From 0056d35e9baf9c8863d8a3a8b4b7b6f2d956c24a Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Fri, 23 Jan 2026 10:08:04 -0600
Subject: [PATCH] ignore more startup errors

---
 lib/towerops/honeybadger_filter.ex | 31 ++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/lib/towerops/honeybadger_filter.ex b/lib/towerops/honeybadger_filter.ex
index a17503db..b7eb559c 100644
--- a/lib/towerops/honeybadger_filter.ex
+++ b/lib/towerops/honeybadger_filter.ex
@@ -2,13 +2,13 @@ defmodule Towerops.HoneybadgerFilter do
   @moduledoc """
   Custom Honeybadger filter to exclude noisy errors during deployments.
 
-  Filters out os_mon supervisor errors (memsup, cpu_sup) that occur
-  during normal node shutdown/restart.
+  Filters out OTP supervisor/gen_server errors that occur during normal
+  node shutdown/restart.
   """
 
   use Honeybadger.Filter.Mixin
 
-  # Supervisors/processes that generate errors during normal shutdown
+  # Named supervisors/processes that generate errors during normal shutdown
   @ignored_registered_names [
     "memsup",
     "cpu_sup",
@@ -17,14 +17,25 @@ defmodule Towerops.HoneybadgerFilter do
 
   @impl Honeybadger.Filter
   def filter_context(context) do
-    # Check if this is an os_mon supervisor error
-    registered_name = get_in(context, [:registered_name])
+    cond do
+      # Named process in our ignore list
+      get_in(context, [:registered_name]) in @ignored_registered_names ->
+        nil
 
-    if registered_name in @ignored_registered_names do
-      # Return nil to filter out this error
-      nil
-    else
-      super(context)
+      # Anonymous gen_server shutdown errors (OTP domain, gen_server error_info)
+      otp_gen_server_shutdown?(context) ->
+        nil
+
+      true ->
+        super(context)
     end
   end
+
+  # Detect anonymous gen_server termination during shutdown
+  defp otp_gen_server_shutdown?(context) do
+    domain = get_in(context, [:domain])
+    mfa = get_in(context, [:mfa])
+
+    domain == ["otp"] and match?(["gen_server", "error_info", _], mfa)
+  end
 end