X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=metrics.h;h=a8156587a5f2484da831eda01af26cc0c4742454;hb=c0961059aa9335a88feb00a667ee32d95a7a888e;hp=e54bbcf41b083ea1dcc36c2a2ab781cad81471dc;hpb=df2284056394481ce5d5216f774d4a146b4983eb;p=nageru

diff --git a/metrics.h b/metrics.h
index e54bbcf..a815658 100644
--- a/metrics.h
+++ b/metrics.h
@@ -7,31 +7,87 @@
 // which makes it quite unwieldy. Thus, we'll package our own for the time being.
 
 #include <atomic>
+#include <map>
+#include <memory>
 #include <mutex>
 #include <string>
-#include <unordered_map>
+#include <vector>
+
+class Histogram;
 
 class Metrics {
 public:
 	enum Type {
 		TYPE_COUNTER,
 		TYPE_GAUGE,
+		TYPE_HISTOGRAM,  // Internal use only.
 	};
 
-	void register_int_metric(const std::string &name, std::atomic<int64_t> *location, Type type = TYPE_COUNTER);
-	void register_double_metric(const std::string &name, std::atomic<double> *location, Type type = TYPE_COUNTER);
+	void add(const std::string &name, std::atomic<int64_t> *location, Type type = TYPE_COUNTER)
+	{
+		add(name, {}, location, type);
+	}
+
+	void add(const std::string &name, std::atomic<double> *location, Type type = TYPE_COUNTER)
+	{
+		add(name, {}, location, type);
+	}
+
+	void add(const std::string &name, Histogram *location)
+	{
+		add(name, {}, location);
+	}
+
+	void add(const std::string &name, const std::vector<std::pair<std::string, std::string>> &labels, std::atomic<int64_t> *location, Type type = TYPE_COUNTER);
+	void add(const std::string &name, const std::vector<std::pair<std::string, std::string>> &labels, std::atomic<double> *location, Type type = TYPE_COUNTER);
+	void add(const std::string &name, const std::vector<std::pair<std::string, std::string>> &labels, Histogram *location);
+
 	std::string serialize() const;
 
 private:
-	template<class T>
+	enum DataType {
+		DATA_TYPE_INT64,
+		DATA_TYPE_DOUBLE,
+		DATA_TYPE_HISTOGRAM,
+	};
+
 	struct Metric {
-		Type type;
-		std::atomic<T> *location;
+		DataType data_type;
+		std::string name;
+		std::vector<std::pair<std::string, std::string>> labels;
+		union {
+			std::atomic<int64_t> *location_int64;
+			std::atomic<double> *location_double;
+			Histogram *location_histogram;
+		};
 	};
 
 	mutable std::mutex mu;
-	std::unordered_map<std::string, Metric<int64_t>> int_metrics;
-	std::unordered_map<std::string, Metric<double>> double_metrics;
+	std::map<std::string, Type> types;
+	std::vector<Metric> metrics;
+	std::vector<Histogram> histograms;
+};
+
+class Histogram {
+public:
+	void init(const std::vector<double> &bucket_vals);
+	void init_uniform(size_t num_buckets);  // Sets up buckets 0..(N-1).
+	void init_geometric(double min, double max, size_t num_buckets);
+	void count_event(double val);
+	std::string serialize(const std::string &name, const std::vector<std::pair<std::string, std::string>> &labels) const;
+
+private:
+	// Bucket <i> counts number of events where val[i - 1] < x <= val[i].
+	// The end histogram ends up being made into a cumulative one,
+	// but that's not how we store it here.
+	struct Bucket {
+		double val;
+		std::atomic<int64_t> count{0};
+	};
+	std::unique_ptr<Bucket[]> buckets;
+	size_t num_buckets;
+	std::atomic<double> sum{0.0};
+	std::atomic<int64_t> count_after_last_bucket{0};
 };
 
 extern Metrics global_metrics;