Get CLI arguments for custom Mix task

I have a custom mix task that I want to use like mix foo.bar 123 where 123 is a command-line argument. How do I get that? I’m striking out on Google… https://hexdocs.pm/mix/Mix.Task.html doesn’t seem to show anything other than prompt or yes?, which allow for an interactive interface, but what about command line arguments?

Thanks for pointers!

I think you’re just looking for the args that the run/1 function receives

Given:

defmodule Mix.Tasks.Echo do
  use Mix.Task

  @impl Mix.Task
  def run(args) do
    IO.puts("running!")
    Mix.shell().info(Enum.join(args, " "))
    IO.inspect(args, label: "Received args")
  end
end

Running that gives you:

$ mix echo foo.bar 123
running!
foo.bar 123
Received args: ["foo.bar", "123"]

Although at least with the umbrella project setup I’m using it’s not picking up changes to the mix task without running mix.compile, but generally you should be good to go.

1 Like

ah, thank you. I also came across OptionParser.parse to work with --flags