meter: rework meter interface

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

meter/noop.go

@@ -6,42 +6,140 @@ import (
 	"github.com/unistack-org/micro/v3/metadata"
 )
 
-// NoopReporter is an noop implementation of Reporter:
-type noopReporter struct {
+// NoopMeter is an noop implementation of Meter
+type noopMeter struct {
 	opts Options
+	md   metadata.Metadata
 }
 
-// NewReporter returns a configured noop reporter:
-func NewReporter(opts ...Option) Reporter {
-	return &noopReporter{
+// NewMeter returns a configured noop reporter:
+func NewMeter(opts ...Option) Meter {
+	return &noopMeter{
 		opts: NewOptions(opts...),
 	}
 }
 
 // Init initialize options
-func (r *noopReporter) Init(opts ...Option) error {
+func (r *noopMeter) Init(opts ...Option) error {
 	for _, o := range opts {
 		o(&r.opts)
 	}
 	return nil
 }
 
-// Count implements the Reporter interface Count method:
-func (r *noopReporter) Count(metricName string, value int64, md metadata.Metadata) error {
-	return nil
+// Counter implements the Meter interface
+func (r *noopMeter) Counter(name string, md metadata.Metadata) Counter {
+	return &noopCounter{}
 }
 
-// Gauge implements the Reporter interface Gauge method:
-func (r *noopReporter) Gauge(metricName string, value float64, md metadata.Metadata) error {
-	return nil
+// FloatCounter implements the Meter interface
+func (r *noopMeter) FloatCounter(name string, md metadata.Metadata) FloatCounter {
+	return &noopFloatCounter{}
 }
 
-// Timing implements the Reporter interface Timing method:
-func (r *noopReporter) Timing(metricName string, value time.Duration, md metadata.Metadata) error {
-	return nil
+// Gauge implements the Meter interface
+func (r *noopMeter) Gauge(name string, f func() float64, md metadata.Metadata) Gauge {
+	return &noopGauge{}
 }
 
-// Options implements the Reporter interface Optios method:
-func (r *noopReporter) Options() Options {
+// Summary implements the Meter interface
+func (r *noopMeter) Summary(name string, md metadata.Metadata) Summary {
+	return &noopSummary{}
+}
+
+// SummaryExt implements the Meter interface
+func (r *noopMeter) SummaryExt(name string, window time.Duration, quantiles []float64, md metadata.Metadata) Summary {
+	return &noopSummary{}
+}
+
+// Histogram implements the Meter interface
+func (r *noopMeter) Histogram(name string, md metadata.Metadata) Histogram {
+	return &noopHistogram{}
+}
+
+// Set implements the Meter interface
+func (r *noopMeter) Set(md metadata.Metadata) Meter {
+	return &noopMeter{opts: r.opts, md: metadata.Copy(md)}
+}
+
+// Options implements the Meter interface
+func (r *noopMeter) Options() Options {
 	return r.opts
 }
+
+// String implements the Meter interface
+func (r *noopMeter) String() string {
+	return "noop"
+}
+
+type noopCounter struct{}
+
+func (r *noopCounter) Add(int) {
+
+}
+
+func (r *noopCounter) Dec() {
+
+}
+
+func (r *noopCounter) Get() uint64 {
+	return 0
+}
+
+func (r *noopCounter) Inc() {
+
+}
+
+func (r *noopCounter) Set(uint64) {
+
+}
+
+type noopFloatCounter struct{}
+
+func (r *noopFloatCounter) Add(float64) {
+
+}
+
+func (r *noopFloatCounter) Get() float64 {
+	return 0
+}
+
+func (r *noopFloatCounter) Set(float64) {
+
+}
+
+func (r *noopFloatCounter) Sub(float64) {
+
+}
+
+type noopGauge struct{}
+
+func (r *noopGauge) Get() float64 {
+	return 0
+}
+
+type noopSummary struct{}
+
+func (r *noopSummary) Update(float64) {
+
+}
+
+func (r *noopSummary) UpdateDuration(time.Time) {
+
+}
+
+type noopHistogram struct{}
+
+func (r *noopHistogram) Reset() {
+
+}
+
+func (r *noopHistogram) Update(float64) {
+
+}
+
+func (r *noopHistogram) UpdateDuration(time.Time) {
+
+}
+
+//func (r *noopHistogram) VisitNonZeroBuckets(f func(vmrange string, count uint64)) {}