fix(event-stream): close immediately if CheckForShutdown is not running

apps/api_web/lib/api_web/event_stream.ex

@@ -27,18 +27,23 @@ defmodule ApiWeb.EventStream do
 
   @spec initialize(Plug.Conn.t(), module) :: state
   def initialize(conn, module, timeout \\ 30_000) do
-    {:ok, pid} = Supervisor.server_subscribe(conn, module)
-    Logger.debug("#{__MODULE__} connected self=#{inspect(self())} server=#{inspect(pid)}")
-    Process.monitor(pid)
-
     conn =
       conn
       |> put_resp_header("content-type", "text/event-stream")
       # prevent nginx from buffering the stream
       |> put_resp_header("x-accel-buffering", "no")
       |> send_chunked(200)
 
-    ensure_timer(%__MODULE__{conn: conn, pid: pid, timeout: timeout})
+    if CheckForShutdown.running?() do
+      {:ok, pid} = Supervisor.server_subscribe(conn, module)
+      Logger.debug("#{__MODULE__} connected self=#{inspect(self())} server=#{inspect(pid)}")
+      Process.monitor(pid)
+
+      ensure_timer(%__MODULE__{conn: conn, pid: pid, timeout: timeout})
+    else
+      send(self(), {:close, conn})
+      %__MODULE__{conn: conn, pid: nil, timeout: timeout}
+    end
   end
 
   @spec hibernate_loop(state) :: Plug.Conn.t()

apps/api_web/test/api_web/event_stream_test.exs

@@ -136,29 +136,23 @@ defmodule ApiWeb.EventStreamTest do
       on_exit(fn -> assert_stopped(state.pid) end)
     end
 
-    test "closes the connection once CheckForShutdown.shutdown() is called (events)", %{
+    test "closes immediately if CheckForShutdown is not running", %{
       conn: conn
     } do
       CheckForShutdown.shutdown()
 
       state = initialize(conn, @module)
-      assert_receive_data()
-
-      send(self(), {:events, []})
-
       assert {:close, conn} = receive_result(state)
 
       assert chunks(conn) == ""
-      on_exit(fn -> assert_stopped(state.pid) end)
     end
 
     test "closes the connection once CheckForShutdown.shutdown() is called (timeout)", %{
       conn: conn
     } do
-      CheckForShutdown.shutdown()
-
       state = initialize(conn, @module)
       assert_receive_data()
+      CheckForShutdown.shutdown()
 
       send(self(), :timeout)
 
@@ -171,10 +165,9 @@ defmodule ApiWeb.EventStreamTest do
     test "closes the connection once CheckForShutdown.shutdown() is called (unknown message)", %{
       conn: conn
     } do
-      CheckForShutdown.shutdown()
-
       state = initialize(conn, @module)
       assert_receive_data()
+      CheckForShutdown.shutdown()
 
       send(self(), :unknown_message)