rabbitmq · mkuratczyk · May 14, 2025 · May 15, 2025 · May 16, 2025 · May 26, 2025
diff --git a/Makefile b/Makefile
@@ -10,7 +10,7 @@ ESCRIPT_EMU_ARGS = -noinput -setcookie ra_fifo_cli
 
 dep_gen_batch_server = hex 0.8.9
 dep_aten = hex 0.6.0
-dep_seshat = hex 0.6.0
+dep_seshat = git https://github.com/rabbitmq/seshat.git prometheus-support
 DEPS = aten gen_batch_server seshat
 
 TEST_DEPS = proper meck eunit_formatters inet_tcp_proxy

diff --git a/README.md b/README.md
@@ -53,7 +53,7 @@ which algorithms such as Raft significantly benefit from.
 
 This library was primarily developed as the foundation of a replication layer for
 [quorum queues](https://rabbitmq.com/quorum-queues.html) in RabbitMQ, and today
-also powers [RabbitMQ streams](https://rabbitmq.com/streams.html) and [Khepri](https://github.com/rabbitmq/khepri). 
+also powers [RabbitMQ streams](https://rabbitmq.com/streams.html) and [Khepri](https://github.com/rabbitmq/khepri).
 
 The design it aims to replace uses
 a variant of [Chain Based Replication](https://www.cs.cornell.edu/home/rvr/papers/OSDI04.pdf)
@@ -405,9 +405,14 @@ is available in a separate repository.
     </tr>
     <tr>
         <td>metrics_key</td>
-        <td>Metrics key. The key used to write metrics into the ra_metrics table.</td>
+        <td>DEPRECATED: Metrics key. The key was used to write metrics into the ra_metrics table. Metrics are now in Seshat.</td>
         <td>Atom</td>
     </tr>
+    <tr>
+        <td>metrics_labels</td>
+        <td>Metrics labels. Labels that are later returned with metrics for this server (eg. `#{vhost => ..., queue => ...}` for quorum queues).</td>
+        <td>Map</td>
+    </tr>
     <tr>
         <td>low_priority_commands_flush_size</td>
         <td>

diff --git a/rebar.config b/rebar.config
@@ -1,7 +1,7 @@
 {deps, [
         {gen_batch_server, "0.8.9"},
         {aten, "0.6.0"},
-        {seshat, "0.6.0"}
+	{seshat, {git, "https://github.com/rabbitmq/seshat.git", {branch, "prometheus-support"}}}
 ]}.
 
 {profiles,

diff --git a/rebar.lock b/rebar.lock
@@ -1,14 +1,11 @@
 {"1.2.0",
 [{<<"aten">>,{pkg,<<"aten">>,<<"0.6.0">>},0},
- {<<"gen_batch_server">>,{pkg,<<"gen_batch_server">>,<<"0.8.9">>},0},
- {<<"seshat">>,{pkg,<<"seshat">>,<<"0.6.0">>},0}]}.
+ {<<"gen_batch_server">>,{pkg,<<"gen_batch_server">>,<<"0.8.9">>},0}]}.
 [
 {pkg_hash,[
  {<<"aten">>, <<"7A57B275A6DAF515AC3683FB9853E280B4D0DCDD74292FD66AC4A01C8694F8C7">>},
- {<<"gen_batch_server">>, <<"1C6BC0F530BF8C17E8B4ACC20C2CC369FFA5BEE2B46DE01E21410745F24B1BC9">>},
- {<<"seshat">>, <<"3172EB1D7A2A4F66108CD6933A4E465AFF80F84AA90ED83F047B92F636123CCD">>}]},
+ {<<"gen_batch_server">>, <<"1C6BC0F530BF8C17E8B4ACC20C2CC369FFA5BEE2B46DE01E21410745F24B1BC9">>}]},
 {pkg_hash_ext,[
  {<<"aten">>, <<"5F39A164206AE3F211EF5880B1F7819415686436E3229D30B6A058564FBAA168">>},
- {<<"gen_batch_server">>, <<"C8581FE4A4B6BCCF91E53CE6A8C7E6C27C8C591BAB5408B160166463F5579C22">>},
- {<<"seshat">>, <<"7CEF700F92831DD7CAE6A6DD223CCC55AC88ECCE0631EE9AB0F2B5FB70E79B90">>}]}
+ {<<"gen_batch_server">>, <<"C8581FE4A4B6BCCF91E53CE6A8C7E6C27C8C591BAB5408B160166463F5579C22">>}]}
 ].
diff --git a/src/ra.hrl b/src/ra.hrl
@@ -389,7 +389,7 @@
           "The last index of the log."},
          {last_written_index, ?C_RA_SVR_METRIC_LAST_WRITTEN_INDEX, counter,
           "The last fully written and fsynced index of the log."},
-         {commit_latency, ?C_RA_SVR_METRIC_COMMIT_LATENCY, gauge,
+         {commit_latency, ?C_RA_SVR_METRIC_COMMIT_LATENCY, {gauge, time_ms},
           "Approximate time taken from an entry being written to the log until it is committed."},
          {term, ?C_RA_SVR_METRIC_TERM, counter, "The current term."},
          {checkpoint_index, ?C_RA_SVR_METRIC_CHECKPOINT_INDEX, counter,

diff --git a/src/ra_bench.erl b/src/ra_bench.erl
@@ -199,9 +199,8 @@ spawn_client(Parent, Leader, Num, DataSize, Pipe, Counter) ->
               end
       end).
 
-print_metrics(Name) ->
+print_metrics(_Name) ->
     io:format("Node: ~w~n", [node()]),
-    io:format("metrics ~p~n", [ets:lookup(ra_metrics, Name)]),
     io:format("counters ~p~n", [ra_counters:overview()]).
 
 
@@ -220,4 +219,3 @@ print_metrics(Name) ->
 %     GzFile = Base ++ ".gz.*",
 %     lg_callgrind:profile_many(GzFile, Base ++ ".out",#{}),
 %     ok.
-
diff --git a/src/ra_counters.erl b/src/ra_counters.erl
@@ -10,6 +10,7 @@
 -export([
          init/0,
          new/2,
+         new/3,
          fetch/1,
          overview/0,
          overview/1,
@@ -32,6 +33,9 @@ init() ->
 new(Name, FieldsSpec) ->
     seshat:new(ra, Name, FieldsSpec).
 
+new(Name, FieldsSpec, MetricLabels) ->
+    seshat:new(ra, Name, FieldsSpec, MetricLabels).
+
 -spec fetch(name()) -> undefined | counters:counters_ref().
 fetch(Name) ->
     seshat:fetch(ra, Name).
@@ -42,11 +46,11 @@ delete(Name) ->
 
 -spec overview() -> #{name() => #{atom() => non_neg_integer()}}.
 overview() ->
-    seshat:overview(ra).
+    seshat:counters(ra).
 
--spec overview(name()) -> #{atom() => non_neg_integer()}.
+-spec overview(name()) -> #{atom() => non_neg_integer()} | undefined.
 overview(Name) ->
-    seshat:overview(ra, Name).
+    seshat:counters(ra, Name).
 
 -spec counters(name(), [atom()]) ->
     #{atom() => non_neg_integer()} | undefined.

diff --git a/src/ra_log_segment_writer.erl b/src/ra_log_segment_writer.erl
@@ -115,7 +115,7 @@ init([#{data_dir := DataDir,
         name := SegWriterName,
         system := System} = Conf]) ->
     process_flag(trap_exit, true),
-    CRef = ra_counters:new(SegWriterName, ?COUNTER_FIELDS),
+    CRef = ra_counters:new(SegWriterName, ?COUNTER_FIELDS, #{ra_system => System, module => ?MODULE}),
     SegmentConf = maps:get(segment_conf, Conf, #{}),
     maybe_upgrade_segment_file_names(System, DataDir),
     {ok, #state{system = System,
@@ -554,4 +554,3 @@ maybe_upgrade_segment_file_names(System, DataDir) ->
         true ->
             ok
     end.
-
diff --git a/src/ra_log_sup.erl b/src/ra_log_sup.erl
@@ -56,7 +56,7 @@ init([#{data_dir := DataDir,
 
 
 make_wal_conf(#{data_dir := DataDir,
-                name := _System,
+                name := System,
                 names := #{wal := WalName,
                            segment_writer := SegWriterName} = Names} = Cfg) ->
     WalDir = case Cfg of
@@ -78,6 +78,7 @@ make_wal_conf(#{data_dir := DataDir,
                                ?MIN_BIN_VHEAP_SIZE),
     MinHeapSize = maps:get(wal_min_heap_size, Cfg, ?MIN_HEAP_SIZE),
     #{name => WalName,
+      system => System,
       names => Names,
       dir => WalDir,
       segment_writer => SegWriterName,

diff --git a/src/ra_log_wal.erl b/src/ra_log_wal.erl
@@ -132,6 +132,7 @@
 
 -type state() :: #state{}.
 -type wal_conf() :: #{name := atom(), %% the name to register the wal as
+                      system := atom(),
                       names := ra_system:names(),
                       dir := file:filename_all(),
                       max_size_bytes => non_neg_integer(),
@@ -254,7 +255,7 @@ start_link(#{name := Name} = Config)
 -spec init(wal_conf()) ->
     {ok, state()} |
     {stop, wal_checksum_validation_failure} | {stop, term()}.
-init(#{dir := Dir} = Conf0) ->
+init(#{dir := Dir, system := System} = Conf0) ->
     #{max_size_bytes := MaxWalSize,
       max_entries := MaxEntries,
       recovery_chunk_size := RecoveryChunkSize,
@@ -278,7 +279,7 @@ init(#{dir := Dir} = Conf0) ->
     process_flag(message_queue_data, off_heap),
     process_flag(min_bin_vheap_size, MinBinVheapSize),
     process_flag(min_heap_size, MinHeapSize),
-    CRef = ra_counters:new(WalName, ?COUNTER_FIELDS),
+    CRef = ra_counters:new(WalName, ?COUNTER_FIELDS, #{ra_system => System, module => ?MODULE}),
     Conf = #conf{dir = Dir,
                  segment_writer = SegWriter,
                  compute_checksums = ComputeChecksums,

diff --git a/src/ra_server.erl b/src/ra_server.erl
@@ -30,7 +30,6 @@
          tick/1,
          log_tick/1,
          overview/1,
-         metrics/1,
          is_new/1,
          is_fully_persisted/1,
          is_fully_replicated/1,
@@ -219,6 +218,7 @@
                               initial_machine_version => ra_machine:version(),
                               friendly_name => unicode:chardata(),
                               metrics_key => term(),
+                              metrics_labels => map(),
                               % TODO: review - only really used for
                               % setting election timeouts
                               broadcast_time => non_neg_integer(), % ms
@@ -258,6 +258,7 @@
 
 -type mutable_config() :: #{cluster_name => ra_cluster_name(),
                             metrics_key => term(),
+                            metrics_labels => map(),
                             broadcast_time => non_neg_integer(), % ms
                             tick_timeout => non_neg_integer(), % ms
                             install_snap_rpc_timeout => non_neg_integer(), % ms
@@ -380,6 +381,7 @@ init(#{id := Id,
                uid = UId,
                log_id = LogId,
                metrics_key = MetricKey,
+               metrics_labels = #{},
                machine = Machine,
                machine_version = LatestMacVer,
                machine_versions = [{SnapshotIdx, EffectiveMacVer}],
@@ -1793,28 +1795,6 @@ cfg_to_map(Cfg) ->
                          {N + 1, Acc#{F => element(N, Cfg)}}
                  end, {2, #{}}, record_info(fields, cfg))).
 
--spec metrics(ra_server_state()) ->
-    {atom(), ra_term(),
-     ra_index(), ra_index(),
-     ra_index(), ra_index(), non_neg_integer()}.
-metrics(#{cfg := #cfg{metrics_key = Key},
-          commit_index := CI,
-          last_applied := LA,
-          current_term := CT,
-          log := Log} = State) ->
-    SnapIdx = case ra_log:snapshot_index_term(Log) of
-                  undefined -> 0;
-                  {I, _} -> I
-              end,
-    CL = case  State of
-             #{commit_latency := L} ->
-                 L;
-             _ ->
-                 0
-         end,
-    {LW, _} = ra_log:last_index_term(Log),
-    {Key, CT, SnapIdx, LA, CI, LW, CL}.
-
 -spec is_new(ra_server_state()) -> boolean().
 is_new(#{log := Log}) ->
     ra_log:next_index(Log) =:= 1.

diff --git a/src/ra_server.hrl b/src/ra_server.hrl
@@ -16,6 +16,7 @@
          uid :: ra_uid(),
          log_id :: unicode:chardata(),
          metrics_key :: term(),
+         metrics_labels :: map(),
          machine :: ra_machine:machine(),
          machine_version :: ra_machine:version(),
          machine_versions :: [{ra_index(), ra_machine:version()}, ...],

diff --git a/src/ra_server_proc.erl b/src/ra_server_proc.erl
@@ -316,8 +316,9 @@ do_init(#{id := Id,
     Key = ra_lib:ra_server_id_to_local_name(Id),
     true = ets:insert(ra_state, {Key, init, unknown}),
     process_flag(trap_exit, true),
+    MetricLabels = maps:get(metrics_labels, Config0, #{}),
     Config = #{counter := Counter,
-               system_config := #{names := Names} = SysConf} = maps:merge(config_defaults(Id),
+               system_config := #{names := Names} = SysConf} = maps:merge(config_defaults(Id, MetricLabels),
                                                       Config0),
     MsgQData = maps:get(message_queue_data, SysConf, off_heap),
     MinBinVheapSize = maps:get(server_min_bin_vheap_size, SysConf,
@@ -413,9 +414,8 @@ recovered(enter, OldState, State0) ->
     {State, Actions} = handle_enter(?FUNCTION_NAME, OldState, State0),
     ok = record_cluster_change(State),
     {keep_state, State, Actions};
-recovered(internal, next, #state{server_state = ServerState} = State) ->
+recovered(internal, next, State) ->
     true = erlang:garbage_collect(),
-    _ = ets:insert(ra_metrics, ra_server:metrics(ServerState)),
     next_state(follower, State, set_tick_timer(State, [])).
 
 leader(enter, OldState, #state{low_priority_commands = Delayed0} = State0) ->
@@ -568,7 +568,7 @@ leader(_, tick_timeout, State0) ->
                                         cast, State1#state{server_state = ServerState}),
     %% try sending any pending applied notifications again
     State = send_applied_notifications(State2, #{}),
-    {keep_state, handle_tick_metrics(State),
+    {keep_state, State,
      set_tick_timer(State, Actions)};
 leader({timeout, Name}, machine_timeout, State0) ->
     % the machine timer timed out, add a timeout message
@@ -645,7 +645,7 @@ candidate(info, {node_event, _Node, _Evt}, State) ->
     {keep_state, State};
 candidate(_, tick_timeout, State0) ->
     State = maybe_persist_last_applied(State0),
-    {keep_state, handle_tick_metrics(State), set_tick_timer(State, [])};
+    {keep_state, State, set_tick_timer(State, [])};
 candidate({call, From}, trigger_election, State) ->
     {keep_state, State, [{reply, From, ok}]};
 candidate(EventType, Msg, State0) ->
@@ -706,7 +706,7 @@ pre_vote(info, {'DOWN', _MRef, process, Pid, Info}, State0) ->
     handle_process_down(Pid, Info, ?FUNCTION_NAME, State0);
 pre_vote(_, tick_timeout, State0) ->
     State = maybe_persist_last_applied(State0),
-    {keep_state, handle_tick_metrics(State), set_tick_timer(State, [])};
+    {keep_state, State, set_tick_timer(State, [])};
 pre_vote({call, From}, trigger_election, State) ->
     {keep_state, State, [{reply, From, ok}]};
 pre_vote(EventType, Msg, State0) ->
@@ -849,8 +849,7 @@ follower(_, tick_timeout, #state{server_state = ServerState0} = State0) ->
     ServerState = ra_server:log_tick(ServerState0),
     {State, Actions} = ?HANDLE_EFFECTS([{aux, tick}], cast,
                                        State0#state{server_state = ServerState}),
-    {keep_state, handle_tick_metrics(State),
-     set_tick_timer(State, Actions)};
+    {keep_state, State, set_tick_timer(State, Actions)};
 follower({call, From}, {log_fold, Fun, Term}, State) ->
     fold_log(From, Fun, Term, State);
 follower(EventType, Msg, #state{conf = #conf{name = Name},
@@ -1074,7 +1073,7 @@ handle_event(_EventType, EventContent, StateName, State) ->
 
 terminate(Reason, StateName,
           #state{conf = #conf{name = Key, cluster_name = ClusterName},
-                 server_state = ServerState = #{cfg := #cfg{metrics_key = MetricsKey}}} = State) ->
+                 server_state = ServerState} = State) ->
     ?DEBUG("~ts: terminating with ~w in state ~w",
            [log_id(State), Reason, StateName]),
     #{names := #{server_sup := SrvSup,
@@ -1115,7 +1114,6 @@ terminate(Reason, StateName,
             ok
     end,
     catch ra_leaderboard:clear(ClusterName),
-    _ = ets:delete(ra_metrics, MetricsKey),
     _ = ets:delete(ra_state, Key),
     ok;
 %% This occurs if there is a crash in the init callback of the ra_machine,
@@ -1805,11 +1803,11 @@ gen_statem_safe_call(ServerId, Msg, Timeout) ->
 do_state_query(QueryName, #state{server_state = State}) ->
     ra_server:state_query(QueryName, State).
 
-config_defaults(ServerId) ->
+config_defaults(ServerId, MetricLabels) ->
     Counter = case ra_counters:fetch(ServerId) of
                   undefined ->
                       ra_counters:new(ServerId,
-                                      {persistent_term, ?FIELDSPEC_KEY});
+                                      {persistent_term, ?FIELDSPEC_KEY}, MetricLabels);
                   C ->
                       C
               end,
@@ -2006,12 +2004,6 @@ get_node({_, Node}) ->
 get_node(Proc) when is_atom(Proc) ->
     node().
 
-handle_tick_metrics(State) ->
-    ServerState = State#state.server_state,
-    Metrics = ra_server:metrics(ServerState),
-    _ = ets:insert(ra_metrics, Metrics),
-    State.
-
 can_execute_locally(RaftState, TargetNode,
                     #state{server_state = ServerState} = State) ->
     case RaftState of

diff --git a/src/ra_server_sup_sup.erl b/src/ra_server_sup_sup.erl
@@ -185,7 +185,6 @@ delete_server_rpc(System, RaName) ->
             %% forcefully clean up ETS tables
             catch ets:delete(ra_log_metrics, UId),
             catch ets:delete(ra_log_snapshot_state, UId),
-            catch ets:delete(ra_metrics, RaName),
             catch ets:delete(ra_state, RaName),
             catch ets:delete(ra_open_file_metrics, Pid),
             catch ra_counters:delete({RaName, node()}),

diff --git a/src/ra_sup.erl b/src/ra_sup.erl
@@ -11,8 +11,7 @@
 -export([start_link/0]).
 -export([init/1]).
 
--define(TABLES, [ra_metrics,
-                 ra_state,
+-define(TABLES, [ra_state,
                  ra_open_file_metrics,
                  ra_io_metrics
                  ]).

diff --git a/test/ra_2_SUITE.erl b/test/ra_2_SUITE.erl
@@ -277,8 +277,7 @@ validate_ets_table_deletes(UIds, Pids, Peers) ->
 
     %% validate by registered name is also cleaned up
     [ [] = ets:lookup(T, Name) || {Name, _} <- Peers,
-                                    T <-  [ra_metrics,
-                                           ra_state]],
+                                    T <-  [ra_state]],
 
     %% validate open file metrics is cleaned up
     [ [] = ets:lookup(T, Pid) || Pid <- Pids,