From 3ab4e63441099b510660ac8666f3b2224da323b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20Casta=C3=B1o?= <alexcastanodev@gmail.com>
Date: Wed, 8 Nov 2023 00:25:19 +0100
Subject: [PATCH] System fetch instrument allocators

---
 lib/phoenix/live_dashboard/system_info.ex       | 12 ++++++++++++
 .../phoenix/live_dashboard/system_info_test.exs | 17 +++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/lib/phoenix/live_dashboard/system_info.ex b/lib/phoenix/live_dashboard/system_info.ex
index 684a2d4c..4211c698 100644
--- a/lib/phoenix/live_dashboard/system_info.ex
+++ b/lib/phoenix/live_dashboard/system_info.ex
@@ -115,6 +115,10 @@ defmodule Phoenix.LiveDashboard.SystemInfo do
     :rpc.call(node, __MODULE__, :memory_allocators_callback, [max_carrier_sizes])
   end
 
+  def fetch_instrument_allocations(node) do
+    :rpc.call(node, __MODULE__, :instrument_allocations_callback, [])
+  end
+
   ## System callbacks
 
   @doc false
@@ -269,6 +273,14 @@ defmodule Phoenix.LiveDashboard.SystemInfo do
     end)
   end
 
+  def instrument_allocations_callback() do
+    if Code.ensure_loaded?(:instrument) do
+      :instrument.allocations()
+    else
+      {:error, :instrument_not_available}
+    end
+  end
+
   ## Process Callbacks
 
   @processes_keys [
diff --git a/test/phoenix/live_dashboard/system_info_test.exs b/test/phoenix/live_dashboard/system_info_test.exs
index 3d312a38..0f6ce469 100644
--- a/test/phoenix/live_dashboard/system_info_test.exs
+++ b/test/phoenix/live_dashboard/system_info_test.exs
@@ -312,4 +312,21 @@ defmodule Phoenix.LiveDashboard.SystemInfoTest do
              ] = list
     end
   end
+
+  describe "fetch_instrument_allocations" do
+    test "works" do
+      assert {:ok, {128, 0, allocs}} = SystemInfo.fetch_instrument_allocations(node())
+
+      assert %{
+               system: %{binary: binary_tuple, nif_internal: nif_tuple, port: port_tuple},
+               prim_file: %{},
+               tcp_inet: %{drv_internal: drv_tuple}
+             } = allocs
+
+      assert tuple_size(binary_tuple) == 18
+      assert tuple_size(nif_tuple) == 18
+      assert tuple_size(port_tuple) == 18
+      assert tuple_size(drv_tuple) == 18
+    end
+  end
 end