Add the first beginnings of Prometheus metrics.

[nageru] / metrics.cpp

diff --git a/metrics.cpp b/metrics.cpp
new file mode 100644 (file)
index 0000000..4755ba0
--- /dev/null
+++ b/metrics.cpp
@@ -0,0 +1,38 @@
+#include "metrics.h"
+
+#include <locale>
+#include <sstream>
+
+using namespace std;
+
+Metrics global_metrics;
+
+void Metrics::register_int_metric(const string &name, atomic<int64_t> *location)
+{
+       lock_guard<mutex> lock(mu);
+       int_metrics.emplace(name, location);
+}
+
+void Metrics::register_double_metric(const string &name, atomic<double> *location)
+{
+       lock_guard<mutex> lock(mu);
+       double_metrics.emplace(name, location);
+}
+
+string Metrics::serialize() const
+{
+       stringstream ss;
+       ss.imbue(locale("C"));
+       ss.precision(20);
+       ss << scientific;
+
+       lock_guard<mutex> lock(mu);
+       for (const auto &key_and_value : int_metrics) {
+               ss << key_and_value.first.c_str() << " " << key_and_value.second->load() << "\n";
+       }
+       for (const auto &key_and_value : double_metrics) {
+               ss << key_and_value.first.c_str() << " " << key_and_value.second->load() << "\n";
+       }
+
+       return ss.str();
+}