How to pass arguments into a Rake task with environment in Rails? [duplicate]

Just to follow up on this old topic; here's what I think a current Rakefile (since a long ago) should do there. It's an upgraded and bugfixed version of the current winning answer (hgimenez):

desc "Testing environment and variables"task :hello, [:message]  => :environment  do |t, args|  args.with_defaults(:message => "Thanks for logging on")  puts "Hello #{User.first.name}. #{args.message}"   # Q&A above had a typo here : #{:message}end

This is how you invoke it (http://guides.rubyonrails.org/v4.2/command_line.html#rake):

  rake "hello[World]" 

For multiple arguments, just add their keywords in the array of the task declaration (task :hello, [:a,:b,:c]...), and pass them comma separated:

  rake "hello[Earth,Mars,Sun,Pluto]" 

Note: the number of arguments is not checked, so the odd planet is left out:)

TLDR;

task :t, [args] => [deps] 

Original Answer

When you pass in arguments to rake tasks, you can require the environment using the :needs option. For example:

desc "Testing environment and variables"task :hello, :message, :needs => :environment do |t, args|  args.with_defaults(:message => "Thanks for logging on")  puts "Hello #{User.first.name}. #{args.message}"end

Updated per @Peiniau's comment below

As for Rails > 3.1

task :t, arg, :needs => [deps] # deprecated

Please use

task :t, [args] => [deps] 

Just for completeness, here the example from the docs mentioned above:

   task :name, [:first_name, :last_name] => [:pre_name] do |t, args|     args.with_defaults(:first_name => "John", :last_name => "Dough")     puts "First name is #{args.first_name}"     puts "Last  name is #{args.last_name}"   end

Notes:

• You may omit the #with_defaults call, obviously.
• You have to use an Array for your arguments, even if there is only one.
• The prerequisites do not need to be an Array.
• args is an instance of Rake::TaskArguments.
• t is an instance of Rake::Task.