meter: add Clone method

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

meter/meter.go

@@ -28,17 +28,31 @@ var (
 
 // Meter is an interface for collecting and instrumenting metrics
 type Meter interface {
+	// Name returns meter name
 	Name() string
+	// Init initialize meter
 	Init(opts ...Option) error
+	// Clone create meter copy with new options
+	Clone(opts ...Option) Meter
+	// Counter get or create counter
 	Counter(name string, labels ...string) Counter
+	// FloatCounter get or create float counter
 	FloatCounter(name string, labels ...string) FloatCounter
+	// Gauge get or create gauge
 	Gauge(name string, fn func() float64, labels ...string) Gauge
+	// Set create new meter metrics set
 	Set(opts ...Option) Meter
+	// Histogram get or create histogram
 	Histogram(name string, labels ...string) Histogram
+	// Summary get or create summary
 	Summary(name string, labels ...string) Summary
+	// SummaryExt get or create summary with spcified quantiles and window time
 	SummaryExt(name string, window time.Duration, quantiles []float64, labels ...string) Summary
+	// Write writes metrics to io.Writer
 	Write(w io.Writer, opts ...Option) error
+	// Options returns meter options
 	Options() Options
+	// String return meter type
 	String() string
 }
 

meter/noop.go

@@ -15,6 +15,15 @@ func NewMeter(opts ...Option) Meter {
 	return &noopMeter{opts: NewOptions(opts...)}
 }
 
+// Clone return old meter with new options
+func (r *noopMeter) Clone(opts ...Option) Meter {
+	options := r.opts
+	for _, o := range opts {
+		o(&options)
+	}
+	return &noopMeter{opts: options}
+}
+
 func (r *noopMeter) Name() string {
 	return r.opts.Name
 }

meter/options.go

@@ -51,6 +51,20 @@ func NewOptions(opt ...Option) Options {
 	return opts
 }
 
+// LabelPrefix sets the labels prefix
+func LabelPrefix(pref string) Option {
+	return func(o *Options) {
+		o.LabelPrefix = pref
+	}
+}
+
+// MetricPrefix sets the metric prefix
+func MetricPrefix(pref string) Option {
+	return func(o *Options) {
+		o.MetricPrefix = pref
+	}
+}
+
 // Context sets the metrics context
 func Context(ctx context.Context) Option {
 	return func(o *Options) {

service.go

@@ -392,8 +392,12 @@ type nameIface interface {
 	Name() string
 }
 
-func getNameIndex(n string, ifaces ...interface{}) int {
-	for idx, iface := range ifaces {
+func getNameIndex(n string, ifaces interface{}) int {
+	values, ok := ifaces.([]interface{})
+	if !ok {
+		return 0
+	}
+	for idx, iface := range values {
 		if ifc, ok := iface.(nameIface); ok && ifc.Name() == n {
 			return idx
 		}

service_test.go

@@ -0,0 +1,22 @@
+package micro
+
+import (
+	"testing"
+)
+
+type testItem struct {
+	name string
+}
+
+func (ti *testItem) Name() string {
+	return ti.name
+}
+
+func TestGetNameIndex(t *testing.T) {
+	item1 := &testItem{name: "first"}
+	item2 := &testItem{name: "second"}
+	items := []interface{}{item1, item2}
+	if idx := getNameIndex("second", items); idx != 1 {
+		t.Fatalf("getNameIndex func error, item not found")
+	}
+}

tracer/context.go

@@ -8,14 +8,14 @@ import (
 type tracerKey struct{}
 
 // FromContext returns a tracer from context
-func FromContext(ctx context.Context) Tracer {
+func FromContext(ctx context.Context) (Tracer, bool) {
 	if ctx == nil {
-		return DefaultTracer
+		return nil, false
 	}
 	if tracer, ok := ctx.Value(tracerKey{}).(Tracer); ok {
-		return tracer
+		return tracer, true
 	}
-	return DefaultTracer
+	return nil, false
 }
 
 // NewContext saves the tracer in the context
@@ -29,14 +29,14 @@ func NewContext(ctx context.Context, tracer Tracer) context.Context {
 type spanKey struct{}
 
 // SpanFromContext returns a span from context
-func SpanFromContext(ctx context.Context) Span {
+func SpanFromContext(ctx context.Context) (Span, bool) {
 	if ctx == nil {
-		return &noopSpan{}
+		return nil, false
 	}
 	if span, ok := ctx.Value(spanKey{}).(Span); ok {
-		return span
+		return span, true
 	}
-	return &noopSpan{}
+	return nil, false
 }
 
 // NewSpanContext saves the span in the context

tracer/noop.go

@@ -35,6 +35,7 @@ type noopSpan struct {
 	ctx    context.Context
 	tracer Tracer
 	name   string
+	labels []Label
 }
 
 func (s *noopSpan) Finish(opts ...SpanOption) {
@@ -56,6 +57,7 @@ func (s *noopSpan) SetName(name string) {
 }
 
 func (s *noopSpan) SetLabels(labels ...Label) {
+	s.labels = labels
 }
 
 // NewTracer returns new memory tracer

tracer/tracer.go

@@ -38,26 +38,26 @@ type Label struct {
 	key string
 }
 
-func Any(k string, v interface{}) Label {
+func LabelAny(k string, v interface{}) Label {
 	return Label{key: k, val: v}
 }
 
-func String(k string, v string) Label {
+func LabelString(k string, v string) Label {
 	return Label{key: k, val: v}
 }
 
-func Int(k string, v int) Label {
+func LabelInt(k string, v int) Label {
 	return Label{key: k, val: v}
 }
 
-func Int64(k string, v int64) Label {
+func LabelInt64(k string, v int64) Label {
 	return Label{key: k, val: v}
 }
 
-func Float64(k string, v float64) Label {
+func LabelFloat64(k string, v float64) Label {
 	return Label{key: k, val: v}
 }
 
-func Bool(k string, v bool) Label {
+func LabelBool(k string, v bool) Label {
 	return Label{key: k, val: v}
 }