feat: init/get/update

lib/juggler.ex

@@ -1,11 +1,37 @@
 defmodule Juggler do
+  require Logger
+
   @juggler_dir "juggler"
   @juggles_file_path "juggles.exs"
+  @juggles_template """
+  # Example for testing against 1.x and 2.x of some dependency
+  # %{
+  #   "dep-name-1-0": [{:dep_name, "~> 1.0"}],
+  #   "dep-name-2-0": [{:dep_name, "~> 2.0"}],
+  # }
+  """
+
+  def init do
+    case File.read(@juggles_file_path) do
+      {:ok, _} ->
+        Logger.info("#{@juggles_file_path} file already exists, doing nothing")
+      {:error, :enoent} ->
+        File.write(@juggles_file_path, @juggles_template)
+        Logger.info("Successfully created #{@juggles_file_path} file")
+    end
+  end
 
   def juggles do
-    with {:ok, contents} <- File.read(@juggles_file_path),
-         {%{} = contents, _} <- Code.eval_string(contents) do
-      contents
+    case File.read(@juggles_file_path) do
+      {:ok, contents} ->
+        case Code.eval_string(contents) do
+          {%{} = map, _} ->
+            map
+          _ ->
+            raise "Couldn't find a map defining your juggles in #{@juggles_file_path} file"
+        end
+      {:error, :enoent} ->
+        raise "Couldn't find a #{@juggles_file_path} file"
     end
   end
 

lib/mix/tasks/juggler/exec.ex

@@ -0,0 +1,17 @@
+defmodule Mix.Tasks.Juggler.Exec do
+  use Mix.Task
+
+  @shortdoc "Executes task within a lockfile context"
+  # @preferred_cli_env :test
+
+  @impl true
+  def run([juggle_id | [task | args]]) do
+    Juggler.within(
+      String.to_atom(juggle_id),
+      fn ->
+        # System.put_env("MIX_ENV", "test")
+        Mix.Task.run(task, args)
+      end
+    )
+  end
+end

lib/mix/tasks/juggler/gen.ex → lib/mix/tasks/juggler/get.ex

@@ -1,16 +1,16 @@
-defmodule Mix.Tasks.Juggler.Gen do
+defmodule Mix.Tasks.Juggler.Get do
   use Mix.Task
 
   @shortdoc "Generates lockfiles from juggles.exs"
 
   @impl true
-  def run(_args) do
+  def run(args) do
     Juggler.juggles()
     |> Enum.map(fn {juggle_id, _deps} ->
       Juggler.within(
         juggle_id,
         fn ->
-          Mix.Task.rerun("deps.get")
+          Mix.Task.rerun("deps.get", args)
         end
       )
     end)

lib/mix/tasks/juggler/init.ex

@@ -0,0 +1,10 @@
+defmodule Mix.Tasks.Juggler.Init do
+  use Mix.Task
+
+  @shortdoc "Initializes an empty juggles.exs file"
+
+  @impl true
+  def run(_args) do
+    Juggler.init()
+  end
+end

lib/mix/tasks/juggler/update.ex

@@ -0,0 +1,18 @@
+defmodule Mix.Tasks.Juggler.Update do
+  use Mix.Task
+
+  @shortdoc "Updates lockfiles from juggles.exs"
+
+  @impl true
+  def run(args) do
+    Juggler.juggles()
+    |> Enum.map(fn {juggle_id, _deps} ->
+      Juggler.within(
+        juggle_id,
+        fn ->
+          Mix.Task.rerun("deps.update", args)
+        end
+      )
+    end)
+  end
+end