Adds mounts to fly backend

lib/flame/fly_backend.ex

@@ -54,6 +54,7 @@ defmodule FLAME.FlyBackend do
              :cpu_kind,
              :cpus,
              :gpu_kind,
+             :mounts,
              :memory_mb,
              :image,
              :app,
@@ -73,6 +74,7 @@ defmodule FLAME.FlyBackend do
             cpus: nil,
             memory_mb: nil,
             gpu_kind: nil,
+            mounts: [],
             image: nil,
             services: [],
             app: nil,
@@ -86,7 +88,7 @@ defmodule FLAME.FlyBackend do
             runner_private_ip: nil,
             runner_node_name: nil
 
-  @valid_opts ~w(app image token host cpu_kind cpus memory_mb gpu_kind boot_timeout env terminator_sup log services)a
+  @valid_opts ~w(app image token host cpu_kind cpus mounts memory_mb gpu_kind boot_timeout env terminator_sup log services)a
 
   @impl true
   def init(opts) do
@@ -103,7 +105,8 @@ defmodule FLAME.FlyBackend do
       memory_mb: 4096,
       boot_timeout: 30_000,
       runner_node_basename: node_base,
-      services: []
+      services: [],
+      mounts: []
     }
 
     provided_opts =
@@ -166,8 +169,57 @@ defmodule FLAME.FlyBackend do
     {result, div(micro, 1000)}
   end
 
+  defp get_volume_id(%FlyBackend{ mounts: [] }), do: {nil, 0}
+  defp get_volume_id(%FlyBackend{ mounts: mounts } = state) when is_list(mounts) do
+        {volumes, time} = get_volumes(state)
+
+        case volumes do
+          [] ->
+            {:error, "no volumes to mount"}
+          all_volumes ->
+            volume_ids_by_name = 
+              all_volumes
+              |> Enum.filter(fn vol ->
+                vol["attached_machine_id"] == nil
+                and vol["state"] == "created"
+              end)
+              |> Enum.group_by(&(&1["name"]), &(&1["id"]))
+
+              new_mounts = Enum.map_reduce(
+                mounts,
+                volume_ids_by_name,
+                fn mount, leftover_vols ->
+                  case List.wrap(leftover_vols[mount.name]) do
+                    [] ->
+                      raise ArgumentError, "not enough fly volumes with the name \"#{mount.name}\" to a FLAME child"
+                    [volume_id | rest] ->
+                      {%{mount | volume: volume_id}, %{leftover_vols | mount.name => rest}}
+                  end
+                end
+              )
+
+            {new_mounts, time}
+        end
+  end
+  defp get_volume_id(_) do
+    raise ArgumentError, "expected a list of mounts"
+  end
+
+  defp get_volumes(%FlyBackend{} = state) do
+      {vols, get_vols_time} = with_elapsed_ms(fn ->
+        Req.get!("#{state.host}/v1/apps/#{state.app}/volumes",
+          connect_options: [timeout: state.boot_timeout],
+          retry: false,
+          auth: {:bearer, state.token}
+        )
+      end)
+
+      {vols.body, get_vols_time}
+  end
+
   @impl true
   def remote_boot(%FlyBackend{parent_ref: parent_ref} = state) do
+    {mounts, volume_validate_time} = get_volume_id(state)
     {req, req_connect_time} =
       with_elapsed_ms(fn ->
         Req.post!("#{state.host}/v1/apps/#{state.app}/machines",
@@ -179,11 +231,12 @@ defmodule FLAME.FlyBackend do
             name: "#{state.app}-flame-#{rand_id(20)}",
             config: %{
               image: state.image,
+              mounts: mounts,
               guest: %{
                 cpu_kind: state.cpu_kind,
                 cpus: state.cpus,
                 memory_mb: state.memory_mb,
-                gpu_kind: state.gpu_kind
+                gpu_kind: state.gpu_kind,
               },
               auto_destroy: true,
               restart: %{policy: "no"},
@@ -194,7 +247,7 @@ defmodule FLAME.FlyBackend do
         )
       end)
 
-    remaining_connect_window = state.boot_timeout - req_connect_time
+    remaining_connect_window = state.boot_timeout - req_connect_time - volume_validate_time
 
     case req.body do
       %{"id" => id, "instance_id" => instance_id, "private_ip" => ip} ->

lib/flame/fly_backend/mounts.ex

@@ -0,0 +1,9 @@
+defmodule FLAME.FlyBackend.Mounts do
+  @derive Jason.Encoder
+  defstruct name: nil,
+            path: nil,
+            volume: nil,
+            extend_threshold_percent: 0,
+            add_size_gb: 0,
+            size_gb_limit: 0
+end