add test, changelog

Signed-off-by: Alex Boten <[email protected]>

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- Add `WithResourceAsConstantLabels` option to apply resource attributes for every metric emitted by the Prometheus exporter. (#4733)
+
 ## [1.21.0/0.44.0] 2023-11-16
 
 ### Removed

exporters/prometheus/exporter_test.go

@@ -36,6 +36,7 @@ import (
 )
 
 func TestPrometheusExporter(t *testing.T) {
+	filter := attribute.NewDenyKeysFilter()
 	testCases := []struct {
 		name               string
 		emptyResource      bool
@@ -368,6 +369,26 @@ func TestPrometheusExporter(t *testing.T) {
 				counter.Add(ctx, 9, opt)
 			},
 		},
+		{
+			name:         "with resource attributes filter",
+			expectedFile: "testdata/with_resource_attributes_filter.txt",
+			options: []Option{
+				WithResourceAsConstantLabels(&filter),
+			},
+			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
+				opt := otelmetric.WithAttributes(
+					attribute.Key("A").String("B"),
+					attribute.Key("C").String("D"),
+					attribute.Key("E").Bool(true),
+					attribute.Key("F").Int(42),
+				)
+				counter, err := meter.Float64Counter("foo", otelmetric.WithDescription("a simple counter"))
+				require.NoError(t, err)
+				counter.Add(ctx, 5, opt)
+				counter.Add(ctx, 10.1, opt)
+				counter.Add(ctx, 9.8, opt)
+			},
+		},
 	}
 
 	for _, tc := range testCases {

exporters/prometheus/testdata/with_resource_attributes_filter.txt

@@ -0,0 +1,9 @@
+# HELP foo_total a simple counter
+# TYPE foo_total counter
+foo_total{A="B",C="D",E="true",F="42",otel_scope_name="testmeter",otel_scope_version="v0.1.0",service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 24.9
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
+# HELP target_info Target metadata
+# TYPE target_info gauge
+target_info{service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1