Understanding What Is Rake In Ruby & Its Role In Automation

What is Rake in Ruby?

Ruby is used to write the build language Rake. It is Ruby’s version of the classic build tools, such as Ant in Java and Unix make.
With Rake, you can create tasks called code blocks that execute particular, routine operations inside a software project. You already have Rake if you have installed Rails. Rake is available as the rake gem.

Rake’s Role in Automation

Even outside of Ruby projects, Rake is a general-purpose build language that can be used anywhere you might use make because the majority of its tasks only involve moving disc files and running external applications.

Rake’s strength is in automating the mundane duties that surround a software project, making them vanish. Rake is capable of automating the following tasks:

• Running unit tests automatically.
• Generating documentation automatically.
• Cleaning up generated files.
• Packaging your code as a gem.
• Gathering statistics about your code.
• Publishing documentation (e.g., to RubyForge).

A Rakefile is a file that specifies Rake tasks. Although this file is a typical Ruby file, it has special methods such as task, file, and directory.

Core Concepts and Code Examples

The task method is the most widely used technique for specifying an executable action in a Rakefile.

Defining and Running Simple Tasks

The task method takes a code block that implements the task and its name, which is typically a symbol. Additionally, tasks can list requirements (dependencies).

Code Example (Simple Rakefile Structure):

Rakefiles frequently use the desc method to supply a description that can be shown when rake -T is executed.

# Rakefile
desc "Build the bridge"
task :build_bridge do
  puts 'Bridge construction is complete.'
end

desc "Cross the bridge."
# :cross_bridge depends on :build_bridge
task :cross_bridge => [:build_bridge] do
  puts "I'm crossing the bridge."
end

# Define a default task that runs :cross_bridge
task :default => [:cross_bridge]

Output When Run (using the default task):

$ rake
Bridge construction is complete.
I'm crossing the bridge.

When running rake build_bridge, only the build_bridge task executes.

Automating Unit Testing with rake test

Rake is essential for quickly and automatically executing unit test suites.

Rake test is the typical Rake job for doing tests. In a Rails application directory, the default Rake task executes all functional and unit tests.

The Rake::TestTask library is usually used to define a test task:

Code Example (Rake::TestTask):

require 'rake/testtask' 

Rake::TestTask.new('test') do |t|
  t.pattern = 'test/**/tc_*.rb' # Defines where test files are located 
  t.warning = true 
end

# Make 'test' the default task (optional) 
task "default" => ["test"] 

In this configuration, test cases are assumed to be located in files beginning with tc_ and ending with.rb under the test directory. In order to prevent the deployment of defective software, if a task that packages your software makes the test task a prerequisite, your package won’t be built if your tests are unsuccessful.

Generating Documentation with RDoc

RDoc-formatted comments in your code can be used by Rake to automatically generate documentation.

This is accomplished by using the Rake::RDocTask package.

Code Example (Rake::RDocTask):

require 'rdoc/task'

RDoc::Task.new(:rdoc) do |t|
  t.rdoc_files.include('README.md', 'lib/**/*.rb')  # Files to process
  t.main = 'README.md'                              # Main index page
  t.title = "MyLib API Documentation"               # HTML title
end

Output

The HTML output files, usually located in the doc/html directory, are created by running rake rdoc. Rake appdoc in particular runs RDoc and creates documentation in doc/app for Rails applications.

Cleaning Up Files

Rake makes it easier to keep a clean source tree by automating the removal of transient or produced files. Using the rake/clean library, this is accomplished.

There are two jobs defined by the rake/clean library:

clean: Eliminates files that may need to be regenerated in the event that your software changes.

clobber: Carries out a more exhaustive cleanup, restoring the source tree to its original state (and makes clean a precondition).

With the CLEAN and CLOBBER FileLists, you can define which files are part of these procedures.

Code Example (Rake Cleanup):

require 'rake/clean'

# Files to remove for a CLOBBER operation
CLOBBER.include('pkg', 'doc', '**/*.o') 

# Additional scratch files to remove for a CLEAN operation
CLEAN.include('InstalledFiles', '.config', 'test/**/*.tmp') 

Raked Clobber eliminates any files that fit both the CLEAN and CLOBBER patterns.

Similar to a master conductor directing an orchestra, Rake offers a strong and reliable method for managing all the auxiliary operations of a software project. It does this by leveraging dependencies to weave them together and make sure each task (or piece) runs precisely when and how it should.

You can also read TDD In Ruby: Emphasizes The Creation Of Automated Tests