From b30f0fa1eeaddb8a3c0967eb8ced0f6a15894a1e Mon Sep 17 00:00:00 2001
From: Claudio Ortolina <cloud8421@gmail.com>
Date: Sun, 8 Mar 2026 13:56:31 +0000
Subject: [PATCH] Add metrics around image resize/convert/dominant color
 extration

---
 lib/music_library/assets/image.ex             | 22 ++++++++++++++----
 lib/music_library/colors/k_means_extractor.ex | 23 +++++++++++++------
 lib/music_library_web/telemetry.ex            | 16 +++++++++++++
 3 files changed, 50 insertions(+), 11 deletions(-)

diff --git a/lib/music_library/assets/image.ex b/lib/music_library/assets/image.ex
index 8eaceaa7..ef140611 100644
--- a/lib/music_library/assets/image.ex
+++ b/lib/music_library/assets/image.ex
@@ -14,8 +14,15 @@ defmodule MusicLibrary.Assets.Image do
 
   @spec resize(binary(), pos_integer(), String.t()) :: {:ok, binary()} | {:error, term()}
   def resize(cover_data, size \\ @default_size, format \\ @default_format) do
-    {:ok, thumb} = Operation.thumbnail_buffer(cover_data, size)
-    Image.write_to_buffer(thumb, extension(format))
+    :telemetry.span(
+      [:music_library, :assets, :image, :resize],
+      %{},
+      fn ->
+        {:ok, thumb} = Operation.thumbnail_buffer(cover_data, size)
+        result = Image.write_to_buffer(thumb, extension(format))
+        {result, %{}}
+      end
+    )
   end
 
   @spec convert(binary(), String.t(), String.t()) :: {:ok, binary()}
@@ -23,8 +30,15 @@ defmodule MusicLibrary.Assets.Image do
     if data_format == target_format do
       {:ok, cover_data}
     else
-      {:ok, image} = Image.new_from_buffer(cover_data)
-      Image.write_to_buffer(image, extension(target_format))
+      :telemetry.span(
+        [:music_library, :assets, :image, :convert],
+        %{},
+        fn ->
+          {:ok, image} = Image.new_from_buffer(cover_data)
+          result = Image.write_to_buffer(image, extension(target_format))
+          {result, %{}}
+        end
+      )
     end
   end
 
diff --git a/lib/music_library/colors/k_means_extractor.ex b/lib/music_library/colors/k_means_extractor.ex
index 42b30d81..4219e92f 100644
--- a/lib/music_library/colors/k_means_extractor.ex
+++ b/lib/music_library/colors/k_means_extractor.ex
@@ -7,12 +7,21 @@ defmodule MusicLibrary.Colors.KMeansExtractor do
 
   @spec extract_dominant_colors(binary(), pos_integer()) :: {:ok, [String.t()]} | {:error, term()}
   def extract_dominant_colors(image_data, num_colors \\ 5) do
-    with {:ok, dir} <- Briefly.create(type: :directory),
-         path = dir <> "/temp_image.jpg",
-         {:ok, image} <- Image.new_from_buffer(image_data),
-         :ok <- Image.write_to_file(image, path),
-         {:ok, colors} <- DominantColors.dominant_colors(path) do
-      {:ok, Enum.take(colors, num_colors)}
-    end
+    :telemetry.span(
+      [:music_library, :colors, :extract],
+      %{},
+      fn ->
+        result =
+          with {:ok, dir} <- Briefly.create(type: :directory),
+               path = dir <> "/temp_image.jpg",
+               {:ok, image} <- Image.new_from_buffer(image_data),
+               :ok <- Image.write_to_file(image, path),
+               {:ok, colors} <- DominantColors.dominant_colors(path) do
+            {:ok, Enum.take(colors, num_colors)}
+          end
+
+        {result, %{}}
+      end
+    )
   end
 end
diff --git a/lib/music_library_web/telemetry.ex b/lib/music_library_web/telemetry.ex
index 00166bc8..b3526e4f 100644
--- a/lib/music_library_web/telemetry.ex
+++ b/lib/music_library_web/telemetry.ex
@@ -157,6 +157,22 @@ defmodule MusicLibraryWeb.Telemetry do
         reporter_options: [nav: "Markdown"]
       ),
 
+      # Color Extraction Metrics
+      summary("music_library.colors.extract.stop.duration",
+        unit: {:native, :millisecond},
+        reporter_options: [nav: "Image Processing"]
+      ),
+
+      # Image Processing Metrics
+      summary("music_library.assets.image.resize.stop.duration",
+        unit: {:native, :millisecond},
+        reporter_options: [nav: "Image Processing"]
+      ),
+      summary("music_library.assets.image.convert.stop.duration",
+        unit: {:native, :millisecond},
+        reporter_options: [nav: "Image Processing"]
+      ),
+
       # VM Metrics
       summary("vm.memory.total", unit: {:byte, :megabyte}),
       summary("vm.total_run_queue_lengths.total"),