fix: Capture IO automatically on execution

README.md

@@ -13,7 +13,7 @@ Add mash to your dependencies like so:
 ```elixir
 def deps do
   [
-    {:mash, "~> 0.1.0"}
+    {:mash, "~> 0.1.1"}
   ]
 end
 ```
@@ -36,6 +36,12 @@ defmodule MashConfig do
         name: :credo, 
         run: mix("credo", ["--all"])
       },
+      %{
+        name: :function_example,
+        run: fn _io_pid ->
+          IO.puts("Hurray!")
+        end
+      }
     ]
   end
 end
@@ -47,7 +53,10 @@ Each entry in the jobs list must, at a minimum, have two keys:
 - `:run` -- a function which defines the work for the job to do. We recommend using the helper functions from Mash.Helpers to define your run function, as they ensure that your function handles setup and teardown correctly for many common scenarios, e.g.:
     - `Mash.Helpers.mix(task_name, args)` -- execute a mix task with the given `task_name` and `args`.
     - `Mash.Helpers.shell(command, args)` -- run an executable/script named `command` with `args`.
-    - `Mash.Helpers.fun(fn -> ... end)` -- execute the Elixir function given. This function must return `:ok` or `{:ok, value}` to indicate success, or return `{:error, error}` or `raise` to indicate job failure.
+    - Or you can pass a function with arity 1. 
+      - The function should return `:ok` or `{:ok, value}` if the job succeeds, or `{:error, error}` if the job fails.
+      - The argument passed to your function will be the PID of the IO device which is capturing IO. Since we make this PID the "group leader" for your job automatically, you can probably ignore this argument, but you may need to for interfacing with certain libraries that
+      require you to pass an io device PID directly.
 
 Optionally, a job may also contain a key `needs` whose value is an array of other jobs that must pass before this job will be run.
 

lib/mash/execution.ex

@@ -8,6 +8,8 @@ defmodule Mash.Execution do
 
     task =
       Task.async(fn ->
+        Process.group_leader(self(), io_pid)
+
         {%{job | io_pid: io_pid}, run.(io_pid)}
       end)
 

lib/mash/helpers.ex

@@ -3,30 +3,48 @@ defmodule Mash.Helpers do
   Helpers that provide a simple way to write Mash configs.
   """
 
-  def mix(task, args \\ []) do
-    preferred_mix_env = Mix.Task.preferred_cli_env(task) || Mix.env()
+  @doc "Create a run function for a job that executes a mix task with name `task_name` and the arguments `args`"
+  @spec mix(String.t(), [String.t()]) :: function()
+  def mix(task_name, args \\ []) do
+    preferred_mix_env = Mix.Task.preferred_cli_env(task_name) || Mix.env()
 
     fn io_pid ->
-      cmd("mix", [task | args], io_pid, [{"MIX_ENV", Atom.to_string(preferred_mix_env)}])
+      cmd("mix", [task_name | args], io_pid, [{"MIX_ENV", Atom.to_string(preferred_mix_env)}])
     end
   end
 
+  @doc """
+  Create a run function which executes the script/binary named `command` with the arguments `args`.
+  """
+  @spec shell(String.t(), [String.t()]) :: function()
   def shell(command, args \\ []) do
     fn io_pid ->
       cmd(command, args, io_pid)
     end
   end
 
+  @doc """
+  Save a cache file as a gzipped tar archive. We use tar because it preserves timestamps which are used
+  by Elixir for determining "staleness" of compilation.
+
+  - `name` is the base name of the archive to save (default: `".mash-cache"`)
+  - `files` is the list of files/directories to save in the archive (default:` ["deps", "_build"]`)
+  """
+  @spec save_cache(String.t(), [String.t()]) :: function()
   def save_cache(name \\ ".mash-cache", files \\ ["deps", "_build"]) do
     fn io_pid ->
       cmd("tar", ["-czpf", "#{name}.tar.gz" | files], io_pid)
     end
   end
 
+  @doc """
+  Restore a cache file.
+
+  - `name` is the base name of the archive to save (default: ".mash-cache")
+  """
+  @spec restore_cache(String.t()) :: function()
   def restore_cache(name \\ ".mash-cache") do
     fn io_pid ->
-      Process.group_leader(self(), io_pid)
-
       path = "#{name}.tar.gz"
 
       if File.exists?(path) do
@@ -41,30 +59,6 @@ defmodule Mash.Helpers do
     end
   end
 
-  def fun(fun) do
-    fn io_pid ->
-      Process.group_leader(self(), io_pid)
-
-      try do
-        case fun.() do
-          :ok ->
-            {[], 0}
-
-          {:ok, _any} ->
-            {[], 0}
-
-          other ->
-            IO.puts(IO.ANSI.red() <> "** (fun) failed: #{inspect(other)}" <> IO.ANSI.reset())
-            {[], 1}
-        end
-      rescue
-        e ->
-          IO.puts(IO.ANSI.red() <> "** (fun) failed: #{Exception.message(e)}" <> IO.ANSI.reset())
-          {[], 1}
-      end
-    end
-  end
-
   defp cmd(command, args, io_pid, env \\ []) do
     exec_string = "-c #{command} #{Enum.join(args, " ")}"
 

lib/mash/runner.ex

@@ -5,6 +5,7 @@ defmodule Mash.Runner do
   use GenServer
 
   @type job_state :: :to_run | :running | :passed | :failed | :skipped
+  @type result :: term()
 
   def tick do
     GenServer.cast(self(), :tick)
@@ -107,12 +108,18 @@ defmodule Mash.Runner do
     end)
   end
 
+  defp interpret_result({_stream_data, 0}), do: :passed
+  defp interpret_result({_stream_data, exit_code}) when exit_code > 0, do: :failed
+  defp interpret_result(:ok), do: :passed
+  defp interpret_result({:ok, _}), do: :passed
+  defp interpret_result(_), do: :failed
+
   @impl GenServer
-  def handle_info({_ref, {job, {_io_stream, exit_code}}}, {parent, jobs}) do
+  def handle_info({_ref, {job, result}}, {parent, jobs}) do
     %{name: job_name} = job
 
     StringIO.close(job.io_pid)
-    new_state = if exit_code == 0, do: :passed, else: :failed
+    new_state = interpret_result(result)
     IO.puts("Finishing #{job_name} -- #{new_state}")
 
     new_job = %{

mix.exs

@@ -4,7 +4,7 @@ defmodule Mash.MixProject do
   def project do
     [
       app: :mash,
-      version: "0.1.0",
+      version: "0.1.1",
       elixir: "~> 1.14",
       start_permanent: Mix.env() == :prod,
       deps: deps(),