From 1836dccf699779d9092a75755cec96cea1734a2a Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Tue, 13 Jun 2017 23:30:37 +0200
Subject: [PATCH] Pre-serialize only the labels for metrics; the ordering
 constraints did not really feel too safe.

---
 metrics.cpp | 11 ++++++++---
 metrics.h   | 11 +++++++----
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/metrics.cpp b/metrics.cpp
index db3c4b8..3fadb72 100644
--- a/metrics.cpp
+++ b/metrics.cpp
@@ -19,9 +19,14 @@ double get_timestamp_for_metrics()
 }
 
 string Metrics::serialize_name(const string &name, const vector<pair<string, string>> &labels)
+{
+	return "nageru_" + name + serialize_labels(labels);
+}
+
+string Metrics::serialize_labels(const vector<pair<string, string>> &labels)
 {
 	if (labels.empty()) {
-		return "nageru_" + name;
+		return "";
 	}
 
 	string label_str;
@@ -31,7 +36,7 @@ string Metrics::serialize_name(const string &name, const vector<pair<string, str
 		}
 		label_str += label.first + "=\"" + label.second + "\"";
 	}
-	return "nageru_" + name + "{" + label_str + "}";
+	return "{" + label_str + "}";
 }
 
 void Metrics::add(const string &name, const vector<pair<string, string>> &labels, atomic<int64_t> *location, Metrics::Type type)
@@ -79,7 +84,7 @@ string Metrics::serialize() const
 	lock_guard<mutex> lock(mu);
 	auto type_it = types.cbegin();
 	for (const auto &key_and_metric : metrics) {
-		const string &name = key_and_metric.first.serialized;
+		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() &&
diff --git a/metrics.h b/metrics.h
index 40aa8f7..0371668 100644
--- a/metrics.h
+++ b/metrics.h
@@ -52,6 +52,7 @@ public:
 
 private:
 	static std::string serialize_name(const std::string &name, const std::vector<std::pair<std::string, std::string>> &labels);
+	static std::string serialize_labels(const std::vector<std::pair<std::string, std::string>> &labels);
 
 	enum DataType {
 		DATA_TYPE_INT64,
@@ -60,18 +61,20 @@ private:
 	};
 	struct MetricKey {
 		MetricKey(const std::string &name, const std::vector<std::pair<std::string, std::string>> labels)
-			: name(name), labels(labels), serialized(serialize_name(name, labels))
+			: name(name), labels(labels), serialized_labels(serialize_labels(labels))
 		{
 		}
 
 		bool operator< (const MetricKey &other) const
 		{
-			return serialized < other.serialized;
+			if (name != other.name)
+				return name < other.name;
+			return serialized_labels < other.serialized_labels;
 		}
 
 		const std::string name;
 		const std::vector<std::pair<std::string, std::string>> labels;
-		const std::string serialized;
+		const std::string serialized_labels;
 	};
 	struct Metric {
 		DataType data_type;
@@ -83,7 +86,7 @@ private:
 	};
 
 	mutable std::mutex mu;
-	std::map<std::string, Type> types;  // Ordered the same as metrics, assuming no { signs in names (which are illegal).
+	std::map<std::string, Type> types;  // Ordered the same as metrics.
 	std::map<MetricKey, Metric> metrics;
 	std::vector<Histogram> histograms;
 
-- 
2.39.2