adding generic attributes interface (#217)

* adding generic attributes interface

* adding unit test

* review changes

* review changes

* review changes

---------

Co-authored-by: Varkeychan Jacob <varkeychanjacob@Varkeychans-MacBook-Pro-2631.local>

instrumentation/opentelemetry/span.go

@@ -31,6 +31,15 @@ func (l *AttributeList) GetValue(key string) interface{} {
 	return nil
 }
 
+func (l *AttributeList) GetAll() []sdk.Attribute {
+	size := len(l.attrs)
+	attributes := make([]sdk.Attribute, size)
+	for i := 0; i < size; i++ {
+		attributes[i] = sdk.Attribute{Key: string(l.attrs[i].Key), Value: l.attrs[i].Value.AsInterface()}
+	}
+	return attributes
+}
+
 var _ sdk.Span = (*Span)(nil)
 
 type Span struct {

instrumentation/opentelemetry/span_test.go

@@ -109,3 +109,25 @@ func TestGetAttributes(t *testing.T) {
 	assert.Equal(t, "string_value", attrs.GetValue("string_key"))
 	assert.Equal(t, nil, attrs.GetValue("non_existent"))
 }
+
+func TestGetAllAttributes(t *testing.T) {
+	sampler := sdktrace.AlwaysSample()
+	tp := sdktrace.NewTracerProvider(
+		sdktrace.WithSampler(sampler),
+	)
+	otel.SetTracerProvider(tp)
+	_, s, _ := StartSpan(context.Background(), "test_span", &sdk.SpanOptions{})
+	s.SetAttribute("k1", "v1")
+	s.SetAttribute("k2", 200)
+	attrs := s.GetAttributes().GetAll()
+
+	// service.instance.id is added implicitly in StartSpan so 3 attributes will be present.
+	assert.Equal(t, 3, len(attrs))
+	for _, attr := range attrs {
+		if attr.Key == "k1" {
+			assert.Equal(t, "v1", fmt.Sprintf("%v", attr.Value))
+		} else if attr.Key == "k2" {
+			assert.Equal(t, "200", fmt.Sprintf("%v", attr.Value))
+		}
+	}
+}

sdk/internal/mock/span.go

@@ -29,6 +29,17 @@ func (l *AttributeList) GetValue(key string) interface{} {
 	return l.attrs[key]
 }
 
+func (l *AttributeList) GetAll() []sdk.Attribute {
+
+	attributes := make([]sdk.Attribute, len(l.attrs))
+	i := 0
+	for key, value := range l.attrs {
+		attributes[i] = sdk.Attribute{Key: key, Value: value}
+		i++
+	}
+	return attributes
+}
+
 var _ sdk.Span = &Span{}
 
 type Span struct {

sdk/span.go

@@ -5,8 +5,14 @@ import (
 	"time"
 )
 
+type Attribute struct {
+	Key   string
+	Value interface{}
+}
+
 type AttributeList interface {
 	GetValue(key string) interface{}
+	GetAll() []Attribute
 }
 
 // Span is an interface that accepts attributes and can be