A Mix Task to Publish docs to GitHub Pages

docs.publish.ex

defmodule Mix.Tasks.Docs.Publish do
  use Mix.Task

  @shortdoc "Publishes docs to GitHub Pages"

  @moduledoc """
  Publishes docs to GitHub Pages.

      mix docs.publish [git-remote]

  """

  def run([]), do: run(["origin"])
  def run([remote|_]) do
    File.rm_rf("doc")
    Mix.Task.run("docs")

    remote_url = get_remote_url(remote)

    Mix.shell.info "Git remote #{remote_url}"
    File.cd!("doc")

    run! "git init ."
    run! "git add ."
    run! "git commit -m \"Generating docs\""
    run! "git remote add origin #{remote_url}"
    run! "git push -f origin master:gh-pages"
  end

  defp get_remote_url(remote) do
    push_url = :os.cmd('git remote show -n #{remote} | grep "Push\s.URL"') |> to_string
    Regex.named_captures(~r/\: (?<git>.*)/, push_url)["git"]
  end

  defp run!(command) do
    if Mix.shell.cmd(command) != 0 do
      raise Mix.Error, message: "command `#{command}` failed"
    end
    :ok
  end
end