feat(profiling): add metric on sample count

Author: KowalskiThomas

ddtrace/internal/datadog/profiling/dd_wrapper/CMakeLists.txt

@@ -45,6 +45,7 @@ add_library(
     src/code_provenance.cpp
     src/code_provenance_interface.cpp
     src/ddup_interface.cpp
+    src/profiler_stats.cpp
     src/profile.cpp
     src/sample.cpp
     src/sample_manager.cpp

ddtrace/internal/datadog/profiling/dd_wrapper/include/profile.hpp

@@ -1,13 +1,11 @@
 #pragma once
 
 #include "constants.hpp"
+#include "profiler_stats.hpp"
 #include "types.hpp"
 
 #include <atomic>
-#include <memory>
 #include <mutex>
-#include <string>
-#include <string_view>
 #include <vector>
 
 extern "C"
@@ -45,6 +43,8 @@ class Profile
     // cannot be used until it's initialized by libdatadog
     ddog_prof_Profile cur_profile{};
 
+    Datadog::ProfilerStats profiler_stats{};
+
   public:
     // State management
     void one_time_init(SampleType type, unsigned int _max_nframes);
@@ -54,6 +54,9 @@ class Profile
     // Getters
     size_t get_sample_type_length();
     ddog_prof_Profile& profile_borrow();
+    ProfilerStats& profiler_stats_borrow();
+
+    void profiler_stats_release();
     void profile_release();
 
     // constref getters

ddtrace/internal/datadog/profiling/dd_wrapper/include/profiler_stats.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <cstddef>
+
+#include <string_view>
+
+namespace Datadog {
+
+class ProfilerStats
+{
+  private:
+    size_t sample_count = 0;
+    size_t sampling_event_count = 0;
+
+  public:
+    ProfilerStats() = default;
+    ~ProfilerStats() = default;
+
+    void increment_sample_count(size_t k_sample_count = 1);
+    size_t get_sample_count();
+
+    void increment_sampling_event_count(size_t k_sampling_event_count = 1);
+    size_t get_sampling_event_count();
+
+    std::string_view get_internal_metadata_json();
+
+    void reset_state();
+};
+
+} // namespace Datadog

ddtrace/internal/datadog/profiling/dd_wrapper/include/sample.hpp

@@ -2,6 +2,7 @@
 
 #include "libdatadog_helpers.hpp"
 #include "profile.hpp"
+#include "profiler_stats.hpp"
 #include "types.hpp"
 
 #include <string>
@@ -135,6 +136,7 @@ class Sample
     bool flush_sample(bool reverse_locations = false);
 
     static ddog_prof_Profile& profile_borrow();
+    static ProfilerStats& profiler_stats_borrow();
     static void profile_release();
     static void postfork_child();
     Sample(SampleType _type_mask, unsigned int _max_nframes);

ddtrace/internal/datadog/profiling/dd_wrapper/include/uploader.hpp

@@ -1,10 +1,8 @@
 #pragma once
 
-#include "sample.hpp"
-#include "types.hpp"
+#include "profiler_stats.hpp"
 
 #include <atomic>
-#include <memory>
 #include <mutex>
 
 extern "C"
@@ -27,7 +25,7 @@ class Uploader
     bool export_to_file(ddog_prof_EncodedProfile* encoded);
 
   public:
-    bool upload(ddog_prof_Profile& profile);
+    bool upload(ddog_prof_Profile& profile, Datadog::ProfilerStats& profiler_stats);
     static void cancel_inflight();
     static void lock();
     static void unlock();

ddtrace/internal/datadog/profiling/dd_wrapper/include/uploader_builder.hpp

@@ -1,8 +1,8 @@
 #pragma once
 
+#include "constants.hpp"
 #include "uploader.hpp"
 
-#include <mutex>
 #include <string>
 #include <string_view>
 #include <unordered_map>

ddtrace/internal/datadog/profiling/dd_wrapper/src/ddup_interface.cpp

@@ -1,8 +1,7 @@
 #include "ddup_interface.hpp"
 
-#include "code_provenance.hpp"
 #include "libdatadog_helpers.hpp"
-#include "profile.hpp"
+#include "profiler_stats.hpp"
 #include "sample.hpp"
 #include "sample_manager.hpp"
 #include "uploader.hpp"
@@ -351,7 +350,8 @@ ddup_upload() // cppcheck-suppress unusedFunction
     //  be modified.  It gets released and cleared after uploading.
     // * Uploading cancels inflight uploads. There are better ways to do this, but this is what
     //   we have for now.
-    uploader.upload(Datadog::Sample::profile_borrow());
+    uploader.upload(Datadog::Sample::profile_borrow(), Datadog::Sample::profiler_stats_borrow());
+    Datadog::Sample::profiler_stats_borrow().reset_state();
     Datadog::Sample::profile_release();
     return true;
 }

ddtrace/internal/datadog/profiling/dd_wrapper/src/profile.cpp

@@ -55,6 +55,8 @@ Datadog::Profile::reset_profile()
         ddog_Error_drop(&err);
         return false;
     }
+
+    profiler_stats.reset_state();
     return true;
 }
 

ddtrace/internal/datadog/profiling/dd_wrapper/src/profiler_stats.cpp

@@ -0,0 +1,62 @@
+#include "profiler_stats.hpp"
+
+#include <charconv>
+#include <string>
+
+namespace {
+
+void
+append_to_string(std::string& s, size_t value)
+{
+    char buf[128];
+    auto [ptr, ec] = std::to_chars(std::begin(buf), std::end(buf), value);
+    s.append(buf, ptr);
+}
+
+} // namespace
+
+void
+Datadog::ProfilerStats::increment_sample_count(size_t k_sample_count)
+{
+    sample_count += k_sample_count;
+}
+
+void
+Datadog::ProfilerStats::increment_sampling_event_count(size_t k_sampling_event_count)
+{
+    sampling_event_count += k_sampling_event_count;
+}
+
+size_t
+Datadog::ProfilerStats::get_sampling_event_count()
+{
+    return sampling_event_count;
+}
+
+size_t
+Datadog::ProfilerStats::get_sample_count()
+{
+    return sample_count;
+}
+
+void
+Datadog::ProfilerStats::reset_state()
+{
+    sample_count = 0;
+}
+
+std::string_view
+Datadog::ProfilerStats::get_internal_metadata_json()
+{
+    static std::string result;
+    result.reserve(2048);
+
+    result = "{";
+
+    result += "\"recorded_samples\": ";
+    append_to_string(result, sample_count);
+
+    result += "}";
+
+    return result;
+}

ddtrace/internal/datadog/profiling/dd_wrapper/src/sample.cpp

@@ -1,11 +1,8 @@
 #include "sample.hpp"
 
-#include "code_provenance.hpp"
-
 #include <algorithm>
 #include <chrono>
 #include <string_view>
-#include <thread>
 
 Datadog::internal::StringArena::StringArena()
 {
@@ -532,6 +529,12 @@ Datadog::Sample::profile_borrow()
     return profile_state.profile_borrow();
 }
 
+Datadog::ProfilerStats&
+Datadog::Sample::profiler_stats_borrow()
+{
+    return profile_state.profiler_stats_borrow();
+}
+
 void
 Datadog::Sample::profile_release()
 {