diff --git a/apps/emqx/include/logger.hrl b/apps/emqx/include/logger.hrl
index 42d598ef9..ddd4349bb 100644
--- a/apps/emqx/include/logger.hrl
+++ b/apps/emqx/include/logger.hrl
@@ -59,15 +59,19 @@
 
 %% structured logging
 -define(SLOG(Level, Data),
-        %% check 'allow' here, only evaluate Data when necessary
-        case logger:allow(Level, ?MODULE) of
-            true ->
-                logger:log(Level, (Data), #{ mfa => {?MODULE, ?FUNCTION_NAME, ?FUNCTION_ARITY}
-                                           , line => ?LINE
-                                           });
-            false ->
-                ok
-        end).
+        ?SLOG(Level, Data, #{})).
+
+%% structured logging, meta is for handler's filter.
+-define(SLOG(Level, Data, Meta),
+%% check 'allow' here, only evaluate Data when necessary
+    case logger:allow(Level, ?MODULE) of
+        true ->
+            logger:log(Level, (Data), Meta#{ mfa => {?MODULE, ?FUNCTION_NAME, ?FUNCTION_ARITY}
+                , line => ?LINE
+            });
+        false ->
+            ok
+    end).
 
 -define(TRACE(Event, Msg, Meta), emqx_trace:log(Event, Msg, Meta)).
 
diff --git a/apps/emqx/src/emqx_authentication_config.erl b/apps/emqx/src/emqx_authentication_config.erl
index 795dd060e..9767a2265 100644
--- a/apps/emqx/src/emqx_authentication_config.erl
+++ b/apps/emqx/src/emqx_authentication_config.erl
@@ -187,7 +187,7 @@ convert_certs(CertsDir, Config) ->
         {ok, SSL} ->
             new_ssl_config(Config, SSL);
         {error, Reason} ->
-            ?SLOG(error, Reason#{msg => bad_ssl_config}),
+            ?SLOG(error, Reason#{msg => "bad_ssl_config"}),
             throw({bad_ssl_config, Reason})
     end.
 
@@ -199,7 +199,7 @@ convert_certs(CertsDir, NewConfig, OldConfig) ->
             ok = emqx_tls_lib:delete_ssl_files(CertsDir, NewSSL1, OldSSL),
             new_ssl_config(NewConfig, NewSSL1);
         {error, Reason} ->
-            ?SLOG(error, Reason#{msg => bad_ssl_config}),
+            ?SLOG(error, Reason#{msg => "bad_ssl_config"}),
             throw({bad_ssl_config, Reason})
     end.
 
diff --git a/apps/emqx/src/emqx_broker.erl b/apps/emqx/src/emqx_broker.erl
index dec753fc2..4085b6130 100644
--- a/apps/emqx/src/emqx_broker.erl
+++ b/apps/emqx/src/emqx_broker.erl
@@ -204,8 +204,9 @@ publish(Msg) when is_record(Msg, message) ->
     _ = emqx_trace:publish(Msg),
     emqx_message:is_sys(Msg) orelse emqx_metrics:inc('messages.publish'),
     case emqx_hooks:run_fold('message.publish', [], emqx_message:clean_dup(Msg)) of
-        #message{headers = #{allow_publish := false}} ->
-            ?TRACE("MQTT", "msg_publish_not_allowed", #{message => emqx_message:to_log_map(Msg)}),
+        #message{headers = #{allow_publish := false}, topic = Topic} ->
+            Message = emqx_message:to_log_map(Msg),
+            ?TRACE("MQTT", "msg_publish_not_allowed", #{message => Message, topic => Topic}),
             [];
         Msg1 = #message{topic = Topic} ->
             emqx_persistent_session:persist_message(Msg1),
@@ -225,7 +226,9 @@ safe_publish(Msg) when is_record(Msg, message) ->
                 reason => Reason,
                 payload => emqx_message:to_log_map(Msg),
                 stacktrace => Stk
-            }),
+            },
+                #{topic => Msg#message.topic}
+            ),
             []
     end.
 
@@ -279,7 +282,7 @@ forward(Node, To, Delivery, async) ->
                 msg => "async_forward_msg_to_node_failed",
                 node => Node,
                 reason => Reason
-            }),
+            }, #{topic => To}),
             {error, badrpc}
     end;
 
@@ -290,7 +293,7 @@ forward(Node, To, Delivery, sync) ->
                 msg => "sync_forward_msg_to_node_failed",
                 node => Node,
                 reason => Reason
-            }),
+            }, #{topic => To}),
             {error, badrpc};
         Result ->
             emqx_metrics:inc('messages.forward'), Result
diff --git a/apps/emqx/src/emqx_channel.erl b/apps/emqx/src/emqx_channel.erl
index 0f83b04ff..d0cb07a68 100644
--- a/apps/emqx/src/emqx_channel.erl
+++ b/apps/emqx/src/emqx_channel.erl
@@ -552,7 +552,7 @@ process_publish(Packet = ?PUBLISH_PACKET(QoS, Topic, PacketId), Channel) ->
                 msg => "cannot_publish_to_topic",
                 topic => Topic,
                 reason => emqx_reason_codes:name(Rc)
-            }),
+            }, #{topic => Topic}),
             case emqx:get_config([authorization, deny_action], ignore) of
                 ignore ->
                     case QoS of
@@ -570,7 +570,7 @@ process_publish(Packet = ?PUBLISH_PACKET(QoS, Topic, PacketId), Channel) ->
                 msg => "cannot_publish_to_topic",
                 topic => Topic,
                 reason => emqx_reason_codes:name(Rc)
-            }),
+            }, #{topic => Topic}),
             case QoS of
                 ?QOS_0 ->
                     ok = emqx_metrics:inc('packets.publish.dropped'),
@@ -585,7 +585,7 @@ process_publish(Packet = ?PUBLISH_PACKET(QoS, Topic, PacketId), Channel) ->
                 msg => "cannot_publish_to_topic",
                 topic => Topic,
                 reason => emqx_reason_codes:name(Rc)
-            }),
+            }, #{topic => Topic}),
             handle_out(disconnect, Rc, NChannel)
     end.
 
@@ -635,7 +635,7 @@ do_publish(PacketId, Msg = #message{qos = ?QOS_2},
                 msg => "dropped_qos2_packet",
                 reason => emqx_reason_codes:name(RC),
                 packet_id => PacketId
-            }),
+            }, #{topic => Msg#message.topic}),
             ok = emqx_metrics:inc('packets.publish.dropped'),
             handle_out(pubrec, {PacketId, RC}, Channel)
     end.
@@ -687,7 +687,7 @@ process_subscribe([Topic = {TopicFilter, SubOpts} | More], SubProps, Channel, Ac
             ?SLOG(warning, #{
                 msg => "cannot_subscribe_topic_filter",
                 reason => emqx_reason_codes:name(ReasonCode)
-            }),
+            }, #{topic => TopicFilter}),
             process_subscribe(More, SubProps, Channel, [{Topic, ReasonCode} | Acc])
     end.
 
@@ -703,7 +703,7 @@ do_subscribe(TopicFilter, SubOpts = #{qos := QoS}, Channel =
             ?SLOG(warning, #{
                 msg => "cannot_subscribe_topic_filter",
                 reason => emqx_reason_codes:text(RC)
-            }),
+            }, #{topic => NTopicFilter}),
             {RC, Channel}
     end.
 
diff --git a/apps/emqx/src/emqx_cm.erl b/apps/emqx/src/emqx_cm.erl
index 162cff2e0..c44cfe15e 100644
--- a/apps/emqx/src/emqx_cm.erl
+++ b/apps/emqx/src/emqx_cm.erl
@@ -448,20 +448,23 @@ kick_session(Action, ClientId, ChanPid) ->
                           , action => Action
                           , error => Error
                           , reason => Reason
-                          })
+                          },
+                #{clientid => unicode:characters_to_list(ClientId, utf8)})
     end.
 
 kick_session(ClientId) ->
     case lookup_channels(ClientId) of
         [] ->
             ?SLOG(warning, #{msg => "kicked_an_unknown_session",
-                             clientid => ClientId}),
+                             clientid => ClientId},
+                #{clientid => unicode:characters_to_list(ClientId, utf8)}),
             ok;
         ChanPids ->
             case length(ChanPids) > 1 of
                 true ->
                     ?SLOG(warning, #{msg => "more_than_one_channel_found",
-                                     chan_pids => ChanPids});
+                                     chan_pids => ChanPids},
+                        #{clientid => unicode:characters_to_list(ClientId, utf8)});
                 false -> ok
             end,
             lists:foreach(fun(Pid) -> kick_session(ClientId, Pid) end, ChanPids)
diff --git a/apps/emqx/src/emqx_config.erl b/apps/emqx/src/emqx_config.erl
index f3e6e1366..35a6c048e 100644
--- a/apps/emqx/src/emqx_config.erl
+++ b/apps/emqx/src/emqx_config.erl
@@ -262,7 +262,7 @@ init_load(SchemaMod, Conf) when is_list(Conf) orelse is_binary(Conf) ->
         {ok, RawRichConf} ->
             init_load(SchemaMod, RawRichConf);
         {error, Reason} ->
-            ?SLOG(error, #{msg => failed_to_load_hocon_conf,
+            ?SLOG(error, #{msg => "failed_to_load_hocon_conf",
                            reason => Reason,
                            include_dirs => IncDir
                           }),
@@ -396,7 +396,7 @@ save_to_override_conf(RawConf, Opts) ->
             case file:write_file(FileName, hocon_pp:do(RawConf, #{})) of
                 ok -> ok;
                 {error, Reason} ->
-                    ?SLOG(error, #{msg => failed_to_write_override_file,
+                    ?SLOG(error, #{msg => "failed_to_write_override_file",
                                    filename => FileName,
                                    reason => Reason}),
                     {error, Reason}
diff --git a/apps/emqx/src/emqx_connection.erl b/apps/emqx/src/emqx_connection.erl
index 37e15f522..e1dab3260 100644
--- a/apps/emqx/src/emqx_connection.erl
+++ b/apps/emqx/src/emqx_connection.erl
@@ -872,7 +872,7 @@ check_limiter(Needs,
                 {ok, Limiter2} ->
                     WhenOk(Data, Msgs, State#state{limiter = Limiter2});
                 {pause, Time, Limiter2} ->
-                    ?SLOG(warning, #{msg => "pause time dueto rate limit",
+                    ?SLOG(warning, #{msg => "pause_time_dueto_rate_limit",
                                      needs => Needs,
                                      time_in_ms => Time}),
 
@@ -912,7 +912,7 @@ retry_limiter(#state{limiter = Limiter} = State) ->
                                 , limiter_timer = undefined
                                 });
             {pause, Time, Limiter2} ->
-                ?SLOG(warning, #{msg => "pause time dueto rate limit",
+                ?SLOG(warning, #{msg => "pause_time_dueto_rate_limit",
                                  types => Types,
                                  time_in_ms => Time}),
 
diff --git a/apps/emqx/src/emqx_flapping.erl b/apps/emqx/src/emqx_flapping.erl
index 600144adc..cb3da361a 100644
--- a/apps/emqx/src/emqx_flapping.erl
+++ b/apps/emqx/src/emqx_flapping.erl
@@ -122,7 +122,7 @@ handle_cast({detected, #flapping{clientid   = ClientId,
                 peer_host => fmt_host(PeerHost),
                 detect_cnt => DetectCnt,
                 wind_time_in_ms => WindTime
-            }),
+            }, #{clientid => unicode:characters_to_list(ClientId, utf8)}),
             Now = erlang:system_time(second),
             Banned = #banned{who    = {clientid, ClientId},
                              by     = <<"flapping detector">>,
@@ -138,7 +138,7 @@ handle_cast({detected, #flapping{clientid   = ClientId,
                 peer_host => fmt_host(PeerHost),
                 detect_cnt => DetectCnt,
                 interval => Interval
-            })
+            }, #{clientid => unicode:characters_to_list(ClientId, utf8)})
     end,
     {noreply, State};
 
diff --git a/apps/emqx/src/emqx_session.erl b/apps/emqx/src/emqx_session.erl
index bf79085af..1695ed6ce 100644
--- a/apps/emqx/src/emqx_session.erl
+++ b/apps/emqx/src/emqx_session.erl
@@ -535,16 +535,20 @@ enqueue(Msg, Session = #session{mqueue = Q}) when is_record(Msg, message) ->
     (Dropped =/= undefined) andalso log_dropped(Dropped, Session),
     Session#session{mqueue = NewQ}.
 
-log_dropped(Msg = #message{qos = QoS}, #session{mqueue = Q}) ->
-    case (QoS == ?QOS_0) andalso (not emqx_mqueue:info(store_qos0, Q)) of
+log_dropped(Msg = #message{qos = QoS, topic = Topic}, #session{mqueue = Q}) ->
+    Payload = emqx_message:to_log_map(Msg),
+     #{store_qos0 := StoreQos0} = QueueInfo = emqx_mqueue:info(Q),
+    case (QoS == ?QOS_0) andalso (not StoreQos0) of
         true  ->
             ok = emqx_metrics:inc('delivery.dropped.qos0_msg'),
             ?SLOG(warning, #{msg => "dropped_qos0_msg",
-                             payload => emqx_message:to_log_map(Msg)});
+                             queue => QueueInfo,
+                             payload => Payload}, #{topic => Topic});
         false ->
             ok = emqx_metrics:inc('delivery.dropped.queue_full'),
             ?SLOG(warning, #{msg => "dropped_msg_due_to_mqueue_is_full",
-                             payload => emqx_message:to_log_map(Msg)})
+                             queue => QueueInfo,
+                             payload => Payload}, #{topic => Topic})
     end.
 
 enrich_fun(Session = #session{subscriptions = Subs}) ->
diff --git a/apps/emqx/src/emqx_session_router.erl b/apps/emqx/src/emqx_session_router.erl
index aaaedcb12..3d3722c32 100644
--- a/apps/emqx/src/emqx_session_router.erl
+++ b/apps/emqx/src/emqx_session_router.erl
@@ -260,7 +260,7 @@ code_change(_OldVsn, State, _Extra) ->
 init_resume_worker(RemotePid, SessionID, #{ pmon := Pmon } = State) ->
     case emqx_session_router_worker_sup:start_worker(SessionID, RemotePid) of
         {error, What} ->
-            ?SLOG(error, #{msg => "Could not start resume worker", reason => What}),
+            ?SLOG(error, #{msg => "failed_to_start_resume_worker", reason => What}),
             error;
         {ok, Pid} ->
             Pmon1 = emqx_pmon:monitor(Pid, Pmon),
diff --git a/apps/emqx/src/emqx_trace/emqx_trace.erl b/apps/emqx/src/emqx_trace/emqx_trace.erl
index 67542a2bf..3869d300d 100644
--- a/apps/emqx/src/emqx_trace/emqx_trace.erl
+++ b/apps/emqx/src/emqx_trace/emqx_trace.erl
@@ -98,7 +98,11 @@ log(Event, Msg, Meta0) ->
     case persistent_term:get(?TRACE_FILTER, undefined) of
         undefined -> ok;
         List ->
-            Meta = maps:merge(logger:get_process_metadata(), Meta0),
+            Meta =
+                case logger:get_process_metadata() of
+                    undefined -> Meta0;
+                    ProcMeta -> maps:merge(ProcMeta, Meta0)
+                end,
             Log = #{level => trace, event => Event, meta => Meta, msg => Msg},
             log_filter(List, Log)
     end.
diff --git a/apps/emqx/src/emqx_ws_connection.erl b/apps/emqx/src/emqx_ws_connection.erl
index f70d7ac6c..e2bdf6c72 100644
--- a/apps/emqx/src/emqx_ws_connection.erl
+++ b/apps/emqx/src/emqx_ws_connection.erl
@@ -549,7 +549,7 @@ check_limiter(Needs,
                 {ok, Limiter2} ->
                     WhenOk(Data, Msgs, State#state{limiter = Limiter2});
                 {pause, Time, Limiter2} ->
-                    ?SLOG(warning, #{msg => "pause time dueto rate limit",
+                    ?SLOG(warning, #{msg => "pause_time_due_to_rate_limit",
                                      needs => Needs,
                                      time_in_ms => Time}),
 
@@ -585,7 +585,7 @@ retry_limiter(#state{limiter = Limiter} = State) ->
                             , limiter_timer = undefined
                             });
         {pause, Time, Limiter2} ->
-            ?SLOG(warning, #{msg => "pause time dueto rate limit",
+            ?SLOG(warning, #{msg => "pause_time_due_to_rate_limit",
                              types => Types,
                              time_in_ms => Time}),
 
diff --git a/apps/emqx_authn/test/emqx_authn_api_SUITE.erl b/apps/emqx_authn/test/emqx_authn_api_SUITE.erl
index 885811fec..820eeb859 100644
--- a/apps/emqx_authn/test/emqx_authn_api_SUITE.erl
+++ b/apps/emqx_authn/test/emqx_authn_api_SUITE.erl
@@ -43,7 +43,6 @@ groups() ->
     [].
 
 init_per_testcase(_, Config) ->
-    {ok, _} = emqx_cluster_rpc:start_link(node(), emqx_cluster_rpc, 1000),
     emqx_authn_test_lib:delete_authenticators(
       [?CONF_NS_ATOM],
       ?GLOBAL),
@@ -56,9 +55,8 @@ init_per_testcase(_, Config) ->
     Config.
 
 init_per_suite(Config) ->
-    _ = application:load(emqx_conf),
     ok = emqx_common_test_helpers:start_apps(
-           [emqx_authn, emqx_dashboard],
+           [emqx_conf, emqx_authn, emqx_dashboard],
            fun set_special_configs/1),
 
     ?AUTHN:delete_chain(?GLOBAL),
diff --git a/apps/emqx_bridge/src/emqx_bridge.erl b/apps/emqx_bridge/src/emqx_bridge.erl
index d4fc3df2d..a6681d3f1 100644
--- a/apps/emqx_bridge/src/emqx_bridge.erl
+++ b/apps/emqx_bridge/src/emqx_bridge.erl
@@ -214,7 +214,7 @@ update(Type, Name, {OldConf, Conf}) ->
             case recreate(Type, Name, Conf) of
                 {ok, _} -> maybe_disable_bridge(Type, Name, Conf);
                 {error, not_found} ->
-                    ?SLOG(warning, #{ msg => "updating a non-exist bridge, create a new one"
+                    ?SLOG(warning, #{ msg => "updating_a_non-exist_bridge_need_create_a_new_one"
                                     , type => Type, name => Name, config => Conf}),
                     create(Type, Name, Conf);
                 {error, Reason} -> {update_bridge_failed, Reason}
@@ -242,7 +242,7 @@ create_dry_run(Type, Conf) ->
     end.
 
 remove(Type, Name, _Conf) ->
-    ?SLOG(info, #{msg => "remove bridge", type => Type, name => Name}),
+    ?SLOG(info, #{msg => "remove_bridge", type => Type, name => Name}),
     case emqx_resource:remove_local(resource_id(Type, Name)) of
         ok -> ok;
         {error, not_found} -> ok;
diff --git a/apps/emqx_conf/src/emqx_cluster_rpc.erl b/apps/emqx_conf/src/emqx_cluster_rpc.erl
index 7ebe7645b..514b9156a 100644
--- a/apps/emqx_conf/src/emqx_cluster_rpc.erl
+++ b/apps/emqx_conf/src/emqx_cluster_rpc.erl
@@ -236,7 +236,7 @@ catch_up(#{node := Node, retry_interval := RetryMs} = State, SkipResult) ->
                 false -> RetryMs
             end;
         {aborted, Reason} ->
-            ?SLOG(error, #{msg => "read_next_mfa transaction failed", error => Reason}),
+            ?SLOG(error, #{msg => "read_next_mfa_transaction_failed", error => Reason}),
             RetryMs
     end.
 
@@ -248,7 +248,7 @@ read_next_mfa(Node) ->
                 TnxId = max(LatestId - 1, 0),
                 commit(Node, TnxId),
                 ?SLOG(notice, #{
-                    msg => "New node first catch up and start commit.",
+                    msg => "new_node_first_catch_up_and_start_commit.",
                     node => Node, tnx_id => TnxId}),
                 TnxId;
             [#cluster_rpc_commit{tnx_id = LastAppliedID}] -> LastAppliedID + 1
@@ -277,7 +277,7 @@ do_catch_up(ToTnxId, Node) ->
                 io_lib:format("~p catch up failed by LastAppliedId(~p) > ToTnxId(~p)",
                 [Node, LastAppliedId, ToTnxId])),
             ?SLOG(error, #{
-                msg => "catch up failed!",
+                msg => "catch_up_failed!",
                 last_applied_id => LastAppliedId,
                 to_tnx_id => ToTnxId
             }),
diff --git a/apps/emqx_conf/src/emqx_conf.erl b/apps/emqx_conf/src/emqx_conf.erl
index dec07f35c..b8a8c211d 100644
--- a/apps/emqx_conf/src/emqx_conf.erl
+++ b/apps/emqx_conf/src/emqx_conf.erl
@@ -144,7 +144,7 @@ multicall(M, F, Args) ->
         {retry, TnxId, Res, Nodes} ->
             %% The init MFA return ok, but other nodes failed.
             %% We return ok and alert an alarm.
-            ?SLOG(error, #{msg => "failed to update config in cluster", nodes => Nodes,
+            ?SLOG(error, #{msg => "failed_to_update_config_in_cluster", nodes => Nodes,
                 tnx_id => TnxId, mfa => {M, F, Args}}),
             Res;
         {error, Error} -> %% all MFA return not ok or {ok, term()}.
diff --git a/apps/emqx_connector/src/emqx_connector_http.erl b/apps/emqx_connector/src/emqx_connector_http.erl
index 7d7771503..f597a5c1d 100644
--- a/apps/emqx_connector/src/emqx_connector_http.erl
+++ b/apps/emqx_connector/src/emqx_connector_http.erl
@@ -143,7 +143,7 @@ on_start(InstId, #{base_url := #{scheme := Scheme,
                    retry_interval := RetryInterval,
                    pool_type := PoolType,
                    pool_size := PoolSize} = Config) ->
-    ?SLOG(info, #{msg => "starting http connector",
+    ?SLOG(info, #{msg => "starting_http_connector",
                   connector => InstId, config => Config}),
     {Transport, TransportOpts} = case Scheme of
                                      http ->
@@ -181,13 +181,13 @@ on_start(InstId, #{base_url := #{scheme := Scheme,
     end.
 
 on_stop(InstId, #{pool_name := PoolName}) ->
-    ?SLOG(info, #{msg => "stopping http connector",
+    ?SLOG(info, #{msg => "stopping_http_connector",
                   connector => InstId}),
     ehttpc_sup:stop_pool(PoolName).
 
 on_query(InstId, {send_message, Msg}, AfterQuery, State) ->
     case maps:get(request, State, undefined) of
-        undefined -> ?SLOG(error, #{msg => "request not found", connector => InstId});
+        undefined -> ?SLOG(error, #{msg => "request_not_found", connector => InstId});
         Request ->
             #{method := Method, path := Path, body := Body, headers := Headers,
               request_timeout := Timeout} = process_request(Request, Msg),
@@ -207,7 +207,7 @@ on_query(InstId, {KeyOrNum, Method, Request, Timeout}, AfterQuery,
                                      _ -> {PoolName, KeyOrNum}
                                  end, Method, NRequest, Timeout) of
         {error, Reason} ->
-            ?SLOG(error, #{msg => "http connector do reqeust failed",
+            ?SLOG(error, #{msg => "http_connector_do_reqeust_failed",
                            request => NRequest, reason => Reason,
                            connector => InstId}),
             emqx_resource:query_failed(AfterQuery);
diff --git a/apps/emqx_connector/src/emqx_connector_ldap.erl b/apps/emqx_connector/src/emqx_connector_ldap.erl
index 97e963f18..c188837ba 100644
--- a/apps/emqx_connector/src/emqx_connector_ldap.erl
+++ b/apps/emqx_connector/src/emqx_connector_ldap.erl
@@ -55,7 +55,7 @@ on_start(InstId, #{servers := Servers0,
                    pool_size := PoolSize,
                    auto_reconnect := AutoReconn,
                    ssl := SSL} = Config) ->
-    ?SLOG(info, #{msg => "starting ldap connector",
+    ?SLOG(info, #{msg => "starting_ldap_connector",
                   connector => InstId, config => Config}),
     Servers = [begin proplists:get_value(host, S) end || S <- Servers0],
     SslOpts = case maps:get(enable, SSL) of
@@ -81,7 +81,7 @@ on_start(InstId, #{servers := Servers0,
     {ok, #{poolname => PoolName}}.
 
 on_stop(InstId, #{poolname := PoolName}) ->
-    ?SLOG(info, #{msg => "stopping ldap connector",
+    ?SLOG(info, #{msg => "stopping_ldap_connector",
                   connector => InstId}),
     emqx_plugin_libs_pool:stop_pool(PoolName).
 
diff --git a/apps/emqx_connector/src/emqx_connector_mongo.erl b/apps/emqx_connector/src/emqx_connector_mongo.erl
index eacb3ec2d..5321ea459 100644
--- a/apps/emqx_connector/src/emqx_connector_mongo.erl
+++ b/apps/emqx_connector/src/emqx_connector_mongo.erl
@@ -128,7 +128,7 @@ on_start(InstId, Config = #{mongo_type := Type,
     {ok, #{poolname => PoolName, type => Type}}.
 
 on_stop(InstId, #{poolname := PoolName}) ->
-    ?SLOG(info, #{msg => "stopping mongodb connector",
+    ?SLOG(info, #{msg => "stopping_mongodb_connector",
                   connector => InstId}),
     emqx_plugin_libs_pool:stop_pool(PoolName).
 
diff --git a/apps/emqx_connector/src/emqx_connector_mysql.erl b/apps/emqx_connector/src/emqx_connector_mysql.erl
index ae8239936..265a6a01e 100644
--- a/apps/emqx_connector/src/emqx_connector_mysql.erl
+++ b/apps/emqx_connector/src/emqx_connector_mysql.erl
@@ -56,7 +56,7 @@ on_start(InstId, #{server := {Host, Port},
                    auto_reconnect := AutoReconn,
                    pool_size := PoolSize,
                    ssl := SSL } = Config) ->
-    ?SLOG(info, #{msg => "starting mysql connector",
+    ?SLOG(info, #{msg => "starting_mysql_connector",
                   connector => InstId, config => Config}),
     SslOpts = case maps:get(enable, SSL) of
         true ->
@@ -76,7 +76,7 @@ on_start(InstId, #{server := {Host, Port},
     {ok, #{poolname => PoolName}}.
 
 on_stop(InstId, #{poolname := PoolName}) ->
-    ?SLOG(info, #{msg => "stopping mysql connector",
+    ?SLOG(info, #{msg => "stopping_mysql_connector",
                   connector => InstId}),
     emqx_plugin_libs_pool:stop_pool(PoolName).
 
diff --git a/apps/emqx_connector/src/emqx_connector_pgsql.erl b/apps/emqx_connector/src/emqx_connector_pgsql.erl
index 9b6f559b4..36bff3386 100644
--- a/apps/emqx_connector/src/emqx_connector_pgsql.erl
+++ b/apps/emqx_connector/src/emqx_connector_pgsql.erl
@@ -56,7 +56,7 @@ on_start(InstId, #{server := {Host, Port},
                    auto_reconnect := AutoReconn,
                    pool_size := PoolSize,
                    ssl := SSL } = Config) ->
-    ?SLOG(info, #{msg => "starting postgresql connector",
+    ?SLOG(info, #{msg => "starting_postgresql_connector",
                   connector => InstId, config => Config}),
     SslOpts = case maps:get(enable, SSL) of
         true ->
diff --git a/apps/emqx_connector/src/emqx_connector_redis.erl b/apps/emqx_connector/src/emqx_connector_redis.erl
index 94f4eca3e..48001ca25 100644
--- a/apps/emqx_connector/src/emqx_connector_redis.erl
+++ b/apps/emqx_connector/src/emqx_connector_redis.erl
@@ -87,7 +87,7 @@ on_start(InstId, #{redis_type := Type,
                    pool_size := PoolSize,
                    auto_reconnect := AutoReconn,
                    ssl := SSL } = Config) ->
-    ?SLOG(info, #{msg => "starting redis connector",
+    ?SLOG(info, #{msg => "starting_redis_connector",
                   connector => InstId, config => Config}),
     Servers = case Type of
                 single -> [{servers, [maps:get(server, Config)]}];
@@ -120,7 +120,7 @@ on_start(InstId, #{redis_type := Type,
     {ok, #{poolname => PoolName, type => Type}}.
 
 on_stop(InstId, #{poolname := PoolName}) ->
-    ?SLOG(info, #{msg => "stopping redis connector",
+    ?SLOG(info, #{msg => "stopping_redis_connector",
                   connector => InstId}),
     emqx_plugin_libs_pool:stop_pool(PoolName).
 
diff --git a/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_mod.erl b/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_mod.erl
index 7d5bb1283..3ab410391 100644
--- a/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_mod.erl
+++ b/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_mod.erl
@@ -158,15 +158,15 @@ handle_puback(#{packet_id := PktId, reason_code := RC}, Parent)
        RC =:= ?RC_NO_MATCHING_SUBSCRIBERS ->
     Parent ! {batch_ack, PktId}, ok;
 handle_puback(#{packet_id := PktId, reason_code := RC}, _Parent) ->
-    ?SLOG(warning, #{msg => "publish to remote node falied",
+    ?SLOG(warning, #{msg => "publish_to_remote_node_falied",
         packet_id => PktId, reason_code => RC}).
 
 handle_publish(Msg, undefined) ->
-    ?SLOG(error, #{msg => "cannot publish to local broker as"
-                          " 'ingress' is not configured",
+    ?SLOG(error, #{msg => "cannot_publish_to_local_broker_as"
+                          "_'ingress'_is_not_configured",
                    message => Msg});
 handle_publish(Msg, Vars) ->
-    ?SLOG(debug, #{msg => "publish to local broker",
+    ?SLOG(debug, #{msg => "publish_to_local_broker",
                    message => Msg, vars => Vars}),
     emqx_metrics:inc('bridge.mqtt.message_received_from_remote', 1),
     case Vars of
diff --git a/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_worker.erl b/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_worker.erl
index 5f6f4b69f..e0d5a2d77 100644
--- a/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_worker.erl
+++ b/apps/emqx_connector/src/mqtt/emqx_connector_mqtt_worker.erl
@@ -188,7 +188,7 @@ callback_mode() -> [state_functions].
 
 %% @doc Config should be a map().
 init(#{name := Name} = ConnectOpts) ->
-    ?SLOG(debug, #{msg => "starting bridge worker",
+    ?SLOG(debug, #{msg => "starting_bridge_worker",
                    name => Name}),
     erlang:process_flag(trap_exit, true),
     Queue = open_replayq(Name, maps:get(replayq, ConnectOpts, #{})),
@@ -335,7 +335,7 @@ common(_StateName, cast, {send_to_remote, Msg}, #{replayq := Q} = State) ->
     NewQ = replayq:append(Q, [Msg]),
     {keep_state, State#{replayq => NewQ}, {next_event, internal, maybe_send}};
 common(StateName, Type, Content, #{name := Name} = State) ->
-    ?SLOG(notice, #{msg => "Bridge discarded event",
+    ?SLOG(notice, #{msg => "bridge_discarded_event",
         name => Name, type => Type, state_name => StateName,
         content => Content}),
     {keep_state, State}.
@@ -349,7 +349,7 @@ do_connect(#{connect_opts := ConnectOpts,
             {ok, State#{connection => Conn}};
         {error, Reason} ->
             ConnectOpts1 = obfuscate(ConnectOpts),
-            ?SLOG(error, #{msg => "Failed to connect",
+            ?SLOG(error, #{msg => "failed_to_connect",
                 config => ConnectOpts1, reason => Reason}),
             {error, Reason, State}
     end.
@@ -386,8 +386,8 @@ pop_and_send_loop(#{replayq := Q} = State, N) ->
     end.
 
 do_send(#{connect_opts := #{forwards := undefined}}, _QAckRef, Msg) ->
-    ?SLOG(error, #{msg => "cannot forward messages to remote broker"
-                          " as 'egress' is not configured",
+    ?SLOG(error, #{msg => "cannot_forward_messages_to_remote_broker"
+                          "_as_'egress'_is_not_configured",
                    messages => Msg});
 do_send(#{inflight := Inflight,
           connection := Connection,
@@ -398,7 +398,7 @@ do_send(#{inflight := Inflight,
                     emqx_metrics:inc('bridge.mqtt.message_sent_to_remote'),
                     emqx_connector_mqtt_msg:to_remote_msg(Message, Vars)
                 end,
-    ?SLOG(debug, #{msg => "publish to remote broker",
+    ?SLOG(debug, #{msg => "publish_to_remote_broker",
         message => Msg, vars => Vars}),
     case emqx_connector_mqtt_mod:send(Connection, [ExportMsg(Msg)]) of
         {ok, Refs} ->