby, Java

– Could call a shell script

Rake Execution

• Loads all Rake files from

cruise_dir/tasks and then the Rakefile of your_project

• The cc:build task is invoked and looks

for all other Rake tasks defined in your_project

– cruise_dir/tasks/cc_build.rake

Rake Execution

Note: project.rake_task and project.build_command both cannot be set

Build Scheduling

• Specify a polling interval in the

cruise_config.rb

– project.scheduler.polling_interval = 5.minutes

• Provide your own custom scheduler

– project.scheduler = MyCustomScheduler.new(project)

Build Artifacts

• Artifacts are visible via dashboard
• CC_BUILD_ARTIFACTS environment

variable is set by CruiseControl.rb

– Make sure your Rakefile task writes to this directory or in a subdirectory

• Coverage reports, build products, etc.

Comparison Matrix

• Just the facts, please

– http://rossniemi.wordpress.com/docs

Slides make me sleepy…

• Where is my Demo!

Questions?