feat: collect serializer on phoenix socket connected metric

Author: edgurgel

lib/realtime/monitoring/prom_ex/plugins/phoenix.ex

@@ -122,14 +122,15 @@ if Code.ensure_loaded?(Phoenix) do
             reporter_options: [
               buckets: [10, 100, 500, 1_000, 5_000, 10_000]
             ],
-            tag_values: fn %{result: result, endpoint: endpoint, transport: transport} ->
+            tag_values: fn %{result: result, endpoint: endpoint, transport: transport, serializer: serializer} ->
               %{
                 transport: transport,
                 result: result,
-                endpoint: normalize_module_name(endpoint)
+                endpoint: normalize_module_name(endpoint),
+                serializer: serializer
               }
             end,
-            tags: [:result, :transport, :endpoint],
+            tags: [:result, :transport, :endpoint, :serializer],
             unit: {:native, :millisecond}
           )
         ]

mix.exs

@@ -4,7 +4,7 @@ defmodule Realtime.MixProject do
   def project do
     [
       app: :realtime,
-      version: "2.63.3",
+      version: "2.64.0",
       elixir: "~> 1.18",
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,

test/realtime/monitoring/prom_ex/plugins/phoenix_test.exs

@@ -11,12 +11,12 @@ defmodule Realtime.PromEx.Plugins.PhoenixTest do
     end
   end
 
-  describe "pooling metrics" do
-    setup do
-      start_supervised!(MetricsTest)
-      %{tenant: Containers.checkout_tenant(run_migrations: true)}
-    end
+  setup do
+    start_supervised!(MetricsTest)
+    %{tenant: Containers.checkout_tenant(run_migrations: true)}
+  end
 
+  describe "pooling metrics" do
     test "number of connections", %{tenant: tenant} do
       {:ok, token} = token_valid(tenant, "anon", %{})
 
@@ -37,17 +37,49 @@ defmodule Realtime.PromEx.Plugins.PhoenixTest do
         )
 
       Process.sleep(200)
-      assert metric_value() >= 2
+      assert metric_value(~r/phoenix_connections_total\s(?<number>\d+)/) >= 2
+    end
+  end
+
+  describe "event metrics" do
+    test "socket connected", %{tenant: tenant} do
+      {:ok, token} = token_valid(tenant, "anon", %{})
+
+      {:ok, _} =
+        WebsocketClient.connect(
+          self(),
+          uri(tenant, Phoenix.Socket.V1.JSONSerializer, 4002),
+          Phoenix.Socket.V1.JSONSerializer,
+          [{"x-api-key", token}]
+        )
+
+      {:ok, _} =
+        WebsocketClient.connect(
+          self(),
+          uri(tenant, RealtimeWeb.Socket.V2Serializer, 4002),
+          RealtimeWeb.Socket.V2Serializer,
+          [{"x-api-key", token}]
+        )
+
+      Process.sleep(200)
+
+      assert metric_value(
+               ~r/phoenix_socket_connected_duration_milliseconds_count{endpoint="RealtimeWeb.Endpoint",result="ok",serializer="Elixir.Phoenix.Socket.V1.JSONSerializer",transport="websocket"}\s(?<number>\d+)/
+             ) == 1
+
+      assert metric_value(
+               ~r/phoenix_socket_connected_duration_milliseconds_count{endpoint="RealtimeWeb.Endpoint",result="ok",serializer="Elixir.RealtimeWeb.Socket.V2Serializer",transport="websocket"}\s(?<number>\d+)/
+             ) == 1
     end
   end
 
-  defp metric_value() do
+  defp metric_value(pattern) do
     PromEx.get_metrics(MetricsTest)
     |> String.split("\n", trim: true)
     |> Enum.find_value(
       "0",
       fn item ->
-        case Regex.run(~r/phoenix_connections_total\s(?<number>\d+)/, item, capture: ["number"]) do
+        case Regex.run(pattern, item, capture: ["number"]) do
           [number] -> number
           _ -> false
         end