From 9ba938b9d9208e6beada92e73c1314a0f3b2c544 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E5=A5=87=E6=80=AA?= <zhanghongtong@foxmail.com>
Date: Sat, 11 Apr 2020 10:18:35 +0800
Subject: [PATCH] EMQX failed to start when the listening port was occupied
 (#3354)

---
 src/emqx_listeners.erl        | 11 +++++------
 test/emqx_listeners_SUITE.erl |  5 +++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/emqx_listeners.erl b/src/emqx_listeners.erl
index 948c8e8d5..ce256d147 100644
--- a/src/emqx_listeners.erl
+++ b/src/emqx_listeners.erl
@@ -44,17 +44,16 @@
 start() ->
     lists:foreach(fun start_listener/1, emqx:get_env(listeners, [])).
 
--spec(start_listener(listener()) -> {ok, pid()} | {error, term()}).
+-spec(start_listener(listener()) -> ok).
 start_listener({Proto, ListenOn, Options}) ->
-    StartRet = start_listener(Proto, ListenOn, Options),
-    case StartRet of
+    case start_listener(Proto, ListenOn, Options) of
         {ok, _} -> io:format("Start mqtt:~s listener on ~s successfully.~n",
                              [Proto, format(ListenOn)]);
         {error, Reason} ->
             io:format(standard_error, "Failed to start mqtt:~s listener on ~s - ~0p~n!",
-                      [Proto, format(ListenOn), Reason])
-    end,
-    StartRet.
+                      [Proto, format(ListenOn), Reason]),
+            error(Reason)
+    end.
 
 %% Start MQTT/TCP listener
 -spec(start_listener(esockd:proto(), esockd:listen_on(), [esockd:option()])
diff --git a/test/emqx_listeners_SUITE.erl b/test/emqx_listeners_SUITE.erl
index bc09a26bb..3bf53e683 100644
--- a/test/emqx_listeners_SUITE.erl
+++ b/test/emqx_listeners_SUITE.erl
@@ -21,6 +21,7 @@
 
 -include("emqx.hrl").
 -include("emqx_mqtt.hrl").
+-include_lib("eunit/include/eunit.hrl").
 
 all() -> emqx_ct:all(?MODULE).
 
@@ -37,7 +38,7 @@ end_per_suite(_Config) ->
 
 t_start_stop_listeners(_) ->
     ok = emqx_listeners:start(),
-    {error, _} = emqx_listeners:start_listener({ws,{"127.0.0.1", 8083}, []}),
+    ?assertException(error, _, emqx_listeners:start_listener({ws,{"127.0.0.1", 8083}, []})),
     ok = emqx_listeners:stop().
 
 t_restart_listeners(_) ->
@@ -90,4 +91,4 @@ get_base_dir(Module) ->
 
 get_base_dir() ->
     get_base_dir(?MODULE).
-    
\ No newline at end of file
+