task-maker.rb

#!/usr/bin/env ruby

# Generates a very opinionated `tasks.json` for Elixir projects.
#
# Usage (from the root of your project)
#
#   mkdir .vscode
#   cp .vscode/tasks.json .vscode/tasks.backup.json
#   task-maker > .vscode/tasks.json
#
# Creates build tasks:
#   Deps.get
#   Compile (MIX_ENV=test)
#   Clean
#   Clobber
#   Dialyzer (MIX_ENV=test)
#   Credo (MIX_ENV=test)
#
# Creates test tasks:
#   All unit tests    -- runs `mix test` in root
#   ExCoveralls       -- runs `mix coveralls.html --umbrella`
#   Everything        -- runs `mix all_tests`
#   component-app-1 tests
#   component-app-2 tests
#   ...
#   component-app-n tests
#
# The component-app-i tests run the tests in the component directories (e.g., apps/component-app-i)
#

require 'json'

class ComponentApp
  def self.list
    Dir.glob("apps/*").map do |dir|
      ComponentApp.new(dir)
    end
  end

  def initialize(dir)
    @dir = dir
  end

  def directory
    @dir
  end

  def name
    @dir.gsub("apps/", "")
  end
end

class TaskJSON
  def self.generate
    new.generate
  end

  def generate
    puts JSON.generate(json, indent: "  ", space: " ", object_nl: "\n", array_nl: "\n")
  end

  def json
    {
      "version": "2.0.0",
      "tasks": tasks
    }
  end

  def tasks
    umbrella_tasks +
      component_app_tasks +
      build_tasks
  end

  def build_tasks
    pm = ["$mixCompileError", "$mixCompileWarning"]
    [
      mix_task(label: "Deps.get", args: "deps.get", group: "build"),
      mix_task(label: "Compile", args: ["compile",  "--force", "--warnings-as-errors"], group: "build", options: {"env": test_env}, problem_matcher: pm),
      mix_task(label: "Clean", args: "clean", group: "build", problem_matcher: pm),
      mix_task(label: "Clobber", args: do_args("clean", "deps.clean -all"), group: "build", problem_matcher: pm),
      mix_task(label: "Dialyzer", args: "dialyzer", group: "build", options: {"env": test_env}, problem_matcher: pm),
      mix_task(label: "Credo", args: ["credo", "--strict"], group: "build", options: {"env": test_env}, problem_matcher: pm)
    ]
  end

  def do_args(*args)
    ["do"] + args.map {|a| "#{a},"}
  end

  def umbrella_tasks
    [
      mix_task(label: "All unit tests", args: ["test"], group: "test"),
      mix_task(label: "ExCoveralls", args: ["coveralls.html", "--umbrella"], group: "test"),
      mix_task(label: "Everything", args: ["all_tests"], group: "test"),
    ]
  end

  def component_app_tasks
    ComponentApp.list.map do |app|
      component_app_test(app)
    end
  end

  def component_app_test(app)
    mix_task(label: "#{app.name} tests", args: ["test"], group: "test", options: {cwd: app.directory})
  end

  def mix_task(label:, args:, group:, problem_matcher: [], options: {})
    base = {
      label: label,
      type: "shell",
      command: "mix",
      args: Array(args),
      group: group,
      presentation: {
        reveal: "always",
        panel: "new"
      },
      problemMatcher: problem_matcher
    }
    base = merge_not_empty(base, :options, options)
    base
  end

  def merge_not_empty(base, field, value)
    if value.empty?
      base
    else
      base.merge(field => value)
    end
  end

  def test_env
    {"MIX_ENV": "test"}
  end
end

TaskJSON.generate