Rake::Task

A Task is the basic unit of work in a Rakefile. Tasks have associated actions (possibly more than one) and a list of prerequisites. When invoked, a task will first ensure that all of its prerequisites have an opportunity to run and then it will execute its own actions.

Tasks are not usually created directly using the new method, but rather use the file and task convenience methods.

Attributes

actions[R]

List of actions attached to a task.

application[RW]

Application owning this task.

comment[R]

Comment for this task. Restricted to a single line of no more than 50 characters.

full_comment[R]

Full text of the (possibly multi-line) comment.

prerequisites[R]

List of prerequisites for a task.

scope[R]

Array of nested namespaces names used for task lookup by this task.

sources[W]

List of sources for task.

Public Class Methods

[](task_name) click to toggle source

Return a task with the given name. If the task is not currently known, try to synthesize one from the defined rules. If no rules are found, but an existing file matches the task name, assume it is a file task with no dependencies or actions.

# File lib/rake.rb, line 728
def [](task_name)
  Rake.application[task_name]
end

clear() click to toggle source

Clear the task list. This cause rake to immediately forget all the tasks that have been assigned. (Normally used in the unit tests.)

# File lib/rake.rb, line 715
def clear
  Rake.application.clear
end

create_rule(*args, &block) click to toggle source

Define a rule for synthesizing tasks.

# File lib/rake.rb, line 745
def create_rule(*args, &block)
  Rake.application.create_rule(*args, &block)
end

define_task(*args, &block) click to toggle source

Define a task given args and an option block. If a rule with the given name already exists, the prerequisites and actions are added to the existing task. Returns the defined task.

# File lib/rake.rb, line 740
def define_task(*args, &block)
  Rake.application.define_task(self, *args, &block)
end

new(task_name, app) click to toggle source

Create a task named task_name with no actions or prerequisites. Use enhance to add actions and prerequisites.

# File lib/rake.rb, line 511
def initialize(task_name, app)
  @name = task_name.to_s
  @prerequisites = []
  @actions = []
  @already_invoked = false
  @full_comment = nil
  @comment = nil
  @lock = Monitor.new
  @application = app
  @scope = app.current_scope
  @arg_names = nil
end

scope_name(scope, task_name) click to toggle source

Apply the scope to the task name according to the rules for this kind of task. Generic tasks will accept the scope as part of the name.

# File lib/rake.rb, line 752
def scope_name(scope, task_name)
  (scope + [task_name]).join(':')
end

task_defined?(task_name) click to toggle source

TRUE if the task name is already defined.

# File lib/rake.rb, line 733
def task_defined?(task_name)
  Rake.application.lookup(task_name) != nil
end

tasks() click to toggle source

List of all defined tasks.

# File lib/rake.rb, line 720
def tasks
  Rake.application.tasks
end

Public Instance Methods

add_description(description) click to toggle source

Add a description to the task. The description can consist of an option argument list (enclosed brackets) and an optional comment.

# File lib/rake.rb, line 654
def add_description(description)
  return if ! description
  comment = description.strip
  add_comment(comment) if comment && ! comment.empty?
end

arg_names() click to toggle source

Name of arguments for this task.

# File lib/rake.rb, line 551
def arg_names
  @arg_names || []
end

clear() click to toggle source

Clear the existing prerequisites and actions of a rake task.

# File lib/rake.rb, line 562
def clear
  clear_prerequisites
  clear_actions
  self
end

clear_actions() click to toggle source

Clear the existing actions on a rake task.

# File lib/rake.rb, line 575
def clear_actions
  actions.clear
  self
end

clear_prerequisites() click to toggle source

Clear the existing prerequisites of a rake task.

# File lib/rake.rb, line 569
def clear_prerequisites
  prerequisites.clear
  self
end

comment=(description) click to toggle source

Writing to the comment attribute is the same as adding a description.

# File lib/rake.rb, line 661
def comment=(description)
  add_description(description)
end

enhance(deps=nil, &block) click to toggle source

Enhance a task with prerequisites or actions. Returns self.

# File lib/rake.rb, line 525
def enhance(deps=nil, &block)
  @prerequisites |= deps if deps
  @actions << block if block_given?
  self
end

execute(args=nil) click to toggle source

Execute the actions associated with this task.

# File lib/rake.rb, line 621
def execute(args=nil)
  args ||= EMPTY_TASK_ARGS
  if application.options.dryrun
    puts "** Execute (dry run) #{name}"
    return
  end
  if application.options.trace
    puts "** Execute #{name}"
  end
  application.enhance_with_matching_rule(name) if @actions.empty?
  @actions.each do |act|
    case act.arity
    when 1
      act.call(self)
    else
      act.call(self, args)
    end
  end
end

inspect() click to toggle source

# File lib/rake.rb, line 494
def inspect
  "<#{self.class} #{name} => [#{prerequisites.join(', ')}]>"
end

investigation() click to toggle source

Return a string describing the internal state of a task. Useful for debugging.

# File lib/rake.rb, line 690
def investigation
  result = "------------------------------\n"
  result << "Investigating #{name}\n"
  result << "class: #{self.class}\n"
  result <<  "task needed: #{needed?}\n"
  result <<  "timestamp: #{timestamp}\n"
  result << "pre-requisites: \n"
  prereqs = @prerequisites.collect {|name| application[name]}
  prereqs.sort! {|a,b| a.timestamp <=> b.timestamp}
  prereqs.each do |p|
    result << "--#{p.name} (#{p.timestamp})\n"
  end
  latest_prereq = @prerequisites.collect{|n| application[n].timestamp}.max
  result <<  "latest-prerequisite time: #{latest_prereq}\n"
  result << "................................\n\n"
  return result
end

invoke(*args) click to toggle source

Invoke the task if it is needed. Prerequites are invoked first.

# File lib/rake.rb, line 581
def invoke(*args)
  task_args = TaskArguments.new(arg_names, args)
  invoke_with_call_chain(task_args, InvocationChain::EMPTY)
end

name() click to toggle source

Name of the task, including any namespace qualifiers.

# File lib/rake.rb, line 532
def name
  @name.to_s
end

needed?() click to toggle source

Is this task needed?

# File lib/rake.rb, line 642
def needed?
  true
end

reenable() click to toggle source

Reenable the task, allowing its tasks to be executed if the task is invoked again.

# File lib/rake.rb, line 557
def reenable
  @already_invoked = false
end

set_arg_names(args) click to toggle source

Set the names of the arguments for this task. args should be an array of symbols, one for each argument name.

# File lib/rake.rb, line 684
def set_arg_names(args)
  @arg_names = args.map { |a| a.to_sym }
end

source() click to toggle source

First source from a rule (nil if no sources)

# File lib/rake.rb, line 505
def source
  @sources.first if defined?(@sources)
end

sources() click to toggle source

# File lib/rake.rb, line 500
def sources
  @sources ||= []
end

timestamp() click to toggle source

Timestamp for this task. Basic tasks return the current time for their time stamp. Other tasks can be more sophisticated.

# File lib/rake.rb, line 648
def timestamp
  @prerequisites.collect { |p| application[p].timestamp }.max || Time.now
end

to_s() click to toggle source

Return task name

# File lib/rake.rb, line 490
def to_s
  name
end

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