Add compile time type assertions

Author: filinvadim

pkg/metrics/noop.go

@@ -12,122 +12,136 @@ import (
 	"net/http"
 )
 
-type counterStub struct{}
+type counterNoop struct{}
 
-func (c counterStub) Desc() *Desc              { return &Desc{} }
-func (c counterStub) Write(_ *MetricDTO) error { return nil }
-func (c counterStub) Describe(_ chan<- *Desc)  { return }
-func (c counterStub) Collect(_ chan<- Metric)  { return }
-func (c counterStub) Inc()                     { return }
-func (c counterStub) Add(_ float64)            { return }
+func (c counterNoop) Desc() *Desc              { return &Desc{} }
+func (c counterNoop) Write(_ *MetricDTO) error { return nil }
+func (c counterNoop) Describe(_ chan<- *Desc)  { return }
+func (c counterNoop) Collect(_ chan<- Metric)  { return }
+func (c counterNoop) Inc()                     { return }
+func (c counterNoop) Add(_ float64)            { return }
 
 func NewCounter(_ CounterOpts) Counter {
-	return &counterStub{}
+	return &counterNoop{}
 }
 
-type counterVecStub struct{}
+var _ CounterMetricVector = (*counterVecNoop)(nil)
 
-func (c counterVecStub) WithLabelValues(lvs ...string) Counter {
+type counterVecNoop struct{}
+
+func (c counterVecNoop) WithLabelValues(lvs ...string) Counter {
 	return NewCounter(CounterOpts{})
 }
 
 func NewCounterVec(opts CounterOpts, names []string) CounterMetricVector {
-	return &counterVecStub{}
+	return &counterVecNoop{}
 }
 
-type gaugeStub struct{}
+type gaugeNoop struct{}
 
-func (g gaugeStub) Desc() *Desc              { return &Desc{} }
-func (g gaugeStub) Write(_ *MetricDTO) error { return nil }
-func (g gaugeStub) Describe(_ chan<- *Desc)  { return }
-func (g gaugeStub) Collect(_ chan<- Metric)  { return }
-func (g gaugeStub) Set(_ float64)            { return }
-func (g gaugeStub) Inc()                     { return }
-func (g gaugeStub) Dec()                     { return }
-func (g gaugeStub) Add(_ float64)            { return }
-func (g gaugeStub) Sub(_ float64)            { return }
-func (g gaugeStub) SetToCurrentTime()        { return }
+func (g gaugeNoop) Desc() *Desc              { return &Desc{} }
+func (g gaugeNoop) Write(_ *MetricDTO) error { return nil }
+func (g gaugeNoop) Describe(_ chan<- *Desc)  { return }
+func (g gaugeNoop) Collect(_ chan<- Metric)  { return }
+func (g gaugeNoop) Set(_ float64)            { return }
+func (g gaugeNoop) Inc()                     { return }
+func (g gaugeNoop) Dec()                     { return }
+func (g gaugeNoop) Add(_ float64)            { return }
+func (g gaugeNoop) Sub(_ float64)            { return }
+func (g gaugeNoop) SetToCurrentTime()        { return }
 
 func NewGauge(_ GaugeOpts) Gauge {
-	return &gaugeStub{}
+	return &gaugeNoop{}
 }
 
-type gaugeVecStub struct{}
+var _ GaugeMetricVector = (*gaugeVecNoop)(nil)
+
+type gaugeVecNoop struct{}
 
-func (g gaugeVecStub) WithLabelValues(lvs ...string) Gauge {
+func (g gaugeVecNoop) WithLabelValues(lvs ...string) Gauge {
 	return NewGauge(GaugeOpts{})
 }
 
 func NewGaugeVec(opts GaugeOpts, names []string) GaugeMetricVector {
-	return &gaugeVecStub{}
+	return &gaugeVecNoop{}
 }
 
-type histogramStub struct{}
+var _ Histogram = (*histogramNoop)(nil)
 
-func (h histogramStub) Desc() *Desc              { return &Desc{} }
-func (h histogramStub) Write(_ *MetricDTO) error { return nil }
-func (h histogramStub) Describe(_ chan<- *Desc)  { return }
-func (h histogramStub) Collect(_ chan<- Metric)  { return }
-func (h histogramStub) Observe(_ float64)        { return }
+type histogramNoop struct{}
+
+func (h histogramNoop) Desc() *Desc              { return &Desc{} }
+func (h histogramNoop) Write(_ *MetricDTO) error { return nil }
+func (h histogramNoop) Describe(_ chan<- *Desc)  { return }
+func (h histogramNoop) Collect(_ chan<- Metric)  { return }
+func (h histogramNoop) Observe(_ float64)        { return }
 
 func NewHistogram(_ HistogramOpts) Histogram {
-	return &histogramStub{}
+	return &histogramNoop{}
 }
 
-type histogramVecStub struct{}
+var _ HistogramMetricVector = (*histogramVecNoop)(nil)
+
+type histogramVecNoop struct{}
 
-func (h histogramVecStub) Describe(descs chan<- *Desc)   { return }
-func (h histogramVecStub) Collect(metrics chan<- Metric) { return }
-func (h histogramVecStub) WithLabelValues(lvs ...string) Observer {
+func (h histogramVecNoop) Describe(descs chan<- *Desc)   { return }
+func (h histogramVecNoop) Collect(metrics chan<- Metric) { return }
+func (h histogramVecNoop) WithLabelValues(lvs ...string) Observer {
 	return NewHistogram(HistogramOpts{})
 }
 
 func NewHistogramVec(opts HistogramOpts, names []string) HistogramMetricVector {
-	return &histogramVecStub{}
+	return &histogramVecNoop{}
 }
 
-type summaryStub struct{}
+var _ Summary = (*summaryNoop)(nil)
 
-func (s summaryStub) Desc() *Desc              { return &Desc{} }
-func (s summaryStub) Write(_ *MetricDTO) error { return nil }
-func (s summaryStub) Describe(_ chan<- *Desc)  { return }
-func (s summaryStub) Collect(_ chan<- Metric)  { return }
-func (s summaryStub) Observe(_ float64)        { return }
+type summaryNoop struct{}
+
+func (s summaryNoop) Desc() *Desc              { return &Desc{} }
+func (s summaryNoop) Write(_ *MetricDTO) error { return nil }
+func (s summaryNoop) Describe(_ chan<- *Desc)  { return }
+func (s summaryNoop) Collect(_ chan<- Metric)  { return }
+func (s summaryNoop) Observe(_ float64)        { return }
 
 func NewSummary(_ SummaryOpts) Summary {
-	return &summaryStub{}
+	return &summaryNoop{}
 }
 
-type collectorStub struct{}
+var _ Collector = (*collectorNoop)(nil)
+
+type collectorNoop struct{}
 
-func (c collectorStub) Describe(_ chan<- *Desc) { return }
-func (c collectorStub) Collect(_ chan<- Metric) { return }
+func (c collectorNoop) Describe(_ chan<- *Desc) { return }
+func (c collectorNoop) Collect(_ chan<- Metric) { return }
 
 func NewGoCollector() Collector {
-	return &collectorStub{}
+	return &collectorNoop{}
 }
 
 func NewProcessCollector(opts ProcessCollectorOpts) Collector {
-	return &collectorStub{}
+	return &collectorNoop{}
 }
 
-type registryStub struct{}
+var _ MetricsRegistererGatherer = (*registryNoop)(nil)
 
-func (r registryStub) Register(collector Collector) error {
+type registryNoop struct{}
+
+func (r registryNoop) Register(collector Collector) error {
 	return nil
 }
 
-func (r registryStub) Unregister(collector Collector) bool {
+func (r registryNoop) Unregister(collector Collector) bool {
 	return true
 }
 
-func (r registryStub) MustRegister(collector ...Collector) { return }
-func (r registryStub) Gather() ([]*MetricFamily, error) {
+func (r registryNoop) MustRegister(collector ...Collector) { return }
+func (r registryNoop) Gather() ([]*MetricFamily, error) {
 	return []*MetricFamily{}, nil
 }
 
 func NewRegistry() MetricsRegistererGatherer {
-	return &registryStub{}
+	return &registryNoop{}
 }
 
 func NewExporter(o ExporterOptions) error {
@@ -146,12 +160,14 @@ func HandlerFor(_ MetricsRegistererGatherer, _ HandlerOpts) http.Handler {
 	return http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) { return })
 }
 
-type encoderStub struct{}
+var _ Encoder = (*encoderNoop)(nil)
+
+type encoderNoop struct{}
 
-func (e encoderStub) Encode(family *MetricFamily) error { return nil }
+func (e encoderNoop) Encode(family *MetricFamily) error { return nil }
 
 func NewEncoder(w io.Writer, format Format, options ...EncoderOption) Encoder {
-	return &encoderStub{}
+	return &encoderNoop{}
 }
 
 func NewFormat(t FormatType) Format {