这里我不明白的一点是如何处理任意参数。如果你传递了任务定义中没有列出的参数，它们仍然可以在args.extras下访问:

task :thing, [:foo] do |task, args|
  puts args[:foo]     # named argument
  puts args.extras    # any additional arguments that were passed
end

要将参数传递给默认任务，可以这样做。例如，说 "version"是你的论点:

task :default, [:version] => [:build]

task :build, :version do |t,args|
  version = args[:version]
  puts version ? "version is #{version}" : "no version passed"
end

然后你可以这样调用它:

$ rake
no version passed

or

$ rake default[3.2.1]
version is 3.2.1

or

$ rake build[3.2.1]
version is 3.2.1

但是，我还没有找到一种方法来避免在传递参数时指定任务名称(默认或构建)。如果有人知道办法，我很乐意听听。

通过向任务调用中添加符号参数，可以在rake中指定正式参数。例如:

require 'rake'

task :my_task, [:arg1, :arg2] do |t, args|
  puts "Args were: #{args} of class #{args.class}"
  puts "arg1 was: '#{args[:arg1]}' of class #{args[:arg1].class}"
  puts "arg2 was: '#{args[:arg2]}' of class #{args[:arg2].class}"
end

task :invoke_my_task do
  Rake.application.invoke_task("my_task[1, 2]")
end

# or if you prefer this syntax...
task :invoke_my_task_2 do
  Rake::Task[:my_task].invoke(3, 4)
end

# a task with prerequisites passes its 
# arguments to it prerequisites
task :with_prerequisite, [:arg1, :arg2] => :my_task #<- name of prerequisite task

# to specify default values, 
# we take advantage of args being a Rake::TaskArguments object
task :with_defaults, :arg1, :arg2 do |t, args|
  args.with_defaults(:arg1 => :default_1, :arg2 => :default_2)
  puts "Args with defaults were: #{args}"
end

然后，从命令行:

> rake my_task[1,false]
Args were: {:arg1=>"1", :arg2=>"false"} of class Rake::TaskArguments
arg1 was: '1' of class String
arg2 was: 'false' of class String

> rake "my_task[1, 2]"
Args were: {:arg1=>"1", :arg2=>"2"}

> rake invoke_my_task
Args were: {:arg1=>"1", :arg2=>"2"}

> rake invoke_my_task_2
Args were: {:arg1=>3, :arg2=>4}

> rake with_prerequisite[5,6]
Args were: {:arg1=>"5", :arg2=>"6"}

> rake with_defaults
Args with defaults were: {:arg1=>:default_1, :arg2=>:default_2}

> rake with_defaults['x','y']
Args with defaults were: {:arg1=>"x", :arg2=>"y"}

正如第二个示例中所演示的，如果您想使用空格，则需要在目标名称周围加上引号，以防止shell在空格处分隔参数。

查看rake中的代码。Rb, rake似乎没有解析任务字符串来提取先决条件的参数，因此不能执行task:t1 => "dep[1,2]"。为先决条件指定不同参数的唯一方法是在依赖任务操作中显式地调用它，如:invoke_my_task和:invoke_my_task_2。

注意，一些shell(如zsh)需要转义括号:

我喜欢参数传递的“querystring”语法，特别是当有很多参数要传递时。

例子:

rake "mytask[width=10&height=20]"

“querystring”是:

width=10&height=20

警告:注意语法是rake“mytask[foo=bar]”而不是rake mytask["foo=bar"]

当在rake任务中使用Rack::Utils进行解析时。parse_nested_query，得到一个哈希值:

=> {"width"=>"10", "height"=>"20"}

(最酷的事情是你可以传递哈希和数组，更多如下)

以下是如何实现这一点:

require 'rack/utils'

task :mytask, :args_expr do |t,args|
  args.with_defaults(:args_expr => "width=10&height=10")
  options = Rack::Utils.parse_nested_query(args[:args_expr])
end

下面是我在delayed_job_active_record_threading gem中使用的一个更扩展的示例:

bundle exec rake "dj:start[ebooks[workers_number]=16&ebooks[worker_timeout]=60&albums[workers_number]=32&albums[worker_timeout]=120]"

以与上面相同的方式解析，使用环境依赖项(为了加载Rails环境)

namespace :dj do
  task :start, [ :args_expr ] => :environment do |t, args|
    # defaults here...
    options = Rack::Utils.parse_nested_query(args[:args_expr])  
  end
end

给出以下选项

=> {"ebooks"=>{"workers_number"=>"16", "worker_timeout"=>"60"}, "albums"=>{"workers_number"=>"32", "worker_timeout"=>"120"}}

上面描述的大多数方法对我来说都不起作用，也许它们在新版本中已弃用。 最新的指南可以在这里找到:http://guides.rubyonrails.org/command_line.html#custom-rake-tasks

下面是该指南的复制粘贴示例:

task :task_name, [:arg_1] => [:pre_1, :pre_2] do |t, args|
  # You can use args from here
end

像这样调用它

bin/rake "task_name[value 1]" # entire argument string should be quoted

如果你懒得记参数位置是什么你想做一些类似ruby参数哈希的东西。您可以使用一个参数传入一个字符串，然后将该字符串正则化为一个选项散列。

namespace :dummy_data do
  desc "Tests options hash like arguments"
  task :test, [:options] => :environment do |t, args|
    arg_options = args[:options] || '' # nil catch incase no options are provided
    two_d_array = arg_options.scan(/\W*(\w*): (\w*)\W*/)
    puts two_d_array.to_s + ' # options are regexed into a 2d array'
    string_key_hash = two_d_array.to_h
    puts string_key_hash.to_s + ' # options are in a hash with keys as strings'
    options = two_d_array.map {|p| [p[0].to_sym, p[1]]}.to_h
    puts options.to_s + ' # options are in a hash with symbols'
    default_options = {users: '50', friends: '25', colour: 'red', name: 'tom'}
    options = default_options.merge(options)
    puts options.to_s + ' # default option values are merged into options'
  end
end

在命令行中。

$ rake dummy_data:test["users: 100 friends: 50 colour: red"]
[["users", "100"], ["friends", "50"], ["colour", "red"]] # options are regexed into a 2d array
{"users"=>"100", "friends"=>"50", "colour"=>"red"} # options are in a hash with keys as strings
{:users=>"100", :friends=>"50", :colour=>"red"} # options are in a hash with symbols
{:users=>"100", :friends=>"50", :colour=>"red", :name=>"tom"} # default option values are merged into options