metrics: Adds metrics_family_config support

Family config is a configuration that relates to all metrics with the
same name but with different labels values.

set_metrics_family_configs allows changing that configuration during run
time. Specifically, change the label aggregation based on a metric name.

The following is an example for setting the aggregate labels for the
metric test_gauge_1 and all metrics matching the regex test_gauge1.*:

std::vector<sm::metrics_family_config> fc(2);
fc[0].name = "test_gauge_1";
fc[0].aggregate_labels = { "lb" };
fc[1].regex_name = "test_gauge1.*";
fc[1].aggregate_labels = { "ll", "aa" };

sm::set_metrics_family_configs(fc);

Signed-off-by: Amnon Heiman <[email protected]>

include/seastar/core/metrics_api.hh

include/seastar/core/metrics_api.hh

@@ -69,6 +69,8 @@ namespace metrics {
 SEASTAR_MODULE_EXPORT
 struct relabel_config;
 
+SEASTAR_MODULE_EXPORT
+struct metrics_family_config;
 /*!
  * \brief result of metric relabeling
  *
@@ -330,10 +332,17 @@ using metric_metadata_fifo = std::deque<metric_info>;
  *
  * The meta data of a metric family compose of the
  * metadata of the family, and a vector of the metadata for
- * each of the metric.
+ * each of the metrics.
+ *
+ * The struct is used for two purposes. First, it allows iterating over all metric_families
+ * and all metrics related to them. Second, it only contains enabled metrics,
+ * making disabled metrics more efficient.
+ * The struct is recreated when impl._value_map changes
+ * Using a pointer to the family_info metadata is an efficient way to get
+ * from a metric_family to its metadata based on its name.
  */
 struct metric_family_metadata {
- metric_family_info& mf;
+ metric_family_info& mf; //This points to impl._value_map
  metric_metadata_fifo metrics;
 };
 
@@ -358,6 +367,7 @@ class impl {
  std::set<sstring> _labels;
  std::vector<std::deque<metric_function>> _current_metrics;
  std::vector<relabel_config> _relabel_configs;
+ std::vector<metrics_family_config> _metrics_family_configs;
 public:
  value_map& get_value_map() {
  return _value_map;
@@ -398,6 +408,13 @@ public:
  const std::vector<relabel_config>& get_relabel_configs() const noexcept {
  return _relabel_configs;
  }
+ const std::vector<metrics_family_config>& get_metrics_family_configs() const noexcept {
+ return _metrics_family_configs;
+ }
+
+ void set_metrics_family_configs(const std::vector<metrics_family_config>& metrics_config);
+
+ void update_aggregate(metric_family_info& mf) const noexcept;
 };
 
 const value_map& get_value_map();
@@ -486,5 +503,29 @@ future<metric_relabeling_result> set_relabel_configs(const std::vector<relabel_c
  */
 const std::vector<relabel_config>& get_relabel_configs();
 
+/*
+ * \brief change the metrics family config
+ *
+ * Family config is a configuration that relates to all metrics with the same name but with different labels.
+ * set_metrics_family_configs allows changing that configuration during run time.
+ * Specifically, change the label aggregation based on a metric name.
+ *
+ * The following is an example for setting the aggregate labels for the metric test_gauge_1
+ * and all metrics matching the regex test_gauge1.*:
+ *
+ * std::vector<sm::metrics_family_config> fc(2);
+ * fc[0].name = "test_gauge_1";
+ * fc[0].aggregate_labels = { "lb" };
+ * fc[1].regex_name = "test_gauge1.*";
+ * fc[1].aggregate_labels = { "ll", "aa" };
+ * sm::set_metrics_family_configs(fc);
+ */
+void set_metrics_family_configs(const std::vector<metrics_family_config>& metrics_config);
+
+/*
+ * \brief return the current metrics_family_config
+ * This function returns a vector of the current metrics family config
+ */
+const std::vector<metrics_family_config>& get_metrics_family_configs();
 }
 }

src/core/metrics.cc

@@ -130,7 +130,20 @@ future<metric_relabeling_result> set_relabel_configs(const std::vector<relabel_c
 const std::vector<relabel_config>& get_relabel_configs() {
  return impl::get_local_impl()->get_relabel_configs();
 }
+void impl::impl::update_aggregate(metric_family_info& mf) const noexcept {
+ for (const auto& fc : _metrics_family_configs) {
+ if (fc.name == mf.name || fc.regex_name.match(mf.name)) {
+ mf.aggregate_labels = fc.aggregate_labels;
+ }
+ }
+}
+void set_metrics_family_configs(const std::vector<metrics_family_config>& family_config) {
+ impl::get_local_impl()->set_metrics_family_configs(family_config);
+}
 
+const std::vector<metrics_family_config>& get_metrics_family_configs() {
+ return impl::get_local_impl()->get_metrics_family_configs();
+}
 
 static bool apply_relabeling(const relabel_config& rc, impl::metric_info& info) {
  std::stringstream s;
@@ -454,6 +467,7 @@ void impl::add_registration(const metric_id& id, const metric_type& type, metric
  _value_map[name].info().inherit_type = type.type_name;
  _value_map[name].info().name = id.full_name();
  _value_map[name].info().aggregate_labels = aggregate_labels;
+ impl::update_aggregate(_value_map[name].info());
  _value_map[name][rm->info().id.labels()] = rm;
  }
  dirty();
@@ -503,6 +517,26 @@ future<metric_relabeling_result> impl::set_relabel_configs(const std::vector<rel
  }
  return make_ready_future<metric_relabeling_result>(conflicts);
 }
+
+void impl::set_metrics_family_configs(const std::vector<metrics_family_config>& family_config) {
+ _metrics_family_configs = family_config;
+ bool has_regex = false;
+ for (const auto& fc : family_config) {
+ has_regex |= !fc.regex_name.empty();
+ if (fc.name != "" && _value_map.find(fc.name) != _value_map.end()) {
+ _value_map[fc.name].info().aggregate_labels = fc.aggregate_labels;
+ }
+ }
+ if (has_regex) {
+ for (auto& [name, family] : _value_map) {
+ for (const auto& fc : family_config) {
+ if (fc.regex_name.match(name)) {
+ family.info().aggregate_labels = fc.aggregate_labels;
+ }
+ }
+ }
+ }
+}
 }
 
 const bool metric_disabled = false;