Ensure Sink implementations fulfill interface

circonus/circonus.go

@@ -9,6 +9,9 @@ import (
 	cgm "github.com/circonus-labs/circonus-gometrics"
 )
 
+// This ensures *CirconusSink implements the MetricSink interface.
+var _ metrics.MetricSink = (*CirconusSink)(nil)
+
 // CirconusSink provides an interface to forward metrics to Circonus with
 // automatic check creation and metric management
 type CirconusSink struct {

datadog/dogstatsd.go

@@ -8,6 +8,9 @@ import (
 	"github.com/armon/go-metrics"
 )
 
+// This ensures *DogStatsdSink implements the MetricSink interface.
+var _ metrics.MetricSink = (*DogStatsdSink)(nil)
+
 // 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 {

inmem.go

@@ -10,6 +10,9 @@ import (
 	"time"
 )
 
+// This ensures *InmemSink implements the MetricSink interface.
+var _ MetricSink = (*InmemSink)(nil)
+
 // 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.

prometheus/prometheus.go

@@ -21,6 +21,9 @@ var (
 	}
 )
 
+// This ensures *PrometheusSink implements the MetricSink interface.
+var _ metrics.MetricSink = (*PrometheusSink)(nil)
+
 // PrometheusOpts is used to configure the Prometheus Sink
 type PrometheusOpts struct {
 	// Expiration is the duration a metric is valid for, after which it will be

statsd.go

@@ -16,6 +16,9 @@ const (
 	statsdMaxLen = 1400
 )
 
+// This ensures *StatsdSink implements the MetricSink interface.
+var _ MetricSink = (*StatsdSink)(nil)
+
 // StatsdSink provides a MetricSink that can be used
 // with a statsite or statsd metrics server. It uses
 // only UDP packets, while StatsiteSink uses TCP.

statsite.go

@@ -17,6 +17,9 @@ const (
 	flushInterval = 100 * time.Millisecond
 )
 
+// This ensures *StatsiteSink implements the MetricSink interface.
+var _ MetricSink = (*StatsiteSink)(nil)
+
 // NewStatsiteSinkFromURL creates an StatsiteSink from a URL. It is used
 // (and tested) from NewMetricSinkFromURL.
 func NewStatsiteSinkFromURL(u *url.URL) (MetricSink, error) {