rake: the familiar stranger

Josh Nichols technicalpickles.com

The Familiar Stranger

Rake


Ruby Make

What is Rake?


A Ruby build tool

Ruby what?


A tool for automating tasks on the command line using plain ol’ Ruby

Which means...?


• Define a task

• Make the task do something, maybe have it depend on other tasks

• You’ve probably already used it

• rake db:migrate

• rake test

What would you use Rake for?


• The basics of Rake

• Creating re-usable tasks for Rails

• Creating re-usable tasks for any Ruby project

• Testing

Overview


# Rakefile (or rakefile or rakefile.rb or Rakefile.rb)

require 'rake'

desc "Hello World!"task :hello_world do puts "Hello World!"end

Hello World


(in /Users/nichoj/Projects/rake_demo)rake hello_world # Hello World!

rake_demo $ rake -T


Hello World!

rake_demo $ rake hello_world


• desc

• provide a human readable description for a task you're about to define

• rake -T doesn’t show the task without this

• task

• provide a task name (can be a symbol or string)

• provide a block

• it's just ruby, yo

Defining tasks


• FileUtils module is included

• cd, pwd, mkdir, mkdir_p, rmdir, ln, ln_s, ln_sf, cp, cp_r, mv, rm, rm_r, rm_rf, install, chmod, touch

• FileList lets you specify a pattern for files/directories, then use it as an Enumerable

• FileList['**/*.rb'].each {|f| puts f }

Defining tasks: playing with the filesystem


require 'rake'

desc "Clean the build directory"task :clean do rm_r 'build'end

desc "Make a backup of all ruby files"task :backup do FileList['**/*.rb'].each do |f| cp f, "#{f}.bak" endend

Defining tasks: playing with the filesystem


• Easily declare a dependency on another task

• A task that is depended on will only be run once... even if you run multiple times

Dependencies between tasks


require 'rake'

task :give_presentation => :prepare_presentation do puts "So there's this thing called 'Rake'..."end

task :prepare_presentation => :take_nap do puts "Just preparing, nothing to see here, move along"end

task :take_nap do puts "zzzzzzzzzzzzzzzzzzz"end

Dependencies between tasks


(in /Users/nichoj/Projects/rake_demo)zzzzzzzzzzzzzzzzzzzNothing to see here, move alongSo there's this thing called 'Rake'...

rake_demo $ rake give_presentation


zzzzzzzzzzzzzzzzzzzNothing to see here, move alongSo there's this thing called 'Rake'...

rake_demo $ rake take_nap give_presentation


• Would be annoying to have a flat namespace

• This isn’t C!

• Rake has the concept of namespaces

• rake namespace:task_name

Group related tasks


require 'rake'

namespace :presentation do task :give => :prepare do puts "So there's this thing called 'Rake'..." end

task :prepare => :take_nap do puts "Just preparing, nothing to see here, move along" endend


Define a namespace


• Just declare the task again, but with dependencies

• These get added to whatever dependencies

Extending tasks: more dependencies


namespace :presentation do task :give => :prepare do puts "So there's this thing called 'Rake'..." end

task :prepare => :take_nap do puts "Just preparing, nothing to see here, move along" end task :prepare => :watch_tvend

task :watch_tv do puts "Previously on Heroes..."end


Moar dependencies


• Rake comes with a few bundled

• Rake::GemPackageTask, Rake::PackageTask, Rake::RDocTask, Rake::TestTask

• Just instantiate an instance in your Rakefile

Rake::TestTask.new do |t| t.libs << 'lib' t.pattern = 'test/*_test.rb' t.verbose = falseend

Using off the shelf tasks


... cuz I ran out of time to make slides

Cue live coding


Done, and done.


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mailto:[email protected]

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rake: the familiar stranger

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