From 08c0ae9b4ca9102dd1e48a677f8b8959e008ff0a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Jan=20Niemier?= <lukasz@supabase.io>
Date: Fri, 13 Dec 2024 18:17:00 +0100
Subject: [PATCH] fix: properly compute socket usage

This partially reverts commit 4b498871ed54b726748d95808a2a840e8a51735c.

The change was not properly implementing previous behaviour in presence
of multiple sockets reporting to the same set of attributes. Instead of
summing their usage it was reporting only the latest one.
---
 lib/supavisor/monitoring/telem.ex  | 10 +++++-----
 lib/supavisor/monitoring/tenant.ex | 14 ++++----------
 2 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/lib/supavisor/monitoring/telem.ex b/lib/supavisor/monitoring/telem.ex
index 9c814511..74d1a40d 100644
--- a/lib/supavisor/monitoring/telem.ex
+++ b/lib/supavisor/monitoring/telem.ex
@@ -25,15 +25,15 @@ defmodule Supavisor.Monitoring.Telem do
 
   @spec network_usage(:client | :db, Supavisor.sock(), Supavisor.id(), map()) ::
           {:ok | :error, map()}
-  def network_usage(type, {mod, socket}, id, _stats) do
+  def network_usage(type, {mod, socket}, id, stats) do
     network_usage_disable do
       mod = if mod == :ssl, do: :ssl, else: :inet
 
       case mod.getstat(socket, [:recv_oct, :send_oct]) do
         {:ok, [{:recv_oct, recv_oct}, {:send_oct, send_oct}]} ->
           stats = %{
-            send_oct: send_oct,
-            recv_oct: recv_oct
+            send_oct: send_oct - stats.send_oct,
+            recv_oct: recv_oct - stats.recv_oct
           }
 
           {{ptype, tenant}, user, mode, db_name, search_path} = id
@@ -51,11 +51,11 @@ defmodule Supavisor.Monitoring.Telem do
             }
           )
 
-          {:ok, %{}}
+          {:ok, %{recv_oct: recv_oct, send_oct: send_oct}}
 
         {:error, reason} ->
           Logger.error("Failed to get socket stats: #{inspect(reason)}")
-          {:error, %{}}
+          {:error, stats}
       end
     end
   end
diff --git a/lib/supavisor/monitoring/tenant.ex b/lib/supavisor/monitoring/tenant.ex
index fe3c5a17..767aa278 100644
--- a/lib/supavisor/monitoring/tenant.ex
+++ b/lib/supavisor/monitoring/tenant.ex
@@ -81,25 +81,19 @@ defmodule Supavisor.PromEx.Plugins.Tenant do
             peep_bucket_calculator: Buckets
           ]
         ),
-        last_value(
+        sum(
           [:supavisor, :client, :network, :recv],
           event_name: [:supavisor, :client, :network, :stat],
           measurement: :recv_oct,
           description: "The total number of bytes received by clients.",
-          tags: @tags,
-          reporter_options: [
-            prometheus_type: :sum
-          ]
+          tags: @tags
         ),
-        last_value(
+        sum(
           [:supavisor, :client, :network, :send],
           event_name: [:supavisor, :client, :network, :stat],
           measurement: :send_oct,
           description: "The total number of bytes sent by clients.",
-          tags: @tags,
-          reporter_options: [
-            prometheus_type: :sum
-          ]
+          tags: @tags
         ),
         counter(
           [:supavisor, :client, :queries, :count],