many improvements with options and noop stuff

* add many options helpers
* fix noop client to allow publish messages to topic in broker
* fix noop server to allow registering in registry
* fix noop server to allow subscribe to topic in broker
* fix new service initialization

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

tracer/context.go

@@ -0,0 +1,36 @@
+// Package trace provides an interface for distributed tracing
+package tracer
+
+import (
+	"context"
+
+	"github.com/unistack-org/micro/v3/metadata"
+)
+
+const (
+	traceIDKey = "Micro-Trace-Id"
+	spanIDKey  = "Micro-Span-Id"
+)
+
+// FromContext returns a span from context
+func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
+	traceID, traceOk := metadata.Get(ctx, traceIDKey)
+	microID, microOk := metadata.Get(ctx, "Micro-Id")
+	if !traceOk && !microOk {
+		isFound = false
+		return
+	}
+	if !traceOk {
+		traceID = microID
+	}
+	parentSpanID, ok := metadata.Get(ctx, spanIDKey)
+	return traceID, parentSpanID, ok
+}
+
+// NewContext saves the trace and span ids in the context
+func NewContext(ctx context.Context, traceID, parentSpanID string) context.Context {
+	return metadata.MergeContext(ctx, map[string]string{
+		traceIDKey: traceID,
+		spanIDKey:  parentSpanID,
+	}, true)
+}

tracer/noop.go

@@ -2,24 +2,24 @@ package tracer
 
 import "context"
 
-type noop struct{}
+type NoopTracer struct{}
 
-func (n *noop) Init(...Option) error {
+func (n *NoopTracer) Init(...Option) error {
 	return nil
 }
 
-func (n *noop) Start(ctx context.Context, name string) (context.Context, *Span) {
+func (n *NoopTracer) Start(ctx context.Context, name string) (context.Context, *Span) {
 	return nil, nil
 }
 
-func (n *noop) Finish(*Span) error {
+func (n *NoopTracer) Finish(*Span) error {
 	return nil
 }
 
-func (n *noop) Read(...ReadOption) ([]*Span, error) {
+func (n *NoopTracer) Read(...ReadOption) ([]*Span, error) {
 	return nil, nil
 }
 
-func newTracer(opts ...Option) Tracer {
-	return &noop{}
+func NewTracer(opts ...Option) Tracer {
+	return &NoopTracer{}
 }

tracer/trace.go

@@ -4,12 +4,10 @@ package tracer
 import (
 	"context"
 	"time"
-
-	"github.com/unistack-org/micro/v3/metadata"
 )
 
 var (
-	DefaultTracer Tracer = newTracer()
+	DefaultTracer Tracer = NewTracer()
 )
 
 // Tracer is an interface for distributed tracing
@@ -51,31 +49,3 @@ type Span struct {
 	// Type
 	Type SpanType
 }
-
-const (
-	traceIDKey = "Micro-Trace-Id"
-	spanIDKey  = "Micro-Span-Id"
-)
-
-// FromContext returns a span from context
-func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
-	traceID, traceOk := metadata.Get(ctx, traceIDKey)
-	microID, microOk := metadata.Get(ctx, "Micro-Id")
-	if !traceOk && !microOk {
-		isFound = false
-		return
-	}
-	if !traceOk {
-		traceID = microID
-	}
-	parentSpanID, ok := metadata.Get(ctx, spanIDKey)
-	return traceID, parentSpanID, ok
-}
-
-// ToContext saves the trace and span ids in the context
-func ToContext(ctx context.Context, traceID, parentSpanID string) context.Context {
-	return metadata.MergeContext(ctx, map[string]string{
-		traceIDKey: traceID,
-		spanIDKey:  parentSpanID,
-	}, true)
-}