[metric][improve]Histgram label expire (#857)

include/ylt/metric/dynamic_metric.hpp

@@ -92,6 +92,15 @@ class dynamic_metric_impl : public dynamic_metric {
     return map_.template copy<std::shared_ptr<metric_pair>>();
   }
 
+  void clean_expired_label() override {
+    erase_if([now = std::chrono::steady_clock::now()](auto& pair) mutable {
+      bool r = std::chrono::duration_cast<std::chrono::seconds>(
+                   now - pair.second->get_created_time())
+                   .count() >= ylt_label_max_age.count();
+      return r;
+    });
+  }
+
  protected:
   template <typename Key, typename... Args>
   std::pair<std::shared_ptr<metric_pair>, bool> try_emplace(Key&& key,
@@ -107,14 +116,7 @@ class dynamic_metric_impl : public dynamic_metric {
         },
         std::forward<Key>(key), std::forward<Args>(args)...);
   }
-  void clean_expired_label() override {
-    erase_if([now = std::chrono::steady_clock::now()](auto& pair) mutable {
-      bool r = std::chrono::duration_cast<std::chrono::seconds>(
-                   now - pair.second->get_created_time())
-                   .count() >= ylt_label_max_age.count();
-      return r;
-    });
-  }
+
   std::shared_ptr<metric_pair> find(std::span<const std::string, N> key) const {
     return map_.find(key);
   }

include/ylt/metric/histogram.hpp

@@ -188,6 +188,13 @@ class basic_dynamic_histogram : public dynamic_metric {
     bucket_counts_[bucket_index]->inc(labels_value);
   }
 
+  void clean_expired_label() override {
+    sum_->clean_expired_label();
+    for (auto &m : bucket_counts_) {
+      m->clean_expired_label();
+    }
+  }
+
   auto get_bucket_counts() { return bucket_counts_; }
 
   bool has_label_value(const std::string &label_val) override {
@@ -202,6 +209,8 @@ class basic_dynamic_histogram : public dynamic_metric {
     return sum_->has_label_value(label_value);
   }
 
+  size_t label_value_count() const { return sum_->label_value_count(); }
+
   void serialize(std::string &str) override {
     auto value_map = sum_->copy();
     if (value_map.empty()) {

src/metric/tests/test_metric.cpp

@@ -1946,14 +1946,32 @@ TEST_CASE("test metric manager clean expired label") {
   auto& inst = dynamic_metric_manager<test_tag>::instance();
   auto pair = inst.create_metric_dynamic<dynamic_counter_1t>(
       std::string("some_counter"), "", std::array<std::string, 1>{"url"});
+  auto summary = std::make_shared<basic_dynamic_summary<2>>(
+      std::string("test_summary"), std::string("summary help"),
+      std::vector<double>{0.5, 0.9, 0.95, 0.99},
+      std::array<std::string, 2>{"method", "url"});
+  auto h = std::make_shared<dynamic_histogram_t>(
+      std::string("test"), std::string("help"),
+      std::vector<double>{5.23, 10.54, 20.0, 50.0, 100.0},
+      std::array<std::string, 2>{"method", "url"});
+  inst.register_metric(summary);
+  inst.register_metric(h);
   auto c = pair.second;
   c->inc({"/"});
   c->inc({"/test"});
+  summary->observe({"GET", "test"}, 10);
+  h->observe({"GET", "test"}, 10);
   CHECK(c->label_value_count() == 2);
+  CHECK(summary->label_value_count() == 1);
+  CHECK(h->label_value_count() == 1);
   std::this_thread::sleep_for(std::chrono::seconds(2));
   c->inc({"/index"});
   size_t count = c->label_value_count();
   CHECK(count == 1);
+  auto ct1 = summary->label_value_count();
+  CHECK(ct1 == 0);
+  auto ct2 = h->label_value_count();
+  CHECK(ct2 == 0);
 }
 
 TEST_CASE("test remove label value") {