Add template processor (#6494)

plugins/processors/template/template_test.go

@@ -0,0 +1,80 @@
+package template
+
+import (
+	"testing"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/testutil"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTagTemplateConcatenate(t *testing.T) {
+	now := time.Now()
+
+	// Create Template processor
+	tmp := TemplateProcessor{Tag: "topic", Template: `{{.Tag "hostname"}}.{{ .Tag "level" }}`}
+	// manually init
+	err := tmp.Init()
+
+	if err != nil {
+		panic(err)
+	}
+
+	// create metric for testing
+	input := []telegraf.Metric{testutil.MustMetric("Tags", map[string]string{"hostname": "localhost", "level": "debug"}, nil, now)}
+
+	// act
+	actual := tmp.Apply(input[0])
+
+	// assert
+	expected := []telegraf.Metric{testutil.MustMetric("Tags", map[string]string{"hostname": "localhost", "level": "debug", "topic": "localhost.debug"}, nil, now)}
+	testutil.RequireMetricsEqual(t, expected, actual)
+}
+
+func TestMetricMissingTagsIsNotLost(t *testing.T) {
+	now := time.Now()
+
+	// Create Template processor
+	tmp := TemplateProcessor{Tag: "topic", Template: `{{.Tag "hostname"}}.{{ .Tag "level" }}`}
+	// manually init
+	err := tmp.Init()
+
+	if err != nil {
+		panic(err)
+	}
+
+	// create metrics for testing
+	m1 := testutil.MustMetric("Works", map[string]string{"hostname": "localhost", "level": "debug"}, nil, now)
+	m2 := testutil.MustMetric("Fails", map[string]string{"hostname": "localhost"}, nil, now)
+
+	// act
+	actual := tmp.Apply(m1, m2)
+
+	// assert
+	// make sure no metrics are lost when a template process fails
+	assert.Equal(t, 2, len(actual), "Number of metrics input should equal number of metrics output")
+}
+
+func TestTagAndFieldConcatenate(t *testing.T) {
+	now := time.Now()
+
+	// Create Template processor
+	tmp := TemplateProcessor{Tag: "LocalTemp", Template: `{{.Tag "location"}} is {{ .Field "temperature" }}`}
+	// manually init
+	err := tmp.Init()
+
+	if err != nil {
+		panic(err)
+	}
+
+	// create metric for testing
+	m1 := testutil.MustMetric("weather", map[string]string{"location": "us-midwest"}, map[string]interface{}{"temperature": "too warm"}, now)
+
+	// act
+	actual := tmp.Apply(m1)
+
+	// assert
+	expected := []telegraf.Metric{testutil.MustMetric("weather", map[string]string{"location": "us-midwest", "LocalTemp": "us-midwest is too warm"}, map[string]interface{}{"temperature": "too warm"}, now)}
+	testutil.RequireMetricsEqual(t, expected, actual)
+}