X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=metrics.cpp;h=5079acb2064e5515a1a549af00c35924edcc57dd;hb=96cb6414f85e0ef4d660b7bd56267303e80fcd05;hp=1f3f8a1c18b6478b2c7d5b3956137a3aa67169d9;hpb=1df7849fad1d0647a02951abaa60f9e4f40ce360;p=nageru

diff --git a/metrics.cpp b/metrics.cpp
index 1f3f8a1..5079acb 100644
--- a/metrics.cpp
+++ b/metrics.cpp
@@ -4,19 +4,29 @@
 #include <math.h>
 
 #include <algorithm>
+#include <chrono>
 #include <locale>
 #include <sstream>
 
 using namespace std;
+using namespace std::chrono;
 
 Metrics global_metrics;
 
-namespace {
+double get_timestamp_for_metrics()
+{
+	return duration<double>(system_clock::now().time_since_epoch()).count();
+}
+
+string Metrics::serialize_name(const string &name, const vector<pair<string, string>> &labels)
+{
+	return "nageru_" + name + serialize_labels(labels);
+}
 
-string serialize_name(const string &name, const vector<pair<string, string>> &labels)
+string Metrics::serialize_labels(const vector<pair<string, string>> &labels)
 {
 	if (labels.empty()) {
-		return "nageru_" + name;
+		return "";
 	}
 
 	string label_str;
@@ -26,21 +36,17 @@ string serialize_name(const string &name, const vector<pair<string, string>> &la
 		}
 		label_str += label.first + "=\"" + label.second + "\"";
 	}
-	return "nageru_" + name + "{" + label_str + "}";
+	return "{" + label_str + "}";
 }
 
-}  // namespace
-
 void Metrics::add(const string &name, const vector<pair<string, string>> &labels, atomic<int64_t> *location, Metrics::Type type)
 {
 	Metric metric;
 	metric.data_type = DATA_TYPE_INT64;
-	metric.name = name;
-	metric.labels = labels;
 	metric.location_int64 = location;
 
 	lock_guard<mutex> lock(mu);
-	metrics.push_back(metric);
+	metrics.emplace(MetricKey(name, labels), metric);
 	assert(types.count(name) == 0 || types[name] == type);
 	types[name] = type;
 }
@@ -49,30 +55,43 @@ void Metrics::add(const string &name, const vector<pair<string, string>> &labels
 {
 	Metric metric;
 	metric.data_type = DATA_TYPE_DOUBLE;
-	metric.name = name;
-	metric.labels = labels;
 	metric.location_double = location;
 
 	lock_guard<mutex> lock(mu);
-	metrics.push_back(metric);
+	metrics.emplace(MetricKey(name, labels), metric);
 	assert(types.count(name) == 0 || types[name] == type);
 	types[name] = type;
 }
 
-void Metrics::add(const string &name, const vector<pair<string, string>> &labels, Histogram *location)
+void Metrics::add(const string &name, const vector<pair<string, string>> &labels, Histogram *location, Laziness laziness)
 {
 	Metric metric;
 	metric.data_type = DATA_TYPE_HISTOGRAM;
-	metric.name = name;
-	metric.labels = labels;
+	metric.laziness = laziness;
 	metric.location_histogram = location;
 
 	lock_guard<mutex> lock(mu);
-	metrics.push_back(metric);
+	metrics.emplace(MetricKey(name, labels), metric);
 	assert(types.count(name) == 0 || types[name] == TYPE_HISTOGRAM);
 	types[name] = TYPE_HISTOGRAM;
 }
 
+void Metrics::remove(const string &name, const vector<pair<string, string>> &labels)
+{
+	lock_guard<mutex> lock(mu);
+
+	auto it = metrics.find(MetricKey(name, labels));
+	assert(it != metrics.end());
+
+	// If this is the last metric with this name, remove the type as well.
+	if (!((it != metrics.begin() && prev(it)->first.name == name) ||
+	      (it != metrics.end() && next(it)->first.name == name))) {
+		types.erase(name);
+	}
+
+	metrics.erase(it);
+}
+
 string Metrics::serialize() const
 {
 	stringstream ss;
@@ -80,22 +99,35 @@ string Metrics::serialize() const
 	ss.precision(20);
 
 	lock_guard<mutex> lock(mu);
-	for (const auto &name_and_type : types) {
-		if (name_and_type.second == TYPE_GAUGE) {
-			ss << "# TYPE nageru_" << name_and_type.first << " gauge\n";
-		} else if (name_and_type.second == TYPE_HISTOGRAM) {
-			ss << "# TYPE nageru_" << name_and_type.first << " histogram\n";
+	auto type_it = types.cbegin();
+	for (const auto &key_and_metric : metrics) {
+		string name = "nageru_" + key_and_metric.first.name + key_and_metric.first.serialized_labels;
+		const Metric &metric = key_and_metric.second;
+
+		if (type_it != types.cend() &&
+		    key_and_metric.first.name == type_it->first) {
+			// It's the first time we print out any metric with this name,
+			// so add the type header.
+			if (type_it->second == TYPE_GAUGE) {
+				ss << "# TYPE nageru_" << type_it->first << " gauge\n";
+			} else if (type_it->second == TYPE_HISTOGRAM) {
+				ss << "# TYPE nageru_" << type_it->first << " histogram\n";
+			}
+			++type_it;
 		}
-	}
-	for (const Metric &metric : metrics) {
-		string name = serialize_name(metric.name, metric.labels);
 
 		if (metric.data_type == DATA_TYPE_INT64) {
 			ss << name << " " << metric.location_int64->load() << "\n";
 		} else if (metric.data_type == DATA_TYPE_DOUBLE) {
-			ss << name << " " << metric.location_double->load() << "\n";
+			double val = metric.location_double->load();
+			if (isnan(val)) {
+				// Prometheus can't handle “-nan”.
+				ss << name << " NaN\n";
+			} else {
+				ss << name << " " << val << "\n";
+			}
 		} else {
-			ss << metric.location_histogram->serialize(metric.name, metric.labels);
+			ss << metric.location_histogram->serialize(metric.laziness, key_and_metric.first.name, key_and_metric.first.labels);
 		}
 	}
 
@@ -144,8 +176,22 @@ void Histogram::count_event(double val)
 	sum = sum + val;
 }
 
-string Histogram::serialize(const string &name, const vector<pair<string, string>> &labels) const
+string Histogram::serialize(Metrics::Laziness laziness, const string &name, const vector<pair<string, string>> &labels) const
 {
+	// Check if the histogram is empty and should not be serialized.
+	if (laziness == Metrics::PRINT_WHEN_NONEMPTY && count_after_last_bucket.load() == 0) {
+		bool empty = true;
+		for (size_t bucket_idx = 0; bucket_idx < num_buckets; ++bucket_idx) {
+			if (buckets[bucket_idx].count.load() != 0) {
+				empty = false;
+				break;
+			}
+		}
+		if (empty) {
+			return "";
+		}
+	}
+
 	stringstream ss;
 	ss.imbue(locale("C"));
 	ss.precision(20);
@@ -160,13 +206,13 @@ string Histogram::serialize(const string &name, const vector<pair<string, string
 		bucket_labels.emplace_back("le", le_ss.str());
 
 		count += buckets[bucket_idx].count.load();
-		ss << serialize_name(name + "_bucket", bucket_labels) << " " << count << "\n";
+		ss << Metrics::serialize_name(name + "_bucket", bucket_labels) << " " << count << "\n";
 	}
 
 	count += count_after_last_bucket.load();
 
-	ss << serialize_name(name + "_sum", labels) << " " << sum.load() << "\n";
-	ss << serialize_name(name + "_count", labels) << " " << count << "\n";
+	ss << Metrics::serialize_name(name + "_sum", labels) << " " << sum.load() << "\n";
+	ss << Metrics::serialize_name(name + "_count", labels) << " " << count << "\n";
 
 	return ss.str();
 }