[FFM-1355]: SDK doesnt support multiple custom attributes and name not set correctly

The Target builder replaces the attributes map with every new custom attribute.  This means
we only ever could have one custom attribute.

Name was stored as a custom attribute instead of as a named field, the problem is if you have
the Java SDK using the same target, then it sends 'name' as a named field, and so conflicts with
custom attributes.

This PR fixes the issue with the custom attributes and ensures name is stored in a named field.

Author: Dave Johnston

analyticsservice/analytics.go

@@ -151,8 +151,8 @@ func (as *AnalyticsService) sendDataAndResetCache(ctx context.Context) {
 				}
 
 				targetName := analytic.target.Identifier
-				if analytic.target.Name != nil {
-					targetName = *analytic.target.Name
+				if analytic.target.Name != "" {
+					targetName = analytic.target.Name
 				}
 
 				td := metricsclient.TargetData{

client/client.go

@@ -191,7 +191,7 @@ func (c *CfClient) authenticate(ctx context.Context, target evaluation.Target) {
 		target.Anonymous,
 		target.Attributes,
 		target.Identifier,
-		target.Name,
+		&target.Name,
 	}
 	c.auth.Target = &t
 	c.mux.RLock()

dto/target_builder.go

@@ -63,7 +63,7 @@ func (b *targetBuilder) Lastname(lastname string) TargetBuilderInterface {
 
 // Name target name object
 func (b *targetBuilder) Name(name string) TargetBuilderInterface {
-	b.Custom("name", name)
+	b.Target.Name = name
 	return b
 }
 
@@ -76,8 +76,8 @@ func (b *targetBuilder) Anonymous(value bool) TargetBuilderInterface {
 // Custom object
 func (b *targetBuilder) Custom(key string, value interface{}) TargetBuilderInterface {
 	m := make(map[string]interface{})
-	if b.Target.Attributes == nil {
-		b.Target.Attributes = &m
+	if b.Target.Attributes != nil {
+		m = *b.Target.Attributes
 	}
 	m[key] = value
 	b.Target.Attributes = &m

evaluation/target.go

@@ -2,6 +2,7 @@ package evaluation
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/drone/ff-golang-server-sdk/types"
 
@@ -11,7 +12,7 @@ import (
 // Target object
 type Target struct {
 	Identifier string
-	Name       *string
+	Name       string
 	Anonymous  *bool
 	Attributes *map[string]interface{}
 }
@@ -24,7 +25,14 @@ func (t Target) GetAttrValue(attr string) reflect.Value {
 	if ok {
 		value = reflect.ValueOf(attrVal)
 	} else {
-		value = GetStructFieldValue(t, attr)
+		// We only have two fields here, so we will access the fields directly, and use reflection if we start adding
+		// more in the future
+		switch strings.ToLower(attr) {
+		case "identifier":
+			value = reflect.ValueOf(t.Identifier)
+		case "name":
+			value = reflect.ValueOf(t.Name)
+		}
 	}
 	return value
 }