move plugin interfaces into separate package

plugins/outputs/graphite/graphite.go

@@ -7,7 +7,7 @@ import (
 	"net"
 	"time"
 
-	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins"
 	"github.com/influxdata/telegraf/plugins/outputs"
 	"github.com/influxdata/telegraf/plugins/serializers"
 )
@@ -73,7 +73,7 @@ func (g *Graphite) Description() string {
 
 // Choose a random server in the cluster to write to until a successful write
 // occurs, logging each unsuccessful. If all servers fail, return error.
-func (g *Graphite) Write(metrics []telegraf.Metric) error {
+func (g *Graphite) Write(metrics []plugins.Metric) error {
 	// Prepare data
 	var batch []byte
 	s, err := serializers.NewGraphiteSerializer(g.Prefix, g.Template)
@@ -116,7 +116,7 @@ func (g *Graphite) Write(metrics []telegraf.Metric) error {
 }
 
 func init() {
-	outputs.Add("graphite", func() telegraf.Output {
+	outputs.Add("graphite", func() plugins.Output {
 		return &Graphite{}
 	})
 }

plugins/outputs/graphite/graphite_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins"
 	"github.com/influxdata/telegraf/metric"
 
 	"github.com/stretchr/testify/assert"
@@ -29,7 +29,7 @@ func TestGraphiteError(t *testing.T) {
 		time.Date(2010, time.November, 10, 23, 0, 0, 0, time.UTC),
 	)
 	// Prepare point list
-	var metrics []telegraf.Metric
+	var metrics []plugins.Metric
 	metrics = append(metrics, m1)
 	// Error
 	err1 := g.Connect()
@@ -72,7 +72,7 @@ func TestGraphiteOK(t *testing.T) {
 	)
 
 	// Prepare point list
-	metrics := []telegraf.Metric{m1, m2, m3}
+	metrics := []plugins.Metric{m1, m2, m3}
 	err1 := g.Connect()
 	require.NoError(t, err1)
 	// Send Data