many fixes for lint and context.Context usage (#5)

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

tracer/noop.go

@@ -2,24 +2,34 @@ package tracer
 
 import "context"
 
-type NoopTracer struct{}
+type noopTracer struct {
+	opts Options
+}
 
-func (n *NoopTracer) Init(...Option) error {
+// Init initilize tracer
+func (n *noopTracer) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&n.opts)
+	}
 	return nil
 }
 
-func (n *NoopTracer) Start(ctx context.Context, name string) (context.Context, *Span) {
+// Start starts new span
+func (n *noopTracer) Start(ctx context.Context, name string) (context.Context, *Span) {
 	return nil, nil
 }
 
-func (n *NoopTracer) Finish(*Span) error {
+// Finish finishes span
+func (n *noopTracer) Finish(*Span) error {
 	return nil
 }
 
-func (n *NoopTracer) Read(...ReadOption) ([]*Span, error) {
+// Read reads span
+func (n *noopTracer) Read(...ReadOption) ([]*Span, error) {
 	return nil, nil
 }
 
+// NewTracer returns new noop tracer
 func NewTracer(opts ...Option) Tracer {
-	return &NoopTracer{}
+	return &noopTracer{opts: NewOptions(opts...)}
 }

tracer/options.go

@@ -1,5 +1,10 @@
 package tracer
 
+var (
+	// DefaultSize of the buffer
+	DefaultSize = 64
+)
+
 // Options struct
 type Options struct {
 	// Size is the size of ring buffer
@@ -9,6 +14,7 @@ type Options struct {
 // Option func
 type Option func(o *Options)
 
+// ReadOptions struct
 type ReadOptions struct {
 	// Trace id
 	Trace string
@@ -24,14 +30,13 @@ func ReadTrace(t string) ReadOption {
 	}
 }
 
-const (
-	// DefaultSize of the buffer
-	DefaultSize = 64
-)
-
-// DefaultOptions returns default options
-func DefaultOptions() Options {
-	return Options{
+// NewOptions returns default options
+func NewOptions(opts ...Option) Options {
+	options := Options{
 		Size: DefaultSize,
 	}
+	for _, o := range opts {
+		o(&options)
+	}
+	return options
 }

tracer/trace.go

@@ -1,4 +1,4 @@
-// Package trace provides an interface for distributed tracing
+// Package tracer provides an interface for distributed tracing
 package tracer
 
 import (
@@ -7,6 +7,7 @@ import (
 )
 
 var (
+	// DefaultTracer is the global default tracer
 	DefaultTracer Tracer = NewTracer()
 )