Merge pull request #658 from weaveworks/report-generation

Move weave ps calls to a background goroutine, instruments probe runtime.

probe/docker/reporter.go

@@ -34,6 +34,9 @@ func NewReporter(registry Registry, hostID string, probe *probe.Probe) *Reporter
 	return reporter
 }
 
+// Name of this reporter, for metrics gathering
+func (Reporter) Name() string { return "Docker" }
+
 // ContainerUpdated should be called whenever a container is updated.
 func (r *Reporter) ContainerUpdated(c Container) {
 	localAddrs, err := report.LocalAddresses()

probe/docker/tagger.go

@@ -34,6 +34,9 @@ func NewTagger(registry Registry, procWalker process.Walker) *Tagger {
 	}
 }
 
+// Name of this tagger, for metrics gathering
+func (Tagger) Name() string { return "Docker" }
+
 // Tag implements Tagger.
 func (t *Tagger) Tag(r report.Report) (report.Report, error) {
 	tree, err := NewProcessTreeStub(t.procWalker)

probe/endpoint/reporter.go

@@ -58,6 +58,9 @@ func NewReporter(hostID, hostName string, includeProcesses bool, useConntrack bo
 	}
 }
 
+// Name of this reporter, for metrics gathering
+func (Reporter) Name() string { return "Endpoint" }
+
 // Stop stop stop
 func (r *Reporter) Stop() {
 	r.flowWalker.stop()

probe/host/reporter.go

@@ -48,6 +48,9 @@ func NewReporter(hostID, hostName string, localNets report.Networks) *Reporter {
 	}
 }
 
+// Name of this reporter, for metrics gathering
+func (Reporter) Name() string { return "Host" }
+
 // Report implements Reporter.
 func (r *Reporter) Report() (report.Report, error) {
 	var (

probe/host/tagger.go

@@ -21,6 +21,9 @@ func NewTagger(hostID, probeID string) Tagger {
 	}
 }
 
+// Name of this tagger, for metrics gathering
+func (Tagger) Name() string { return "Host" }
+
 // Tag implements Tagger.
 func (t Tagger) Tag(r report.Report) (report.Report, error) {
 	metadata := map[string]string{

probe/kubernetes/reporter.go

@@ -16,6 +16,9 @@ func NewReporter(client Client) *Reporter {
 	}
 }
 
+// Name of this reporter, for metrics gathering
+func (Reporter) Name() string { return "K8s" }
+
 // Report generates a Report containing Container and ContainerImage topologies
 func (r *Reporter) Report() (report.Report, error) {
 	result := report.MakeReport()

probe/overlay/weave.go

@@ -9,6 +9,7 @@ import (
 	"regexp"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/weaveworks/scope/common/exec"
 	"github.com/weaveworks/scope/common/sanitize"
@@ -44,8 +45,11 @@ type Weave struct {
 	url    string
 	hostID string
 
+	quit   chan struct{}
+	done   sync.WaitGroup
 	mtx    sync.RWMutex
 	status weaveStatus
+	ps     map[string]psEntry
 }
 
 type weaveStatus struct {
@@ -68,9 +72,51 @@ type weaveStatus struct {
 // NewWeave returns a new Weave tagger based on the Weave router at
 // address. The address should be an IP or FQDN, no port.
 func NewWeave(hostID, weaveRouterAddress string) *Weave {
-	return &Weave{
+	w := &Weave{
 		url:    sanitize.URL("http://", 6784, "/report")(weaveRouterAddress),
 		hostID: hostID,
+		quit:   make(chan struct{}),
+		ps:     map[string]psEntry{},
+	}
+	w.done.Add(1)
+	go w.loop()
+	return w
+}
+
+// Name of this reporter/tagger/ticker, for metrics gathering
+func (*Weave) Name() string { return "Weave" }
+
+// Stop gathering weave ps output.
+func (w *Weave) Stop() {
+	close(w.quit)
+	w.done.Wait()
+}
+
+func (w *Weave) loop() {
+	defer w.done.Done()
+	tick := time.Tick(5 * time.Second)
+
+	for {
+		psEntries, err := w.getPSEntries()
+		if err != nil {
+			log.Printf("Error running weave ps: %v", err)
+			break
+		}
+
+		psEntriesByPrefix := map[string]psEntry{}
+		for _, entry := range psEntries {
+			psEntriesByPrefix[entry.containerIDPrefix] = entry
+		}
+
+		w.mtx.Lock()
+		w.ps = psEntriesByPrefix
+		w.mtx.Unlock()
+
+		select {
+		case <-w.quit:
+			return
+		case <-tick:
+		}
 	}
 }
 
@@ -108,7 +154,7 @@ type psEntry struct {
 	ips               []string
 }
 
-func (w *Weave) ps() ([]psEntry, error) {
+func (w *Weave) getPSEntries() ([]psEntry, error) {
 	var result []psEntry
 	cmd := exec.Command("weave", "--local", "ps")
 	out, err := cmd.StdoutPipe()
@@ -160,17 +206,11 @@ func (w *Weave) Tag(r report.Report) (report.Report, error) {
 	}
 
 	// Put information from weave ps on the container nodes
-	psEntries, err := w.ps()
-	if err != nil {
-		return r, nil
-	}
-	psEntriesByPrefix := map[string]psEntry{}
-	for _, entry := range psEntries {
-		psEntriesByPrefix[entry.containerIDPrefix] = entry
-	}
+	w.mtx.RLock()
+	defer w.mtx.RUnlock()
 	for id, node := range r.Container.Nodes {
 		prefix := node.Metadata[docker.ContainerID][:12]
-		entry, ok := psEntriesByPrefix[prefix]
+		entry, ok := w.ps[prefix]
 		if !ok {
 			continue
 		}

probe/overlay/weave_test.go

@@ -26,6 +26,7 @@ func TestWeaveTaggerOverlayTopology(t *testing.T) {
 	defer s.Close()
 
 	w := overlay.NewWeave(mockHostID, s.URL)
+	defer w.Stop()
 	w.Tick()
 
 	{

probe/probe.go

@@ -5,6 +5,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/armon/go-metrics"
+
 	"github.com/weaveworks/scope/report"
 	"github.com/weaveworks/scope/xfer"
 )
@@ -31,11 +33,13 @@ type Probe struct {
 
 // Tagger tags nodes with value-add node metadata.
 type Tagger interface {
+	Name() string
 	Tag(r report.Report) (report.Report, error)
 }
 
 // Reporter generates Reports.
 type Reporter interface {
+	Name() string
 	Report() (report.Report, error)
 }
 
@@ -43,6 +47,7 @@ type Reporter interface {
 // It's useful for things that should be updated on that interval.
 // For example, cached shared state between Taggers and Reporters.
 type Ticker interface {
+	Name() string
 	Tick() error
 }
 
@@ -100,32 +105,36 @@ func (p *Probe) spyLoop() {
 	for {
 		select {
 		case <-spyTick:
-			start := time.Now()
-			for _, ticker := range p.tickers {
-				if err := ticker.Tick(); err != nil {
-					log.Printf("error doing ticker: %v", err)
-				}
-			}
-
+			t := time.Now()
+			p.tick()
 			rpt := p.report()
 			rpt = p.tag(rpt)
 			p.spiedReports <- rpt
-
-			if took := time.Since(start); took > p.spyInterval {
-				log.Printf("report generation took too long (%s)", took)
-			}
-
+			metrics.MeasureSince([]string{"Report Generaton"}, t)
 		case <-p.quit:
 			return
 		}
 	}
 }
 
+func (p *Probe) tick() {
+	for _, ticker := range p.tickers {
+		t := time.Now()
+		err := ticker.Tick()
+		metrics.MeasureSince([]string{ticker.Name(), "ticker"}, t)
+		if err != nil {
+			log.Printf("error doing ticker: %v", err)
+		}
+	}
+}
+
 func (p *Probe) report() report.Report {
 	reports := make(chan report.Report, len(p.reporters))
 	for _, rep := range p.reporters {
 		go func(rep Reporter) {
+			t := time.Now()
 			newReport, err := rep.Report()
+			metrics.MeasureSince([]string{rep.Name(), "reporter"}, t)
 			if err != nil {
 				log.Printf("error generating report: %v", err)
 				newReport = report.MakeReport() // empty is OK to merge
@@ -144,7 +153,9 @@ func (p *Probe) report() report.Report {
 func (p *Probe) tag(r report.Report) report.Report {
 	var err error
 	for _, tagger := range p.taggers {
+		t := time.Now()
 		r, err = tagger.Tag(r)
+		metrics.MeasureSince([]string{tagger.Name(), "tagger"}, t)
 		if err != nil {
 			log.Printf("error applying tagger: %v", err)
 		}

probe/probe_internal_test.go

@@ -50,6 +50,8 @@ func (m mockReporter) Report() (report.Report, error) {
 	return m.r.Copy(), nil
 }
 
+func (mockReporter) Name() string { return "Mock" }
+
 type mockPublisher struct {
 	have chan report.Report
 }

probe/process/reporter.go

@@ -29,6 +29,9 @@ func NewReporter(walker Walker, scope string) *Reporter {
 	}
 }
 
+// Name of this reporter, for metrics gathering
+func (Reporter) Name() string { return "Process" }
+
 // Report implements Reporter.
 func (r *Reporter) Report() (report.Report, error) {
 	result := report.MakeReport()

probe/process/walker.go

@@ -28,6 +28,9 @@ func NewCachingWalker(source Walker) *CachingWalker {
 	return &CachingWalker{source: source}
 }
 
+// Name of this ticker, for metrics gathering
+func (*CachingWalker) Name() string { return "Process" }
+
 // Walk walks a cached copy of process list
 func (c *CachingWalker) Walk(f func(Process)) error {
 	c.cacheLock.RLock()

probe/topology_tagger.go

@@ -15,6 +15,8 @@ func NewTopologyTagger() Tagger {
 	return &topologyTagger{}
 }
 
+func (topologyTagger) Name() string { return "Topology" }
+
 // Tag implements Tagger
 func (topologyTagger) Tag(r report.Report) (report.Report, error) {
 	for val, topology := range map[string]*report.Topology{

prog/probe/main.go

@@ -15,6 +15,8 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/armon/go-metrics"
+
 	"github.com/weaveworks/scope/probe"
 	"github.com/weaveworks/scope/probe/controls"
 	"github.com/weaveworks/scope/probe/docker"
@@ -57,6 +59,12 @@ func main() {
 		return
 	}
 
+	// Setup in memory metrics sink
+	inm := metrics.NewInmemSink(time.Minute, 2*time.Minute)
+	sig := metrics.DefaultInmemSignal(inm)
+	defer sig.Stop()
+	metrics.NewGlobal(metrics.DefaultConfig("scope-probe"), inm)
+
 	if !strings.HasSuffix(*logPrefix, " ") {
 		*logPrefix += " "
 	}
@@ -151,6 +159,7 @@ func main() {
 
 	if *weaveRouterAddr != "" {
 		weave := overlay.NewWeave(hostID, *weaveRouterAddr)
+		defer weave.Stop()
 		p.AddTicker(weave)
 		p.AddTagger(weave)
 		p.AddReporter(weave)

vendor/github.com/DataDog/datadog-go/statsd/README.md

@@ -0,0 +1,45 @@
+## Overview
+
+Package `statsd` provides a Go [dogstatsd](http://docs.datadoghq.com/guides/dogstatsd/) client.  Dogstatsd extends Statsd, adding tags
+and histograms.
+
+## Get the code
+
+    $ go get github.com/DataDog/datadog-go/statsd
+
+## Usage
+
+```go
+// Create the client
+c, err := statsd.New("127.0.0.1:8125")
+if err != nil {
+    log.Fatal(err)
+}
+// Prefix every metric with the app name
+c.Namespace = "flubber."
+// Send the EC2 availability zone as a tag with every metric
+c.Tags = append(c.Tags, "us-east-1a")
+err = c.Gauge("request.duration", 1.2, nil, 1)
+```
+
+## Buffering Client
+
+Dogstatsd accepts packets with multiple statsd payloads in them.  Using the BufferingClient via `NewBufferingClient` will buffer up commands and send them when the buffer is reached or after 100msec.
+
+## Development
+
+Run the tests with:
+
+    $ go test
+
+## Documentation
+
+Please see: http://godoc.org/github.com/DataDog/datadog-go/statsd
+
+## License
+
+go-dogstatsd is released under the [MIT license](http://www.opensource.org/licenses/mit-license.php).
+
+## Credits
+
+Original code by [ooyala](https://github.com/ooyala/go-dogstatsd).

vendor/github.com/DataDog/datadog-go/statsd/statsd.go

@@ -0,0 +1,353 @@
+// Copyright 2013 Ooyala, Inc.
+
+/*
+Package statsd provides a Go dogstatsd client. Dogstatsd extends the popular statsd,
+adding tags and histograms and pushing upstream to Datadog.
+
+Refer to http://docs.datadoghq.com/guides/dogstatsd/ for information about DogStatsD.
+
+Example Usage:
+
+    // Create the client
+    c, err := statsd.New("127.0.0.1:8125")
+    if err != nil {
+        log.Fatal(err)
+    }
+    // Prefix every metric with the app name
+    c.Namespace = "flubber."
+    // Send the EC2 availability zone as a tag with every metric
+    c.Tags = append(c.Tags, "us-east-1a")
+    err = c.Gauge("request.duration", 1.2, nil, 1)
+
+statsd is based on go-statsd-client.
+*/
+package statsd
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+	"net"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// A Client is a handle for sending udp messages to dogstatsd.  It is safe to
+// use one Client from multiple goroutines simultaneously.
+type Client struct {
+	conn net.Conn
+	// Namespace to prepend to all statsd calls
+	Namespace string
+	// Tags are global tags to be added to every statsd call
+	Tags []string
+	// BufferLength is the length of the buffer in commands.
+	bufferLength int
+	flushTime    time.Duration
+	commands     []string
+	stop         bool
+	sync.Mutex
+}
+
+// New returns a pointer to a new Client given an addr in the format "hostname:port".
+func New(addr string) (*Client, error) {
+	udpAddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+	conn, err := net.DialUDP("udp", nil, udpAddr)
+	if err != nil {
+		return nil, err
+	}
+	client := &Client{conn: conn}
+	return client, nil
+}
+
+// NewBuffered returns a Client that buffers its output and sends it in chunks.
+// Buflen is the length of the buffer in number of commands.
+func NewBuffered(addr string, buflen int) (*Client, error) {
+	client, err := New(addr)
+	if err != nil {
+		return nil, err
+	}
+	client.bufferLength = buflen
+	client.commands = make([]string, 0, buflen)
+	client.flushTime = time.Millisecond * 100
+	go client.watch()
+	return client, nil
+}
+
+// format a message from its name, value, tags and rate.  Also adds global
+// namespace and tags.
+func (c *Client) format(name, value string, tags []string, rate float64) string {
+	var buf bytes.Buffer
+	if c.Namespace != "" {
+		buf.WriteString(c.Namespace)
+	}
+	buf.WriteString(name)
+	buf.WriteString(":")
+	buf.WriteString(value)
+	if rate < 1 {
+		buf.WriteString(`|@`)
+		buf.WriteString(strconv.FormatFloat(rate, 'f', -1, 64))
+	}
+
+	tags = append(c.Tags, tags...)
+	if len(tags) > 0 {
+		buf.WriteString("|#")
+		buf.WriteString(tags[0])
+		for _, tag := range tags[1:] {
+			buf.WriteString(",")
+			buf.WriteString(tag)
+		}
+	}
+	return buf.String()
+}
+
+func (c *Client) watch() {
+	for _ = range time.Tick(c.flushTime) {
+		if c.stop {
+			return
+		}
+		c.Lock()
+		if len(c.commands) > 0 {
+			// FIXME: eating error here
+			c.flush()
+		}
+		c.Unlock()
+	}
+}
+
+func (c *Client) append(cmd string) error {
+	c.Lock()
+	c.commands = append(c.commands, cmd)
+	// if we should flush, lets do it
+	if len(c.commands) == c.bufferLength {
+		if err := c.flush(); err != nil {
+			c.Unlock()
+			return err
+		}
+	}
+	c.Unlock()
+	return nil
+}
+
+// flush the commands in the buffer.  Lock must be held by caller.
+func (c *Client) flush() error {
+	data := strings.Join(c.commands, "\n")
+	_, err := c.conn.Write([]byte(data))
+	// clear the slice with a slice op, doesn't realloc
+	c.commands = c.commands[:0]
+	return err
+}
+
+func (c *Client) sendMsg(msg string) error {
+	// if this client is buffered, then we'll just append this
+	if c.bufferLength > 0 {
+		return c.append(msg)
+	}
+	c.Lock()
+	_, err := c.conn.Write([]byte(msg))
+	c.Unlock()
+	return err
+}
+
+// send handles sampling and sends the message over UDP. It also adds global namespace prefixes and tags.
+func (c *Client) send(name, value string, tags []string, rate float64) error {
+	if c == nil {
+		return nil
+	}
+	if rate < 1 && rand.Float64() > rate {
+		return nil
+	}
+	data := c.format(name, value, tags, rate)
+	return c.sendMsg(data)
+}
+
+// Gauge measures the value of a metric at a particular time.
+func (c *Client) Gauge(name string, value float64, tags []string, rate float64) error {
+	stat := fmt.Sprintf("%f|g", value)
+	return c.send(name, stat, tags, rate)
+}
+
+// Count tracks how many times something happened per second.
+func (c *Client) Count(name string, value int64, tags []string, rate float64) error {
+	stat := fmt.Sprintf("%d|c", value)
+	return c.send(name, stat, tags, rate)
+}
+
+// Histogram tracks the statistical distribution of a set of values.
+func (c *Client) Histogram(name string, value float64, tags []string, rate float64) error {
+	stat := fmt.Sprintf("%f|h", value)
+	return c.send(name, stat, tags, rate)
+}
+
+// Set counts the number of unique elements in a group.
+func (c *Client) Set(name string, value string, tags []string, rate float64) error {
+	stat := fmt.Sprintf("%s|s", value)
+	return c.send(name, stat, tags, rate)
+}
+
+// TimeInMilliseconds sends timing information in milliseconds.
+// It is flushed by statsd with percentiles, mean and other info (https://github.com/etsy/statsd/blob/master/docs/metric_types.md#timing)
+func (c *Client) TimeInMilliseconds(name string, value float64, tags []string, rate float64) error {
+	stat := fmt.Sprintf("%f|ms", value)
+	return c.send(name, stat, tags, rate)
+}
+
+// Event sends the provided Event.
+func (c *Client) Event(e *Event) error {
+	stat, err := e.Encode(c.Tags...)
+	if err != nil {
+		return err
+	}
+	return c.sendMsg(stat)
+}
+
+// SimpleEvent sends an event with the provided title and text.
+func (c *Client) SimpleEvent(title, text string) error {
+	e := NewEvent(title, text)
+	return c.Event(e)
+}
+
+// Close the client connection.
+func (c *Client) Close() error {
+	if c == nil {
+		return nil
+	}
+	c.stop = true
+	return c.conn.Close()
+}
+
+// Events support
+
+type eventAlertType string
+
+const (
+	// Info is the "info" AlertType for events
+	Info eventAlertType = "info"
+	// Error is the "error" AlertType for events
+	Error eventAlertType = "error"
+	// Warning is the "warning" AlertType for events
+	Warning eventAlertType = "warning"
+	// Success is the "success" AlertType for events
+	Success eventAlertType = "success"
+)
+
+type eventPriority string
+
+const (
+	// Normal is the "normal" Priority for events
+	Normal eventPriority = "normal"
+	// Low is the "low" Priority for events
+	Low eventPriority = "low"
+)
+
+// An Event is an object that can be posted to your DataDog event stream.
+type Event struct {
+	// Title of the event.  Required.
+	Title string
+	// Text is the description of the event.  Required.
+	Text string
+	// Timestamp is a timestamp for the event.  If not provided, the dogstatsd
+	// server will set this to the current time.
+	Timestamp time.Time
+	// Hostname for the event.
+	Hostname string
+	// AggregationKey groups this event with others of the same key.
+	AggregationKey string
+	// Priority of the event.  Can be statsd.Low or statsd.Normal.
+	Priority eventPriority
+	// SourceTypeName is a source type for the event.
+	SourceTypeName string
+	// AlertType can be statsd.Info, statsd.Error, statsd.Warning, or statsd.Success.
+	// If absent, the default value applied by the dogstatsd server is Info.
+	AlertType eventAlertType
+	// Tags for the event.
+	Tags []string
+}
+
+// NewEvent creates a new event with the given title and text.  Error checking
+// against these values is done at send-time, or upon running e.Check.
+func NewEvent(title, text string) *Event {
+	return &Event{
+		Title: title,
+		Text:  text,
+	}
+}
+
+// Check verifies that an event is valid.
+func (e Event) Check() error {
+	if len(e.Title) == 0 {
+		return fmt.Errorf("statsd.Event title is required")
+	}
+	if len(e.Text) == 0 {
+		return fmt.Errorf("statsd.Event text is required")
+	}
+	return nil
+}
+
+// Encode returns the dogstatsd wire protocol representation for an event.
+// Tags may be passed which will be added to the encoded output but not to
+// the Event's list of tags, eg. for default tags.
+func (e Event) Encode(tags ...string) (string, error) {
+	err := e.Check()
+	if err != nil {
+		return "", err
+	}
+	var buffer bytes.Buffer
+	buffer.WriteString("_e{")
+	buffer.WriteString(strconv.FormatInt(int64(len(e.Title)), 10))
+	buffer.WriteRune(',')
+	buffer.WriteString(strconv.FormatInt(int64(len(e.Text)), 10))
+	buffer.WriteString("}:")
+	buffer.WriteString(e.Title)
+	buffer.WriteRune('|')
+	buffer.WriteString(e.Text)
+
+	if !e.Timestamp.IsZero() {
+		buffer.WriteString("|d:")
+		buffer.WriteString(strconv.FormatInt(int64(e.Timestamp.Unix()), 10))
+	}
+
+	if len(e.Hostname) != 0 {
+		buffer.WriteString("|h:")
+		buffer.WriteString(e.Hostname)
+	}
+
+	if len(e.AggregationKey) != 0 {
+		buffer.WriteString("|k:")
+		buffer.WriteString(e.AggregationKey)
+
+	}
+
+	if len(e.Priority) != 0 {
+		buffer.WriteString("|p:")
+		buffer.WriteString(string(e.Priority))
+	}
+
+	if len(e.SourceTypeName) != 0 {
+		buffer.WriteString("|s:")
+		buffer.WriteString(e.SourceTypeName)
+	}
+
+	if len(e.AlertType) != 0 {
+		buffer.WriteString("|t:")
+		buffer.WriteString(string(e.AlertType))
+	}
+
+	if len(tags)+len(e.Tags) > 0 {
+		all := make([]string, 0, len(tags)+len(e.Tags))
+		all = append(all, tags...)
+		all = append(all, e.Tags...)
+		buffer.WriteString("|#")
+		buffer.WriteString(all[0])
+		for _, tag := range all[1:] {
+			buffer.WriteString(",")
+			buffer.WriteString(tag)
+		}
+	}
+
+	return buffer.String(), nil
+}

vendor/github.com/DataDog/datadog-go/statsd/statsd_test.go

@@ -0,0 +1,312 @@
+// Copyright 2013 Ooyala, Inc.
+
+package statsd
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+var dogstatsdTests = []struct {
+	GlobalNamespace string
+	GlobalTags      []string
+	Method          string
+	Metric          string
+	Value           interface{}
+	Tags            []string
+	Rate            float64
+	Expected        string
+}{
+	{"", nil, "Gauge", "test.gauge", 1.0, nil, 1.0, "test.gauge:1.000000|g"},
+	{"", nil, "Gauge", "test.gauge", 1.0, nil, 0.999999, "test.gauge:1.000000|g|@0.999999"},
+	{"", nil, "Gauge", "test.gauge", 1.0, []string{"tagA"}, 1.0, "test.gauge:1.000000|g|#tagA"},
+	{"", nil, "Gauge", "test.gauge", 1.0, []string{"tagA", "tagB"}, 1.0, "test.gauge:1.000000|g|#tagA,tagB"},
+	{"", nil, "Gauge", "test.gauge", 1.0, []string{"tagA"}, 0.999999, "test.gauge:1.000000|g|@0.999999|#tagA"},
+	{"", nil, "Count", "test.count", int64(1), []string{"tagA"}, 1.0, "test.count:1|c|#tagA"},
+	{"", nil, "Count", "test.count", int64(-1), []string{"tagA"}, 1.0, "test.count:-1|c|#tagA"},
+	{"", nil, "Histogram", "test.histogram", 2.3, []string{"tagA"}, 1.0, "test.histogram:2.300000|h|#tagA"},
+	{"", nil, "Set", "test.set", "uuid", []string{"tagA"}, 1.0, "test.set:uuid|s|#tagA"},
+	{"flubber.", nil, "Set", "test.set", "uuid", []string{"tagA"}, 1.0, "flubber.test.set:uuid|s|#tagA"},
+	{"", []string{"tagC"}, "Set", "test.set", "uuid", []string{"tagA"}, 1.0, "test.set:uuid|s|#tagC,tagA"},
+}
+
+func assertNotPanics(t *testing.T, f func()) {
+	defer func() {
+		if r := recover(); r != nil {
+			t.Fatal(r)
+		}
+	}()
+	f()
+}
+
+func TestClient(t *testing.T) {
+	addr := "localhost:1201"
+	udpAddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	server, err := net.ListenUDP("udp", udpAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer server.Close()
+
+	client, err := New(addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, tt := range dogstatsdTests {
+		client.Namespace = tt.GlobalNamespace
+		client.Tags = tt.GlobalTags
+		method := reflect.ValueOf(client).MethodByName(tt.Method)
+		e := method.Call([]reflect.Value{
+			reflect.ValueOf(tt.Metric),
+			reflect.ValueOf(tt.Value),
+			reflect.ValueOf(tt.Tags),
+			reflect.ValueOf(tt.Rate)})[0]
+		errInter := e.Interface()
+		if errInter != nil {
+			t.Fatal(errInter.(error))
+		}
+
+		bytes := make([]byte, 1024)
+		n, err := server.Read(bytes)
+		if err != nil {
+			t.Fatal(err)
+		}
+		message := bytes[:n]
+		if string(message) != tt.Expected {
+			t.Errorf("Expected: %s. Actual: %s", tt.Expected, string(message))
+		}
+	}
+}
+
+func TestBufferedClient(t *testing.T) {
+	addr := "localhost:1201"
+	udpAddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	server, err := net.ListenUDP("udp", udpAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer server.Close()
+
+	conn, err := net.DialUDP("udp", nil, udpAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	bufferLength := 5
+	client := &Client{
+		conn:         conn,
+		commands:     make([]string, 0, bufferLength),
+		bufferLength: bufferLength,
+	}
+
+	client.Namespace = "foo."
+	client.Tags = []string{"dd:2"}
+
+	client.Count("cc", 1, nil, 1)
+	client.Gauge("gg", 10, nil, 1)
+	client.Histogram("hh", 1, nil, 1)
+	client.Set("ss", "ss", nil, 1)
+
+	if len(client.commands) != 4 {
+		t.Errorf("Expected client to have buffered 4 commands, but found %d\n", len(client.commands))
+	}
+
+	client.Set("ss", "xx", nil, 1)
+	err = client.flush()
+	if err != nil {
+		t.Errorf("Error sending: %s", err)
+	}
+
+	if len(client.commands) != 0 {
+		t.Errorf("Expecting send to flush commands, but found %d\n", len(client.commands))
+	}
+
+	buffer := make([]byte, 4096)
+	n, err := io.ReadAtLeast(server, buffer, 1)
+	result := string(buffer[:n])
+
+	if err != nil {
+		t.Error(err)
+	}
+
+	expected := []string{
+		`foo.cc:1|c|#dd:2`,
+		`foo.gg:10.000000|g|#dd:2`,
+		`foo.hh:1.000000|h|#dd:2`,
+		`foo.ss:ss|s|#dd:2`,
+		`foo.ss:xx|s|#dd:2`,
+	}
+
+	for i, res := range strings.Split(result, "\n") {
+		if res != expected[i] {
+			t.Errorf("Got `%s`, expected `%s`", res, expected[i])
+		}
+	}
+
+	client.Event(&Event{Title: "title1", Text: "text1", Priority: Normal, AlertType: Success, Tags: []string{"tagg"}})
+	client.SimpleEvent("event1", "text1")
+
+	if len(client.commands) != 2 {
+		t.Errorf("Expected to find %d commands, but found %d\n", 2, len(client.commands))
+	}
+
+	err = client.flush()
+
+	if err != nil {
+		t.Errorf("Error sending: %s", err)
+	}
+
+	if len(client.commands) != 0 {
+		t.Errorf("Expecting send to flush commands, but found %d\n", len(client.commands))
+	}
+
+	buffer = make([]byte, 1024)
+	n, err = io.ReadAtLeast(server, buffer, 1)
+	result = string(buffer[:n])
+
+	if err != nil {
+		t.Error(err)
+	}
+
+	if n == 0 {
+		t.Errorf("Read 0 bytes but expected more.")
+	}
+
+	expected = []string{
+		`_e{6,5}:title1|text1|p:normal|t:success|#dd:2,tagg`,
+		`_e{6,5}:event1|text1|#dd:2`,
+	}
+
+	for i, res := range strings.Split(result, "\n") {
+		if res != expected[i] {
+			t.Errorf("Got `%s`, expected `%s`", res, expected[i])
+		}
+	}
+
+}
+
+func TestNilSafe(t *testing.T) {
+	var c *Client
+	assertNotPanics(t, func() { c.Close() })
+	assertNotPanics(t, func() { c.Count("", 0, nil, 1) })
+	assertNotPanics(t, func() { c.Histogram("", 0, nil, 1) })
+	assertNotPanics(t, func() { c.Gauge("", 0, nil, 1) })
+	assertNotPanics(t, func() { c.Set("", "", nil, 1) })
+	assertNotPanics(t, func() { c.send("", "", nil, 1) })
+}
+
+func TestEvents(t *testing.T) {
+	matrix := []struct {
+		event   *Event
+		encoded string
+	}{
+		{
+			NewEvent("Hello", "Something happened to my event"),
+			`_e{5,30}:Hello|Something happened to my event`,
+		}, {
+			&Event{Title: "hi", Text: "okay", AggregationKey: "foo"},
+			`_e{2,4}:hi|okay|k:foo`,
+		}, {
+			&Event{Title: "hi", Text: "okay", AggregationKey: "foo", AlertType: Info},
+			`_e{2,4}:hi|okay|k:foo|t:info`,
+		}, {
+			&Event{Title: "hi", Text: "w/e", AlertType: Error, Priority: Normal},
+			`_e{2,3}:hi|w/e|p:normal|t:error`,
+		}, {
+			&Event{Title: "hi", Text: "uh", Tags: []string{"host:foo", "app:bar"}},
+			`_e{2,2}:hi|uh|#host:foo,app:bar`,
+		},
+	}
+
+	for _, m := range matrix {
+		r, err := m.event.Encode()
+		if err != nil {
+			t.Errorf("Error encoding: %s\n", err)
+			continue
+		}
+		if r != m.encoded {
+			t.Errorf("Expected `%s`, got `%s`\n", m.encoded, r)
+		}
+	}
+
+	e := NewEvent("", "hi")
+	if _, err := e.Encode(); err == nil {
+		t.Errorf("Expected error on empty Title.")
+	}
+
+	e = NewEvent("hi", "")
+	if _, err := e.Encode(); err == nil {
+		t.Errorf("Expected error on empty Text.")
+	}
+
+	e = NewEvent("hello", "world")
+	s, err := e.Encode("tag1", "tag2")
+	if err != nil {
+		t.Error(err)
+	}
+	expected := "_e{5,5}:hello|world|#tag1,tag2"
+	if s != expected {
+		t.Errorf("Expected %s, got %s", expected, s)
+	}
+	if len(e.Tags) != 0 {
+		t.Errorf("Modified event in place illegally.")
+	}
+}
+
+// These benchmarks show that using a buffer instead of sprintf-ing together
+// a bunch of intermediate strings is 4-5x faster
+
+func BenchmarkFormatNew(b *testing.B) {
+	b.StopTimer()
+	c := &Client{}
+	c.Namespace = "foo.bar."
+	c.Tags = []string{"app:foo", "host:bar"}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		c.format("system.cpu.idle", "10", []string{"foo"}, 1)
+		c.format("system.cpu.load", "0.1", nil, 0.9)
+	}
+}
+
+// Old formatting function, added to client for tests
+func (c *Client) formatOld(name, value string, tags []string, rate float64) string {
+	if rate < 1 {
+		value = fmt.Sprintf("%s|@%f", value, rate)
+	}
+	if c.Namespace != "" {
+		name = fmt.Sprintf("%s%s", c.Namespace, name)
+	}
+
+	tags = append(c.Tags, tags...)
+	if len(tags) > 0 {
+		value = fmt.Sprintf("%s|#%s", value, strings.Join(tags, ","))
+	}
+
+	return fmt.Sprintf("%s:%s", name, value)
+
+}
+
+func BenchmarkFormatOld(b *testing.B) {
+	b.StopTimer()
+	c := &Client{}
+	c.Namespace = "foo.bar."
+	c.Tags = []string{"app:foo", "host:bar"}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		c.formatOld("system.cpu.idle", "10", []string{"foo"}, 1)
+		c.formatOld("system.cpu.load", "0.1", nil, 0.9)
+	}
+}

vendor/github.com/armon/go-metrics/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 Armon Dadgar
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/armon/go-metrics/README.md

@@ -0,0 +1,71 @@
+go-metrics
+==========
+
+This library provides a `metrics` package which can be used to instrument code,
+expose application metrics, and profile runtime performance in a flexible manner.
+
+Current API: [![GoDoc](https://godoc.org/github.com/armon/go-metrics?status.svg)](https://godoc.org/github.com/armon/go-metrics)
+
+Sinks
+=====
+
+The `metrics` package makes use of a `MetricSink` interface to support delivery
+to any type of backend. Currently the following sinks are provided:
+
+* StatsiteSink : Sinks to a [statsite](https://github.com/armon/statsite/) instance (TCP)
+* StatsdSink: Sinks to a [StatsD](https://github.com/etsy/statsd/) / statsite instance (UDP)
+* PrometheusSink: Sinks to a [Prometheus](http://prometheus.io/) metrics endpoint (exposed via HTTP for scrapes)
+* InmemSink : Provides in-memory aggregation, can be used to export stats
+* FanoutSink : Sinks to multiple sinks. Enables writing to multiple statsite instances for example.
+* BlackholeSink : Sinks to nowhere
+
+In addition to the sinks, the `InmemSignal` can be used to catch a signal,
+and dump a formatted output of recent metrics. For example, when a process gets
+a SIGUSR1, it can dump to stderr recent performance metrics for debugging.
+
+Examples
+========
+
+Here is an example of using the package:
+
+    func SlowMethod() {
+        // Profiling the runtime of a method
+        defer metrics.MeasureSince([]string{"SlowMethod"}, time.Now())
+    }
+
+    // Configure a statsite sink as the global metrics sink
+    sink, _ := metrics.NewStatsiteSink("statsite:8125")
+    metrics.NewGlobal(metrics.DefaultConfig("service-name"), sink)
+
+    // Emit a Key/Value pair
+    metrics.EmitKey([]string{"questions", "meaning of life"}, 42)
+
+
+Here is an example of setting up an signal handler:
+
+    // Setup the inmem sink and signal handler
+    inm := metrics.NewInmemSink(10*time.Second, time.Minute)
+    sig := metrics.DefaultInmemSignal(inm)
+    metrics.NewGlobal(metrics.DefaultConfig("service-name"), inm)
+
+    // Run some code
+    inm.SetGauge([]string{"foo"}, 42)
+    inm.EmitKey([]string{"bar"}, 30)
+
+    inm.IncrCounter([]string{"baz"}, 42)
+    inm.IncrCounter([]string{"baz"}, 1)
+    inm.IncrCounter([]string{"baz"}, 80)
+
+    inm.AddSample([]string{"method", "wow"}, 42)
+    inm.AddSample([]string{"method", "wow"}, 100)
+    inm.AddSample([]string{"method", "wow"}, 22)
+
+    ....
+
+When a signal comes in, output like the following will be dumped to stderr:
+
+    [2014-01-28 14:57:33.04 -0800 PST][G] 'foo': 42.000
+    [2014-01-28 14:57:33.04 -0800 PST][P] 'bar': 30.000
+    [2014-01-28 14:57:33.04 -0800 PST][C] 'baz': Count: 3 Min: 1.000 Mean: 41.000 Max: 80.000 Stddev: 39.509
+    [2014-01-28 14:57:33.04 -0800 PST][S] 'method.wow': Count: 3 Min: 22.000 Mean: 54.667 Max: 100.000 Stddev: 40.513
+

vendor/github.com/armon/go-metrics/const_unix.go

@@ -0,0 +1,12 @@
+// +build !windows
+
+package metrics
+
+import (
+	"syscall"
+)
+
+const (
+	// DefaultSignal is used with DefaultInmemSignal
+	DefaultSignal = syscall.SIGUSR1
+)

vendor/github.com/armon/go-metrics/const_windows.go

@@ -0,0 +1,13 @@
+// +build windows
+
+package metrics
+
+import (
+	"syscall"
+)
+
+const (
+	// DefaultSignal is used with DefaultInmemSignal
+	// Windows has no SIGUSR1, use SIGBREAK
+	DefaultSignal = syscall.Signal(21)
+)

vendor/github.com/armon/go-metrics/datadog/dogstatsd.go

@@ -0,0 +1,109 @@
+package datadog
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/DataDog/datadog-go/statsd"
+)
+
+// DogStatsdSink provides a MetricSink that can be used
+// with a dogstatsd server. It utilizes the Dogstatsd client at github.com/DataDog/datadog-go/statsd
+type DogStatsdSink struct {
+	client            *statsd.Client
+	hostName          string
+	propagateHostname bool
+}
+
+// NewDogStatsdSink is used to create a new DogStatsdSink with sane defaults
+func NewDogStatsdSink(addr string, hostName string) (*DogStatsdSink, error) {
+	client, err := statsd.New(addr)
+	if err != nil {
+		return nil, err
+	}
+	sink := &DogStatsdSink{
+		client:            client,
+		hostName:          hostName,
+		propagateHostname: false,
+	}
+	return sink, nil
+}
+
+// SetTags sets common tags on the Dogstatsd Client that will be sent
+// along with all dogstatsd packets.
+// Ref: http://docs.datadoghq.com/guides/dogstatsd/#tags
+func (s *DogStatsdSink) SetTags(tags []string) {
+	s.client.Tags = tags
+}
+
+// EnableHostnamePropagation forces a Dogstatsd `host` tag with the value specified by `s.HostName`
+// Since the go-metrics package has its own mechanism for attaching a hostname to metrics,
+// setting the `propagateHostname` flag ensures that `s.HostName` overrides the host tag naively set by the DogStatsd server
+func (s *DogStatsdSink) EnableHostNamePropagation() {
+	s.propagateHostname = true
+}
+
+func (s *DogStatsdSink) flattenKey(parts []string) string {
+	joined := strings.Join(parts, ".")
+	return strings.Map(func(r rune) rune {
+		switch r {
+		case ':':
+			fallthrough
+		case ' ':
+			return '_'
+		default:
+			return r
+		}
+	}, joined)
+}
+
+func (s *DogStatsdSink) parseKey(key []string) ([]string, []string) {
+	// Since DogStatsd supports dimensionality via tags on metric keys, this sink's approach is to splice the hostname out of the key in favor of a `host` tag
+	// The `host` tag is either forced here, or set downstream by the DogStatsd server
+
+	var tags []string
+	hostName := s.hostName
+
+	//Splice the hostname out of the key
+	for i, el := range key {
+		if el == hostName {
+			key = append(key[:i], key[i+1:]...)
+		}
+	}
+
+	if s.propagateHostname {
+		tags = append(tags, fmt.Sprintf("host:%s", hostName))
+	}
+	return key, tags
+}
+
+// Implementation of methods in the MetricSink interface
+
+func (s *DogStatsdSink) SetGauge(key []string, val float32) {
+	key, tags := s.parseKey(key)
+	flatKey := s.flattenKey(key)
+
+	rate := 1.0
+	s.client.Gauge(flatKey, float64(val), tags, rate)
+}
+
+func (s *DogStatsdSink) IncrCounter(key []string, val float32) {
+	key, tags := s.parseKey(key)
+	flatKey := s.flattenKey(key)
+
+	rate := 1.0
+	s.client.Count(flatKey, int64(val), tags, rate)
+}
+
+// EmitKey is not implemented since DogStatsd does not provide a metric type that holds an
+// arbitrary number of values
+func (s *DogStatsdSink) EmitKey(key []string, val float32) {
+}
+
+func (s *DogStatsdSink) AddSample(key []string, val float32) {
+	key, tags := s.parseKey(key)
+	flatKey := s.flattenKey(key)
+
+	rate := 1.0
+	s.client.TimeInMilliseconds(flatKey, float64(val), tags, rate)
+}

vendor/github.com/armon/go-metrics/datadog/dogstatsd_test.go

@@ -0,0 +1,121 @@
+package datadog
+
+import (
+	"fmt"
+	"net"
+	"reflect"
+	"testing"
+)
+
+var EmptyTags []string
+
+const (
+	DogStatsdAddr    = "127.0.0.1:7254"
+	HostnameEnabled  = true
+	HostnameDisabled = false
+	TestHostname     = "test_hostname"
+)
+
+func MockGetHostname() string {
+	return TestHostname
+}
+
+var ParseKeyTests = []struct {
+	KeyToParse        []string
+	Tags              []string
+	PropagateHostname bool
+	ExpectedKey       []string
+	ExpectedTags      []string
+}{
+	{[]string{"a", MockGetHostname(), "b", "c"}, EmptyTags, HostnameDisabled, []string{"a", "b", "c"}, EmptyTags},
+	{[]string{"a", "b", "c"}, EmptyTags, HostnameDisabled, []string{"a", "b", "c"}, EmptyTags},
+	{[]string{"a", "b", "c"}, EmptyTags, HostnameEnabled, []string{"a", "b", "c"}, []string{fmt.Sprintf("host:%s", MockGetHostname())}},
+}
+
+var FlattenKeyTests = []struct {
+	KeyToFlatten []string
+	Expected     string
+}{
+	{[]string{"a", "b", "c"}, "a.b.c"},
+	{[]string{"spaces must", "flatten", "to", "underscores"}, "spaces_must.flatten.to.underscores"},
+}
+
+var MetricSinkTests = []struct {
+	Method            string
+	Metric            []string
+	Value             interface{}
+	Tags              []string
+	PropagateHostname bool
+	Expected          string
+}{
+	{"SetGauge", []string{"foo", "bar"}, float32(42), EmptyTags, HostnameDisabled, "foo.bar:42.000000|g"},
+	{"SetGauge", []string{"foo", "bar", "baz"}, float32(42), EmptyTags, HostnameDisabled, "foo.bar.baz:42.000000|g"},
+	{"AddSample", []string{"sample", "thing"}, float32(4), EmptyTags, HostnameDisabled, "sample.thing:4.000000|ms"},
+	{"IncrCounter", []string{"count", "me"}, float32(3), EmptyTags, HostnameDisabled, "count.me:3|c"},
+
+	{"SetGauge", []string{"foo", "baz"}, float32(42), []string{"my_tag:my_value"}, HostnameDisabled, "foo.baz:42.000000|g|#my_tag:my_value"},
+	{"SetGauge", []string{"foo", "bar"}, float32(42), []string{"my_tag:my_value", "other_tag:other_value"}, HostnameDisabled, "foo.bar:42.000000|g|#my_tag:my_value,other_tag:other_value"},
+	{"SetGauge", []string{"foo", "bar"}, float32(42), []string{"my_tag:my_value", "other_tag:other_value"}, HostnameEnabled, "foo.bar:42.000000|g|#my_tag:my_value,other_tag:other_value,host:test_hostname"},
+}
+
+func MockNewDogStatsdSink(addr string, tags []string, tagWithHostname bool) *DogStatsdSink {
+	dog, _ := NewDogStatsdSink(addr, MockGetHostname())
+	dog.SetTags(tags)
+	if tagWithHostname {
+		dog.EnableHostNamePropagation()
+	}
+
+	return dog
+}
+
+func TestParseKey(t *testing.T) {
+	for _, tt := range ParseKeyTests {
+		dog := MockNewDogStatsdSink(DogStatsdAddr, tt.Tags, tt.PropagateHostname)
+		key, tags := dog.parseKey(tt.KeyToParse)
+
+		if !reflect.DeepEqual(key, tt.ExpectedKey) {
+			t.Fatalf("Key Parsing failed for %v", tt.KeyToParse)
+		}
+
+		if !reflect.DeepEqual(tags, tt.ExpectedTags) {
+			t.Fatalf("Tag Parsing Failed for %v", tt.KeyToParse)
+		}
+	}
+}
+
+func TestFlattenKey(t *testing.T) {
+	dog := MockNewDogStatsdSink(DogStatsdAddr, EmptyTags, HostnameDisabled)
+	for _, tt := range FlattenKeyTests {
+		if !reflect.DeepEqual(dog.flattenKey(tt.KeyToFlatten), tt.Expected) {
+			t.Fatalf("Flattening %v failed", tt.KeyToFlatten)
+		}
+	}
+}
+
+func TestMetricSink(t *testing.T) {
+	udpAddr, err := net.ResolveUDPAddr("udp", DogStatsdAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	server, err := net.ListenUDP("udp", udpAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer server.Close()
+
+	buf := make([]byte, 1024)
+
+	for _, tt := range MetricSinkTests {
+		dog := MockNewDogStatsdSink(DogStatsdAddr, tt.Tags, tt.PropagateHostname)
+		method := reflect.ValueOf(dog).MethodByName(tt.Method)
+		method.Call([]reflect.Value{
+			reflect.ValueOf(tt.Metric),
+			reflect.ValueOf(tt.Value)})
+
+		n, _ := server.Read(buf)
+		msg := buf[:n]
+		if string(msg) != tt.Expected {
+			t.Fatalf("Line %s does not match expected: %s", string(msg), tt.Expected)
+		}
+	}
+}

vendor/github.com/armon/go-metrics/inmem.go

@@ -0,0 +1,241 @@
+package metrics
+
+import (
+	"fmt"
+	"math"
+	"strings"
+	"sync"
+	"time"
+)
+
+// InmemSink provides a MetricSink that does in-memory aggregation
+// without sending metrics over a network. It can be embedded within
+// an application to provide profiling information.
+type InmemSink struct {
+	// How long is each aggregation interval
+	interval time.Duration
+
+	// Retain controls how many metrics interval we keep
+	retain time.Duration
+
+	// maxIntervals is the maximum length of intervals.
+	// It is retain / interval.
+	maxIntervals int
+
+	// intervals is a slice of the retained intervals
+	intervals    []*IntervalMetrics
+	intervalLock sync.RWMutex
+}
+
+// IntervalMetrics stores the aggregated metrics
+// for a specific interval
+type IntervalMetrics struct {
+	sync.RWMutex
+
+	// The start time of the interval
+	Interval time.Time
+
+	// Gauges maps the key to the last set value
+	Gauges map[string]float32
+
+	// Points maps the string to the list of emitted values
+	// from EmitKey
+	Points map[string][]float32
+
+	// Counters maps the string key to a sum of the counter
+	// values
+	Counters map[string]*AggregateSample
+
+	// Samples maps the key to an AggregateSample,
+	// which has the rolled up view of a sample
+	Samples map[string]*AggregateSample
+}
+
+// NewIntervalMetrics creates a new IntervalMetrics for a given interval
+func NewIntervalMetrics(intv time.Time) *IntervalMetrics {
+	return &IntervalMetrics{
+		Interval: intv,
+		Gauges:   make(map[string]float32),
+		Points:   make(map[string][]float32),
+		Counters: make(map[string]*AggregateSample),
+		Samples:  make(map[string]*AggregateSample),
+	}
+}
+
+// AggregateSample is used to hold aggregate metrics
+// about a sample
+type AggregateSample struct {
+	Count       int       // The count of emitted pairs
+	Sum         float64   // The sum of values
+	SumSq       float64   // The sum of squared values
+	Min         float64   // Minimum value
+	Max         float64   // Maximum value
+	LastUpdated time.Time // When value was last updated
+}
+
+// Computes a Stddev of the values
+func (a *AggregateSample) Stddev() float64 {
+	num := (float64(a.Count) * a.SumSq) - math.Pow(a.Sum, 2)
+	div := float64(a.Count * (a.Count - 1))
+	if div == 0 {
+		return 0
+	}
+	return math.Sqrt(num / div)
+}
+
+// Computes a mean of the values
+func (a *AggregateSample) Mean() float64 {
+	if a.Count == 0 {
+		return 0
+	}
+	return a.Sum / float64(a.Count)
+}
+
+// Ingest is used to update a sample
+func (a *AggregateSample) Ingest(v float64) {
+	a.Count++
+	a.Sum += v
+	a.SumSq += (v * v)
+	if v < a.Min || a.Count == 1 {
+		a.Min = v
+	}
+	if v > a.Max || a.Count == 1 {
+		a.Max = v
+	}
+	a.LastUpdated = time.Now()
+}
+
+func (a *AggregateSample) String() string {
+	if a.Count == 0 {
+		return "Count: 0"
+	} else if a.Stddev() == 0 {
+		return fmt.Sprintf("Count: %d Sum: %0.3f LastUpdated: %s", a.Count, a.Sum, a.LastUpdated)
+	} else {
+		return fmt.Sprintf("Count: %d Min: %0.3f Mean: %0.3f Max: %0.3f Stddev: %0.3f Sum: %0.3f LastUpdated: %s",
+			a.Count, a.Min, a.Mean(), a.Max, a.Stddev(), a.Sum, a.LastUpdated)
+	}
+}
+
+// NewInmemSink is used to construct a new in-memory sink.
+// Uses an aggregation interval and maximum retention period.
+func NewInmemSink(interval, retain time.Duration) *InmemSink {
+	i := &InmemSink{
+		interval:     interval,
+		retain:       retain,
+		maxIntervals: int(retain / interval),
+	}
+	i.intervals = make([]*IntervalMetrics, 0, i.maxIntervals)
+	return i
+}
+
+func (i *InmemSink) SetGauge(key []string, val float32) {
+	k := i.flattenKey(key)
+	intv := i.getInterval()
+
+	intv.Lock()
+	defer intv.Unlock()
+	intv.Gauges[k] = val
+}
+
+func (i *InmemSink) EmitKey(key []string, val float32) {
+	k := i.flattenKey(key)
+	intv := i.getInterval()
+
+	intv.Lock()
+	defer intv.Unlock()
+	vals := intv.Points[k]
+	intv.Points[k] = append(vals, val)
+}
+
+func (i *InmemSink) IncrCounter(key []string, val float32) {
+	k := i.flattenKey(key)
+	intv := i.getInterval()
+
+	intv.Lock()
+	defer intv.Unlock()
+
+	agg := intv.Counters[k]
+	if agg == nil {
+		agg = &AggregateSample{}
+		intv.Counters[k] = agg
+	}
+	agg.Ingest(float64(val))
+}
+
+func (i *InmemSink) AddSample(key []string, val float32) {
+	k := i.flattenKey(key)
+	intv := i.getInterval()
+
+	intv.Lock()
+	defer intv.Unlock()
+
+	agg := intv.Samples[k]
+	if agg == nil {
+		agg = &AggregateSample{}
+		intv.Samples[k] = agg
+	}
+	agg.Ingest(float64(val))
+}
+
+// Data is used to retrieve all the aggregated metrics
+// Intervals may be in use, and a read lock should be acquired
+func (i *InmemSink) Data() []*IntervalMetrics {
+	// Get the current interval, forces creation
+	i.getInterval()
+
+	i.intervalLock.RLock()
+	defer i.intervalLock.RUnlock()
+
+	intervals := make([]*IntervalMetrics, len(i.intervals))
+	copy(intervals, i.intervals)
+	return intervals
+}
+
+func (i *InmemSink) getExistingInterval(intv time.Time) *IntervalMetrics {
+	i.intervalLock.RLock()
+	defer i.intervalLock.RUnlock()
+
+	n := len(i.intervals)
+	if n > 0 && i.intervals[n-1].Interval == intv {
+		return i.intervals[n-1]
+	}
+	return nil
+}
+
+func (i *InmemSink) createInterval(intv time.Time) *IntervalMetrics {
+	i.intervalLock.Lock()
+	defer i.intervalLock.Unlock()
+
+	// Check for an existing interval
+	n := len(i.intervals)
+	if n > 0 && i.intervals[n-1].Interval == intv {
+		return i.intervals[n-1]
+	}
+
+	// Add the current interval
+	current := NewIntervalMetrics(intv)
+	i.intervals = append(i.intervals, current)
+	n++
+
+	// Truncate the intervals if they are too long
+	if n >= i.maxIntervals {
+		copy(i.intervals[0:], i.intervals[n-i.maxIntervals:])
+		i.intervals = i.intervals[:i.maxIntervals]
+	}
+	return current
+}
+
+// getInterval returns the current interval to write to
+func (i *InmemSink) getInterval() *IntervalMetrics {
+	intv := time.Now().Truncate(i.interval)
+	if m := i.getExistingInterval(intv); m != nil {
+		return m
+	}
+	return i.createInterval(intv)
+}
+
+// Flattens the key for formatting, removes spaces
+func (i *InmemSink) flattenKey(parts []string) string {
+	joined := strings.Join(parts, ".")
+	return strings.Replace(joined, " ", "_", -1)
+}

vendor/github.com/armon/go-metrics/inmem_signal.go

@@ -0,0 +1,100 @@
+package metrics
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+// InmemSignal is used to listen for a given signal, and when received,
+// to dump the current metrics from the InmemSink to an io.Writer
+type InmemSignal struct {
+	signal syscall.Signal
+	inm    *InmemSink
+	w      io.Writer
+	sigCh  chan os.Signal
+
+	stop     bool
+	stopCh   chan struct{}
+	stopLock sync.Mutex
+}
+
+// NewInmemSignal creates a new InmemSignal which listens for a given signal,
+// and dumps the current metrics out to a writer
+func NewInmemSignal(inmem *InmemSink, sig syscall.Signal, w io.Writer) *InmemSignal {
+	i := &InmemSignal{
+		signal: sig,
+		inm:    inmem,
+		w:      w,
+		sigCh:  make(chan os.Signal, 1),
+		stopCh: make(chan struct{}),
+	}
+	signal.Notify(i.sigCh, sig)
+	go i.run()
+	return i
+}
+
+// DefaultInmemSignal returns a new InmemSignal that responds to SIGUSR1
+// and writes output to stderr. Windows uses SIGBREAK
+func DefaultInmemSignal(inmem *InmemSink) *InmemSignal {
+	return NewInmemSignal(inmem, DefaultSignal, os.Stderr)
+}
+
+// Stop is used to stop the InmemSignal from listening
+func (i *InmemSignal) Stop() {
+	i.stopLock.Lock()
+	defer i.stopLock.Unlock()
+
+	if i.stop {
+		return
+	}
+	i.stop = true
+	close(i.stopCh)
+	signal.Stop(i.sigCh)
+}
+
+// run is a long running routine that handles signals
+func (i *InmemSignal) run() {
+	for {
+		select {
+		case <-i.sigCh:
+			i.dumpStats()
+		case <-i.stopCh:
+			return
+		}
+	}
+}
+
+// dumpStats is used to dump the data to output writer
+func (i *InmemSignal) dumpStats() {
+	buf := bytes.NewBuffer(nil)
+
+	data := i.inm.Data()
+	// Skip the last period which is still being aggregated
+	for i := 0; i < len(data)-1; i++ {
+		intv := data[i]
+		intv.RLock()
+		for name, val := range intv.Gauges {
+			fmt.Fprintf(buf, "[%v][G] '%s': %0.3f\n", intv.Interval, name, val)
+		}
+		for name, vals := range intv.Points {
+			for _, val := range vals {
+				fmt.Fprintf(buf, "[%v][P] '%s': %0.3f\n", intv.Interval, name, val)
+			}
+		}
+		for name, agg := range intv.Counters {
+			fmt.Fprintf(buf, "[%v][C] '%s': %s\n", intv.Interval, name, agg)
+		}
+		for name, agg := range intv.Samples {
+			fmt.Fprintf(buf, "[%v][S] '%s': %s\n", intv.Interval, name, agg)
+		}
+		intv.RUnlock()
+	}
+
+	// Write out the bytes
+	i.w.Write(buf.Bytes())
+}

vendor/github.com/armon/go-metrics/inmem_signal_test.go

@@ -0,0 +1,46 @@
+package metrics
+
+import (
+	"bytes"
+	"os"
+	"strings"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func TestInmemSignal(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	inm := NewInmemSink(10*time.Millisecond, 50*time.Millisecond)
+	sig := NewInmemSignal(inm, syscall.SIGUSR1, buf)
+	defer sig.Stop()
+
+	inm.SetGauge([]string{"foo"}, 42)
+	inm.EmitKey([]string{"bar"}, 42)
+	inm.IncrCounter([]string{"baz"}, 42)
+	inm.AddSample([]string{"wow"}, 42)
+
+	// Wait for period to end
+	time.Sleep(15 * time.Millisecond)
+
+	// Send signal!
+	syscall.Kill(os.Getpid(), syscall.SIGUSR1)
+
+	// Wait for flush
+	time.Sleep(10 * time.Millisecond)
+
+	// Check the output
+	out := string(buf.Bytes())
+	if !strings.Contains(out, "[G] 'foo': 42") {
+		t.Fatalf("bad: %v", out)
+	}
+	if !strings.Contains(out, "[P] 'bar': 42") {
+		t.Fatalf("bad: %v", out)
+	}
+	if !strings.Contains(out, "[C] 'baz': Count: 1 Sum: 42") {
+		t.Fatalf("bad: %v", out)
+	}
+	if !strings.Contains(out, "[S] 'wow': Count: 1 Sum: 42") {
+		t.Fatalf("bad: %v", out)
+	}
+}

vendor/github.com/armon/go-metrics/inmem_test.go

@@ -0,0 +1,104 @@
+package metrics
+
+import (
+	"math"
+	"testing"
+	"time"
+)
+
+func TestInmemSink(t *testing.T) {
+	inm := NewInmemSink(10*time.Millisecond, 50*time.Millisecond)
+
+	data := inm.Data()
+	if len(data) != 1 {
+		t.Fatalf("bad: %v", data)
+	}
+
+	// Add data points
+	inm.SetGauge([]string{"foo", "bar"}, 42)
+	inm.EmitKey([]string{"foo", "bar"}, 42)
+	inm.IncrCounter([]string{"foo", "bar"}, 20)
+	inm.IncrCounter([]string{"foo", "bar"}, 22)
+	inm.AddSample([]string{"foo", "bar"}, 20)
+	inm.AddSample([]string{"foo", "bar"}, 22)
+
+	data = inm.Data()
+	if len(data) != 1 {
+		t.Fatalf("bad: %v", data)
+	}
+
+	intvM := data[0]
+	intvM.RLock()
+
+	if time.Now().Sub(intvM.Interval) > 10*time.Millisecond {
+		t.Fatalf("interval too old")
+	}
+	if intvM.Gauges["foo.bar"] != 42 {
+		t.Fatalf("bad val: %v", intvM.Gauges)
+	}
+	if intvM.Points["foo.bar"][0] != 42 {
+		t.Fatalf("bad val: %v", intvM.Points)
+	}
+
+	agg := intvM.Counters["foo.bar"]
+	if agg.Count != 2 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.Sum != 42 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.SumSq != 884 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.Min != 20 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.Max != 22 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.Mean() != 21 {
+		t.Fatalf("bad val: %v", agg)
+	}
+	if agg.Stddev() != math.Sqrt(2) {
+		t.Fatalf("bad val: %v", agg)
+	}
+
+	if agg.LastUpdated.IsZero() {
+		t.Fatalf("agg.LastUpdated is not set: %v", agg)
+	}
+
+	diff := time.Now().Sub(agg.LastUpdated).Seconds()
+	if diff > 1 {
+		t.Fatalf("time diff too great: %f", diff)
+	}
+
+	if agg = intvM.Samples["foo.bar"]; agg == nil {
+		t.Fatalf("missing sample")
+	}
+
+	intvM.RUnlock()
+
+	for i := 1; i < 10; i++ {
+		time.Sleep(10 * time.Millisecond)
+		inm.SetGauge([]string{"foo", "bar"}, 42)
+		data = inm.Data()
+		if len(data) != min(i+1, 5) {
+			t.Fatalf("bad: %v", data)
+		}
+	}
+
+	// Should not exceed 5 intervals!
+	time.Sleep(10 * time.Millisecond)
+	inm.SetGauge([]string{"foo", "bar"}, 42)
+	data = inm.Data()
+	if len(data) != 5 {
+		t.Fatalf("bad: %v", data)
+	}
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}

vendor/github.com/armon/go-metrics/metrics.go

@@ -0,0 +1,115 @@
+package metrics
+
+import (
+	"runtime"
+	"time"
+)
+
+func (m *Metrics) SetGauge(key []string, val float32) {
+	if m.HostName != "" && m.EnableHostname {
+		key = insert(0, m.HostName, key)
+	}
+	if m.EnableTypePrefix {
+		key = insert(0, "gauge", key)
+	}
+	if m.ServiceName != "" {
+		key = insert(0, m.ServiceName, key)
+	}
+	m.sink.SetGauge(key, val)
+}
+
+func (m *Metrics) EmitKey(key []string, val float32) {
+	if m.EnableTypePrefix {
+		key = insert(0, "kv", key)
+	}
+	if m.ServiceName != "" {
+		key = insert(0, m.ServiceName, key)
+	}
+	m.sink.EmitKey(key, val)
+}
+
+func (m *Metrics) IncrCounter(key []string, val float32) {
+	if m.EnableTypePrefix {
+		key = insert(0, "counter", key)
+	}
+	if m.ServiceName != "" {
+		key = insert(0, m.ServiceName, key)
+	}
+	m.sink.IncrCounter(key, val)
+}
+
+func (m *Metrics) AddSample(key []string, val float32) {
+	if m.EnableTypePrefix {
+		key = insert(0, "sample", key)
+	}
+	if m.ServiceName != "" {
+		key = insert(0, m.ServiceName, key)
+	}
+	m.sink.AddSample(key, val)
+}
+
+func (m *Metrics) MeasureSince(key []string, start time.Time) {
+	if m.EnableTypePrefix {
+		key = insert(0, "timer", key)
+	}
+	if m.ServiceName != "" {
+		key = insert(0, m.ServiceName, key)
+	}
+	now := time.Now()
+	elapsed := now.Sub(start)
+	msec := float32(elapsed.Nanoseconds()) / float32(m.TimerGranularity)
+	m.sink.AddSample(key, msec)
+}
+
+// Periodically collects runtime stats to publish
+func (m *Metrics) collectStats() {
+	for {
+		time.Sleep(m.ProfileInterval)
+		m.emitRuntimeStats()
+	}
+}
+
+// Emits various runtime statsitics
+func (m *Metrics) emitRuntimeStats() {
+	// Export number of Goroutines
+	numRoutines := runtime.NumGoroutine()
+	m.SetGauge([]string{"runtime", "num_goroutines"}, float32(numRoutines))
+
+	// Export memory stats
+	var stats runtime.MemStats
+	runtime.ReadMemStats(&stats)
+	m.SetGauge([]string{"runtime", "alloc_bytes"}, float32(stats.Alloc))
+	m.SetGauge([]string{"runtime", "sys_bytes"}, float32(stats.Sys))
+	m.SetGauge([]string{"runtime", "malloc_count"}, float32(stats.Mallocs))
+	m.SetGauge([]string{"runtime", "free_count"}, float32(stats.Frees))
+	m.SetGauge([]string{"runtime", "heap_objects"}, float32(stats.HeapObjects))
+	m.SetGauge([]string{"runtime", "total_gc_pause_ns"}, float32(stats.PauseTotalNs))
+	m.SetGauge([]string{"runtime", "total_gc_runs"}, float32(stats.NumGC))
+
+	// Export info about the last few GC runs
+	num := stats.NumGC
+
+	// Handle wrap around
+	if num < m.lastNumGC {
+		m.lastNumGC = 0
+	}
+
+	// Ensure we don't scan more than 256
+	if num-m.lastNumGC >= 256 {
+		m.lastNumGC = num - 255
+	}
+
+	for i := m.lastNumGC; i < num; i++ {
+		pause := stats.PauseNs[i%256]
+		m.AddSample([]string{"runtime", "gc_pause_ns"}, float32(pause))
+	}
+	m.lastNumGC = num
+}
+
+// Inserts a string value at an index into the slice
+func insert(i int, v string, s []string) []string {
+	s = append(s, "")
+	copy(s[i+1:], s[i:])
+	s[i] = v
+	return s
+}

vendor/github.com/armon/go-metrics/metrics_test.go

@@ -0,0 +1,262 @@
+package metrics
+
+import (
+	"reflect"
+	"runtime"
+	"testing"
+	"time"
+)
+
+func mockMetric() (*MockSink, *Metrics) {
+	m := &MockSink{}
+	met := &Metrics{sink: m}
+	return m, met
+}
+
+func TestMetrics_SetGauge(t *testing.T) {
+	m, met := mockMetric()
+	met.SetGauge([]string{"key"}, float32(1))
+	if m.keys[0][0] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.HostName = "test"
+	met.EnableHostname = true
+	met.SetGauge([]string{"key"}, float32(1))
+	if m.keys[0][0] != "test" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.EnableTypePrefix = true
+	met.SetGauge([]string{"key"}, float32(1))
+	if m.keys[0][0] != "gauge" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.ServiceName = "service"
+	met.SetGauge([]string{"key"}, float32(1))
+	if m.keys[0][0] != "service" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+}
+
+func TestMetrics_EmitKey(t *testing.T) {
+	m, met := mockMetric()
+	met.EmitKey([]string{"key"}, float32(1))
+	if m.keys[0][0] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.EnableTypePrefix = true
+	met.EmitKey([]string{"key"}, float32(1))
+	if m.keys[0][0] != "kv" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.ServiceName = "service"
+	met.EmitKey([]string{"key"}, float32(1))
+	if m.keys[0][0] != "service" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+}
+
+func TestMetrics_IncrCounter(t *testing.T) {
+	m, met := mockMetric()
+	met.IncrCounter([]string{"key"}, float32(1))
+	if m.keys[0][0] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.EnableTypePrefix = true
+	met.IncrCounter([]string{"key"}, float32(1))
+	if m.keys[0][0] != "counter" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.ServiceName = "service"
+	met.IncrCounter([]string{"key"}, float32(1))
+	if m.keys[0][0] != "service" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+}
+
+func TestMetrics_AddSample(t *testing.T) {
+	m, met := mockMetric()
+	met.AddSample([]string{"key"}, float32(1))
+	if m.keys[0][0] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.EnableTypePrefix = true
+	met.AddSample([]string{"key"}, float32(1))
+	if m.keys[0][0] != "sample" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.ServiceName = "service"
+	met.AddSample([]string{"key"}, float32(1))
+	if m.keys[0][0] != "service" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] != 1 {
+		t.Fatalf("")
+	}
+}
+
+func TestMetrics_MeasureSince(t *testing.T) {
+	m, met := mockMetric()
+	met.TimerGranularity = time.Millisecond
+	n := time.Now()
+	met.MeasureSince([]string{"key"}, n)
+	if m.keys[0][0] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] > 0.1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.TimerGranularity = time.Millisecond
+	met.EnableTypePrefix = true
+	met.MeasureSince([]string{"key"}, n)
+	if m.keys[0][0] != "timer" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] > 0.1 {
+		t.Fatalf("")
+	}
+
+	m, met = mockMetric()
+	met.TimerGranularity = time.Millisecond
+	met.ServiceName = "service"
+	met.MeasureSince([]string{"key"}, n)
+	if m.keys[0][0] != "service" || m.keys[0][1] != "key" {
+		t.Fatalf("")
+	}
+	if m.vals[0] > 0.1 {
+		t.Fatalf("")
+	}
+}
+
+func TestMetrics_EmitRuntimeStats(t *testing.T) {
+	runtime.GC()
+	m, met := mockMetric()
+	met.emitRuntimeStats()
+
+	if m.keys[0][0] != "runtime" || m.keys[0][1] != "num_goroutines" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[0] <= 1 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[1][0] != "runtime" || m.keys[1][1] != "alloc_bytes" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[1] <= 40000 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[2][0] != "runtime" || m.keys[2][1] != "sys_bytes" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[2] <= 100000 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[3][0] != "runtime" || m.keys[3][1] != "malloc_count" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[3] <= 100 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[4][0] != "runtime" || m.keys[4][1] != "free_count" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[4] <= 100 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[5][0] != "runtime" || m.keys[5][1] != "heap_objects" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[5] <= 100 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[6][0] != "runtime" || m.keys[6][1] != "total_gc_pause_ns" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[6] <= 100000 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[7][0] != "runtime" || m.keys[7][1] != "total_gc_runs" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[7] <= 1 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+
+	if m.keys[8][0] != "runtime" || m.keys[8][1] != "gc_pause_ns" {
+		t.Fatalf("bad key %v", m.keys)
+	}
+	if m.vals[8] <= 1000 {
+		t.Fatalf("bad val: %v", m.vals)
+	}
+}
+
+func TestInsert(t *testing.T) {
+	k := []string{"hi", "bob"}
+	exp := []string{"hi", "there", "bob"}
+	out := insert(1, "there", k)
+	if !reflect.DeepEqual(exp, out) {
+		t.Fatalf("bad insert %v %v", exp, out)
+	}
+}

vendor/github.com/armon/go-metrics/prometheus/prometheus.go

@@ -0,0 +1,88 @@
+// +build go1.3
+package prometheus
+
+import (
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type PrometheusSink struct {
+	mu        sync.Mutex
+	gauges    map[string]prometheus.Gauge
+	summaries map[string]prometheus.Summary
+	counters  map[string]prometheus.Counter
+}
+
+func NewPrometheusSink() (*PrometheusSink, error) {
+	return &PrometheusSink{
+		gauges:    make(map[string]prometheus.Gauge),
+		summaries: make(map[string]prometheus.Summary),
+		counters:  make(map[string]prometheus.Counter),
+	}, nil
+}
+
+func (p *PrometheusSink) flattenKey(parts []string) string {
+	joined := strings.Join(parts, "_")
+	joined = strings.Replace(joined, " ", "_", -1)
+	joined = strings.Replace(joined, ".", "_", -1)
+	joined = strings.Replace(joined, "-", "_", -1)
+	return joined
+}
+
+func (p *PrometheusSink) SetGauge(parts []string, val float32) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	key := p.flattenKey(parts)
+	g, ok := p.gauges[key]
+	if !ok {
+		g = prometheus.NewGauge(prometheus.GaugeOpts{
+			Name: key,
+			Help: key,
+		})
+		prometheus.MustRegister(g)
+		p.gauges[key] = g
+	}
+	g.Set(float64(val))
+}
+
+func (p *PrometheusSink) AddSample(parts []string, val float32) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	key := p.flattenKey(parts)
+	g, ok := p.summaries[key]
+	if !ok {
+		g = prometheus.NewSummary(prometheus.SummaryOpts{
+			Name:   key,
+			Help:   key,
+			MaxAge: 10 * time.Second,
+		})
+		prometheus.MustRegister(g)
+		p.summaries[key] = g
+	}
+	g.Observe(float64(val))
+}
+
+// EmitKey is not implemented. Prometheus doesn’t offer a type for which an
+// arbitrary number of values is retained, as Prometheus works with a pull
+// model, rather than a push model.
+func (p *PrometheusSink) EmitKey(key []string, val float32) {
+}
+
+func (p *PrometheusSink) IncrCounter(parts []string, val float32) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	key := p.flattenKey(parts)
+	g, ok := p.counters[key]
+	if !ok {
+		g = prometheus.NewCounter(prometheus.CounterOpts{
+			Name: key,
+			Help: key,
+		})
+		prometheus.MustRegister(g)
+		p.counters[key] = g
+	}
+	g.Add(float64(val))
+}

vendor/github.com/armon/go-metrics/sink.go

@@ -0,0 +1,52 @@
+package metrics
+
+// The MetricSink interface is used to transmit metrics information
+// to an external system
+type MetricSink interface {
+	// A Gauge should retain the last value it is set to
+	SetGauge(key []string, val float32)
+
+	// Should emit a Key/Value pair for each call
+	EmitKey(key []string, val float32)
+
+	// Counters should accumulate values
+	IncrCounter(key []string, val float32)
+
+	// Samples are for timing information, where quantiles are used
+	AddSample(key []string, val float32)
+}
+
+// BlackholeSink is used to just blackhole messages
+type BlackholeSink struct{}
+
+func (*BlackholeSink) SetGauge(key []string, val float32)    {}
+func (*BlackholeSink) EmitKey(key []string, val float32)     {}
+func (*BlackholeSink) IncrCounter(key []string, val float32) {}
+func (*BlackholeSink) AddSample(key []string, val float32)   {}
+
+// FanoutSink is used to sink to fanout values to multiple sinks
+type FanoutSink []MetricSink
+
+func (fh FanoutSink) SetGauge(key []string, val float32) {
+	for _, s := range fh {
+		s.SetGauge(key, val)
+	}
+}
+
+func (fh FanoutSink) EmitKey(key []string, val float32) {
+	for _, s := range fh {
+		s.EmitKey(key, val)
+	}
+}
+
+func (fh FanoutSink) IncrCounter(key []string, val float32) {
+	for _, s := range fh {
+		s.IncrCounter(key, val)
+	}
+}
+
+func (fh FanoutSink) AddSample(key []string, val float32) {
+	for _, s := range fh {
+		s.AddSample(key, val)
+	}
+}

vendor/github.com/armon/go-metrics/sink_test.go

@@ -0,0 +1,120 @@
+package metrics
+
+import (
+	"reflect"
+	"testing"
+)
+
+type MockSink struct {
+	keys [][]string
+	vals []float32
+}
+
+func (m *MockSink) SetGauge(key []string, val float32) {
+	m.keys = append(m.keys, key)
+	m.vals = append(m.vals, val)
+}
+func (m *MockSink) EmitKey(key []string, val float32) {
+	m.keys = append(m.keys, key)
+	m.vals = append(m.vals, val)
+}
+func (m *MockSink) IncrCounter(key []string, val float32) {
+	m.keys = append(m.keys, key)
+	m.vals = append(m.vals, val)
+}
+func (m *MockSink) AddSample(key []string, val float32) {
+	m.keys = append(m.keys, key)
+	m.vals = append(m.vals, val)
+}
+
+func TestFanoutSink_Gauge(t *testing.T) {
+	m1 := &MockSink{}
+	m2 := &MockSink{}
+	fh := &FanoutSink{m1, m2}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	fh.SetGauge(k, v)
+
+	if !reflect.DeepEqual(m1.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m2.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m1.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+	if !reflect.DeepEqual(m2.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func TestFanoutSink_Key(t *testing.T) {
+	m1 := &MockSink{}
+	m2 := &MockSink{}
+	fh := &FanoutSink{m1, m2}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	fh.EmitKey(k, v)
+
+	if !reflect.DeepEqual(m1.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m2.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m1.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+	if !reflect.DeepEqual(m2.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func TestFanoutSink_Counter(t *testing.T) {
+	m1 := &MockSink{}
+	m2 := &MockSink{}
+	fh := &FanoutSink{m1, m2}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	fh.IncrCounter(k, v)
+
+	if !reflect.DeepEqual(m1.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m2.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m1.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+	if !reflect.DeepEqual(m2.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func TestFanoutSink_Sample(t *testing.T) {
+	m1 := &MockSink{}
+	m2 := &MockSink{}
+	fh := &FanoutSink{m1, m2}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	fh.AddSample(k, v)
+
+	if !reflect.DeepEqual(m1.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m2.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m1.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+	if !reflect.DeepEqual(m2.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}

vendor/github.com/armon/go-metrics/start.go

@@ -0,0 +1,95 @@
+package metrics
+
+import (
+	"os"
+	"time"
+)
+
+// Config is used to configure metrics settings
+type Config struct {
+	ServiceName          string        // Prefixed with keys to seperate services
+	HostName             string        // Hostname to use. If not provided and EnableHostname, it will be os.Hostname
+	EnableHostname       bool          // Enable prefixing gauge values with hostname
+	EnableRuntimeMetrics bool          // Enables profiling of runtime metrics (GC, Goroutines, Memory)
+	EnableTypePrefix     bool          // Prefixes key with a type ("counter", "gauge", "timer")
+	TimerGranularity     time.Duration // Granularity of timers.
+	ProfileInterval      time.Duration // Interval to profile runtime metrics
+}
+
+// Metrics represents an instance of a metrics sink that can
+// be used to emit
+type Metrics struct {
+	Config
+	lastNumGC uint32
+	sink      MetricSink
+}
+
+// Shared global metrics instance
+var globalMetrics *Metrics
+
+func init() {
+	// Initialize to a blackhole sink to avoid errors
+	globalMetrics = &Metrics{sink: &BlackholeSink{}}
+}
+
+// DefaultConfig provides a sane default configuration
+func DefaultConfig(serviceName string) *Config {
+	c := &Config{
+		ServiceName:          serviceName, // Use client provided service
+		HostName:             "",
+		EnableHostname:       true,             // Enable hostname prefix
+		EnableRuntimeMetrics: true,             // Enable runtime profiling
+		EnableTypePrefix:     false,            // Disable type prefix
+		TimerGranularity:     time.Millisecond, // Timers are in milliseconds
+		ProfileInterval:      time.Second,      // Poll runtime every second
+	}
+
+	// Try to get the hostname
+	name, _ := os.Hostname()
+	c.HostName = name
+	return c
+}
+
+// New is used to create a new instance of Metrics
+func New(conf *Config, sink MetricSink) (*Metrics, error) {
+	met := &Metrics{}
+	met.Config = *conf
+	met.sink = sink
+
+	// Start the runtime collector
+	if conf.EnableRuntimeMetrics {
+		go met.collectStats()
+	}
+	return met, nil
+}
+
+// NewGlobal is the same as New, but it assigns the metrics object to be
+// used globally as well as returning it.
+func NewGlobal(conf *Config, sink MetricSink) (*Metrics, error) {
+	metrics, err := New(conf, sink)
+	if err == nil {
+		globalMetrics = metrics
+	}
+	return metrics, err
+}
+
+// Proxy all the methods to the globalMetrics instance
+func SetGauge(key []string, val float32) {
+	globalMetrics.SetGauge(key, val)
+}
+
+func EmitKey(key []string, val float32) {
+	globalMetrics.EmitKey(key, val)
+}
+
+func IncrCounter(key []string, val float32) {
+	globalMetrics.IncrCounter(key, val)
+}
+
+func AddSample(key []string, val float32) {
+	globalMetrics.AddSample(key, val)
+}
+
+func MeasureSince(key []string, start time.Time) {
+	globalMetrics.MeasureSince(key, start)
+}

vendor/github.com/armon/go-metrics/start_test.go

@@ -0,0 +1,110 @@
+package metrics
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestDefaultConfig(t *testing.T) {
+	conf := DefaultConfig("service")
+	if conf.ServiceName != "service" {
+		t.Fatalf("Bad name")
+	}
+	if conf.HostName == "" {
+		t.Fatalf("missing hostname")
+	}
+	if !conf.EnableHostname || !conf.EnableRuntimeMetrics {
+		t.Fatalf("expect true")
+	}
+	if conf.EnableTypePrefix {
+		t.Fatalf("expect false")
+	}
+	if conf.TimerGranularity != time.Millisecond {
+		t.Fatalf("bad granularity")
+	}
+	if conf.ProfileInterval != time.Second {
+		t.Fatalf("bad interval")
+	}
+}
+
+func Test_GlobalMetrics_SetGauge(t *testing.T) {
+	m := &MockSink{}
+	globalMetrics = &Metrics{sink: m}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	SetGauge(k, v)
+
+	if !reflect.DeepEqual(m.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func Test_GlobalMetrics_EmitKey(t *testing.T) {
+	m := &MockSink{}
+	globalMetrics = &Metrics{sink: m}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	EmitKey(k, v)
+
+	if !reflect.DeepEqual(m.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func Test_GlobalMetrics_IncrCounter(t *testing.T) {
+	m := &MockSink{}
+	globalMetrics = &Metrics{sink: m}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	IncrCounter(k, v)
+
+	if !reflect.DeepEqual(m.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func Test_GlobalMetrics_AddSample(t *testing.T) {
+	m := &MockSink{}
+	globalMetrics = &Metrics{sink: m}
+
+	k := []string{"test"}
+	v := float32(42.0)
+	AddSample(k, v)
+
+	if !reflect.DeepEqual(m.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if !reflect.DeepEqual(m.vals[0], v) {
+		t.Fatalf("val not equal")
+	}
+}
+
+func Test_GlobalMetrics_MeasureSince(t *testing.T) {
+	m := &MockSink{}
+	globalMetrics = &Metrics{sink: m}
+	globalMetrics.TimerGranularity = time.Millisecond
+
+	k := []string{"test"}
+	now := time.Now()
+	MeasureSince(k, now)
+
+	if !reflect.DeepEqual(m.keys[0], k) {
+		t.Fatalf("key not equal")
+	}
+	if m.vals[0] > 0.1 {
+		t.Fatalf("val too large %v", m.vals[0])
+	}
+}

vendor/github.com/armon/go-metrics/statsd.go

@@ -0,0 +1,154 @@
+package metrics
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"net"
+	"strings"
+	"time"
+)
+
+const (
+	// statsdMaxLen is the maximum size of a packet
+	// to send to statsd
+	statsdMaxLen = 1400
+)
+
+// StatsdSink provides a MetricSink that can be used
+// with a statsite or statsd metrics server. It uses
+// only UDP packets, while StatsiteSink uses TCP.
+type StatsdSink struct {
+	addr        string
+	metricQueue chan string
+}
+
+// NewStatsdSink is used to create a new StatsdSink
+func NewStatsdSink(addr string) (*StatsdSink, error) {
+	s := &StatsdSink{
+		addr:        addr,
+		metricQueue: make(chan string, 4096),
+	}
+	go s.flushMetrics()
+	return s, nil
+}
+
+// Close is used to stop flushing to statsd
+func (s *StatsdSink) Shutdown() {
+	close(s.metricQueue)
+}
+
+func (s *StatsdSink) SetGauge(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|g\n", flatKey, val))
+}
+
+func (s *StatsdSink) EmitKey(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|kv\n", flatKey, val))
+}
+
+func (s *StatsdSink) IncrCounter(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|c\n", flatKey, val))
+}
+
+func (s *StatsdSink) AddSample(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|ms\n", flatKey, val))
+}
+
+// Flattens the key for formatting, removes spaces
+func (s *StatsdSink) flattenKey(parts []string) string {
+	joined := strings.Join(parts, ".")
+	return strings.Map(func(r rune) rune {
+		switch r {
+		case ':':
+			fallthrough
+		case ' ':
+			return '_'
+		default:
+			return r
+		}
+	}, joined)
+}
+
+// Does a non-blocking push to the metrics queue
+func (s *StatsdSink) pushMetric(m string) {
+	select {
+	case s.metricQueue <- m:
+	default:
+	}
+}
+
+// Flushes metrics
+func (s *StatsdSink) flushMetrics() {
+	var sock net.Conn
+	var err error
+	var wait <-chan time.Time
+	ticker := time.NewTicker(flushInterval)
+	defer ticker.Stop()
+
+CONNECT:
+	// Create a buffer
+	buf := bytes.NewBuffer(nil)
+
+	// Attempt to connect
+	sock, err = net.Dial("udp", s.addr)
+	if err != nil {
+		log.Printf("[ERR] Error connecting to statsd! Err: %s", err)
+		goto WAIT
+	}
+
+	for {
+		select {
+		case metric, ok := <-s.metricQueue:
+			// Get a metric from the queue
+			if !ok {
+				goto QUIT
+			}
+
+			// Check if this would overflow the packet size
+			if len(metric)+buf.Len() > statsdMaxLen {
+				_, err := sock.Write(buf.Bytes())
+				buf.Reset()
+				if err != nil {
+					log.Printf("[ERR] Error writing to statsd! Err: %s", err)
+					goto WAIT
+				}
+			}
+
+			// Append to the buffer
+			buf.WriteString(metric)
+
+		case <-ticker.C:
+			if buf.Len() == 0 {
+				continue
+			}
+
+			_, err := sock.Write(buf.Bytes())
+			buf.Reset()
+			if err != nil {
+				log.Printf("[ERR] Error flushing to statsd! Err: %s", err)
+				goto WAIT
+			}
+		}
+	}
+
+WAIT:
+	// Wait for a while
+	wait = time.After(time.Duration(5) * time.Second)
+	for {
+		select {
+		// Dequeue the messages to avoid backlog
+		case _, ok := <-s.metricQueue:
+			if !ok {
+				goto QUIT
+			}
+		case <-wait:
+			goto CONNECT
+		}
+	}
+QUIT:
+	s.metricQueue = nil
+}

vendor/github.com/armon/go-metrics/statsd_test.go

@@ -0,0 +1,105 @@
+package metrics
+
+import (
+	"bufio"
+	"bytes"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestStatsd_Flatten(t *testing.T) {
+	s := &StatsdSink{}
+	flat := s.flattenKey([]string{"a", "b", "c", "d"})
+	if flat != "a.b.c.d" {
+		t.Fatalf("Bad flat")
+	}
+}
+
+func TestStatsd_PushFullQueue(t *testing.T) {
+	q := make(chan string, 1)
+	q <- "full"
+
+	s := &StatsdSink{metricQueue: q}
+	s.pushMetric("omit")
+
+	out := <-q
+	if out != "full" {
+		t.Fatalf("bad val %v", out)
+	}
+
+	select {
+	case v := <-q:
+		t.Fatalf("bad val %v", v)
+	default:
+	}
+}
+
+func TestStatsd_Conn(t *testing.T) {
+	addr := "127.0.0.1:7524"
+	done := make(chan bool)
+	go func() {
+		list, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 7524})
+		if err != nil {
+			panic(err)
+		}
+		defer list.Close()
+		buf := make([]byte, 1500)
+		n, err := list.Read(buf)
+		if err != nil {
+			panic(err)
+		}
+		buf = buf[:n]
+		reader := bufio.NewReader(bytes.NewReader(buf))
+
+		line, err := reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "gauge.val:1.000000|g\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "key.other:2.000000|kv\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "counter.me:3.000000|c\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "sample.slow_thingy:4.000000|ms\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		done <- true
+	}()
+	s, err := NewStatsdSink(addr)
+	if err != nil {
+		t.Fatalf("bad error")
+	}
+
+	s.SetGauge([]string{"gauge", "val"}, float32(1))
+	s.EmitKey([]string{"key", "other"}, float32(2))
+	s.IncrCounter([]string{"counter", "me"}, float32(3))
+	s.AddSample([]string{"sample", "slow thingy"}, float32(4))
+
+	select {
+	case <-done:
+		s.Shutdown()
+	case <-time.After(3 * time.Second):
+		t.Fatalf("timeout")
+	}
+}

vendor/github.com/armon/go-metrics/statsite.go

@@ -0,0 +1,142 @@
+package metrics
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"net"
+	"strings"
+	"time"
+)
+
+const (
+	// We force flush the statsite metrics after this period of
+	// inactivity. Prevents stats from getting stuck in a buffer
+	// forever.
+	flushInterval = 100 * time.Millisecond
+)
+
+// StatsiteSink provides a MetricSink that can be used with a
+// statsite metrics server
+type StatsiteSink struct {
+	addr        string
+	metricQueue chan string
+}
+
+// NewStatsiteSink is used to create a new StatsiteSink
+func NewStatsiteSink(addr string) (*StatsiteSink, error) {
+	s := &StatsiteSink{
+		addr:        addr,
+		metricQueue: make(chan string, 4096),
+	}
+	go s.flushMetrics()
+	return s, nil
+}
+
+// Close is used to stop flushing to statsite
+func (s *StatsiteSink) Shutdown() {
+	close(s.metricQueue)
+}
+
+func (s *StatsiteSink) SetGauge(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|g\n", flatKey, val))
+}
+
+func (s *StatsiteSink) EmitKey(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|kv\n", flatKey, val))
+}
+
+func (s *StatsiteSink) IncrCounter(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|c\n", flatKey, val))
+}
+
+func (s *StatsiteSink) AddSample(key []string, val float32) {
+	flatKey := s.flattenKey(key)
+	s.pushMetric(fmt.Sprintf("%s:%f|ms\n", flatKey, val))
+}
+
+// Flattens the key for formatting, removes spaces
+func (s *StatsiteSink) flattenKey(parts []string) string {
+	joined := strings.Join(parts, ".")
+	return strings.Map(func(r rune) rune {
+		switch r {
+		case ':':
+			fallthrough
+		case ' ':
+			return '_'
+		default:
+			return r
+		}
+	}, joined)
+}
+
+// Does a non-blocking push to the metrics queue
+func (s *StatsiteSink) pushMetric(m string) {
+	select {
+	case s.metricQueue <- m:
+	default:
+	}
+}
+
+// Flushes metrics
+func (s *StatsiteSink) flushMetrics() {
+	var sock net.Conn
+	var err error
+	var wait <-chan time.Time
+	var buffered *bufio.Writer
+	ticker := time.NewTicker(flushInterval)
+	defer ticker.Stop()
+
+CONNECT:
+	// Attempt to connect
+	sock, err = net.Dial("tcp", s.addr)
+	if err != nil {
+		log.Printf("[ERR] Error connecting to statsite! Err: %s", err)
+		goto WAIT
+	}
+
+	// Create a buffered writer
+	buffered = bufio.NewWriter(sock)
+
+	for {
+		select {
+		case metric, ok := <-s.metricQueue:
+			// Get a metric from the queue
+			if !ok {
+				goto QUIT
+			}
+
+			// Try to send to statsite
+			_, err := buffered.Write([]byte(metric))
+			if err != nil {
+				log.Printf("[ERR] Error writing to statsite! Err: %s", err)
+				goto WAIT
+			}
+		case <-ticker.C:
+			if err := buffered.Flush(); err != nil {
+				log.Printf("[ERR] Error flushing to statsite! Err: %s", err)
+				goto WAIT
+			}
+		}
+	}
+
+WAIT:
+	// Wait for a while
+	wait = time.After(time.Duration(5) * time.Second)
+	for {
+		select {
+		// Dequeue the messages to avoid backlog
+		case _, ok := <-s.metricQueue:
+			if !ok {
+				goto QUIT
+			}
+		case <-wait:
+			goto CONNECT
+		}
+	}
+QUIT:
+	s.metricQueue = nil
+}

vendor/github.com/armon/go-metrics/statsite_test.go

@@ -0,0 +1,101 @@
+package metrics
+
+import (
+	"bufio"
+	"net"
+	"testing"
+	"time"
+)
+
+func acceptConn(addr string) net.Conn {
+	ln, _ := net.Listen("tcp", addr)
+	conn, _ := ln.Accept()
+	return conn
+}
+
+func TestStatsite_Flatten(t *testing.T) {
+	s := &StatsiteSink{}
+	flat := s.flattenKey([]string{"a", "b", "c", "d"})
+	if flat != "a.b.c.d" {
+		t.Fatalf("Bad flat")
+	}
+}
+
+func TestStatsite_PushFullQueue(t *testing.T) {
+	q := make(chan string, 1)
+	q <- "full"
+
+	s := &StatsiteSink{metricQueue: q}
+	s.pushMetric("omit")
+
+	out := <-q
+	if out != "full" {
+		t.Fatalf("bad val %v", out)
+	}
+
+	select {
+	case v := <-q:
+		t.Fatalf("bad val %v", v)
+	default:
+	}
+}
+
+func TestStatsite_Conn(t *testing.T) {
+	addr := "localhost:7523"
+	done := make(chan bool)
+	go func() {
+		conn := acceptConn(addr)
+		reader := bufio.NewReader(conn)
+
+		line, err := reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "gauge.val:1.000000|g\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "key.other:2.000000|kv\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "counter.me:3.000000|c\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			t.Fatalf("unexpected err %s", err)
+		}
+		if line != "sample.slow_thingy:4.000000|ms\n" {
+			t.Fatalf("bad line %s", line)
+		}
+
+		conn.Close()
+		done <- true
+	}()
+	s, err := NewStatsiteSink(addr)
+	if err != nil {
+		t.Fatalf("bad error")
+	}
+
+	s.SetGauge([]string{"gauge", "val"}, float32(1))
+	s.EmitKey([]string{"key", "other"}, float32(2))
+	s.IncrCounter([]string{"counter", "me"}, float32(3))
+	s.AddSample([]string{"sample", "slow thingy"}, float32(4))
+
+	select {
+	case <-done:
+		s.Shutdown()
+	case <-time.After(3 * time.Second):
+		t.Fatalf("timeout")
+	}
+}

vendor/manifest

@@ -7,6 +7,13 @@
 			"revision": "75cd24fc2f2c",
 			"branch": "default"
 		},
+		{
+			"importpath": "github.com/DataDog/datadog-go/statsd",
+			"repository": "https://github.com/DataDog/datadog-go",
+			"revision": "b050cd8f4d7c394545fd7d966c8e2909ce89d552",
+			"branch": "master",
+			"path": "/statsd"
+		},
 		{
 			"importpath": "github.com/PuerkitoBio/ghost",
 			"repository": "https://github.com/PuerkitoBio/ghost",
@@ -20,6 +27,12 @@
 			"branch": "master",
 			"path": "/handlers"
 		},
+		{
+			"importpath": "github.com/armon/go-metrics",
+			"repository": "https://github.com/armon/go-metrics",
+			"revision": "6c5fa0d8f48f4661c9ba8709799c88d425ad20f0",
+			"branch": "master"
+		},
 		{
 			"importpath": "github.com/beorn7/perks/quantile",
 			"repository": "https://github.com/beorn7/perks",