CliOptions

An opinionated command line arguments parser.

CliOptions is an alternative to OptionParser that allows you to validate CLI arguments based on a definition. Out of the box you get a polished CLI experience including:

• Support for common options types and custom validations.
• Strict validation by design, an error is returned if an invalid. argument is passed.
• Supports required options, default values, aliases, mutually exclusive options and much more.
• Auto-generated docs for the supported arguments.

Usage

A definition is a keyword list specifying among other the expected command line arguments, their types and aliases. For example:

schema = [
  project: [
    type: :string,
    short: "p",
    doc: "The project name",
    required: true
  ],
  tags: [
    type: :string,
    multiple: true,
    long: "tag",
    doc: "Tags to consider"
  ],
  verbose: [
    type: :boolean,
    doc: "Enable verbose logging",
  ],
  timeout: [
    type: :integer,
    doc: "The timeout in seconds",
    default: 10
  ]
]

Now you can validate some argv using CliOptions.parse/2.

iex> CliOptions.parse(["-p", "foo", "--timeout", "30"], schema)
{:ok, {[project: "foo", verbose: false, timeout: 30], [], []}}

If the input arguments are valid a tuple of the form {options, args, extra} is returned. Check the CliOptions docs for more details.

If the input is invalid an error will be returned:

# invalid type
iex> CliOptions.parse(["-p", "foo", "--timeout", "a30"], schema)
{:error, ":timeout expected an integer argument, got: a"}

# missing required argument
iex> CliOptions.parse([], schema)
{:error, "option :project is required"}

# with undefined argument
iex> CliOptions.parse(["-p", "foo", "--other", "x"], schema)
{:error, "invalid option other"}

Auto-generated docs

Cli.Options.docs/2 can be used to automatically generate documentation from a valid schema. You can use it directly in the @moduledoc of your mix tasks as following:

defmodule Mix.Tasks.SomeTask do
  schema = [...]

  @moduledoc """
  Some task.

  ## CLI Options

  #{CliOptions.docs(schema)}
  """
end

Installation

The package can be installed by adding cli_options to your list of dependencies in mix.exs:

def deps do
  [
    {:cli_options, "~> 0.1.4"}
  ]
end

Acknowledgements

• The awesome clap Rust CLI parser.
• nimble_options.

License

Copyright (c) 2023 Panagiotis Nezis, Sportradar

CliOptions is released under the MIT License. See the LICENSE file for more details.