NSQ Output plugin

NSQ output plugin, following the NSQ methodology output is a producer
to one instance of NSQD. The go library does not accept array values be
default for a Producer. Additionally service discovery is generally
done as a consumer.

Follows same methodology as Kafka Output without the tag reference.

outputs/nsq/README.md

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+# NSQ Output Plugin
+
+This plugin writes to a specified NSQD instance, usually local to the producer. It requires
+a `server` name and a `topic` name.

outputs/nsq/nsq.go

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+package nsq
+
+import (
+	"fmt"
+	"github.com/influxdb/influxdb/client"
+	"github.com/influxdb/telegraf/outputs"
+	"github.com/nsqio/go-nsq"
+	"time"
+)
+
+type NSQ struct {
+	Server   string
+	Topic    string
+	producer *nsq.Producer
+}
+
+var sampleConfig = `
+  # Location of nsqd instance listening on TCP
+  server = "localhost:4150"
+  # NSQ topic for producer messages
+  topic = "telegraf"
+`
+
+func (n *NSQ) Connect() error {
+	config := nsq.NewConfig()
+	producer, err := nsq.NewProducer(n.Server, config)
+
+	if err != nil {
+		return err
+	}
+
+	n.producer = producer
+	return nil
+}
+
+func (n *NSQ) Close() error {
+	n.producer.Stop()
+	return nil
+}
+
+func (n *NSQ) SampleConfig() string {
+	return sampleConfig
+}
+
+func (n *NSQ) Description() string {
+	return "Send telegraf measurements to NSQD"
+}
+
+func (n *NSQ) Write(bp client.BatchPoints) error {
+	if len(bp.Points) == 0 {
+		return nil
+	}
+
+	var zeroTime time.Time
+	for _, p := range bp.Points {
+		// Combine tags from Point and BatchPoints and grab the resulting
+		// line-protocol output string to write to NSQ
+		var value string
+		if p.Raw != "" {
+			value = p.Raw
+		} else {
+			for k, v := range bp.Tags {
+				if p.Tags == nil {
+					p.Tags = make(map[string]string, len(bp.Tags))
+				}
+				p.Tags[k] = v
+			}
+			if p.Time == zeroTime {
+				if bp.Time == zeroTime {
+					p.Time = time.Now()
+				} else {
+					p.Time = bp.Time
+				}
+			}
+			value = p.MarshalString()
+		}
+
+		err := n.producer.Publish(n.Topic, []byte(value))
+
+		if err != nil {
+			return fmt.Errorf("FAILED to send NSQD message: %s", err)
+		}
+	}
+	return nil
+
+}
+
+func init() {
+	outputs.Add("nsq", func() outputs.Output {
+		return &NSQ{}
+	})
+}

outputs/nsq/nsq_test.go

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+package nsq
+
+import (
+	"testing"
+
+	"github.com/influxdb/telegraf/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConnectAndWrite(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	server := []string{testutil.GetLocalHost() + ":4150"}
+	n := &NSQ{
+		Server: server,
+		Topic:  "telegraf",
+	}
+
+	// Verify that we can connect to the NSQ daemon
+	err := n.Connect()
+	require.NoError(t, err)
+
+	// Verify that we can successfully write data to the NSQ daemon
+	err = n.Write(testutil.MockBatchPoints())
+	require.NoError(t, err)
+}