Add a no-op WavefrontSender implementation (#65)

* Add a no-op WavefrontSender implementation
* Added unit tests for noop_sender
Co-authored-by: mssrinivas <>

senders/client_noop.go

@@ -0,0 +1,56 @@
+package senders
+
+import (
+	"github.com/wavefronthq/wavefront-sdk-go/event"
+	"github.com/wavefronthq/wavefront-sdk-go/histogram"
+)
+
+type wavefrontNoOpSender struct {
+}
+
+var (
+	defaultNoopClient Sender = &wavefrontNoOpSender{}
+)
+
+// NewWavefrontNoOpClient returns a Wavefront Client instance for which all operations are no-ops.
+func NewWavefrontNoOpClient() (Sender, error) {
+	return defaultNoopClient, nil
+}
+
+func (sender *wavefrontNoOpSender) Start() {
+	// no-op
+}
+
+func (sender *wavefrontNoOpSender) SendMetric(name string, value float64, ts int64, source string, tags map[string]string) error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) SendDeltaCounter(name string, value float64, source string, tags map[string]string) error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) SendDistribution(name string, centroids []histogram.Centroid,
+	hgs map[histogram.Granularity]bool, ts int64, source string, tags map[string]string) error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) SendSpan(name string, startMillis, durationMillis int64, source, traceId, spanId string,
+	parents, followsFrom []string, tags []SpanTag, spanLogs []SpanLog) error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) SendEvent(name string, startMillis, endMillis int64, source string, tags map[string]string, setters ...event.Option) error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) Close() {
+	// no-op
+}
+
+func (sender *wavefrontNoOpSender) Flush() error {
+	return nil
+}
+
+func (sender *wavefrontNoOpSender) GetFailureCount() int64 {
+	return 0
+}

senders/client_noop_test.go

@@ -0,0 +1,59 @@
+package senders_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/wavefronthq/wavefront-sdk-go/histogram"
+	"github.com/wavefronthq/wavefront-sdk-go/senders"
+)
+
+func TestNoOpSender(t *testing.T) {
+	wf, err := senders.NewSender("http://DUMMY_TOKEN@localhost:8080")
+	assert.Nil(t, err)
+	if wf == nil {
+		t.Error("Failed Initialize NewSender", err)
+	}
+
+	if err := wf.SendMetric("new-york.power.usage", 42422.0, 0, "go_test", map[string]string{"env": "test"}); err != nil {
+		t.Error("Failed SendMetric", err)
+	}
+
+	centroids := []histogram.Centroid{
+		{Value: 30.0, Count: 20},
+		{Value: 5.1, Count: 10},
+	}
+
+	hgs := map[histogram.Granularity]bool{
+		histogram.MINUTE: true,
+		histogram.HOUR:   true,
+		histogram.DAY:    true,
+	}
+
+	if err := wf.SendDistribution("request.latency", centroids, hgs, 0, "appServer1", map[string]string{"region": "us-west"}); err != nil {
+		t.Error("Failed SendDistribution", err)
+	}
+
+	if err := wf.SendDeltaCounter("invocation.count", 0, "appServer2", map[string]string{"region": "us-west"}); err != nil {
+		t.Error("Failed SendDeltaCounter", err)
+	}
+
+	if err := wf.SendSpan("getAllUsers", 0, 343500, "localhost",
+		"7b3bf470-9456-11e8-9eb6-529269fb1459", "0313bafe-9457-11e8-9eb6-529269fb1459",
+		[]string{"2f64e538-9457-11e8-9eb6-529269fb1459"}, nil,
+		[]senders.SpanTag{
+			{Key: "application", Value: "Wavefront"},
+			{Key: "http.method", Value: "GET"},
+		},
+		nil); err != nil {
+		t.Error("Failed SendSpan", err)
+	}
+
+	if err := wf.SendEvent("updateAllUsers", 0, 37484, "localhost", map[string]string{"region": "us-west"}); err != nil {
+		t.Error("Failed SendEvent", err)
+	}
+
+	wf.Flush()
+	wf.Close()
+	assert.Equal(t, int64(0), wf.GetFailureCount(), "GetFailureCount")
+}