WIP: MQTT Consumer ServiceInput plugin

metric.go

@@ -63,20 +63,34 @@ func NewMetric(
 	}, nil
 }
 
+// MetricParser is an object for Parsing incoming metrics.
+type MetricParser struct {
+	// DefaultTags will be added to every parsed metric
+	DefaultTags map[string]string
+}
+
+func NewMetricParser() *MetricParser {
+	return &MetricParser{}
+}
+
 // ParseMetrics returns a slice of Metrics from a text representation of a
 // metric (in line-protocol format)
 // with each metric separated by newlines. If any metrics fail to parse,
 // a non-nil error will be returned in addition to the metrics that parsed
 // successfully.
-func ParseMetrics(buf []byte) ([]Metric, error) {
+func (mp *MetricParser) Parse(buf []byte) ([]Metric, error) {
 	// parse even if the buffer begins with a newline
 	buf = bytes.TrimPrefix(buf, []byte("\n"))
 	points, err := models.ParsePoints(buf)
 	metrics := make([]Metric, len(points))
 	for i, point := range points {
+		tags := point.Tags()
+		for k, v := range mp.DefaultTags {
+			tags[k] = v
+		}
 		// Ignore error here because it's impossible that a model.Point
 		// wouldn't parse into client.Point properly
-		metrics[i], _ = NewMetric(point.Name(), point.Tags(),
+		metrics[i], _ = NewMetric(point.Name(), tags,
 			point.Fields(), point.Time())
 	}
 	return metrics, err

metric_test.go

@@ -28,7 +28,7 @@ cpu,host usage_idle=99
 `
 
 func TestParseValidMetrics(t *testing.T) {
-	metrics, err := ParseMetrics([]byte(validMs))
+	metrics, err := NewMetricParser().Parse([]byte(validMs))
 	assert.NoError(t, err)
 	assert.Len(t, metrics, 1)
 	m := metrics[0]
@@ -50,13 +50,13 @@ func TestParseValidMetrics(t *testing.T) {
 }
 
 func TestParseInvalidMetrics(t *testing.T) {
-	metrics, err := ParseMetrics([]byte(invalidMs))
+	metrics, err := NewMetricParser().Parse([]byte(invalidMs))
 	assert.Error(t, err)
 	assert.Len(t, metrics, 0)
 }
 
 func TestParseValidAndInvalidMetrics(t *testing.T) {
-	metrics, err := ParseMetrics([]byte(validInvalidMs))
+	metrics, err := NewMetricParser().Parse([]byte(validInvalidMs))
 	assert.Error(t, err)
 	assert.Len(t, metrics, 3)
 }

plugins/inputs/all/all.go

@@ -19,6 +19,7 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/inputs/mailchimp"
 	_ "github.com/influxdata/telegraf/plugins/inputs/memcached"
 	_ "github.com/influxdata/telegraf/plugins/inputs/mongodb"
+	_ "github.com/influxdata/telegraf/plugins/inputs/mqtt_consumer"
 	_ "github.com/influxdata/telegraf/plugins/inputs/mysql"
 	_ "github.com/influxdata/telegraf/plugins/inputs/nginx"
 	_ "github.com/influxdata/telegraf/plugins/inputs/nsq"

plugins/inputs/exec/exec.go

@@ -91,7 +91,7 @@ func (e *Exec) Gather(acc telegraf.Accumulator) error {
 		acc.AddFields("exec", f.Fields, nil)
 	case "influx":
 		now := time.Now()
-		metrics, err := telegraf.ParseMetrics(out)
+		metrics, err := telegraf.NewMetricParser().Parse(out)
 		for _, metric := range metrics {
 			acc.AddFields(metric.Name(), metric.Fields(), metric.Tags(), now)
 		}

plugins/inputs/kafka_consumer/kafka_consumer.go

@@ -17,16 +17,18 @@ type Kafka struct {
 	Topics         []string
 	ZookeeperPeers []string
 	Consumer       *consumergroup.ConsumerGroup
-	PointBuffer    int
-	Offset         string
+	MetricBuffer   int
+	// TODO remove PointBuffer, legacy support
+	PointBuffer int
+	Offset      string
 
 	sync.Mutex
 
 	// channel for all incoming kafka messages
 	in <-chan *sarama.ConsumerMessage
 	// channel for all kafka consumer errors
 	errs <-chan *sarama.ConsumerError
-	// channel for all incoming parsed kafka points
+	// channel for all incoming parsed kafka metrics
 	metricC chan telegraf.Metric
 	done    chan struct{}
 
@@ -42,8 +44,8 @@ var sampleConfig = `
   zookeeper_peers = ["localhost:2181"]
   # the name of the consumer group
   consumer_group = "telegraf_metrics_consumers"
-  # Maximum number of points to buffer between collection intervals
-  point_buffer = 100000
+  # Maximum number of metrics to buffer between collection intervals
+  metric_buffer = 100000
   # Offset (must be either "oldest" or "newest")
   offset = "oldest"
 `
@@ -90,10 +92,13 @@ func (k *Kafka) Start() error {
 	}
 
 	k.done = make(chan struct{})
-	if k.PointBuffer == 0 {
-		k.PointBuffer = 100000
+	if k.PointBuffer == 0 && k.MetricBuffer == 0 {
+		k.MetricBuffer = 100000
+	} else if k.PointBuffer > 0 {
+		// Legacy support of PointBuffer field TODO remove
+		k.MetricBuffer = k.PointBuffer
 	}
-	k.metricC = make(chan telegraf.Metric, k.PointBuffer)
+	k.metricC = make(chan telegraf.Metric, k.MetricBuffer)
 
 	// Start the kafka message reader
 	go k.parser()
@@ -112,7 +117,7 @@ func (k *Kafka) parser() {
 		case err := <-k.errs:
 			log.Printf("Kafka Consumer Error: %s\n", err.Error())
 		case msg := <-k.in:
-			metrics, err := telegraf.ParseMetrics(msg.Value)
+			metrics, err := telegraf.NewMetricParser().Parse(msg.Value)
 			if err != nil {
 				log.Printf("Could not parse kafka message: %s, error: %s",
 					string(msg.Value), err.Error())
@@ -124,7 +129,7 @@ func (k *Kafka) parser() {
 					continue
 				default:
 					log.Printf("Kafka Consumer buffer is full, dropping a metric." +
-						" You may want to increase the point_buffer setting")
+						" You may want to increase the metric_buffer setting")
 				}
 			}
 
@@ -151,10 +156,10 @@ func (k *Kafka) Stop() {
 func (k *Kafka) Gather(acc telegraf.Accumulator) error {
 	k.Lock()
 	defer k.Unlock()
-	npoints := len(k.metricC)
-	for i := 0; i < npoints; i++ {
-		point := <-k.metricC
-		acc.AddFields(point.Name(), point.Fields(), point.Tags(), point.Time())
+	nmetrics := len(k.metricC)
+	for i := 0; i < nmetrics; i++ {
+		metric := <-k.metricC
+		acc.AddFields(metric.Name(), metric.Fields(), metric.Tags(), metric.Time())
 	}
 	return nil
 }

plugins/inputs/mqtt_consumer/README.md

@@ -0,0 +1,39 @@
+# mqtt_consumer Input Plugin
+
+The example plugin gathers metrics about example things
+
+### Configuration:
+
+```
+# Description
+[[inputs.example]]
+  # SampleConfig
+```
+
+### Measurements & Fields:
+
+<optional description>
+
+- measurement1
+    - field1 (type, unit)
+    - field2 (float, percent)
+- measurement2
+    - field3 (integer, bytes)
+
+### Tags:
+
+- All measurements have the following tags:
+    - tag1 (optional description)
+    - tag2
+- measurement2 has the following tags:
+    - tag3
+
+### Example Output:
+
+Give an example `-test` output here
+
+```
+$ ./telegraf -config telegraf.conf -input-filter example -test
+measurement1,tag1=foo,tag2=bar field1=1i,field2=2.1 1453831884664956455
+measurement2,tag1=foo,tag2=bar,tag3=baz field3=1i 1453831884664956455
+```