Improve try catch syntax (#2263)

* Replace case catch.. with try ... catch
Prior to this change, case catch ... would cost a lot of performance
because it would retrieve the whole stacktrace. However, try...catch
will not retrieve the whole stacktrace. So try...catch syntax is better.

include/logger.hrl

@@ -39,4 +39,3 @@
         begin
           (logger:log(Level,#{},#{report_cb => fun(_) -> {(Format), (Args)} end}))
         end).
-

src/emqx_access_control.erl

@@ -17,6 +17,7 @@
 -behaviour(gen_server).
 
 -include("emqx.hrl").
+-include("logger.hrl").
 
 -export([start_link/0]).
 -export([authenticate/2]).
@@ -68,7 +69,7 @@ authenticate(Credentials, _Password, []) ->
     end;
 
 authenticate(Credentials, Password, [{Mod, State, _Seq} | Mods]) ->
-    case catch Mod:check(Credentials, Password, State) of
+    try Mod:check(Credentials, Password, State) of
         ok -> ok;
         {ok, IsSuper} when is_boolean(IsSuper) ->
             {ok, #{is_superuser => IsSuper}};
@@ -79,9 +80,11 @@ authenticate(Credentials, Password, [{Mod, State, _Seq} | Mods]) ->
         ignore ->
             authenticate(Credentials, Password, Mods);
         {error, Reason} ->
-            {error, Reason};
+            {error, Reason}
-        {'EXIT', Error} ->
+    catch
-            {error, Error}
+        error:Reason:StackTrace ->
+            ?LOG(error, "Authenticate failed. StackTrace: ~p", [StackTrace]),
+            {error, Reason}
     end.
 
 %% @doc Check ACL
@@ -206,4 +209,3 @@ code_change(_OldVsn, State, _Extra) ->
 
 reply(Reply, State) ->
     {reply, Reply, State}.
-

src/emqx_acl_internal.erl

@@ -17,6 +17,7 @@
 -behaviour(emqx_acl_mod).
 
 -include("emqx.hrl").
+-include("logger.hrl").
 
 -export([all_rules/0]).
 
@@ -105,17 +106,18 @@ match(Credentials, Topic, [Rule|Rules]) ->
 
 -spec(reload_acl(state()) -> ok | {error, term()}).
 reload_acl(#{acl_file := AclFile}) ->
-    case catch load_rules_from_file(AclFile) of
+    try load_rules_from_file(AclFile) of
         ok ->
             emqx_logger:info("Reload acl_file ~s successfully", [AclFile]),
             ok;
         {error, Error} ->
-            {error, Error};
-        {'EXIT', Error} ->
             {error, Error}
+    catch
+        error:Reason:StackTrace ->
+            ?LOG(error, "Reload acl failed. StackTrace: ~p", [StackTrace]),
+            {error, Reason}
     end.
 
 -spec(description() -> string()).
 description() ->
     "Internal ACL with etc/acl.conf".
-

src/emqx_bridge.erl

@@ -60,19 +60,21 @@ show_forwards(Name) ->
 
 -spec(add_forward(atom(), binary()) -> ok | {error, already_exists | validate_fail}).
 add_forward(Name, Topic) ->
-    case catch emqx_topic:validate({filter, Topic}) of
+    try emqx_topic:validate({filter, Topic}) of
         true ->
-            gen_server:call(name(Name), {add_forward, Topic});
+            gen_server:call(name(Name), {add_forward, Topic})
-        {'EXIT', _Reason} ->
+    catch
+        _Error:_Reason ->
             {error, validate_fail}
     end.
 
 -spec(del_forward(atom(), binary()) -> ok | {error, validate_fail}).
 del_forward(Name, Topic) ->
-    case catch emqx_topic:validate({filter, Topic}) of
+    try emqx_topic:validate({filter, Topic}) of
         true ->
-            gen_server:call(name(Name), {del_forward, Topic});
+            gen_server:call(name(Name), {del_forward, Topic})
-        _ ->
+    catch
+        _Error:_Reason ->
             {error, validate_fail}
     end.
 
@@ -82,19 +84,21 @@ show_subscriptions(Name) ->
 
 -spec(add_subscription(atom(), binary(), integer()) -> ok | {error, already_exists | validate_fail}).
 add_subscription(Name, Topic, QoS) ->
-    case catch emqx_topic:validate({filter, Topic}) of
+    try emqx_topic:validate({filter, Topic}) of
         true ->
-            gen_server:call(name(Name), {add_subscription, Topic, QoS});
+            gen_server:call(name(Name), {add_subscription, Topic, QoS})
-        {'EXIT', _Reason} ->
+    catch
+        _Error:_Reason ->
             {error, validate_fail}
     end.
 
 -spec(del_subscription(atom(), binary()) -> ok | {error, validate_fail}).
 del_subscription(Name, Topic) ->
-    case catch emqx_topic:validate({filter, Topic}) of
+    try emqx_topic:validate({filter, Topic}) of
         true ->
-            gen_server:call(name(Name), {del_subscription, Topic});
+            gen_server:call(name(Name), {del_subscription, Topic})
-        _ ->
+    catch
+        error:_Reason ->
             {error, validate_fail}
     end.
 

src/emqx_keepalive.erl

@@ -27,21 +27,22 @@
 start(_, 0, _) ->
     {ok, #keepalive{}};
 start(StatFun, TimeoutSec, TimeoutMsg) ->
-    case catch StatFun() of
+    try StatFun() of
         {ok, StatVal} ->
             {ok, #keepalive{statfun = StatFun, statval = StatVal,
                             tsec = TimeoutSec, tmsg = TimeoutMsg,
                             tref = timer(TimeoutSec, TimeoutMsg)}};
         {error, Error} ->
-            {error, Error};
+            {error, Error}
-        {'EXIT', Reason} ->
+    catch
+        _Error:Reason ->
             {error, Reason}
     end.
 
 %% @doc Check keepalive, called when timeout...
 -spec(check(keepalive()) -> {ok, keepalive()} | {error, term()}).
 check(KeepAlive = #keepalive{statfun = StatFun, statval = LastVal, repeat = Repeat}) ->
-    case catch StatFun() of
+    try StatFun() of
         {ok, NewVal} ->
             if NewVal =/= LastVal ->
                     {ok, resume(KeepAlive#keepalive{statval = NewVal, repeat = 0})};
@@ -51,8 +52,9 @@ check(KeepAlive = #keepalive{statfun = StatFun, statval = LastVal, repeat = Repe
                     {error, timeout}
             end;
         {error, Error} ->
-            {error, Error};
+            {error, Error}
-        {'EXIT', Reason} ->
+    catch
+        _Error:Reason ->
             {error, Reason}
     end.
 
@@ -69,4 +71,3 @@ cancel(_) ->
 
 timer(Secs, Msg) ->
     erlang:send_after(timer:seconds(Secs), self(), Msg).
-

src/emqx_mountpoint.erl

@@ -15,6 +15,7 @@
 -module(emqx_mountpoint).
 
 -include("emqx.hrl").
+-include("logger.hrl").
 
 -export([mount/2, unmount/2]).
 -export([replvar/2]).
@@ -33,9 +34,12 @@ mount(MountPoint, TopicFilters) when is_list(TopicFilters) ->
 unmount(undefined, Msg) ->
     Msg;
 unmount(MountPoint, Msg = #message{topic = Topic}) ->
-    case catch split_binary(Topic, byte_size(MountPoint)) of
+    try split_binary(Topic, byte_size(MountPoint)) of
-        {MountPoint, Topic1} -> Msg#message{topic = Topic1};
+        {MountPoint, Topic1} -> Msg#message{topic = Topic1}
-        _Other -> Msg
+    catch
+        _Error:Reason ->
+            ?LOG(error, "Unmount error : ~p", [Reason]),
+            Msg
     end.
 
 replvar(undefined, _Vars) ->
@@ -49,4 +53,3 @@ feed_var({<<"%u">>, undefined}, MountPoint) ->
     MountPoint;
 feed_var({<<"%u">>, Username}, MountPoint) ->
     emqx_topic:feed_var(<<"%u">>, Username, MountPoint).
-

src/emqx_protocol.erl

@@ -245,22 +245,22 @@ received(Packet = ?PACKET(Type), PState) ->
                     process_packet(Packet1, inc_stats(recv, Type, PState2))
             end
     catch
-        error : protocol_error ->
+        error:protocol_error ->
             deliver({disconnect, ?RC_PROTOCOL_ERROR}, PState1),
             {error, protocol_error, PState};
-        error : subscription_identifier_invalid ->
+        error:subscription_identifier_invalid ->
             deliver({disconnect, ?RC_SUBSCRIPTION_IDENTIFIERS_NOT_SUPPORTED}, PState1),
             {error, subscription_identifier_invalid, PState1};
-        error : topic_alias_invalid ->
+        error:topic_alias_invalid ->
             deliver({disconnect, ?RC_TOPIC_ALIAS_INVALID}, PState1),
             {error, topic_alias_invalid, PState1};
-        error : topic_filters_invalid ->
+        error:topic_filters_invalid ->
             deliver({disconnect, ?RC_TOPIC_FILTER_INVALID}, PState1),
             {error, topic_filters_invalid, PState1};
-        error : topic_name_invalid ->
+        error:topic_name_invalid ->
             deliver({disconnect, ?RC_TOPIC_FILTER_INVALID}, PState1),
             {error, topic_filters_invalid, PState1};
-        error : Reason ->
+        error:Reason ->
             deliver({disconnect, ?RC_MALFORMED_PACKET}, PState1),
             {error, Reason, PState1}
     end.
@@ -974,4 +974,3 @@ reason_codes_compat(unsuback, _ReasonCodes, _ProtoVer) ->
     undefined;
 reason_codes_compat(PktType, ReasonCodes, _ProtoVer) ->
     [emqx_reason_codes:compat(PktType, RC) || RC <- ReasonCodes].
-

src/emqx_vm.erl

@@ -354,21 +354,29 @@ port_info(PortTerm, specific) ->
                 {_, Type} when Type =:= "udp_inet";
                        Type =:= "tcp_inet";
                        Type =:= "sctp_inet" ->
-                    case catch inet:getstat(Port) of
+                    try inet:getstat(Port) of
                         {ok, Stats} -> [{statistics, Stats}];
-                        _           -> []
-                    end ++
-                    case catch inet:peername(Port) of
-                        {ok, Peer} -> [{peername, Peer}];
                         {error, _} -> []
+                    catch
+                        _Error:_Reason -> []
                     end ++
-                    case catch inet:sockname(Port) of
+                    try inet:peername(Port) of
+                        {ok, Peer} -> [{peername, Peer}];
+                        _ -> []
+                    catch
+                        _Error:_Reason -> []
+                    end ++
+                    try inet:sockname(Port) of
                         {ok, Local} -> [{sockname, Local}];
                         {error, _}  -> []
+                    catch
+                        _Error:_Reason -> []
                     end ++
-                    case catch inet:getopts(Port, ?SOCKET_OPTS ) of
+                    try inet:getopts(Port, ?SOCKET_OPTS ) of
                         {ok, Opts} -> [{options, Opts}];
                         {error, _} -> []
+                    catch
+                        _Error:_Reason -> []
                     end;
                 {_, "efile"} ->
                     [];