cmd

Create command line applications from R packages.

How it works

It's a code generator that outputs Go code which produces a Command Line Application.

It's a bit ugly and unwieldy but it does the job.

Using the generated CLI requires an installation of R

Install

go get -u devOpifex/cmd

go install -u devOpifex/cmd@latest

Config

Create a config file called cmd.json at the root of your R package.

{
  "program": "rshiny",
  "package": "shiny",
  "description": "shiny from the command line",
  "install": "install.packages('shiny')",
  "commands": [
    {
      "name": "run",
      "short": "r",
      "description": "run the application",
      "function": "runApp",
      "arguments": [
        {
          "name": "dir",
          "short": "d",
          "description": "directory where the app.R is location",
          "type": "string",
          "required": false,
          "default": "."
        }
      ]
    }
  ]
}

Root

Specify the name of the program this is what users will call as root command in their shell. Indicate the package this CLI wraps.

In the example above we create a CLI for the shiny package and call the program rshiny, e.g.: rshiny -h will bring up the help.

Commands

List the commands you want to expose to the users of the CLIU, these map to functions from the package. The short is the short version of the command so one can use rshiny run or rshiny r: this will run shiny::runApp().

Arguments

List the arguments the function should take: these are currently passed unnamed so order matters

Type can be one of string, numeric, integer or, logical.

Above makes it such that we can call rshiny run -d="this/dir" or rshiny run --dir=/some/path

Install

Is used to generate the rshiny install command which installs the required R dependencies.

Generate

Once the config file created and cmd installed run cmd generate from the root of the package where the config file is located.

This creates a directory named after your program.

Move into the created directory (e.g.: cd rshiny in the example above) then run the folowing.

go mod init github.com/<username>/<repo>/<program>
go mod tidy

The first line will (in part) ensure you can work with go outside of your GOROOT, the second downloads dependencies if there are any (currently only cobra).

You should only need to run the above once. No need to repeat the process if you want to update your config and regenerate the code with cmd generate.

Then to build run the following.

go build

This should produce a program you can call from the command line. If you only need it on your own system you can just call go install.

By default go build builds for your system, you can easily build for other system with:

GOOS=linux go build
GOOS=windows go build
GOOS=darwin go build