use original newrelic context functions

.travis.yml

@@ -1,8 +1,8 @@
-dist: trusty
+dist: bionic
 sudo: false
 
 language: go
-go: [ "1.11" ]
+go: [ "1.15" ]
 env:
   global:
   - PATH=$PATH:$HOME/gopath/bin

go.mod

@@ -1,5 +1,7 @@
 module github.com/gettaxi/newrelicutil
 
+go 1.15
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gorilla/context v1.1.1 // indirect

newrelicutil.go

@@ -11,24 +11,20 @@ import (
 type key int
 
 const (
-	transaction key = iota
-	segment
+	segment key = iota
 	externalSegment
 	datastoreSegment
 )
 
 // Transaction returns the New Relic Transaction object from context.
 func Transaction(ctx context.Context) newrelic.Transaction {
-	if txn, ok := ctx.Value(transaction).(newrelic.Transaction); ok {
-		return txn
-	}
-	return nil
+	return newrelic.FromContext(ctx)
 }
 
 // WithTransaction puts the New Relic Transaction object to the given context
 // and returns the new context.
 func WithTransaction(ctx context.Context, txn newrelic.Transaction) context.Context {
-	return context.WithValue(ctx, transaction, txn)
+	return newrelic.NewContext(ctx, txn)
 }
 
 // WrapHandler return the given http handler that is wrapped to New Relic Transaction.

newrelicutil_test.go

@@ -6,10 +6,10 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"github.com/gettaxi/newrelicutil"
+	newrelic "github.com/newrelic/go-agent"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"github.com/gettaxi/newrelicutil"
-	"github.com/newrelic/go-agent"
 )
 
 func TestTransaction(t *testing.T) {