Extract metrics to own package and refactor implementations

metrics/datadog.go

@@ -0,0 +1,69 @@
+package metrics
+
+import (
+	"time"
+
+	"github.com/containous/traefik/log"
+	"github.com/containous/traefik/safe"
+	"github.com/containous/traefik/types"
+	kitlog "github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/metrics/dogstatsd"
+)
+
+var datadogClient = dogstatsd.New("traefik.", kitlog.LoggerFunc(func(keyvals ...interface{}) error {
+	log.Info(keyvals)
+	return nil
+}))
+
+var datadogTicker *time.Ticker
+
+// Metric names consistent with https://github.com/DataDog/integrations-extras/pull/64
+const (
+	ddMetricsReqsName    = "requests.total"
+	ddMetricsLatencyName = "request.duration"
+	ddRetriesTotalName   = "backend.retries.total"
+)
+
+// RegisterDatadog registers the metrics pusher if this didn't happen yet and creates a datadog Registry instance.
+func RegisterDatadog(config *types.Datadog) Registry {
+	if datadogTicker == nil {
+		datadogTicker = initDatadogClient(config)
+	}
+
+	registry := &standardRegistry{
+		enabled:              true,
+		reqsCounter:          datadogClient.NewCounter(ddMetricsReqsName, 1.0),
+		reqDurationHistogram: datadogClient.NewHistogram(ddMetricsLatencyName, 1.0),
+		retriesCounter:       datadogClient.NewCounter(ddRetriesTotalName, 1.0),
+	}
+
+	return registry
+}
+
+func initDatadogClient(config *types.Datadog) *time.Ticker {
+	address := config.Address
+	if len(address) == 0 {
+		address = "localhost:8125"
+	}
+	pushInterval, err := time.ParseDuration(config.PushInterval)
+	if err != nil {
+		log.Warnf("Unable to parse %s into pushInterval, using 10s as default value", config.PushInterval)
+		pushInterval = 10 * time.Second
+	}
+
+	report := time.NewTicker(pushInterval)
+
+	safe.Go(func() {
+		datadogClient.SendLoop(report.C, "udp", address)
+	})
+
+	return report
+}
+
+// StopDatadog stops internal datadogTicker which controls the pushing of metrics to DD Agent and resets it to `nil`.
+func StopDatadog() {
+	if datadogTicker != nil {
+		datadogTicker.Stop()
+	}
+	datadogTicker = nil
+}