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

I am able to pass in arguments as follows:

desc "Testing args"
task: :hello, :user, :message do |t, args|
  args.with_defaults(:message => "Thanks for logging on")
  puts "Hello #{args[:user]}. #{:message}"
end

I am also able to load the current environment for a Rails application

desc "Testing environment"
task: :hello => :environment do 
  puts "Hello #{User.first.name}."
end

What I would like to do is be able to have variables and environment

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

But that is not a valid task call. Does anyone know how I can achieve this?

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.

An alternate way to go about this: use OS environment variables. Benefits of this approach:

• All dependent rake tasks get the options.
• The syntax is a lot simpler, not depending on the rake DSL which is hard to figure out and changes over time.

I have a rake task which requires three command-line options. Here's how I invoke it:

$ rake eaternet:import country=us region=or agency=multco

That's very clean, simple, and just bash syntax, which I like. Here's my rake task. Also very clean and no magic:

task import: [:environment] do
  agency = agency_to_import
  puts "Importing data for #{agency}..."
  agency.import_businesses
end

def agency_to_import
  country_code = ENV['country'] or raise "No country specified"
  region_slug  = ENV['region']  or raise "No region specified"
  agency_slug  = ENV['agency']  or raise "No agency specified"
  Agency.from_slugs(country_code, region_slug, agency_slug)
end

This particular example doesn't show the use of dependencies. But if the :import task did depend on others, they'd also have access to these options. But using the normal rake options method, they wouldn't.