Clean up parent code_sync artifacts on pool shutdown

lib/flame/pool.ex

@@ -201,6 +201,7 @@ defmodule FLAME.Pool do
       :name,
       :runner_sup,
       :task_sup,
+      :cleaner,
       :terminator_sup,
       :child_placement_sup,
       :idle_shutdown_after,
@@ -222,6 +223,9 @@ defmodule FLAME.Pool do
     ])
 
     Keyword.validate!(opts[:code_sync] || [], [
+      :get_path,
+      :extract_dir,
+      :tmp_dir,
       :copy_apps,
       :copy_paths,
       :sync_beams,
@@ -395,6 +399,7 @@ defmodule FLAME.Pool do
     )
 
     terminator_sup = Keyword.fetch!(opts, :terminator_sup)
+    cleaner = Keyword.fetch!(opts, :cleaner)
     child_placement_sup = Keyword.fetch!(opts, :child_placement_sup)
     runner_opts = runner_opts(opts, terminator_sup)
     min = Keyword.fetch!(opts, :min)
@@ -415,6 +420,9 @@ defmodule FLAME.Pool do
           |> CodeSync.compute_changed_paths()
 
         %CodeSync.PackagedStream{} = parent_stream = CodeSync.package_to_stream(code_sync)
+
+        :ok = FLAME.Pool.Cleaner.watch_path(cleaner, parent_stream.stream.path)
+
         parent_stream
       end
 

lib/flame/pool/cleaner.ex

@@ -0,0 +1,35 @@
+defmodule FLAME.Pool.Cleaner do
+  @moduledoc false
+  use GenServer
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, name: Keyword.fetch!(opts, :name))
+  end
+
+  def watch_path(server, path) do
+    GenServer.call(server, {:watch, path})
+  end
+
+  def list_paths(server) do
+    GenServer.call(server, :list)
+  end
+
+  def init(_opts) do
+    Process.flag(:trap_exit, true)
+    {:ok, %{paths: []}}
+  end
+
+  def handle_call({:watch, path}, _from, state) do
+    {:reply, :ok, %{state | paths: [path | state.paths]}}
+  end
+
+  def handle_call(:list, _from, state) do
+    {:reply, state.paths, state}
+  end
+
+  def terminate(_reason, state) do
+    for path <- state.paths, do: File.rm!(path)
+
+    :ok
+  end
+end

lib/flame/pool/supervisor.ex

@@ -13,6 +13,7 @@ defmodule FLAME.Pool.Supervisor do
   def init(opts) do
     name = Keyword.fetch!(opts, :name)
     runner_sup = Module.concat(name, "RunnerSup")
+    cleaner = Module.concat(name, "Cleaner")
     terminator_sup = Module.concat(name, "TerminatorSup")
     task_sup = Module.concat(name, "TaskSup")
 
@@ -22,13 +23,15 @@ defmodule FLAME.Pool.Supervisor do
     pool_opts =
       Keyword.merge(opts,
         task_sup: task_sup,
+        cleaner: cleaner,
         runner_sup: runner_sup,
         terminator_sup: terminator_sup,
         child_placement_sup: child_placement_sup
       )
 
     children =
       [
+        {FLAME.Pool.Cleaner, name: cleaner},
         {Task.Supervisor, name: task_sup, strategy: :one_for_one},
         {DynamicSupervisor, name: runner_sup, strategy: :one_for_one},
         {DynamicSupervisor, name: terminator_sup, strategy: :one_for_one},

test/flame_test.exs

@@ -21,11 +21,16 @@ defmodule FLAME.FLAMETest do
   end
 
   setup config do
-    runner_opts = Map.fetch!(config, :runner)
-    runner_sup = Module.concat(config.test, "RunnerSup")
-    pool_pid = start_supervised!({Pool, Keyword.merge(runner_opts, name: config.test)})
+    case config do
+      %{runner: runner_opts} ->
+        runner_sup = Module.concat(config.test, "RunnerSup")
+        pool_pid = start_supervised!({Pool, Keyword.merge(runner_opts, name: config.test)})
 
-    {:ok, runner_sup: runner_sup, pool_pid: pool_pid}
+        {:ok, runner_sup: runner_sup, pool_pid: pool_pid}
+
+      %{} ->
+        :ok
+    end
   end
 
   @tag runner: [min: 1, max: 2, max_concurrency: 2]
@@ -619,4 +624,21 @@ defmodule FLAME.FLAMETest do
       assert_receive {:DOWN, _, _, ^runner, {:shutdown, :idle}}, 1000
     end
   end
+
+  test "code_sync artifact cleaner", config do
+    mock = FLAME.Test.CodeSyncMock.new()
+
+    cleaner = Module.concat(config.test, "Cleaner")
+
+    pool_pid =
+      start_supervised!(
+        {Pool, min: 1, max: 1, max_concurrency: 1, name: config.test, code_sync: mock.opts}
+      )
+
+    assert [artifact] = FLAME.Pool.Cleaner.list_paths(cleaner)
+    assert File.exists?(artifact)
+    assert FLAME.call(config.test, fn -> :works end) == :works
+    Supervisor.stop(pool_pid)
+    refute File.exists?(artifact)
+  end
 end