rake: not your father's build tool
DESCRIPTION
Rake is a fantastic toolTRANSCRIPT
rakeNot your father’s build tool
1
whatchutalk’nboutwillis
• Where it came from
• What it’s related to
• How to use it
2
What’s in a name?
• Usually the first thing people learn about rake is the etymology of the name: “Ruby Make”.
• But it’s much more than a catchy turn of phrase.
• It’s a fully featured Build Language. That almost never existed...
3
Ruby Version of Make?
• Jim tells the birth of rake as code he never intended to write.
• It started with a simple itch to scratch...
4
Jim Thought “What if...”
"What if you could specify the make tasks in Ruby, like this ..."
task "build" do
java_compile(...args, etc ...)
end
"The task function would register "build" as a target to be made,
and the block would be the action executed whenever the build
system determined that it was time to do the build target."
5
100 Lines Later
• It worked!
• Rake’s prototype lives in the repo: doc/proto_rake.rdoc
• But it didn’t have timebased file dependencies... so back to the text-editor.
• And the rest is in the commit history.
6
A Build Language
• The basic unit of a build language are tasks.
• A build has source files that it uses to produce a desired product.
• The two most common other build languages are make and ant.
7
Comparison
make ant rake
Imperative Style Imperative Style Dependency Based
External DSL External DSL Internal DSL
Custom Syntax XML based Syntax Ruby Syntax
8
Imperative Style
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Imperative Style
• Both the code_generation methods will be called during test.
• At best that will waste time.
• At worst that can produce undesired results.
10
Dependency Based
11
Dependency Based
• A dependency based system gives the test method the power to evaluate what prerequisites it has.
• Then because ruby can evaluate the code without running it, it can prepare it to be run in the correct order that will only run each task once.
12
Comparison
make ant rake
Imperative Style Imperative Style Dependency Based
External DSL External DSL Internal DSL
Custom Syntax XML based Syntax Ruby Syntax
13
External vs Internal DSL
• With make and ant you need to use external scripts or nasty syntax to be creative.
• Rake can use full power of Ruby at any time.
14
Hello World
15
Building Blocks of Rake
• task
• file
• directory
• namespace
• multitask
• FileUtils
• clean
• clobber
16
task
In the DSL of rake, a task is a method that takes two arguments. The first argument is a hash, and the second is a block.
17
task dependencies
18
file
Rake file tasks are most similar to tasks in make. They get run only when needed. File tasks are declared using a string rather than a symbol. The following file task creates a executable program (named prog) given two object files name a.o and b.o.
19
directory
It is common to need to create directories upon demand. The directory convenience method is a short-hand for creating a FileTask that creates the directory.
20
directory
The directory method does not accept prerequisites or actions, but both prerequisites and actions can be added later.
21
namespaces
22
multitask
Multitask can help you save time by running tasks in your build that are safe to run in parallel.
23
multitask
It even has the ability to determine any prerequisites that need to be run before hand. It will complete this prep_for_copy only once then the three tasks would begin to run together.
24
FileUtils
• Use the FileUtils module and rake gives you the most common filesystem commands:
• cd, pwd, mkdir, mkdir_p, rmdir, ln, ln_s, ln_sf, cp, cp_r, mv, rm, rm_r, rm_rf, install, chmod, touch
• Create a map of files with FileList:
• FileList[‘**/*.rb’].each {|f| puts f}
25
Clean/Clobber
• require 'rake/clean'
• Use a pair of file lists: CLEAN and CLOBBER.
• You can then add items to the file lists with expressions like CLEAN.include('*.o').
• Remember that the clean task removes everything in the clean list, and clobber removes everything in both lists.
26
Built In Tasks
• GemPackageTask (in Ruby Gems now)
• PackageTask
• RdocTask (in Rdoc now)
• TestTask
27
Rake & Rails
• The default task for a rails project runs your test suite.
• If you want to see how the rake tasks you enjoy with Rails are built search for .rake in the gem source.
• Because as we all know, Rails is Magic!
28
rake
• Jim Weirich created in 2003.
• Similar to make and ant. With the power of Ruby.
• Hope you’ve got some ideas on how you’d like to use it.
29
Credits
• Jim Weirich - Rakehttp://rake.rubyforge.org/
• Martin Fowler - Using the Rake Build Languagehttp://martinfowler.com/articles/rake.html
• Josh Nichols - Rake: The Familiar Strangerhttp://vimeo.com/2496890
30
Thank You
• @filmprog
• filmprog.com
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