feat(config): merge with global defaults when put new zone

apps/emqx/src/emqx_config.erl

@@ -218,6 +218,9 @@ find_listener_conf(Type, Listener, KeyPath) ->
 
 -spec put(map()) -> ok.
 put(Config) ->
+    put_with_order(Config).
+
+put1(Config) ->
     maps:fold(
         fun(RootName, RootValue, _) ->
             ?MODULE:put([atom(RootName)], RootValue)
@@ -233,10 +236,8 @@ erase(RootName) ->
 
 -spec put(emqx_utils_maps:config_key_path(), term()) -> ok.
 put(KeyPath, Config) ->
-    Putter = fun(Path, Map, Value0) ->
+    Putter = fun(_Path, Map, Value) ->
-        Value = emqx_utils_maps:deep_put(Path, Map, Value0),
+        maybe_update_zone(KeyPath, Map, Value)
-        maybe_update_zone(KeyPath, Value0),
-        Value
     end,
     do_put(?CONF, Putter, KeyPath, Config).
 
@@ -329,7 +330,9 @@ init_load(SchemaMod, Conf) when is_list(Conf) orelse is_binary(Conf) ->
     %% check configs against the schema
     {AppEnvs, CheckedConf} = check_config(SchemaMod, RawConf, #{}),
     save_to_app_env(AppEnvs),
-    ok = save_to_config_map(CheckedConf, RawConf).
+    ok = save_to_config_map(CheckedConf, RawConf),
+    maybe_init_default_zone(),
+    ok.
 
 %% Merge environment variable overrides on top, then merge with overrides.
 overlay_v0(SchemaMod, RawConf) when is_map(RawConf) ->
@@ -586,15 +589,6 @@ save_to_app_env(AppEnvs0) ->
 -spec save_to_config_map(config(), raw_config()) -> ok.
 save_to_config_map(Conf, RawConf) ->
     ?MODULE:put(Conf),
-    try emqx_config:get([zones]) of
-        Zones when is_map(Zones) ->
-            init_default_zone()
-    catch
-        error:{config_not_found, [zones]} ->
-            %% emqx schema is not loaded.
-            %% note, don't trust get_root_names/0
-            skip
-    end,
     ?MODULE:put_raw(RawConf).
 
 -spec save_to_override_conf(boolean(), raw_config(), update_opts()) -> ok | {error, term()}.
@@ -796,63 +790,121 @@ to_atom_conf_path(Path, OnFail) ->
 %%
 %% note1, this should be called as post action after emqx_config terms (zones, and GlobalDefaults)
 %%       are written in the PV storage during emqx config loading/initialization.
--spec init_default_zone() -> ok.
+-spec maybe_init_default_zone() -> skip | ok.
-init_default_zone() ->
+maybe_init_default_zone() ->
+    case emqx_config:get([zones], ?CONFIG_NOT_FOUND_MAGIC) of
+        ?CONFIG_NOT_FOUND_MAGIC ->
+            skip;
+        Zones0 when is_map(Zones0) ->
             Zones =
-        case ?MODULE:get([zones], #{}) of
+                case Zones0 of
                     #{default := _DefaultZone} = Z1 ->
                         Z1;
                     Z2 ->
                         Z2#{default => #{}}
                 end,
-    GlobalDefaults = maps:from_list([{K, ?MODULE:get([K])} || K <- zone_roots()]),
+            GLD = zone_global_defaults(),
             NewZones = maps:map(
                 fun(_ZoneName, ZoneVal) ->
-            merge_with_global_defaults(ZoneVal, GlobalDefaults)
+                    merge_with_global_defaults(GLD, ZoneVal)
                 end,
                 Zones
             ),
-    ?MODULE:put([zones], NewZones).
+            ?MODULE:put([zones], NewZones)
+    end.
 
-%% @TODO just use deep merge?
 -spec merge_with_global_defaults(map(), map()) -> map().
-merge_with_global_defaults(Val, Defaults) ->
+merge_with_global_defaults(GlobalDefaults, ZoneVal) ->
-    maps:fold(
+    emqx_utils_maps:deep_merge(GlobalDefaults, ZoneVal).
-        fun(K, V, Acc) ->
-            case maps:get(K, Acc, ?CONFIG_NOT_FOUND_MAGIC) of
-                ?CONFIG_NOT_FOUND_MAGIC ->
-                    %% Use the value of global default
-                    Acc#{K => V};
-                Override ->
-                    %% Merge with overrides
-                    Acc#{K => emqx_utils_maps:deep_merge(V, Override)}
-            end
-        end,
-        Val,
-        Defaults
-    ).
 
-%% @doc Update zones in case global defaults are changed.
+%% @doc Update zones
--spec maybe_update_zone(runtime_config_key_path(), Val :: term()) -> skip | ok.
+%%    when 1) zone updates, return *new* zones
-maybe_update_zone([], _Value) ->
+%%    when 2) zone global config updates, write to PT directly.
-    skip;
+%% Zone global defaults are always presented in the configmap (PT) when updating zone
-maybe_update_zone([RootName | _T] = Path, Value) ->
+-spec maybe_update_zone(runtime_config_key_path(), RootValue :: map(), Val :: term()) ->
-    case lists:member(RootName, zone_roots()) of
+    NewZoneVal :: map().
+maybe_update_zone([zones | T], ZonesValue, Value) ->
+    %% note, do not write to PT, return *New value* instead
+    NewZonesValue = emqx_utils_maps:deep_put(T, ZonesValue, Value),
+    ExistingZoneNames = maps:keys(?MODULE:get([zones], #{})),
+    %% Update only new zones with global defaults
+    GLD = zone_global_defaults(),
+    maps:fold(
+        fun(ZoneName, ZoneValue, Acc) ->
+            Acc#{ZoneName := merge_with_global_defaults(GLD, ZoneValue)}
+        end,
+        NewZonesValue,
+        maps:without(ExistingZoneNames, NewZonesValue)
+    );
+maybe_update_zone([RootName | T], RootValue, Value) when is_atom(RootName) ->
+    NewRootValue = emqx_utils_maps:deep_put(T, RootValue, Value),
+    case is_zone_root(RootName) of
         false ->
             skip;
         true ->
-            Zones = ?MODULE:get([zones], #{}),
+            %% When updates on global default roots.
+            ExistingZones = ?MODULE:get([zones], #{}),
+            RootNameBin = atom_to_binary(RootName),
             NewZones = maps:map(
-                fun(_ZoneName, ZoneVal) ->
+                fun(ZoneName, ZoneVal) ->
-                    %% @TODO we should not overwrite if it is a user defined value
+                    BinPath = [<<"zones">>, atom_to_binary(ZoneName), RootNameBin],
-                    emqx_utils_maps:deep_put(Path, ZoneVal, Value)
+                    case
-                end,
+                        %% look for user defined value from RAWCONF
-                Zones
+                        ?MODULE:get_raw(
+                            BinPath,
+                            ?CONFIG_NOT_FOUND_MAGIC
+                        )
+                    of
+                        ?CONFIG_NOT_FOUND_MAGIC ->
+                            ZoneVal#{RootName => NewRootValue};
+                        RawUserZoneRoot ->
+                            UserDefinedValues = rawconf_to_conf(
+                                emqx_schema, BinPath, RawUserZoneRoot
                             ),
-            ?MODULE:put([zones], NewZones),
+                            ZoneVal#{
-            ok
+                                RootName :=
-    end.
+                                    emqx_utils_maps:deep_merge(
+                                        NewRootValue,
+                                        UserDefinedValues
+                                    )
+                            }
+                    end
+                end,
+                ExistingZones
+            ),
+            persistent_term:put(?PERSIS_KEY(?CONF, zones), NewZones)
+    end,
+    NewRootValue.
+
+zone_global_defaults() ->
+    maps:from_list([{K, ?MODULE:get([K])} || K <- zone_roots()]).
+
+-spec is_zone_root(atom) -> boolean().
+is_zone_root(Name) ->
+    lists:member(Name, zone_roots()).
 
 -spec zone_roots() -> [atom()].
 zone_roots() ->
     lists:map(fun list_to_atom/1, emqx_zone_schema:roots()).
+
+%%%
+%%% @doc During init, ensure order of puts that zone is put after the other global defaults.
+%%%
+put_with_order(#{zones := _Zones} = Conf) ->
+    put1(maps:without([zones], Conf)),
+    put1(maps:with([zones], Conf));
+put_with_order(Conf) ->
+    put1(Conf).
+
+%%
+%% @doc Helper function that converts raw conf val to runtime conf val
+%%      with the types info from schema module
+-spec rawconf_to_conf(module(), RawPath :: [binary()], RawValue :: term()) -> term().
+rawconf_to_conf(SchemaModule, RawPath, RawValue) ->
+    {_, RawUserDefinedValues} =
+        check_config(
+            SchemaModule,
+            emqx_utils_maps:deep_put(RawPath, #{}, RawValue)
+        ),
+    AtomPath = to_atom_conf_path(RawPath, {raise_error, maybe_update_zone_error}),
+    emqx_utils_maps:deep_get(AtomPath, RawUserDefinedValues).

apps/emqx/test/emqx_config_SUITE.erl

@@ -107,25 +107,32 @@ t_init_load_emqx_schema(Config) ->
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
     %% Then default zone is injected with all global defaults
     Default = emqx_config:get([zones, default]),
+    MQTT = emqx_config:get([mqtt]),
+    Stats = emqx_config:get([stats]),
+    FD = emqx_config:get([flapping_detect]),
+    FS = emqx_config:get([force_shutdown]),
+    CC = emqx_config:get([conn_congestion]),
+    FG = emqx_config:get([force_gc]),
+    OP = emqx_config:get([overload_protection]),
     ?assertMatch(
         #{
-            mqtt := _,
+            mqtt := MQTT,
-            stats := _,
+            stats := Stats,
-            flapping_detect := _,
+            flapping_detect := FD,
-            force_shutdown := _,
+            force_shutdown := FS,
-            conn_congestion := _,
+            conn_congestion := CC,
-            force_gc := _,
+            force_gc := FG,
-            overload_protection := _
+            overload_protection := OP
         },
         Default
     ).
 
-t_init_zones_load_emqx_schema_no_default(Config) ->
+t_init_zones_load_emqx_schema_no_default_for_none_existing(Config) ->
     emqx_config:erase_all(),
     %% Given empty config file
     ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"">>, Config),
     application:set_env(emqx, config_files, [ConfFile]),
-    %% When load emqx_schema
+    %% When emqx_schema is loaded
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
     %% Then read for none existing zone should throw error
     ?assertError(
@@ -138,9 +145,14 @@ t_init_zones_load_other_schema(Config) ->
     %% Given empty config file
     ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"">>, Config),
     application:set_env(emqx, config_files, [ConfFile]),
-    %% When load schema other than emqx_schema
+    %% When load emqx_limiter_schema, not emqx_schema
     %% Then load should success
     ?assertEqual(ok, emqx_config:init_load(emqx_limiter_schema)),
+    %% Then no zones is loaded.
+    ?assertError(
+        {config_not_found, [zones]},
+        emqx_config:get([zones])
+    ),
     %% Then no default zone is loaded.
     ?assertError(
         {config_not_found, [zones, default]},
@@ -154,70 +166,15 @@ t_init_zones_with_user_defined_default_zone(Config) ->
         ?FUNCTION_NAME, <<"zones.default.mqtt.max_topic_alias=1024">>, Config
     ),
     application:set_env(emqx, config_files, [ConfFile]),
-    %% When load schema
+    %% When schema is loaded
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
-    %% Then user defined value is set and others are defaults
 
-    ?assertMatch(
+    %% Then user defined value is set
-        #{
+    {MqttV, Others} = maps:take(mqtt, emqx_config:get([zones, default])),
-            conn_congestion :=
+    {ZGDMQTT, ExpectedOthers} = maps:take(mqtt, zone_global_defaults()),
-                #{enable_alarm := true, min_alarm_sustain_duration := 60000},
+    ?assertEqual(ZGDMQTT#{max_topic_alias := 1024}, MqttV),
-            flapping_detect :=
+    %% Then others are defaults
-                #{ban_time := 300000, max_count := 15, window_time := disabled},
+    ?assertEqual(ExpectedOthers, Others).
-            force_gc :=
-                #{bytes := 16777216, count := 16000, enable := true},
-            force_shutdown :=
-                #{
-                    enable := true,
-                    max_heap_size := 4194304,
-                    max_mailbox_size := 1000
-                },
-            mqtt :=
-                #{
-                    await_rel_timeout := 300000,
-                    exclusive_subscription := false,
-                    idle_timeout := 15000,
-                    ignore_loop_deliver := false,
-                    keepalive_backoff := 0.75,
-                    keepalive_multiplier := 1.5,
-                    max_awaiting_rel := 100,
-                    max_clientid_len := 65535,
-                    max_inflight := 32,
-                    max_mqueue_len := 1000,
-                    max_packet_size := 1048576,
-                    max_qos_allowed := 2,
-                    max_subscriptions := infinity,
-                    %% <=== here!
-                    max_topic_alias := 1024,
-                    max_topic_levels := 128,
-                    mqueue_default_priority := lowest,
-                    mqueue_priorities := disabled,
-                    mqueue_store_qos0 := true,
-                    peer_cert_as_clientid := disabled,
-                    peer_cert_as_username := disabled,
-                    response_information := [],
-                    retain_available := true,
-                    retry_interval := 30000,
-                    server_keepalive := disabled,
-                    session_expiry_interval := 7200000,
-                    shared_subscription := true,
-                    strict_mode := false,
-                    upgrade_qos := false,
-                    use_username_as_clientid := false,
-                    wildcard_subscription := true
-                },
-            overload_protection :=
-                #{
-                    backoff_delay := 1,
-                    backoff_gc := false,
-                    backoff_hibernation := true,
-                    backoff_new_conn := true,
-                    enable := false
-                },
-            stats := #{enable := true}
-        },
-        emqx_config:get([zones, default])
-    ).
 
 t_init_zones_with_user_defined_other_zone(Config) ->
     emqx_config:erase_all(),
@@ -226,270 +183,149 @@ t_init_zones_with_user_defined_other_zone(Config) ->
         ?FUNCTION_NAME, <<"zones.myzone.mqtt.max_topic_alias=1024">>, Config
     ),
     application:set_env(emqx, config_files, [ConfFile]),
-    %% When load schema
+    %% When schema is loaded
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
     %% Then user defined value is set and others are defaults
-    ?assertMatch(
-        #{
-            conn_congestion :=
-                #{enable_alarm := true, min_alarm_sustain_duration := 60000},
-            flapping_detect :=
-                #{ban_time := 300000, max_count := 15, window_time := disabled},
-            force_gc :=
-                #{bytes := 16777216, count := 16000, enable := true},
-            force_shutdown :=
-                #{
-                    enable := true,
-                    max_heap_size := 4194304,
-                    max_mailbox_size := 1000
-                },
-            mqtt :=
-                #{
-                    await_rel_timeout := 300000,
-                    exclusive_subscription := false,
-                    idle_timeout := 15000,
-                    ignore_loop_deliver := false,
-                    keepalive_backoff := 0.75,
-                    keepalive_multiplier := 1.5,
-                    max_awaiting_rel := 100,
-                    max_clientid_len := 65535,
-                    max_inflight := 32,
-                    max_mqueue_len := 1000,
-                    max_packet_size := 1048576,
-                    max_qos_allowed := 2,
-                    max_subscriptions := infinity,
-                    %% <=== here!
-                    max_topic_alias := 1024,
-                    max_topic_levels := 128,
-                    mqueue_default_priority := lowest,
-                    mqueue_priorities := disabled,
-                    mqueue_store_qos0 := true,
-                    peer_cert_as_clientid := disabled,
-                    peer_cert_as_username := disabled,
-                    response_information := [],
-                    retain_available := true,
-                    retry_interval := 30000,
-                    server_keepalive := disabled,
-                    session_expiry_interval := 7200000,
-                    shared_subscription := true,
-                    strict_mode := false,
-                    upgrade_qos := false,
-                    use_username_as_clientid := false,
-                    wildcard_subscription := true
-                },
-            overload_protection :=
-                #{
-                    backoff_delay := 1,
-                    backoff_gc := false,
-                    backoff_hibernation := true,
-                    backoff_new_conn := true,
-                    enable := false
-                },
-            stats := #{enable := true}
-        },
-        emqx_config:get([zones, myzone])
-    ),
 
+    %% Then user defined value is set
+    {MqttV, Others} = maps:take(mqtt, emqx_config:get([zones, myzone])),
+    {ZGDMQTT, ExpectedOthers} = maps:take(mqtt, zone_global_defaults()),
+    ?assertEqual(ZGDMQTT#{max_topic_alias := 1024}, MqttV),
+    %% Then others are defaults
+    ?assertEqual(ExpectedOthers, Others),
     %% Then default zone still have the defaults
-    ?assertMatch(
+    ?assertEqual(zone_global_defaults(), emqx_config:get([zones, default])).
-        #{
-            conn_congestion :=
-                #{enable_alarm := true, min_alarm_sustain_duration := 60000},
-            flapping_detect :=
-                #{ban_time := 300000, max_count := 15, window_time := disabled},
-            force_gc :=
-                #{bytes := 16777216, count := 16000, enable := true},
-            force_shutdown :=
-                #{
-                    enable := true,
-                    max_heap_size := 4194304,
-                    max_mailbox_size := 1000
-                },
-            mqtt :=
-                #{
-                    await_rel_timeout := 300000,
-                    exclusive_subscription := false,
-                    idle_timeout := 15000,
-                    ignore_loop_deliver := false,
-                    keepalive_backoff := 0.75,
-                    keepalive_multiplier := 1.5,
-                    max_awaiting_rel := 100,
-                    max_clientid_len := 65535,
-                    max_inflight := 32,
-                    max_mqueue_len := 1000,
-                    max_packet_size := 1048576,
-                    max_qos_allowed := 2,
-                    max_subscriptions := infinity,
-                    max_topic_alias := 65535,
-                    max_topic_levels := 128,
-                    mqueue_default_priority := lowest,
-                    mqueue_priorities := disabled,
-                    mqueue_store_qos0 := true,
-                    peer_cert_as_clientid := disabled,
-                    peer_cert_as_username := disabled,
-                    response_information := [],
-                    retain_available := true,
-                    retry_interval := 30000,
-                    server_keepalive := disabled,
-                    session_expiry_interval := 7200000,
-                    shared_subscription := true,
-                    strict_mode := false,
-                    upgrade_qos := false,
-                    use_username_as_clientid := false,
-                    wildcard_subscription := true
-                },
-            overload_protection :=
-                #{
-                    backoff_delay := 1,
-                    backoff_gc := false,
-                    backoff_hibernation := true,
-                    backoff_new_conn := true,
-                    enable := false
-                },
-            stats := #{enable := true}
-        },
-        emqx_config:get([zones, default])
-    ).
 
 t_init_zones_with_cust_root_mqtt(Config) ->
     emqx_config:erase_all(),
-    %% Given user defined non default mqtt schema in config file
+    %% Given config file with mqtt user overrides
-    ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"mqtt.retry_interval=600000">>, Config),
+    ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"mqtt.retry_interval=10m">>, Config),
     application:set_env(emqx, config_files, [ConfFile]),
     %% When emqx_schema is loaded
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
-    %% Then the value is reflected in default `zone' and other fields under mqtt are default.
+    %% Then the value is reflected as internal representation in default `zone'
-    ?assertMatch(
+    %% and other fields under mqtt are defaults.
-        #{
+    GDefaultMqtt = maps:get(mqtt, zone_global_defaults()),
-            await_rel_timeout := 300000,
+    ?assertEqual(
-            exclusive_subscription := false,
+        GDefaultMqtt#{retry_interval := 600000},
-            idle_timeout := 15000,
-            ignore_loop_deliver := false,
-            keepalive_backoff := 0.75,
-            keepalive_multiplier := 1.5,
-            max_awaiting_rel := 100,
-            max_clientid_len := 65535,
-            max_inflight := 32,
-            max_mqueue_len := 1000,
-            max_packet_size := 1048576,
-            max_qos_allowed := 2,
-            max_subscriptions := infinity,
-            max_topic_alias := 65535,
-            max_topic_levels := 128,
-            mqueue_default_priority := lowest,
-            mqueue_priorities := disabled,
-            mqueue_store_qos0 := true,
-            peer_cert_as_clientid := disabled,
-            peer_cert_as_username := disabled,
-            response_information := [],
-            retain_available := true,
-            %% <=== here
-            retry_interval := 600000,
-            server_keepalive := disabled,
-            session_expiry_interval := 7200000,
-            shared_subscription := true,
-            strict_mode := false,
-            upgrade_qos := false,
-            use_username_as_clientid := false,
-            wildcard_subscription := true
-        },
         emqx_config:get([zones, default, mqtt])
     ).
 
 t_default_zone_is_updated_after_global_defaults_updated(Config) ->
     emqx_config:erase_all(),
-    %% Given user defined non default mqtt schema in config file
+    %% Given empty emqx conf
     ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"">>, Config),
     application:set_env(emqx, config_files, [ConfFile]),
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
     ?assertNotEqual(900000, emqx_config:get([zones, default, mqtt, retry_interval])),
     %% When emqx_schema is loaded
     emqx_config:put([mqtt, retry_interval], 900000),
-    %% Then the value is reflected in default `zone' and other fields under mqtt are default.
+    %% Then the value is reflected in default `zone' and other fields under mqtt are defaults.
-    ?assertMatch(
+    GDefaultMqtt = maps:get(mqtt, zone_global_defaults()),
-        #{
+    ?assertEqual(
-            await_rel_timeout := 300000,
+        GDefaultMqtt#{retry_interval := 900000},
-            exclusive_subscription := false,
-            idle_timeout := 15000,
-            ignore_loop_deliver := false,
-            keepalive_backoff := 0.75,
-            keepalive_multiplier := 1.5,
-            max_awaiting_rel := 100,
-            max_clientid_len := 65535,
-            max_inflight := 32,
-            max_mqueue_len := 1000,
-            max_packet_size := 1048576,
-            max_qos_allowed := 2,
-            max_subscriptions := infinity,
-            max_topic_alias := 65535,
-            max_topic_levels := 128,
-            mqueue_default_priority := lowest,
-            mqueue_priorities := disabled,
-            mqueue_store_qos0 := true,
-            peer_cert_as_clientid := disabled,
-            peer_cert_as_username := disabled,
-            response_information := [],
-            retain_available := true,
-            %% <=== here
-            retry_interval := 900000,
-            server_keepalive := disabled,
-            session_expiry_interval := 7200000,
-            shared_subscription := true,
-            strict_mode := false,
-            upgrade_qos := false,
-            use_username_as_clientid := false,
-            wildcard_subscription := true
-        },
         emqx_config:get([zones, default, mqtt])
     ).
 
-t_other_zone_is_updated_after_global_defaults_updated(Config) ->
+t_myzone_is_updated_after_global_defaults_updated(Config) ->
     emqx_config:erase_all(),
-    %% Given user defined non default mqtt schema in config file
+    %% Given emqx conf file with user override in myzone (none default zone)
     ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"zones.myzone.mqtt.max_inflight=32">>, Config),
     application:set_env(emqx, config_files, [ConfFile]),
     ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
     ?assertNotEqual(900000, emqx_config:get([zones, myzone, mqtt, retry_interval])),
-    %% When emqx_schema is loaded
+    %% When update another value of global default
     emqx_config:put([mqtt, retry_interval], 900000),
-    %% Then the value is reflected in default `zone' and other fields under mqtt are default.
+    %% Then the value is reflected in myzone and the user defined value unchanged.
-    ?assertMatch(
+    GDefaultMqtt = maps:get(mqtt, zone_global_defaults()),
-        #{
+    ?assertEqual(
-            await_rel_timeout := 300000,
+        GDefaultMqtt#{
-            exclusive_subscription := false,
-            idle_timeout := 15000,
-            ignore_loop_deliver := false,
-            keepalive_backoff := 0.75,
-            keepalive_multiplier := 1.5,
-            max_awaiting_rel := 100,
-            max_clientid_len := 65535,
-            max_inflight := 32,
-            max_mqueue_len := 1000,
-            max_packet_size := 1048576,
-            max_qos_allowed := 2,
-            max_subscriptions := infinity,
-            max_topic_alias := 65535,
-            max_topic_levels := 128,
-            mqueue_default_priority := lowest,
-            mqueue_priorities := disabled,
-            mqueue_store_qos0 := true,
-            peer_cert_as_clientid := disabled,
-            peer_cert_as_username := disabled,
-            response_information := [],
-            retain_available := true,
-            %% <=== here
             retry_interval := 900000,
-            server_keepalive := disabled,
+            max_inflight := 32
-            session_expiry_interval := 7200000,
-            shared_subscription := true,
-            strict_mode := false,
-            upgrade_qos := false,
-            use_username_as_clientid := false,
-            wildcard_subscription := true
         },
         emqx_config:get([zones, myzone, mqtt])
+    ),
+    %% Then the value is reflected in default zone as well.
+    ?assertEqual(
+        GDefaultMqtt#{retry_interval := 900000},
+        emqx_config:get([zones, default, mqtt])
     ).
 
+t_zone_no_user_defined_overrides(Config) ->
+    emqx_config:erase_all(),
+    %% Given emqx conf file with user specified myzone
+    ConfFile = prepare_conf_file(
+        ?FUNCTION_NAME, <<"zones.myzone.mqtt.retry_interval=10m">>, Config
+    ),
+    application:set_env(emqx, config_files, [ConfFile]),
+    ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
+    ?assertEqual(600000, emqx_config:get([zones, myzone, mqtt, retry_interval])),
+    %% When there is an update in global default
+    emqx_config:put([mqtt, max_inflight], 2),
+    %% Then the value is reflected in both default and myzone
+    ?assertMatch(2, emqx_config:get([zones, default, mqtt, max_inflight])),
+    ?assertMatch(2, emqx_config:get([zones, myzone, mqtt, max_inflight])),
+    %% Then user defined value from config is not overwritten
+    ?assertMatch(600000, emqx_config:get([zones, myzone, mqtt, retry_interval])).
+
+t_zone_no_user_defined_overrides_internal_represent(Config) ->
+    emqx_config:erase_all(),
+    %% Given emqx conf file with user specified myzone
+    ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"zones.myzone.mqtt.max_inflight=1">>, Config),
+    application:set_env(emqx, config_files, [ConfFile]),
+    ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
+    ?assertEqual(1, emqx_config:get([zones, myzone, mqtt, max_inflight])),
+    %% When there is an update in global default
+    emqx_config:put([mqtt, max_inflight], 2),
+    %% Then the value is reflected in default `zone' but not user-defined zone
+    ?assertMatch(2, emqx_config:get([zones, default, mqtt, max_inflight])),
+    ?assertMatch(1, emqx_config:get([zones, myzone, mqtt, max_inflight])).
+
+t_update_global_defaults_no_updates_on_user_overrides(Config) ->
+    emqx_config:erase_all(),
+    %% Given default zone config in conf file.
+    ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"zones.default.mqtt.max_inflight=1">>, Config),
+    application:set_env(emqx, config_files, [ConfFile]),
+    ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
+    ?assertEqual(1, emqx_config:get([zones, default, mqtt, max_inflight])),
+    %% When there is an update in global default
+    emqx_config:put([mqtt, max_inflight], 20),
+    %% Then the value is not reflected in default `zone'
+    ?assertMatch(1, emqx_config:get([zones, default, mqtt, max_inflight])).
+
+t_zone_update_with_new_zone(Config) ->
+    emqx_config:erase_all(),
+    %% Given loaded an empty conf file
+    ConfFile = prepare_conf_file(?FUNCTION_NAME, <<"">>, Config),
+    application:set_env(emqx, config_files, [ConfFile]),
+    ?assertEqual(ok, emqx_config:init_load(emqx_schema)),
+    %% When there is an update for creating new zone config
+    ok = emqx_config:put([zones, myzone, mqtt, max_inflight], 2),
+    %% Then the value is set and other roots are created with defaults.
+    GDefaultMqtt = maps:get(mqtt, zone_global_defaults()),
+    ?assertEqual(
+        GDefaultMqtt#{max_inflight := 2},
+        emqx_config:get([zones, myzone, mqtt])
+    ).
+
+t_init_zone_with_global_defaults(_Config) ->
+    %% Given uninitialized empty config
+    emqx_config:erase_all(),
+    Zones = #{myzone => #{mqtt => #{max_inflight => 3}}},
+    %% when put zones with global default with emqx_config:put/1
+    GlobalDefaults = zone_global_defaults(),
+    AllConf = maps:put(zones, Zones, GlobalDefaults),
+    %% Then put sucess
+    ?assertEqual(ok, emqx_config:put(AllConf)),
+    %% Then GlobalDefaults are set
+    ?assertEqual(GlobalDefaults, maps:with(maps:keys(GlobalDefaults), emqx_config:get([]))),
+    %% Then my zone and default zone are set
+    {MqttV, Others} = maps:take(mqtt, emqx_config:get([zones, myzone])),
+    {ZGDMQTT, ExpectedOthers} = maps:take(mqtt, GlobalDefaults),
+    ?assertEqual(ZGDMQTT#{max_inflight := 3}, MqttV),
+    %% Then others are defaults
+    ?assertEqual(ExpectedOthers, Others).
+
 %%%
 %%% Helpers
 %%%
@@ -502,3 +338,61 @@ prepare_conf_file(Name, Content, CTConfig) ->
 tc_conf_file(TC, Config) ->
     DataDir = ?config(data_dir, Config),
     filename:join([DataDir, TC, 'emqx.conf']).
+
+zone_global_defaults() ->
+    #{
+        conn_congestion =>
+            #{enable_alarm => true, min_alarm_sustain_duration => 60000},
+        flapping_detect =>
+            #{ban_time => 300000, max_count => 15, window_time => disabled},
+        force_gc =>
+            #{bytes => 16777216, count => 16000, enable => true},
+        force_shutdown =>
+            #{
+                enable => true,
+                max_heap_size => 4194304,
+                max_mailbox_size => 1000
+            },
+        mqtt =>
+            #{
+                await_rel_timeout => 300000,
+                exclusive_subscription => false,
+                idle_timeout => 15000,
+                ignore_loop_deliver => false,
+                keepalive_backoff => 0.75,
+                keepalive_multiplier => 1.5,
+                max_awaiting_rel => 100,
+                max_clientid_len => 65535,
+                max_inflight => 32,
+                max_mqueue_len => 1000,
+                max_packet_size => 1048576,
+                max_qos_allowed => 2,
+                max_subscriptions => infinity,
+                max_topic_alias => 65535,
+                max_topic_levels => 128,
+                mqueue_default_priority => lowest,
+                mqueue_priorities => disabled,
+                mqueue_store_qos0 => true,
+                peer_cert_as_clientid => disabled,
+                peer_cert_as_username => disabled,
+                response_information => [],
+                retain_available => true,
+                retry_interval => 30000,
+                server_keepalive => disabled,
+                session_expiry_interval => 7200000,
+                shared_subscription => true,
+                strict_mode => false,
+                upgrade_qos => false,
+                use_username_as_clientid => false,
+                wildcard_subscription => true
+            },
+        overload_protection =>
+            #{
+                backoff_delay => 1,
+                backoff_gc => false,
+                backoff_hibernation => true,
+                backoff_new_conn => true,
+                enable => false
+            },
+        stats => #{enable => true}
+    }.

apps/emqx/test/emqx_takeover_SUITE.erl

@@ -33,6 +33,7 @@
 all() -> emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
+    emqx_common_test_helpers:boot_modules(all),
     ?check_trace(
         ?wait_async_action(
             emqx_common_test_helpers:start_apps([]),