add test for mdatagen telemetry metrics

cmd/mdatagen/internal/command_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/pdata/pmetric"
 )
 
 func TestNewCommand(t *testing.T) {
@@ -644,6 +645,96 @@ func Meter(settings component.TelemetrySettings) metric.Meter {
 func Tracer(settings component.TelemetrySettings) trace.Tracer {
 	return settings.TracerProvider.Tracer("")
 }
+`,
+		},
+		{
+			name: "foo component with telemetry metrics",
+			md: Metadata{
+				Type: "foo",
+				Status: &Status{
+					Stability: map[component.StabilityLevel][]string{
+						component.StabilityLevelAlpha: {"metrics"},
+					},
+					Distributions: []string{"contrib"},
+					Class:         "receiver",
+				},
+				Telemetry: Telemetry{
+					Metrics: map[MetricName]Metric{
+						"foo_count": {
+							Sum: &Sum{
+								MetricValueType: MetricValueType{
+									ValueType: pmetric.NumberDataPointValueTypeInt,
+								},
+							},
+						},
+					},
+				},
+			},
+			expected: `// Code generated by mdatagen. DO NOT EDIT.
+
+package metadata
+
+import (
+	"errors"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/noop"
+	"go.opentelemetry.io/otel/trace"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configtelemetry"
+)
+
+func Meter(settings component.TelemetrySettings) metric.Meter {
+	return settings.MeterProvider.Meter("")
+}
+
+func Tracer(settings component.TelemetrySettings) trace.Tracer {
+	return settings.TracerProvider.Tracer("")
+}
+
+// TelemetryBuilder provides an interface for components to report telemetry
+// as defined in metadata and user config.
+type TelemetryBuilder struct {
+	meter    metric.Meter
+	FooCount metric.Int64UpDownCounter
+}
+
+// TelemetryBuilderOption applies changes to default builder.
+type TelemetryBuilderOption interface {
+	apply(*TelemetryBuilder)
+}
+
+type telemetryBuilderOptionFunc func(mb *TelemetryBuilder)
+
+func (tbof telemetryBuilderOptionFunc) apply(mb *TelemetryBuilder) {
+	tbof(mb)
+}
+
+// NewTelemetryBuilder provides a struct with methods to update all internal telemetry
+// for a component
+func NewTelemetryBuilder(settings component.TelemetrySettings, options ...TelemetryBuilderOption) (*TelemetryBuilder, error) {
+	builder := TelemetryBuilder{}
+	for _, op := range options {
+		op.apply(&builder)
+	}
+	builder.meter = Meter(settings)
+	var err, errs error
+	builder.FooCount, err = getLeveledMeter(builder.meter, configtelemetry.LevelBasic, settings.MetricsLevel).Int64UpDownCounter(
+		"otelcol_foo_count",
+		metric.WithDescription(""),
+		metric.WithUnit("<nil>"),
+	)
+	errs = errors.Join(errs, err)
+	return &builder, errs
+}
+
+func getLeveledMeter(meter metric.Meter, cfgLevel, srvLevel configtelemetry.Level) metric.Meter {
+	if cfgLevel <= srvLevel {
+		return meter
+	}
+	return noop.Meter{}
+}
 `,
 		},
 	}

cmd/mdatagen/internal/templates/telemetry.go.tmpl

@@ -14,7 +14,9 @@ import (
     {{- end }}
 
 	"go.opentelemetry.io/otel/metric"
+    {{- if .Telemetry.Metrics }}
 	"go.opentelemetry.io/otel/metric/noop"
+    {{- end }}
 	"go.opentelemetry.io/otel/trace"
 
 	"go.opentelemetry.io/collector/component"