Minor changes

- add exported comments
- rename `g` to `gatherer` in test
- Format copyright as it as ™️
- Remove TODO

metrics/prometheus/interfaces.go

@@ -2,6 +2,8 @@
 // See the file LICENSE for licensing terms.
 package prometheus
 
+// Registry is a narrower interface of [prometheus.Registry] containing
+// only the required functions for the [Gatherer].
 type Registry interface {
 	// Call the given function for each registered metric.
 	Each(func(string, any))

metrics/prometheus/prometheus.go

@@ -1,4 +1,4 @@
-// (c) 2021-2025 Ava Labs, Inc. All rights reserved.
+// (c) 2021-2025, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
 package prometheus
@@ -16,20 +16,23 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )
 
+// Gatherer implements [prometheus.Gatherer] interface by
+// gathering all metrics from the given Prometheus registry.
 type Gatherer struct {
 	registry Registry
 }
 
 var _ prometheus.Gatherer = (*Gatherer)(nil)
 
-// NewGatherer returns a gatherer using the given registry.
-// Note this gatherer implements the [prometheus.Gatherer] interface.
+// NewGatherer returns a [Gatherer] using the given registry.
 func NewGatherer(registry Registry) *Gatherer {
 	return &Gatherer{
 		registry: registry,
 	}
 }
 
+// Gather gathers metrics from the registry and converts them to
+// a slice of metric families.
 func (g *Gatherer) Gather() (mfs []*dto.MetricFamily, err error) {
 	// Gather and pre-sort the metrics to avoid random listings
 	var names []string
@@ -42,8 +45,8 @@ func (g *Gatherer) Gather() (mfs []*dto.MetricFamily, err error) {
 	for _, name := range names {
 		mf, err := metricFamily(g.registry, name)
 		if err != nil {
-		if errors.Is(err, errMetricSkip) {
-			continue
+			if errors.Is(err, errMetricSkip) {
+				continue
 			}
 			return nil, err
 		}
@@ -184,9 +187,7 @@ func metricFamily(registry Registry, name string) (mf *dto.MetricFamily, err err
 			Metric: []*dto.Metric{{
 				Summary: &dto.Summary{
 					SampleCount: ptrTo(uint64(snapshot.Count())), //nolint:gosec
-					// TODO: do we need to specify SampleSum here? and if so
-					// what should that be?
-					Quantile: dtoQuantiles,
+					Quantile:    dtoQuantiles,
 				},
 			}},
 		}, nil

metrics/prometheus/prometheus_test.go

@@ -1,4 +1,4 @@
-// (c) 2021-2025 Ava Labs, Inc. All rights reserved.
+// (c) 2021-2025, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
 package prometheus
@@ -69,9 +69,9 @@ func TestGatherer_Gather(t *testing.T) {
 	emptyResettingTimer.Update(time.Second) // no effect because of snapshot below
 	register(t, "test/empty_resetting_timer_snapshot", emptyResettingTimer.Snapshot())
 
-	g := NewGatherer(registry)
+	gatherer := NewGatherer(registry)
 
-	families, err := g.Gather()
+	families, err := gatherer.Gather()
 	require.NoError(t, err)
 	familyStrings := make([]string, len(families))
 	for i := range families {
@@ -90,7 +90,7 @@ func TestGatherer_Gather(t *testing.T) {
 	assert.Equal(t, want, familyStrings)
 
 	register(t, "unsupported", metrics.NewGaugeInfo())
-	families, err = g.Gather()
+	families, err = gatherer.Gather()
 	assert.EqualError(t, err, "metric \"unsupported\": type is not supported: *metrics.StandardGaugeInfo")
 	assert.Empty(t, families)
 }