feat: integrate OpenTelemetry log handler

apps/emqx_conf/src/emqx_conf_schema.erl

@@ -77,7 +77,8 @@
 
 %% Callback to upgrade config after loaded from config file but before validation.
 upgrade_raw_conf(RawConf) ->
-    emqx_connector_schema:transform_bridges_v1_to_connectors_and_bridges_v2(RawConf).
+    RawConf1 = emqx_connector_schema:transform_bridges_v1_to_connectors_and_bridges_v2(RawConf),
+    emqx_otel_schema:upgrade_legacy_metrics(RawConf1).
 
 %% root config should not have a namespace
 namespace() -> undefined.

apps/emqx_machine/src/emqx_machine_boot.erl

@@ -69,9 +69,9 @@ stop_apps() ->
     ?SLOG(notice, #{msg => "stopping_emqx_apps"}),
     _ = emqx_alarm_handler:unload(),
     ok = emqx_conf_app:unset_config_loaded(),
+    lists:foreach(fun stop_one_app/1, lists:reverse(sorted_reboot_apps())),
     %% Mute otel deps application.
-    _ = emqx_otel:stop_otel(),
-    lists:foreach(fun stop_one_app/1, lists:reverse(sorted_reboot_apps())).
+    ok = emqx_otel_app:stop_deps().
 
 %% Those port apps are terminated after the main apps
 %% Don't need to stop when reboot.

apps/emqx_opentelemetry/src/emqx_opentelemetry.app.src

@@ -1,9 +1,15 @@
 {application, emqx_opentelemetry, [
     {description, "OpenTelemetry for EMQX Broker"},
-    {vsn, "0.1.3"},
+    {vsn, "0.2.0"},
     {registered, []},
     {mod, {emqx_otel_app, []}},
-    {applications, [kernel, stdlib, emqx]},
+    {applications, [
+        kernel,
+        stdlib,
+        emqx,
+        %% otel metrics depend on emqx_mgmt_cache
+        emqx_management
+    ]},
     {env, []},
     {modules, []},
     {licenses, ["Apache 2.0"]},

apps/emqx_opentelemetry/src/emqx_otel_api.erl

@@ -103,10 +103,24 @@ otel_config_schema() ->
 
 otel_config_example() ->
     #{
-        enable => true,
-        exporter =>
-            #{
+        logs => #{
+            enable => true,
+            exporter => #{
+                endpoint => "http://localhost:4317",
+                ssl_options => #{
+                    enable => false
+                }
+            },
+            level => warning
+        },
+        metrics => #{
+            enable => true,
+            exporter => #{
                 endpoint => "http://localhost:4317",
-                interval => "10s"
+                interval => "10s",
+                ssl_options => #{
+                    enable => false
+                }
             }
+        }
     }.

apps/emqx_opentelemetry/src/emqx_otel_app.erl

@@ -19,11 +19,17 @@
 -behaviour(application).
 
 -export([start/2, stop/1]).
+-export([stop_deps/0]).
 
 start(_StartType, _StartArgs) ->
     emqx_otel_config:add_handler(),
+    ok = emqx_otel_config:add_otel_log_handler(),
     emqx_otel_sup:start_link().
 
 stop(_State) ->
     emqx_otel_config:remove_handler(),
+    _ = emqx_otel_config:remove_otel_log_handler(),
     ok.
+
+stop_deps() ->
+    emqx_otel_config:stop_all_otel_apps().

apps/emqx_opentelemetry/src/emqx_otel_config.erl

@@ -19,9 +19,16 @@
 
 -define(OPTL, [opentelemetry]).
 
+-define(OTEL_EXPORTER, opentelemetry_exporter).
+-define(OTEL_LOG_HANDLER, otel_log_handler).
+-define(OTEL_LOG_HANDLER_ID, opentelemetry_handler).
+
 -export([add_handler/0, remove_handler/0]).
 -export([post_config_update/5]).
 -export([update/1]).
+-export([add_otel_log_handler/0, remove_otel_log_handler/0]).
+-export([stop_all_otel_apps/0]).
+-export([otel_exporter/1]).
 
 update(Config) ->
     case
@@ -45,14 +52,109 @@ remove_handler() ->
     ok = emqx_config_handler:remove_handler(?OPTL),
     ok.
 
+post_config_update(?OPTL, _Req, Old, Old, _AppEnvs) ->
+    ok;
 post_config_update(?OPTL, _Req, New, _Old, AppEnvs) ->
     application:set_env(AppEnvs),
-    ensure_otel(New);
+    MetricsRes = ensure_otel_metrics(New),
+    LogsRes = ensure_otel_logs(New),
+    _ = maybe_stop_all_otel_apps(New),
+    case {MetricsRes, LogsRes} of
+        {ok, ok} -> ok;
+        Other -> {error, Other}
+    end;
 post_config_update(_ConfPath, _Req, _NewConf, _OldConf, _AppEnvs) ->
     ok.
 
-ensure_otel(#{enable := true} = Conf) ->
-    _ = emqx_otel:stop_otel(),
-    emqx_otel:start_otel(Conf);
-ensure_otel(#{enable := false}) ->
-    emqx_otel:stop_otel().
+stop_all_otel_apps() ->
+    _ = application:stop(opentelemetry),
+    _ = application:stop(opentelemetry_experimental),
+    _ = application:stop(opentelemetry_experimental_api),
+    _ = application:stop(opentelemetry_exporter),
+    ok.
+
+add_otel_log_handler() ->
+    ensure_otel_logs(emqx:get_config(?OPTL)).
+
+remove_otel_log_handler() ->
+    remove_handler_if_present(?OTEL_LOG_HANDLER_ID).
+
+otel_exporter(ExporterConf) ->
+    #{
+        endpoint := Endpoint,
+        protocol := Proto,
+        ssl_options := SSLOpts
+    } = ExporterConf,
+    {?OTEL_EXPORTER, #{
+        endpoint => Endpoint,
+        protocol => Proto,
+        ssl_options => ssl_opts(Endpoint, SSLOpts)
+    }}.
+
+%% Internal functions
+
+ensure_otel_metrics(#{metrics := #{enable := true} = MetricsConf}) ->
+    _ = emqx_otel_metrics:stop_otel(),
+    emqx_otel_metrics:start_otel(MetricsConf);
+ensure_otel_metrics(#{metrics := #{enable := false}}) ->
+    emqx_otel_metrics:stop_otel();
+ensure_otel_metrics(_) ->
+    ok.
+
+ensure_otel_logs(#{logs := #{enable := true} = LogsConf}) ->
+    ok = remove_handler_if_present(?OTEL_LOG_HANDLER_ID),
+    ok = ensure_log_apps(),
+    HandlerConf = tr_handler_conf(LogsConf),
+    %% NOTE: should primary logger level be updated if it's higher than otel log level?
+    logger:add_handler(?OTEL_LOG_HANDLER_ID, ?OTEL_LOG_HANDLER, HandlerConf);
+ensure_otel_logs(#{logs := #{enable := false}}) ->
+    remove_handler_if_present(?OTEL_LOG_HANDLER_ID).
+
+remove_handler_if_present(HandlerId) ->
+    case logger:get_handler_config(HandlerId) of
+        {ok, _} ->
+            ok = logger:remove_handler(HandlerId);
+        _ ->
+            ok
+    end.
+
+ensure_log_apps() ->
+    {ok, _} = application:ensure_all_started(opentelemetry_exporter),
+    {ok, _} = application:ensure_all_started(opentelemetry_experimental),
+    ok.
+
+maybe_stop_all_otel_apps(#{metrics := #{enable := false}, logs := #{enable := false}}) ->
+    stop_all_otel_apps();
+maybe_stop_all_otel_apps(_) ->
+    ok.
+
+tr_handler_conf(Conf) ->
+    #{
+        level := Level,
+        max_queue_size := MaxQueueSize,
+        exporting_timeout := ExportingTimeout,
+        scheduled_delay := ScheduledDelay,
+        exporter := ExporterConf
+    } = Conf,
+    #{
+        level => Level,
+        config => #{
+            max_queue_size => MaxQueueSize,
+            exporting_timeout_ms => ExportingTimeout,
+            scheduled_delay_ms => ScheduledDelay,
+            exporter => otel_exporter(ExporterConf)
+        }
+    }.
+
+ssl_opts(Endpoint, SSLOpts) ->
+    case is_ssl(Endpoint) of
+        true ->
+            emqx_tls_lib:to_client_opts(SSLOpts#{enable => true});
+        false ->
+            []
+    end.
+
+is_ssl(<<"https://", _/binary>> = _Endpoint) ->
+    true;
+is_ssl(_Endpoint) ->
+    false.

apps/emqx_opentelemetry/src/emqx_otel.erl

@@ -14,7 +14,7 @@
 %% limitations under the License.
 %%--------------------------------------------------------------------
 
--module(emqx_otel).
+-module(emqx_otel_metrics).
 -include_lib("emqx/include/logger.hrl").
 
 -export([start_otel/1, stop_otel/0]).
@@ -29,17 +29,19 @@ start_otel(Conf) ->
     assert_started(supervisor:start_child(?SUPERVISOR, Spec)).
 
 stop_otel() ->
+    Res =
+        case erlang:whereis(?SUPERVISOR) of
+            undefined ->
+                ok;
+            Pid ->
+                case supervisor:terminate_child(Pid, ?MODULE) of
+                    ok -> supervisor:delete_child(Pid, ?MODULE);
+                    {error, not_found} -> ok;
+                    Error -> Error
+                end
+        end,
     ok = cleanup(),
-    case erlang:whereis(?SUPERVISOR) of
-        undefined ->
-            ok;
-        Pid ->
-            case supervisor:terminate_child(Pid, ?MODULE) of
-                ok -> supervisor:delete_child(Pid, ?MODULE);
-                {error, not_found} -> ok;
-                Error -> Error
-            end
-    end.
+    Res.
 
 start_link(Conf) ->
     gen_server:start_link({local, ?MODULE}, ?MODULE, Conf, []).
@@ -71,32 +73,40 @@ setup(_Conf) ->
     ok.
 
 ensure_apps(Conf) ->
-    #{exporter := #{interval := ExporterInterval}} = Conf,
+    #{exporter := #{interval := ExporterInterval} = Exporter} = Conf,
     {ok, _} = application:ensure_all_started(opentelemetry_exporter),
     {ok, _} = application:ensure_all_started(opentelemetry),
-    _ = application:stop(opentelemetry_experimental),
+    {ok, _} = application:ensure_all_started(opentelemetry_experimental),
+    {ok, _} = application:ensure_all_started(opentelemetry_api_experimental),
+
+    _ = opentelemetry_experimental:stop_default_metrics(),
     ok = application:set_env(
         opentelemetry_experimental,
         readers,
         [
             #{
+                id => emqx_otel_metric_reader,
                 module => otel_metric_reader,
                 config => #{
-                    exporter => {opentelemetry_exporter, #{}},
+                    exporter => emqx_otel_config:otel_exporter(Exporter),
                     export_interval_ms => ExporterInterval
                 }
             }
         ]
     ),
-    {ok, _} = application:ensure_all_started(opentelemetry_experimental),
-    {ok, _} = application:ensure_all_started(opentelemetry_api_experimental),
+    {ok, _} = opentelemetry_experimental:start_default_metrics(),
     ok.
 
 cleanup() ->
-    _ = application:stop(opentelemetry),
-    _ = application:stop(opentelemetry_experimental),
-    _ = application:stop(opentelemetry_experimental_api),
-    _ = application:stop(opentelemetry_exporter),
+    safe_stop_default_metrics().
+
+safe_stop_default_metrics() ->
+    try
+        _ = opentelemetry_experimental:stop_default_metrics()
+    catch
+        %% noramal scenario, metrics supervisor is not started
+        exit:{noproc, _} -> ok
+    end,
     ok.
 
 create_metric_views() ->

apps/emqx_opentelemetry/src/emqx_otel_schema.erl

@@ -24,16 +24,48 @@
     desc/1
 ]).
 
+-export([upgrade_legacy_metrics/1]).
+
+%% Compatibility with the previous schema that defined only metric fields
+upgrade_legacy_metrics(RawConf) ->
+    case RawConf of
+        #{<<"opentelemetry">> := Otel} ->
+            LegacyMetricsFields = [<<"enable">>, <<"exporter">>],
+            Otel1 = maps:without(LegacyMetricsFields, Otel),
+            Metrics = maps:with(LegacyMetricsFields, Otel),
+            case Metrics =:= #{} of
+                true ->
+                    RawConf;
+                false ->
+                    RawConf#{<<"opentelemetry">> => Otel1#{<<"metrics">> => Metrics}}
+            end;
+        _ ->
+            RawConf
+    end.
+
 namespace() -> opentelemetry.
+
 roots() -> ["opentelemetry"].
 
 fields("opentelemetry") ->
     [
-        {exporter,
+        {metrics,
             ?HOCON(
-                ?R_REF("exporter"),
-                #{desc => ?DESC(exporter)}
+                ?R_REF("otel_metrics"),
+                #{
+                    desc => ?DESC(otel_metrics)
+                }
             )},
+        {logs,
+            ?HOCON(
+                ?R_REF("otel_logs"),
+                #{
+                    desc => ?DESC(otel_logs)
+                }
+            )}
+    ];
+fields("otel_metrics") ->
+    [
         {enable,
             ?HOCON(
                 boolean(),
@@ -42,41 +74,130 @@ fields("opentelemetry") ->
                     required => true,
                     desc => ?DESC(enable)
                 }
+            )},
+        {exporter,
+            ?HOCON(
+                ?R_REF("otel_metrics_exporter"),
+                #{desc => ?DESC(exporter)}
             )}
     ];
-fields("exporter") ->
+fields("otel_logs") ->
     [
-        {"protocol",
+        {level,
             ?HOCON(
-                %% http_protobuf is not support for metrics yet.
-                ?ENUM([grpc]),
+                emqx_conf_schema:log_level(),
                 #{
-                    mapping => "opentelemetry_exporter.otlp_protocol",
-                    desc => ?DESC(protocol),
-                    default => grpc,
+                    default => warning,
+                    desc => ?DESC(otel_log_handler_level),
+                    importance => ?IMPORTANCE_HIGH
+                }
+            )},
+        {enable,
+            ?HOCON(
+                boolean(),
+                #{
+                    default => false,
+                    desc => ?DESC(enable),
+                    importance => ?IMPORTANCE_HIGH
+                }
+            )},
+        {max_queue_size,
+            ?HOCON(
+                pos_integer(),
+                #{
+                    default => 2048,
+                    desc => ?DESC(max_queue_size),
                     importance => ?IMPORTANCE_HIDDEN
                 }
             )},
-        {"endpoint",
+        {exporting_timeout,
             ?HOCON(
-                emqx_schema:url(),
+                emqx_schema:timeout_duration_ms(),
                 #{
-                    mapping => "opentelemetry_exporter.otlp_endpoint",
-                    default => <<"http://localhost:4317">>,
-                    desc => ?DESC(endpoint)
+                    default => <<"30s">>,
+                    desc => ?DESC(exporting_timeout),
+                    importance => ?IMPORTANCE_HIDDEN
                 }
             )},
-        {"interval",
+        {scheduled_delay,
             ?HOCON(
                 emqx_schema:timeout_duration_ms(),
                 #{
-                    default => <<"10s">>,
-                    required => true,
-                    desc => ?DESC(interval)
+                    default => <<"1s">>,
+                    desc => ?DESC(scheduled_delay),
+                    importance => ?IMPORTANCE_HIDDEN
+                }
+            )},
+        {exporter,
+            ?HOCON(
+                ?R_REF("otel_logs_exporter"),
+                #{
+                    desc => ?DESC(exporter),
+                    importance => ?IMPORTANCE_HIGH
                 }
             )}
-    ].
+    ];
+fields("otel_metrics_exporter") ->
+    exporter_fields(metrics);
+fields("otel_logs_exporter") ->
+    exporter_fields(logs);
+fields("ssl_opts") ->
+    Schema = emqx_schema:client_ssl_opts_schema(#{}),
+    lists:keydelete("enable", 1, Schema).
 
 desc("opentelemetry") -> ?DESC(opentelemetry);
 desc("exporter") -> ?DESC(exporter);
+desc("otel_logs_exporter") -> ?DESC(exporter);
+desc("otel_metrics_exporter") -> ?DESC(exporter);
+desc("otel_logs") -> ?DESC(otel_logs);
+desc("otel_metrics") -> ?DESC(otel_metrics);
+desc("ssl_opts") -> ?DESC(exporter_ssl);
 desc(_) -> undefined.
+
+exporter_fields(OtelSignal) ->
+    [
+        {endpoint,
+            ?HOCON(
+                emqx_schema:url(),
+                #{
+                    default => "http://localhost:4317",
+                    desc => ?DESC(exporter_endpoint),
+                    importance => ?IMPORTANCE_HIGH
+                }
+            )},
+        {protocol,
+            ?HOCON(
+                %% http protobuf/json may be added in future
+                ?ENUM([grpc]),
+                #{
+                    default => grpc,
+                    desc => ?DESC(exporter_protocol),
+                    importance => ?IMPORTANCE_HIDDEN
+                }
+            )},
+        {ssl_options,
+            ?HOCON(
+                ?R_REF("ssl_opts"),
+                #{
+                    desc => ?DESC(exporter_ssl),
+                    importance => ?IMPORTANCE_LOW
+                }
+            )}
+    ] ++ exporter_extra_fields(OtelSignal).
+
+%% Let's keep it in exporter config for metrics, as it is different from
+%% scheduled_delay_ms opt used for otel traces and logs
+exporter_extra_fields(metrics) ->
+    [
+        {interval,
+            ?HOCON(
+                emqx_schema:timeout_duration_ms(),
+                #{
+                    default => <<"10s">>,
+                    required => true,
+                    desc => ?DESC(scheduled_delay)
+                }
+            )}
+    ];
+exporter_extra_fields(_OtelSignal) ->
+    [].

apps/emqx_opentelemetry/src/emqx_otel_sup.erl

@@ -41,8 +41,8 @@ init([]) ->
         period => 512
     },
     Children =
-        case emqx_conf:get([opentelemetry]) of
+        case emqx_conf:get([opentelemetry, metrics]) of
             #{enable := false} -> [];
-            #{enable := true} = Conf -> [worker_spec(emqx_otel, Conf)]
+            #{enable := true} = Conf -> [worker_spec(emqx_otel_metrics, Conf)]
         end,
     {ok, {SupFlags, Children}}.

changes/ce/feat-11921.en.md

@@ -0,0 +1,2 @@
+Introduced Open Telemetry Logs Handler that allows to format log events according to Open Telemetry log data model and
+export them to the configured Open Telemetry collector or back-end.

mix.exs

@@ -102,31 +102,31 @@ defmodule EMQXUmbrella.MixProject do
       {:opentelemetry_api,
        github: "emqx/opentelemetry-erlang",
        sparse: "apps/opentelemetry_api",
-       tag: "v1.3.2-emqx",
+       tag: "v1.4.2-emqx",
        override: true,
        runtime: false},
       {:opentelemetry,
        github: "emqx/opentelemetry-erlang",
        sparse: "apps/opentelemetry",
-       tag: "v1.3.2-emqx",
+       tag: "v1.4.2-emqx",
        override: true,
        runtime: false},
       {:opentelemetry_api_experimental,
        github: "emqx/opentelemetry-erlang",
        sparse: "apps/opentelemetry_api_experimental",
-       tag: "v1.3.2-emqx",
+       tag: "v1.4.2-emqx",
        override: true,
        runtime: false},
       {:opentelemetry_experimental,
        github: "emqx/opentelemetry-erlang",
        sparse: "apps/opentelemetry_experimental",
-       tag: "v1.3.2-emqx",
+       tag: "v1.4.2-emqx",
        override: true,
        runtime: false},
       {:opentelemetry_exporter,
        github: "emqx/opentelemetry-erlang",
        sparse: "apps/opentelemetry_exporter",
-       tag: "v1.3.2-emqx",
+       tag: "v1.4.2-emqx",
        override: true,
        runtime: false}
     ] ++

rebar.config

@@ -85,13 +85,13 @@
     , {jsone, {git, "https://github.com/emqx/jsone.git", {tag, "1.7.1"}}}
     , {uuid, {git, "https://github.com/okeuday/uuid.git", {tag, "v2.0.6"}}}
     %% trace
-    , {opentelemetry_api, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.3.2-emqx"}, "apps/opentelemetry_api"}}
-    , {opentelemetry, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.3.2-emqx"}, "apps/opentelemetry"}}
+    , {opentelemetry_api, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.4.2-emqx"}, "apps/opentelemetry_api"}}
+    , {opentelemetry, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.4.2-emqx"}, "apps/opentelemetry"}}
     %% log metrics
-    , {opentelemetry_experimental, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.3.2-emqx"}, "apps/opentelemetry_experimental"}}
-    , {opentelemetry_api_experimental, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.3.2-emqx"}, "apps/opentelemetry_api_experimental"}}
+    , {opentelemetry_experimental, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.4.2-emqx"}, "apps/opentelemetry_experimental"}}
+    , {opentelemetry_api_experimental, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.4.2-emqx"}, "apps/opentelemetry_api_experimental"}}
     %% export
-    , {opentelemetry_exporter, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.3.2-emqx"}, "apps/opentelemetry_exporter"}}
+    , {opentelemetry_exporter, {git_subdir, "https://github.com/emqx/opentelemetry-erlang", {tag, "v1.4.2-emqx"}, "apps/opentelemetry_exporter"}}
     ]}.
 
 {xref_ignores,

rel/i18n/emqx_otel_schema.hocon

@@ -1,15 +1,44 @@
 emqx_otel_schema {
 
 opentelemetry.desc: "Open Telemetry Toolkit configuration"
+opentelemetry.label: "Open Telemetry"
+
+otel_logs.desc:
+"""Open Telemetry Logs configuration. If enabled, EMQX installs a log handler that formats events according to Open Telemetry log data model and
+exports them to the configured Open Telemetry collector or backend."""
+otel_logs.label: "Open Telemetry Logs"
+
+otel_metrics.desc: "Open Telemetry Metrics configuration."
+otel_metrics.label: "Open Telemetry Metrics"
+
+enable.desc: "Enable or disable Open Telemetry signal."
+enable.label: "Enable."
 
 exporter.desc: "Open Telemetry Exporter"
+exporter.label: "Exporter"
+
+max_queue_size.desc:
+"""The maximum queue size. After the size is reached Open Telemetry signals are dropped."""
+max_queue_size.label: "Max Queue Size"
+
+exporting_timeout.desc: "The time Open Telemetry signal export can run before it is cancelled."
+exporting_timeout.label: "Exporting Timeout"
+
+scheduled_delay.desc: "The delay interval between two consecutive exports of Open Telemetry signals."
+scheduled_delay.label: "Scheduled Delay Interval"
 
-enable.desc: "Enable or disable open telemetry metrics"
+exporter_endpoint.desc:
+"""The target URL to which the exporter is going to send Open Telemetry signal data."""
+exporter_endpoint.label: "Exporter Endpoint"
 
-protocol.desc: "Open Telemetry Exporter Protocol"
+exporter_protocol.desc: "The transport protocol of Open Telemetry Exporter"
+exporter_protocol.label: "Exporter Protocol"
 
-endpoint.desc: "Open Telemetry Exporter Endpoint"
+exporter_ssl.desc: "SSL configuration for the Open Telemetry exporter"
+exporter_ssl.label: "SSL Options"
 
-interval.desc: "The interval of sending metrics to Open Telemetry Endpoint"
+otel_log_handler_level.desc:
+"""The log level of the Open Telemetry log handler."""
+otel_log_handler_level.label: "Log Level"
 
 }