[VOL-2312] Logging - Integrate voltctl with new etcd-based dynamic loglevel mechanism. Testing is in progress

Change-Id: I2e13bb79008c9a49ebb6f58e575f51efebe6dbfd
diff --git a/vendor/github.com/armon/go-metrics/sink.go b/vendor/github.com/armon/go-metrics/sink.go
new file mode 100644
index 0000000..0b7d6e4
--- /dev/null
+++ b/vendor/github.com/armon/go-metrics/sink.go
@@ -0,0 +1,115 @@
+package metrics
+
+import (
+	"fmt"
+	"net/url"
+)
+
+// 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)
+	SetGaugeWithLabels(key []string, val float32, labels []Label)
+
+	// Should emit a Key/Value pair for each call
+	EmitKey(key []string, val float32)
+
+	// Counters should accumulate values
+	IncrCounter(key []string, val float32)
+	IncrCounterWithLabels(key []string, val float32, labels []Label)
+
+	// Samples are for timing information, where quantiles are used
+	AddSample(key []string, val float32)
+	AddSampleWithLabels(key []string, val float32, labels []Label)
+}
+
+// BlackholeSink is used to just blackhole messages
+type BlackholeSink struct{}
+
+func (*BlackholeSink) SetGauge(key []string, val float32)                              {}
+func (*BlackholeSink) SetGaugeWithLabels(key []string, val float32, labels []Label)    {}
+func (*BlackholeSink) EmitKey(key []string, val float32)                               {}
+func (*BlackholeSink) IncrCounter(key []string, val float32)                           {}
+func (*BlackholeSink) IncrCounterWithLabels(key []string, val float32, labels []Label) {}
+func (*BlackholeSink) AddSample(key []string, val float32)                             {}
+func (*BlackholeSink) AddSampleWithLabels(key []string, val float32, labels []Label)   {}
+
+// FanoutSink is used to sink to fanout values to multiple sinks
+type FanoutSink []MetricSink
+
+func (fh FanoutSink) SetGauge(key []string, val float32) {
+	fh.SetGaugeWithLabels(key, val, nil)
+}
+
+func (fh FanoutSink) SetGaugeWithLabels(key []string, val float32, labels []Label) {
+	for _, s := range fh {
+		s.SetGaugeWithLabels(key, val, labels)
+	}
+}
+
+func (fh FanoutSink) EmitKey(key []string, val float32) {
+	for _, s := range fh {
+		s.EmitKey(key, val)
+	}
+}
+
+func (fh FanoutSink) IncrCounter(key []string, val float32) {
+	fh.IncrCounterWithLabels(key, val, nil)
+}
+
+func (fh FanoutSink) IncrCounterWithLabels(key []string, val float32, labels []Label) {
+	for _, s := range fh {
+		s.IncrCounterWithLabels(key, val, labels)
+	}
+}
+
+func (fh FanoutSink) AddSample(key []string, val float32) {
+	fh.AddSampleWithLabels(key, val, nil)
+}
+
+func (fh FanoutSink) AddSampleWithLabels(key []string, val float32, labels []Label) {
+	for _, s := range fh {
+		s.AddSampleWithLabels(key, val, labels)
+	}
+}
+
+// sinkURLFactoryFunc is an generic interface around the *SinkFromURL() function provided
+// by each sink type
+type sinkURLFactoryFunc func(*url.URL) (MetricSink, error)
+
+// sinkRegistry supports the generic NewMetricSink function by mapping URL
+// schemes to metric sink factory functions
+var sinkRegistry = map[string]sinkURLFactoryFunc{
+	"statsd":   NewStatsdSinkFromURL,
+	"statsite": NewStatsiteSinkFromURL,
+	"inmem":    NewInmemSinkFromURL,
+}
+
+// NewMetricSinkFromURL allows a generic URL input to configure any of the
+// supported sinks. The scheme of the URL identifies the type of the sink, the
+// and query parameters are used to set options.
+//
+// "statsd://" - Initializes a StatsdSink. The host and port are passed through
+// as the "addr" of the sink
+//
+// "statsite://" - Initializes a StatsiteSink. The host and port become the
+// "addr" of the sink
+//
+// "inmem://" - Initializes an InmemSink. The host and port are ignored. The
+// "interval" and "duration" query parameters must be specified with valid
+// durations, see NewInmemSink for details.
+func NewMetricSinkFromURL(urlStr string) (MetricSink, error) {
+	u, err := url.Parse(urlStr)
+	if err != nil {
+		return nil, err
+	}
+
+	sinkURLFactoryFunc := sinkRegistry[u.Scheme]
+	if sinkURLFactoryFunc == nil {
+		return nil, fmt.Errorf(
+			"cannot create metric sink, unrecognized sink name: %q", u.Scheme)
+	}
+
+	return sinkURLFactoryFunc(u)
+}