From 977d1d8273d2e2549cbb6bdda0d5b70b35c277c4 Mon Sep 17 00:00:00 2001
From: Vince Foley <vincefoley@gmail.com>
Date: Sun, 14 Jun 2020 22:25:20 -0700
Subject: [PATCH] skip exception for normal exit

---
 src/cowboy_telemetry_h.erl     |  2 +-
 test/plug/cowboy/conn_test.exs | 13 ++++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/cowboy_telemetry_h.erl b/src/cowboy_telemetry_h.erl
index d348489..2c5c816 100644
--- a/src/cowboy_telemetry_h.erl
+++ b/src/cowboy_telemetry_h.erl
@@ -31,7 +31,7 @@ info(StreamID, Info, [Next0 | StartTime]) ->
         #{duration => EndTime - StartTime},
         #{stream_id => StreamID, response => Response}
       );
-    {'EXIT', _, Reason} ->
+    {'EXIT', _, Reason} when Reason /= normal ->
       telemetry:execute(
         [cowboy, request, exception],
         #{duration => EndTime - StartTime},
diff --git a/test/plug/cowboy/conn_test.exs b/test/plug/cowboy/conn_test.exs
index 375cfbc..0a3a825 100644
--- a/test/plug/cowboy/conn_test.exs
+++ b/test/plug/cowboy/conn_test.exs
@@ -152,7 +152,8 @@ defmodule Plug.Cowboy.ConnTest do
       :start_stop_test,
       [
         [:cowboy, :request, :start],
-        [:cowboy, :request, :stop]
+        [:cowboy, :request, :stop],
+        [:cowboy, :request, :exception]
       ],
       fn event, measurements, metadata, test ->
         send(test, {:telemetry, event, measurements, metadata})
@@ -175,6 +176,8 @@ defmodule Plug.Cowboy.ConnTest do
     assert duration_ms >= 30
     assert duration_ms < 100
 
+    refute_received {:telemetry, [:cowboy, :request, :exception], _, _}
+
     :telemetry.detach(:start_stop_test)
   end
 
@@ -182,6 +185,7 @@ defmodule Plug.Cowboy.ConnTest do
     :telemetry.attach_many(
       :exception_test,
       [
+        [:cowboy, :request, :start],
         [:cowboy, :request, :exception]
       ],
       fn event, measurements, metadata, test ->
@@ -192,11 +196,10 @@ defmodule Plug.Cowboy.ConnTest do
 
     request(:get, "/telemetry_exception")
 
+    assert_receive {:telemetry, [:cowboy, :request, :start], _, _}
+
     assert_receive {:telemetry, [:cowboy, :request, :exception], %{},
-                    %{
-                      kind: :exit,
-                      reason: _reason
-                    }}
+                    %{kind: :exit, reason: _reason}}
 
     :telemetry.detach(:exception_test)
   end