Toys

Toys is a configurable command line tool. Write commands in Ruby using a simple DSL, and Toys will provide the command line executable and take care of all the details such as argument parsing, online help, and error reporting.

Toys is designed for software developers, IT professionals, and other power users who want to write and organize scripts to automate their workflows. It can also be used as a replacement for Rake, providing a more natural command line interface for your project's build tasks.

This repository includes the source for two gems:

toys provides the Toys executable itself and all its capabilities.
toys-core provides the underlying command line framework, and can be used to build other command line executables.

Introductory tutorial

Here's a tutorial to help you get a feel of what Toys can do.

Install and try out Toys

Install the toys gem using:

$ gem install toys

This installs the toys executable, along with some builtin tools and libraries. You can run the executable immediately:

$ toys

This displays overall help for Toys. If you have less installed, Toys will use it to display the help screen. Press q to exit.

You may notice that the help screen lists some tools that are preinstalled. Let's run one of them:

$ toys system version

The system version tool displays the current version of the toys gem.

Toys also provides optional tab completion for bash. To install it, execute the following command in your shell, or add it to your bash configuration file (e.g. ~/.bashrc).

$(toys system bash-completion install)

Toys does not yet specially implement tab completion for zsh or other shells. However, if you are using zsh, installing bash completion using bashcompinit mostly works.

Write your first tool

You can define tools by creating a Toys file. Go into any directory, and, using your favorite editor, create a new file called .toys.rb (note the leading period). Copy the following text into the file, and save it:

tool "greet" do
  desc "My first tool!"
  flag :whom, default: "world"
  def run
    puts "Hello, #{whom}!"
  end
end

This defines a tool named "greet". Try running it:

$ toys greet

The tool also recognizes a flag on the command line. Try this:

$ toys greet --whom=ruby

Toys provides a rich set of features for defining command line arguments and flags. It can also validate arguments. Try this:

$ toys greet --bye

Notice that Toys automatically generated a usage summary for your tool. It also automatically generates a full help screen, which you can view using the --help flag:

$ toys greet --help

Toys searches up the directory hierarchy for Toys files. So it will find this .toys.rb if you are located in this directory or any subdirectory. It will also read multiple files if it finds them, so you can "scope" your tools more specifically or generally by locating them in your directory hierarchy.

If you want to define "global" tools that apply anywhere, write a Toys file either in your home directory, or in the system configuration directory (usually /etc). Toys always searches these locations.

A more sophisticated example

Let's take a look at another example that exercises some of the features you're likely to see in real-world usage. Add the following to your .toys.rb file. (You don't need to replace the greet tool you just wrote; just add this new tool to the end of the file.)

tool "new-repo" do
  desc "Create a new git repo"

  optional_arg :name, desc: "Name of the directory to create"

  include :exec, exit_on_nonzero_status: true
  include :fileutils
  include :terminal

  def run
    if name.nil?
      response = ask "Please enter a directory name: "
      set :name, response
    end
    if File.exist? name
      puts "Aborting because #{name} already exists", :red, :bold
      exit 1
    end
    logger.info "Creating new repo in directory #{name}..."
    mkdir name
    cd name do
      create_repo
    end
    puts "Created repo in #{name}", :green, :bold
  end

  def create_repo
    exec "git init"
    File.write ".gitignore", <<~CONTENT
      tmp
      .DS_Store
    CONTENT
    # You can add additional files here.
    exec "git add ."
    exec "git commit -m 'Initial commit'"
  end
end

Now you should have an additional tool called new-repo available. Type:

$ toys

The help screen lists both the greet tool we started with, and the new new-repo tool. This new tool creates a directory containing a newly created git repo. (It assumes you have git available on your path.) Try running it:

$ toys new-repo foo

That should create a directory foo, initialize a git repository within it, and make a commit.

Notice that this tool accepts a positional command line argument. Toys supports any combination of flags and required and optional arguments. This tool's argument is declared with a description string, which you can see if you view the tool's help:

$ toys new-repo --help

The argument is marked as "optional" which means you can omit it. Notice that the tool's code detects that it has been omitted and responds by prompting you interactively for a directory name. You can also mark a positional argument as "required", which causes Toys to report a usage error if it is omitted.

Next, notice this tool includes two methods, create_repo as well as run. The "entrypoint" for a tool is always the run method, but each tool is actually a class under the hood, and you can add any helper methods you want. You can even define and include modules if you want to share code across tools.

For our tool, notice that the three "include" lines are taking symbols rather than modules. These symbols are the names of some of Toys's built-in helper mixins, which are configurable modules that enhance your tool. They may provide methods your tool can call, or invoke other behavior. In our example:

The :exec mixin provides a variety of methods for running external commands. In this example, we use the exec method to run shell commands, but you can also signal and control these commands, capture and redirect streams, and so forth. Note that we pass the :exit_on_nonzero_status option, which configures the :exec mixin to abort the tool automatically if any of the external commands fails (similar to set -e in bash). This is a common pattern when writing tools that invoke external commands. (If you want more control, the :exec mixin also provides ways to respond to result codes individually.)
The :fileutils mixin provides the methods of the Ruby FileUtils library, such as mkdir and cd used in this example. It's effectively shorthand for require "fileutils"; include ::FileUtils.
The :terminal mixin provides styled output, as you can see with the style codes being passed to puts. It also provides some user interaction commands such as ask, as well as spinners and other controls. You can see operation of the :terminal mixin in the tool's output, which is styled either green (for success) or red (on error) when running on a supported tty.

Now try running this:

$ toys new-repo bar --verbose

You'll notice some diagnostic log output. Toys provides a standard Ruby Logger for each tool, and you can use it to emit diagnostic logs directly as demonstrated in the example. Some other Toys features might also emit log entries: the :exec mixin, for example, by default logs every external command it runs (although this can be customized).

By default, only warnings and higher severity logs are displayed, but you can change that by applying the --verbose or --quiet flags as we have done here. These flags, like --help, are provided automatically to every tool.

A better Rake?

Let's look at one more example. Traditionally, Ruby developers often use Rakefiles to write scripts for tasks such as build, test, and deploy. And Toys is similar to Rake in how it uses directory-scoped files to define tools.

But Rake is really designed for dependency management, not for writing scripts. As a result, some features, such as passing arguments to a task, are very clumsy with Rake.

If you have a project with a Rakefile, move into that directory and create a new file called .toys.rb in that same directory (next to the Rakefile). Add the following line to your .toys.rb file:

expand :rake

This syntax is called a "template expansion." It's a way to generate tools programmatically. In this case, Toys provides the :rake template, which reads your Rakefile and generates Toys tools corresponding to all your Rake tasks! Now if you run:

$ toys

You'll see that you now have tools associated with each of your Rake tasks. So if you have a rake test task, you can run it using toys test.

Note that if you normally run Rake with Bundler (e.g. bundle exec rake test), you may need to add Toys to your Gemfile and use Bundler to invoke Toys (i.e. bundle exec toys test). This is because Toys is just calling the Rake API to run your task, and the Rake task might require the bundle. However, when Toys is not wrapping Rake, typical practice is actually not to use bundle exec. Toys provides its own mechanisms to manage bundles or install gems for you.

So far, we've made Toys a front-end for your Rake tasks. This may be useful by itself. Toys lets you pass command line arguments "normally" to tools, whereas Rake requires a weird square bracket syntax (which may also require escaping depending on your shell.) Toys also provides more sophisticated online help than Rake does.

But you also might find Toys a more natural way to write tasks, and indeed you can often rewrite an entire Rakefile as a Toys file and get quite a bit of benefit in readability and maintainability. For an example, see the Toys file for the Toys gem itself. It contains Toys scripts that I use to develop, test, and release Toys itself. Yes, Toys is self-hosted. You'll notice most of this Toys file consists of template expansions. Toys provides templates for a lot of common build, test, and release tasks for Ruby projects.

If you're feeling adventurous, try translating some of your Rake tasks into native Toys tools. You can do so in your existing .toys.rb file. Keep the expand :rake line at the end of the file, and locate your tools (whether simple tools or template expansions) before it. That way, your Toys-native tools will take precedence, and expand :rake will proxy out to Rake only for the remaining tasks that haven't been ported explicitly.

Learning more

This introduction should be enough to get you started. However, Toys is a deep tool with many more features, all explained in detail in the User Guide.

For example, Toys lets you create tool namespaces and "subtools", and search for tools by name and description. There are various ways to validate and interpret command line arguments. You can create your own mixins and templates, and take advantage of a variety of third-party libraries such as Highline and TTY. Finally, if your .toys.rb files are growing too large or complicated, you can replace them with .toys directories that contain tool definitions in separate files. Such directories are versatile, letting you organize your tool definitions, along with shared code, normal Ruby classes, tests, and even data files for use by tools.

Unlike most command line frameworks, Toys is not primarily designed to help you build and ship a custom command line executable written in Ruby. However, you can use it in that way with the "toys-core" API, available as a separate gem. You would effectively write your command line executable using the same Toys DSL that you use to write .toys.rb files. For more info on using toys-core, see its documentation.

Why Toys?

I originally wrote Toys because I was accumulating dozens of ad hoc Ruby scripts I had written to automate various tasks in my workflow, everything from refreshing credentials, to displaying git history in my favorite format, to running builds and tests of complex multi-component projects. It was becoming difficult to remember which scripts did what, and what arguments each required, and I was constantly digging back into their source just to remember how to use them. Furthermore, when writing new scripts, I was repeating the same OptionParser boilerplate and common functionality.

Toys was designed to address those problems by providing a framework for writing and organizing your own command line scripts. You provide the actual functionality by writing Toys files, and Toys takes care of all the other details expected from a good command line tool. It provides a streamlined interface for defining and handling command line flags and positional arguments, and sensible ways to organize shared code. It automatically generates help text so you can see usage information at a glance, provides a search feature to help you find the script you need, and generates tab completion for your shell.

Toys can also be used to share scripts. For example, it can be used instead of Rake to provide build and test scripts for a project. Unlike Rake tasks, scripts written for Toys can be invoked and passed arguments and flags using familiar unix command line conventions. The Toys github repo itself comes with Toys scripts instead of Rakefiles.

System requirements

Toys requires Ruby 2.4 or later.

Most parts of Toys work on JRuby. However, JRuby is not recommended because of JVM boot latency, lack of support for Kernel#fork, and other issues.

Most parts of Toys work on TruffleRuby. However, TruffleRuby is not recommended because it has a few known bugs that affect Toys.

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

dazuma/toys

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