From 83a9736e399a3ca4b7950a97b265edd42393148c Mon Sep 17 00:00:00 2001
From: Cluas <Cluas@live.cn>
Date: Tue, 31 Jan 2023 23:12:49 +0800
Subject: [PATCH] [processor/spanmetricsprocessor] Allow set metrics namespace

---
 processor/spanmetricsprocessor/config.go      |  3 +++
 processor/spanmetricsprocessor/processor.go   | 17 +++++++++++++++--
 .../spanmetricsprocessor/processor_test.go    | 19 +++++++++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/processor/spanmetricsprocessor/config.go b/processor/spanmetricsprocessor/config.go
index b46800bb02dd..7b4c1d655afc 100644
--- a/processor/spanmetricsprocessor/config.go
+++ b/processor/spanmetricsprocessor/config.go
@@ -72,6 +72,9 @@ type Config struct {
 
 	// MetricsEmitInterval is the time period between when metrics are flushed or emitted to the configured MetricsExporter.
 	MetricsFlushInterval time.Duration `mapstructure:"metrics_flush_interval"`
+
+	// Namespace
+	Namespace string
 }
 
 // GetAggregationTemporality converts the string value given in the config into a AggregationTemporality.
diff --git a/processor/spanmetricsprocessor/processor.go b/processor/spanmetricsprocessor/processor.go
index dd056a83401b..15eee60ed799 100644
--- a/processor/spanmetricsprocessor/processor.go
+++ b/processor/spanmetricsprocessor/processor.go
@@ -46,6 +46,9 @@ const (
 	metricKeySeparator = string(byte(0))
 
 	defaultDimensionsCacheSize = 1000
+
+	metricLatency    = "latency"
+	metricCallsTotal = "calls_total"
 )
 
 var defaultLatencyHistogramBucketsMs = []float64{
@@ -317,11 +320,21 @@ func (p *processorImp) buildMetrics() pmetric.Metrics {
 	return m
 }
 
+// buildMetricName builds a metric name by concatenating the namespace and the metric name with an underscore.
+// If the namespace is not empty, the namespace and metric name will be separated by an underscore.
+// Otherwise, only the metric name will be returned.
+func buildMetricName(namespace, metricName string) string {
+	if namespace != "" {
+		return namespace + "_" + metricName
+	}
+	return metricName
+}
+
 // collectLatencyMetrics collects the raw latency metrics, writing the data
 // into the given instrumentation library metrics.
 func (p *processorImp) collectLatencyMetrics(ilm pmetric.ScopeMetrics) {
 	mLatency := ilm.Metrics().AppendEmpty()
-	mLatency.SetName("latency")
+	mLatency.SetName(buildMetricName(p.config.Namespace, metricLatency))
 	mLatency.SetUnit("ms")
 	mLatency.SetEmptyHistogram().SetAggregationTemporality(p.config.GetAggregationTemporality())
 	dps := mLatency.Histogram().DataPoints()
@@ -349,7 +362,7 @@ func (p *processorImp) collectLatencyMetrics(ilm pmetric.ScopeMetrics) {
 // into the given instrumentation library metrics.
 func (p *processorImp) collectCallMetrics(ilm pmetric.ScopeMetrics) {
 	mCalls := ilm.Metrics().AppendEmpty()
-	mCalls.SetName("calls_total")
+	mCalls.SetName(buildMetricName(p.config.Namespace, metricCallsTotal))
 	mCalls.SetEmptySum().SetIsMonotonic(true)
 	mCalls.Sum().SetAggregationTemporality(p.config.GetAggregationTemporality())
 	dps := mCalls.Sum().DataPoints()
diff --git a/processor/spanmetricsprocessor/processor_test.go b/processor/spanmetricsprocessor/processor_test.go
index d99e48c32490..8937f172311c 100644
--- a/processor/spanmetricsprocessor/processor_test.go
+++ b/processor/spanmetricsprocessor/processor_test.go
@@ -1101,3 +1101,22 @@ func TestConsumeTracesEvictedCacheKey(t *testing.T) {
 	wg.Wait()
 	assert.Empty(t, wantDataPointCounts)
 }
+
+func TestBuildMetricName(t *testing.T) {
+	tests := []struct {
+		namespace  string
+		metricName string
+		expected   string
+	}{
+		{"", "metric", "metric"},
+		{"ns", "metric", "ns_metric"},
+		{"longer_namespace", "metric", "longer_namespace_metric"},
+	}
+
+	for _, test := range tests {
+		actual := buildMetricName(test.namespace, test.metricName)
+		if actual != test.expected {
+			t.Errorf("buildMetricName(%q, %q) = %q, expected %q", test.namespace, test.metricName, actual, test.expected)
+		}
+	}
+}