WIP Phoenix.ActionClauseError

lib/tower/bandit_exception_handler.ex

@@ -39,8 +39,11 @@ defmodule Tower.BanditExceptionHandler do
          },
          stacktrace: stacktrace
        }) do
-    Exception.normalize(:error, reason, stacktrace)
-    |> Tower.report_exception(stacktrace, plug_conn: conn)
+    exception = Exception.normalize(:error, reason, stacktrace)
+
+    if report?(exception) do
+      Tower.report_exception(exception, stacktrace, plug_conn: conn)
+    end
   end
 
   defp handle_event_metadata(%{
@@ -50,8 +53,11 @@ defmodule Tower.BanditExceptionHandler do
          conn: conn
        })
        when is_exception(reason) do
-    Exception.normalize(:error, reason, stacktrace)
-    |> Tower.report_exception(stacktrace, plug_conn: conn)
+    exception = Exception.normalize(:error, reason, stacktrace)
+
+    if report?(exception) do
+      Tower.report_exception(exception, stacktrace, plug_conn: conn)
+    end
   end
 
   defp handle_event_metadata(event_metadata) do
@@ -61,4 +67,8 @@ defmodule Tower.BanditExceptionHandler do
 
     :ignored
   end
+
+  defp report?(exception) do
+    Plug.Exception.status(exception) in 500..599
+  end
 end

test/support/phoenix_app/endpoint.ex

@@ -1,5 +1,7 @@
 defmodule Tower.PhoenixApp.Endpoint do
   use Phoenix.Endpoint, otp_app: :phoenix_app
 
-  plug(Tower.TestPlug)
+  # So that it fetches query params
+  plug(Plug.Parsers, parsers: [])
+  plug(Tower.PhoenixApp.Router)
 end

test/support/phoenix_app/error_html.ex

@@ -1,5 +1,5 @@
 defmodule Tower.PhoenixApp.ErrorHTML do
-  def render("500.html", _assigns) do
-    "Internal Server Error"
+  def render(template, _assigns) do
+    Phoenix.Controller.status_message_from_template(template)
   end
 end

test/support/phoenix_app/home_controller.ex

@@ -0,0 +1,25 @@
+defmodule Tower.PhoenixApp.HomeController do
+  use Phoenix.Controller, formats: [:html], put_default_views: false
+
+  def show(conn, %{"param" => "valid"}) do
+    Plug.Conn.send_resp(conn, 200, "Hey!")
+  end
+
+  def runtime_error(conn, _params) do
+    raise "an error"
+
+    Plug.Conn.send_resp(conn, 200, "OK")
+  end
+
+  def abnormal_exit(conn, _params) do
+    exit(:abnormal)
+
+    Plug.Conn.send_resp(conn, 200, "OK")
+  end
+
+  def uncaught_throw(conn, _params) do
+    throw("something")
+
+    Plug.Conn.send_resp(conn, 200, "OK")
+  end
+end

test/support/phoenix_app/router.ex

@@ -0,0 +1,8 @@
+defmodule Tower.PhoenixApp.Router do
+  use Phoenix.Router, helpers: false
+
+  get("/runtime-error", Tower.PhoenixApp.HomeController, :runtime_error)
+  get("/abnormal-exit", Tower.PhoenixApp.HomeController, :abnormal_exit)
+  get("/uncaught-throw", Tower.PhoenixApp.HomeController, :uncaught_throw)
+  get("/show", Tower.PhoenixApp.HomeController, :show)
+end

test/tower/phoenix_test.exs

@@ -5,7 +5,7 @@ defmodule TowerPhoenixTest do
 
   import ExUnit.CaptureLog, only: [capture_log: 1]
 
-  setup do
+  setup context do
     on_exit(fn ->
       Tower.EphemeralReporter.reset()
     end)
@@ -17,7 +17,11 @@ defmodule TowerPhoenixTest do
     Application.put_env(
       :phoenix_app,
       Tower.PhoenixApp.Endpoint,
-      adapter: Bandit.PhoenixAdapter,
+      adapter:
+        case context[:adapter] do
+          :bandit -> Bandit.PhoenixAdapter
+          :cowboy -> Phoenix.Endpoint.Cowboy2Adapter
+        end,
       server: true,
       http: [port: port],
       url: [scheme: "http", port: port, host: host],
@@ -31,6 +35,7 @@ defmodule TowerPhoenixTest do
     %{base_url: "http://#{host}:#{port}"}
   end
 
+  @tag adapter: :bandit
   test "reports runtime error during Phoenix.Endpoint dispatch with Bandit", %{base_url: base_url} do
     url = base_url <> "/runtime-error"
 
@@ -58,6 +63,7 @@ defmodule TowerPhoenixTest do
     assert Plug.Conn.request_url(plug_conn) == url
   end
 
+  @tag adapter: :bandit
   test "reports uncaught throw during Phoenix.Endpoint dispatch with Bandit", %{
     base_url: base_url
   } do
@@ -89,6 +95,7 @@ defmodule TowerPhoenixTest do
     assert [] = stacktrace
   end
 
+  @tag adapter: :bandit
   test "reports abnormal exit during Phoenix.Endpoint dispatch with Bandit", %{base_url: base_url} do
     capture_log(fn ->
       {:ok, {{_, 500, _}, _, _}} = :httpc.request(base_url <> "/abnormal-exit")
@@ -114,6 +121,30 @@ defmodule TowerPhoenixTest do
     assert [_ | _] = stacktrace
   end
 
+  @tag adapter: :cowboy
+  test "doesn't report exceptions that return 4xx status codes with Cowboy", %{base_url: base_url} do
+    # Forcing Phoenix.ActionClauseError
+    url = base_url <> "/show?param=invalid"
+
+    capture_log(fn ->
+      {:ok, {{_, 400, _}, _, _}} = :httpc.request(url)
+    end)
+
+    assert [] = Tower.EphemeralReporter.events()
+  end
+
+  @tag adapter: :bandit
+  test "doesn't report exceptions that return 4xx status codes with Bandit", %{base_url: base_url} do
+    # Forcing Phoenix.ActionClauseError
+    url = base_url <> "/show?param=invalid"
+
+    capture_log(fn ->
+      {:ok, {{_, 400, _}, _, _}} = :httpc.request(url)
+    end)
+
+    assert [] = Tower.EphemeralReporter.events()
+  end
+
   defp recent_datetime?(datetime) do
     diff =
       :logger.timestamp()