Separate Connection and Request lifetimes

src/metric.cpp

@@ -454,7 +454,7 @@ struct Metric {
     Arena arena;
     ThreadInit() {
       // Register this thread's arena for memory tracking
-      std::unique_lock<std::mutex> _{mutex};
+      std::unique_lock _{mutex};
       get_thread_arenas()[std::this_thread::get_id()] = &arena;
     }
     ~ThreadInit() {
@@ -462,7 +462,7 @@ struct Metric {
       // THREAD SAFETY: All operations below are protected by the global mutex,
       // including writes to global accumulated state, preventing races with
       // render thread
-      std::unique_lock<std::mutex> _{mutex};
+      std::unique_lock _{mutex};
       // NOTE: registration_version increment is REQUIRED here because:
       // - Cached render plan has pre-resolved pointers to thread-local state
       // - When threads disappear, these pointers become invalid
@@ -501,7 +501,7 @@ struct Metric {
         if (thread_it != family->per_thread_state.end()) {
           for (auto &[labels_key, instance] : thread_it->second.instances) {
             // Acquire lock to get consistent snapshot
-            std::lock_guard<std::mutex> lock(instance->mutex);
+            std::lock_guard lock(instance->mutex);
 
             // Global accumulator should have been created when we made the
             // histogram
@@ -592,7 +592,7 @@ struct Metric {
     // Force thread_local initialization
     (void)thread_init;
 
-    std::unique_lock<std::mutex> _{mutex};
+    std::unique_lock _{mutex};
     ++Metric::registration_version;
     const LabelsKey &key = intern_labels(labels);
 
@@ -633,7 +633,7 @@ struct Metric {
   static Gauge create_gauge_instance(
       Family<Gauge> *family,
       std::span<const std::pair<std::string_view, std::string_view>> labels) {
-    std::unique_lock<std::mutex> _{mutex};
+    std::unique_lock _{mutex};
     ++Metric::registration_version;
     const LabelsKey &key = intern_labels(labels);
 
@@ -659,7 +659,7 @@ struct Metric {
     // Force thread_local initialization
     (void)thread_init;
 
-    std::unique_lock<std::mutex> _{mutex};
+    std::unique_lock _{mutex};
     ++Metric::registration_version;
     const LabelsKey &key = intern_labels(labels);
 
@@ -1137,7 +1137,7 @@ struct Metric {
           uint64_t observations_snapshot;
 
           {
-            std::lock_guard<std::mutex> lock(instance->mutex);
+            std::lock_guard lock(instance->mutex);
             for (size_t i = 0; i < instance->counts.size(); ++i) {
               counts_snapshot[i] = instance->counts[i];
             }
@@ -1423,7 +1423,7 @@ update_histogram_buckets_simd(std::span<const double> thresholds,
 void Histogram::observe(double x) {
   assert(p->thresholds.size() == p->counts.size());
 
-  std::lock_guard<std::mutex> lock(p->mutex);
+  std::lock_guard lock(p->mutex);
 
   // Update bucket counts using SIMD
   update_histogram_buckets_simd(p->thresholds, p->counts, x, 0);
@@ -1458,7 +1458,7 @@ Histogram Family<Histogram>::create(
 Family<Counter> create_counter(std::string_view name, std::string_view help) {
   validate_or_abort(is_valid_metric_name(name), "invalid counter name", name);
 
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   auto &global_arena = Metric::get_global_arena();
   auto name_view = arena_copy_string(name, global_arena);
@@ -1480,7 +1480,7 @@ Family<Counter> create_counter(std::string_view name, std::string_view help) {
 Family<Gauge> create_gauge(std::string_view name, std::string_view help) {
   validate_or_abort(is_valid_metric_name(name), "invalid gauge name", name);
 
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   auto &global_arena = Metric::get_global_arena();
   auto name_view = arena_copy_string(name, global_arena);
@@ -1504,7 +1504,7 @@ Family<Histogram> create_histogram(std::string_view name, std::string_view help,
                                    std::span<const double> buckets) {
   validate_or_abort(is_valid_metric_name(name), "invalid histogram name", name);
 
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   auto &global_arena = Metric::get_global_arena();
   auto name_view = arena_copy_string(name, global_arena);
@@ -1693,7 +1693,7 @@ std::span<std::string_view> render(Arena &arena) {
   // Hold lock throughout all phases to prevent registry changes
   // THREAD SAFETY: Global mutex protects cached_plan initialization and access,
   // prevents races during static member initialization at program startup
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
 
   // Call all registered collectors to update their metrics
   for (const auto &collector : Metric::get_collectors()) {
@@ -1723,7 +1723,7 @@ template <>
 void Family<Counter>::register_callback(
     std::span<const std::pair<std::string_view, std::string_view>> labels,
     MetricCallback<Counter> callback) {
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   const LabelsKey &key = Metric::intern_labels(labels);
 
@@ -1748,7 +1748,7 @@ template <>
 void Family<Gauge>::register_callback(
     std::span<const std::pair<std::string_view, std::string_view>> labels,
     MetricCallback<Gauge> callback) {
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   const LabelsKey &key = Metric::intern_labels(labels);
 
@@ -1804,7 +1804,7 @@ void reset_metrics_for_testing() {
 }
 
 void register_collector(Ref<Collector> collector) {
-  std::unique_lock<std::mutex> _{Metric::mutex};
+  std::unique_lock _{Metric::mutex};
   ++Metric::registration_version;
   Metric::get_collectors().push_back(std::move(collector));
 }