Emit identity info in prometheus /metrics/detailed endpoint

This is needed to make filtering metrics on a cluster name possible.

(cherry picked from commit 989a2997209045b0093e967ded1aa973303ca907)

2 files changed, 14 insertions, 5 deletions

diff --git a/deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl b/deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl
index bd1cd9067f..2e46eae4fd 100644
--- a/deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl
+++ b/deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl
@@ -233,15 +233,19 @@ deregister_cleanup(_) -> ok.
 
 collect_mf('detailed', Callback) ->
     collect(true, ?DETAILED_METRIC_NAME_PREFIX, vhosts_filter_from_pdict(), enabled_mfs_from_pdict(), Callback),
+    %% identity is here to enable filtering on a cluster name (as already happens in existing dashboards)
+    emit_identity_info(Callback),
     ok;
 collect_mf('per-object', Callback) ->
     collect(true, ?METRIC_NAME_PREFIX, false, ?METRICS_RAW, Callback),
     totals(Callback),
+    emit_identity_info(Callback),
     ok;
 collect_mf(_Registry, Callback) ->
     PerObjectMetrics = application:get_env(rabbitmq_prometheus, return_per_object_metrics, false),
     collect(PerObjectMetrics, ?METRIC_NAME_PREFIX, false, ?METRICS_RAW, Callback),
     totals(Callback),
+    emit_identity_info(Callback),
     ok.
 
 collect(PerObjectMetrics, Prefix, VHostsFilter, IncludedMFs, Callback) ->
@@ -255,8 +259,12 @@ totals(Callback) ->
          Size = ets:info(Table, size),
          mf_totals(Callback, Name, Type, Help, Size)
      end || {Table, Name, Type, Help} <- ?TOTALS],
+    ok.
+
+emit_identity_info(Callback) ->
     add_metric_family(build_info(), Callback),
-    add_metric_family(identity_info(), Callback).
+    add_metric_family(identity_info(), Callback),
+    ok.
 
 %% Aggregated `auth``_attempt_detailed_metrics` and
 %% `auth_attempt_metrics` are the same numbers. The former is just
diff --git a/deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl b/deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl
index a8c80afd98..e2380932de 100644
--- a/deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl
+++ b/deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl
@@ -515,14 +515,15 @@ parse_response(Body) ->
                 || L = [C|_] <- Lines, C /= $#
               ],
     lists:foldl(fun ({Metric, Label, Value}, MetricMap) ->
-                        case string:prefix(atom_to_list(Metric), "telemetry") of
-                            nomatch ->
+                        case re:run(atom_to_list(Metric), "^(telemetry|rabbitmq_identity_info|rabbitmq_build_info)", [{capture, none}]) of
+                            match ->
+                                MetricMap;
+                            _ ->
                                 OldLabelMap = maps:get(Metric, MetricMap, #{}),
                                 OldValues = maps:get(Label, OldLabelMap, []),
                                 NewValues = [Value|OldValues],
                                 NewLabelMap = maps:put(Label, NewValues, OldLabelMap),
-                                maps:put(Metric, NewLabelMap, MetricMap);
-                            _ -> MetricMap
+                                maps:put(Metric, NewLabelMap, MetricMap)
                         end
                 end, #{}, Metrics).