Add Accumulator to the ServiceInput Start() function

closes #666

Author: sparrc

agent/agent.go

@@ -58,7 +58,8 @@ func (a *Agent) Connect() error {
 		}
 		err := o.Output.Connect()
 		if err != nil {
-			log.Printf("Failed to connect to output %s, retrying in 15s, error was '%s' \n", o.Name, err)
+			log.Printf("Failed to connect to output %s, retrying in 15s, "+
+				"error was '%s' \n", o.Name, err)
 			time.Sleep(15 * time.Second)
 			err = o.Output.Connect()
 			if err != nil {
@@ -241,7 +242,7 @@ func (a *Agent) Test() error {
 	return nil
 }
 
-// flush writes a list of points to all configured outputs
+// flush writes a list of metrics to all configured outputs
 func (a *Agent) flush() {
 	var wg sync.WaitGroup
 
@@ -260,7 +261,7 @@ func (a *Agent) flush() {
 	wg.Wait()
 }
 
-// flusher monitors the points input channel and flushes on the minimum interval
+// flusher monitors the metrics input channel and flushes on the minimum interval
 func (a *Agent) flusher(shutdown chan struct{}, metricC chan telegraf.Metric) error {
 	// Inelegant, but this sleep is to allow the Gather threads to run, so that
 	// the flusher will flush after metrics are collected.
@@ -271,14 +272,14 @@ func (a *Agent) flusher(shutdown chan struct{}, metricC chan telegraf.Metric) er
 	for {
 		select {
 		case <-shutdown:
-			log.Println("Hang on, flushing any cached points before shutdown")
+			log.Println("Hang on, flushing any cached metrics before shutdown")
 			a.flush()
 			return nil
 		case <-ticker.C:
 			a.flush()
 		case m := <-metricC:
 			for _, o := range a.Config.Outputs {
-				o.AddPoint(m)
+				o.AddMetric(m)
 			}
 		}
 	}
@@ -318,8 +319,8 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 		a.Config.Agent.Interval.Duration, a.Config.Agent.Debug, a.Config.Agent.Quiet,
 		a.Config.Agent.Hostname, a.Config.Agent.FlushInterval.Duration)
 
-	// channel shared between all input threads for accumulating points
-	metricC := make(chan telegraf.Metric, 1000)
+	// channel shared between all input threads for accumulating metrics
+	metricC := make(chan telegraf.Metric, 10000)
 
 	// Round collection to nearest interval by sleeping
 	if a.Config.Agent.RoundInterval {
@@ -342,7 +343,10 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 		// Start service of any ServicePlugins
 		switch p := input.Input.(type) {
 		case telegraf.ServiceInput:
-			if err := p.Start(); err != nil {
+			acc := NewAccumulator(input.Config, metricC)
+			acc.SetDebug(a.Config.Agent.Debug)
+			acc.setDefaultTags(a.Config.Tags)
+			if err := p.Start(acc); err != nil {
 				log.Printf("Service for input %s failed to start, exiting\n%s\n",
 					input.Name, err.Error())
 				return err

input.go

@@ -24,7 +24,7 @@ type ServiceInput interface {
 	Gather(Accumulator) error
 
 	// Start starts the ServiceInput's service, whatever that may be
-	Start() error
+	Start(Accumulator) error
 
 	// Stop stops the services and closes any necessary channels and connections
 	Stop()

internal/config/config.go

@@ -68,7 +68,7 @@ type AgentConfig struct {
 	// same time, which can have a measurable effect on the system.
 	CollectionJitter internal.Duration
 
-	// Interval at which to flush data
+	// FlushInterval is the Interval at which to flush data
 	FlushInterval internal.Duration
 
 	// FlushJitter Jitters the flush interval by a random amount.
@@ -82,6 +82,11 @@ type AgentConfig struct {
 	// full, the oldest metrics will be overwritten.
 	MetricBufferLimit int
 
+	// FlushBufferWhenFull tells Telegraf to flush the metric buffer whenever
+	// it fills up, regardless of FlushInterval. Setting this option to true
+	// does _not_ deactivate FlushInterval.
+	FlushBufferWhenFull bool
+
 	// TODO(cam): Remove UTC and Precision parameters, they are no longer
 	// valid for the agent config. Leaving them here for now for backwards-
 	// compatability
@@ -157,6 +162,8 @@ var header = `##################################################################
   ### Telegraf will cache metric_buffer_limit metrics for each output, and will
   ### flush this buffer on a successful write.
   metric_buffer_limit = 10000
+  ### Flush the buffer whenever full, regardless of flush_interval.
+  flush_buffer_when_full = true
 
   ### Collection jitter is used to jitter the collection by a random amount.
   ### Each plugin will sleep for a random time within jitter before collecting.
@@ -421,8 +428,9 @@ func (c *Config) addOutput(name string, table *ast.Table) error {
 
 	ro := internal_models.NewRunningOutput(name, output, outputConfig)
 	if c.Agent.MetricBufferLimit > 0 {
-		ro.PointBufferLimit = c.Agent.MetricBufferLimit
+		ro.MetricBufferLimit = c.Agent.MetricBufferLimit
 	}
+	ro.FlushBufferWhenFull = c.Agent.FlushBufferWhenFull
 	ro.Quiet = c.Agent.Quiet
 	c.Outputs = append(c.Outputs, ro)
 	return nil

internal/models/running_output.go

@@ -2,22 +2,34 @@ package internal_models
 
 import (
 	"log"
+	"sync"
 	"time"
 
 	"github.com/influxdata/telegraf"
 )
 
-const DEFAULT_POINT_BUFFER_LIMIT = 10000
+const (
+	// Default number of metrics kept between flushes.
+	DEFAULT_METRIC_BUFFER_LIMIT = 10000
+
+	// Limit how many full metric buffers are kept due to failed writes.
+	FULL_METRIC_BUFFERS_LIMIT = 100
+)
 
 type RunningOutput struct {
-	Name             string
-	Output           telegraf.Output
-	Config           *OutputConfig
-	Quiet            bool
-	PointBufferLimit int
+	Name                string
+	Output              telegraf.Output
+	Config              *OutputConfig
+	Quiet               bool
+	MetricBufferLimit   int
+	FlushBufferWhenFull bool
 
-	metrics          []telegraf.Metric
-	overwriteCounter int
+	metrics    []telegraf.Metric
+	tmpmetrics map[int][]telegraf.Metric
+	overwriteI int
+	mapI       int
+
+	sync.Mutex
 }
 
 func NewRunningOutput(
@@ -26,47 +38,98 @@ func NewRunningOutput(
 	conf *OutputConfig,
 ) *RunningOutput {
 	ro := &RunningOutput{
-		Name:             name,
-		metrics:          make([]telegraf.Metric, 0),
-		Output:           output,
-		Config:           conf,
-		PointBufferLimit: DEFAULT_POINT_BUFFER_LIMIT,
+		Name:              name,
+		metrics:           make([]telegraf.Metric, 0),
+		tmpmetrics:        make(map[int][]telegraf.Metric),
+		Output:            output,
+		Config:            conf,
+		MetricBufferLimit: DEFAULT_METRIC_BUFFER_LIMIT,
 	}
 	return ro
 }
 
-func (ro *RunningOutput) AddPoint(point telegraf.Metric) {
+// AddMetric adds a metric to the output. This function can also write cached
+// points if FlushBufferWhenFull is true.
+func (ro *RunningOutput) AddMetric(metric telegraf.Metric) {
 	if ro.Config.Filter.IsActive {
-		if !ro.Config.Filter.ShouldMetricPass(point) {
+		if !ro.Config.Filter.ShouldMetricPass(metric) {
 			return
 		}
 	}
 
-	if len(ro.metrics) < ro.PointBufferLimit {
-		ro.metrics = append(ro.metrics, point)
+	if len(ro.metrics) < ro.MetricBufferLimit {
+		ro.Lock()
+		ro.metrics = append(ro.metrics, metric)
+		ro.Unlock()
 	} else {
-		log.Printf("WARNING: overwriting cached metrics, you may want to " +
-			"increase the metric_buffer_limit setting in your [agent] config " +
-			"if you do not wish to overwrite metrics.\n")
-		if ro.overwriteCounter == len(ro.metrics) {
-			ro.overwriteCounter = 0
+		if ro.FlushBufferWhenFull {
+			ro.Lock()
+			tmpmetrics := make([]telegraf.Metric, len(ro.metrics))
+			copy(tmpmetrics, ro.metrics)
+			ro.metrics = make([]telegraf.Metric, 0)
+			ro.Unlock()
+			err := ro.write(tmpmetrics)
+			if err != nil {
+				log.Printf("ERROR writing full metric buffer to output %s, %s",
+					ro.Name, err)
+				if len(ro.tmpmetrics) == FULL_METRIC_BUFFERS_LIMIT {
+					ro.mapI = 0
+					// overwrite one
+					ro.tmpmetrics[ro.mapI] = tmpmetrics
+					ro.mapI++
+				} else {
+					ro.tmpmetrics[ro.mapI] = tmpmetrics
+					ro.mapI++
+				}
+			}
+		} else {
+			log.Printf("WARNING: overwriting cached metrics, you may want to " +
+				"increase the metric_buffer_limit setting in your [agent] " +
+				"config if you do not wish to overwrite metrics.\n")
+			ro.Lock()
+			if ro.overwriteI == len(ro.metrics) {
+				ro.overwriteI = 0
+			}
+			ro.metrics[ro.overwriteI] = metric
+			ro.overwriteI++
+			ro.Unlock()
 		}
-		ro.metrics[ro.overwriteCounter] = point
-		ro.overwriteCounter++
 	}
 }
 
+// Write writes all cached points to this output.
 func (ro *RunningOutput) Write() error {
+	ro.Lock()
+	err := ro.write(ro.metrics)
+	if err != nil {
+		return err
+	} else {
+		ro.metrics = make([]telegraf.Metric, 0)
+		ro.overwriteI = 0
+	}
+	ro.Unlock()
+
+	// Write any cached metric buffers that failed previously
+	for i, tmpmetrics := range ro.tmpmetrics {
+		if err := ro.write(tmpmetrics); err != nil {
+			return err
+		} else {
+			delete(ro.tmpmetrics, i)
+		}
+	}
+
+	return nil
+}
+
+func (ro *RunningOutput) write(metrics []telegraf.Metric) error {
 	start := time.Now()
-	err := ro.Output.Write(ro.metrics)
+	err := ro.Output.Write(metrics)
 	elapsed := time.Since(start)
 	if err == nil {
 		if !ro.Quiet {
 			log.Printf("Wrote %d metrics to output %s in %s\n",
-				len(ro.metrics), ro.Name, elapsed)
+				len(metrics), ro.Name, elapsed)
 		}
-		ro.metrics = make([]telegraf.Metric, 0)
-		ro.overwriteCounter = 0
 	}
 	return err
 }

plugins/inputs/github_webhooks/github_webhooks.go

@@ -61,7 +61,7 @@ func (gh *GithubWebhooks) Listen() {
 	}
 }
 
-func (gh *GithubWebhooks) Start() error {
+func (gh *GithubWebhooks) Start(_ telegraf.Accumulator) error {
 	go gh.Listen()
 	log.Printf("Started the github_webhooks service on %s\n", gh.ServiceAddress)
 	return nil

plugins/inputs/kafka_consumer/kafka_consumer.go

@@ -1,7 +1,6 @@
 package kafka_consumer
 
 import (
-	"fmt"
 	"log"
 	"strings"
 	"sync"
@@ -19,11 +18,13 @@ type Kafka struct {
 	Topics         []string
 	ZookeeperPeers []string
 	Consumer       *consumergroup.ConsumerGroup
-	MetricBuffer   int
+
+	// Legacy metric buffer support
+	MetricBuffer int
 	// TODO remove PointBuffer, legacy support
 	PointBuffer int
-	Offset      string
 
+	Offset string
 	parser parsers.Parser
 
 	sync.Mutex
@@ -32,9 +33,10 @@ type Kafka struct {
 	in <-chan *sarama.ConsumerMessage
 	// channel for all kafka consumer errors
 	errs <-chan *sarama.ConsumerError
-	// channel for all incoming parsed kafka metrics
-	metricC chan telegraf.Metric
-	done    chan struct{}
+	done chan struct{}
+
+	// keep the accumulator internally:
+	acc telegraf.Accumulator
 
 	// doNotCommitMsgs tells the parser not to call CommitUpTo on the consumer
 	// this is mostly for test purposes, but there may be a use-case for it later.
@@ -48,8 +50,6 @@ var sampleConfig = `
   zookeeper_peers = ["localhost:2181"]
   ### the name of the consumer group
   consumer_group = "telegraf_metrics_consumers"
-  ### Maximum number of metrics to buffer between collection intervals
-  metric_buffer = 100000
   ### Offset (must be either "oldest" or "newest")
   offset = "oldest"
 
@@ -72,11 +72,13 @@ func (k *Kafka) SetParser(parser parsers.Parser) {
 	k.parser = parser
 }
 
-func (k *Kafka) Start() error {
+func (k *Kafka) Start(acc telegraf.Accumulator) error {
 	k.Lock()
 	defer k.Unlock()
 	var consumerErr error
 
+	k.acc = acc
+
 	config := consumergroup.NewConfig()
 	switch strings.ToLower(k.Offset) {
 	case "oldest", "":
@@ -106,13 +108,6 @@ func (k *Kafka) Start() error {
 	}
 
 	k.done = make(chan struct{})
-	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.MetricBuffer)
 
 	// Start the kafka message reader
 	go k.receiver()
@@ -138,14 +133,7 @@ func (k *Kafka) receiver() {
 			}
 
 			for _, metric := range metrics {
-				fmt.Println(string(metric.Name()))
-				select {
-				case k.metricC <- metric:
-					continue
-				default:
-					log.Printf("Kafka Consumer buffer is full, dropping a metric." +
-						" You may want to increase the metric_buffer setting")
-				}
+				k.acc.AddFields(metric.Name(), metric.Fields(), metric.Tags(), metric.Time())
 			}
 
 			if !k.doNotCommitMsgs {
@@ -169,13 +157,6 @@ func (k *Kafka) Stop() {
 }
 
 func (k *Kafka) Gather(acc telegraf.Accumulator) error {
-	k.Lock()
-	defer k.Unlock()
-	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
 }