Simplified inc/dec logic based on PR feedback.

There is no need to add the string to all event types as only Gauge
is compatible with inc/dec functionality.  Removed valueStr from all
events and added a simple boolean to the Gauge event instead

bridge_test.go

@@ -33,7 +33,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      2,
-					valueStr:  "2",
 					labels:     map[string]string{},
 				},
 			},
@@ -44,18 +43,6 @@ func TestHandlePacket(t *testing.T) {
 				&GaugeEvent{
 					metricName: "foo",
 					value:      3,
-					valueStr:  "3",
-					labels:     map[string]string{},
-				},
-			},
-		}, {
-			name: "simple gauge with sampling",
-			in:   "foo:100|g|@0.1",
-			out: Events{
-				&GaugeEvent{
-					metricName: "foo",
-					value:      1000,
-					valueStr:  "1000",
 					labels:     map[string]string{},
 				},
 			},
@@ -66,7 +53,7 @@ func TestHandlePacket(t *testing.T) {
 				&GaugeEvent{
 					metricName: "foo",
 					value:      -10,
-					valueStr:  "-10",
+					relative:   true,
 					labels:     map[string]string{},
 				},
 			},
@@ -77,7 +64,6 @@ func TestHandlePacket(t *testing.T) {
 				&TimerEvent{
 					metricName: "foo",
 					value:      200,
-					valueStr:  "200",
 					labels:     map[string]string{},
 				},
 			},
@@ -88,7 +74,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{"tag1": "bar", "tag2": "baz"},
 				},
 			},
@@ -99,7 +84,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{"tag1": "bar", "tag2": "baz"},
 				},
 			},
@@ -110,7 +94,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{"_09digits": "0", "tag_with_dots": "1"},
 				},
 			},
@@ -121,7 +104,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{},
 				},
 			},
@@ -132,7 +114,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{"tag": "value"},
 				},
 			},
@@ -143,7 +124,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      100,
-					valueStr:  "100",
 					labels:     map[string]string{"tag": "value"},
 				},
 			},
@@ -154,7 +134,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      1000,
-					valueStr:  "1000",
 					labels:     map[string]string{"tag1": "bar", "tag2": "baz"},
 				},
 			},
@@ -165,7 +144,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      1000,
-					valueStr:  "1000",
 					labels:     map[string]string{"tag1": "foo:bar"},
 				},
 			},
@@ -182,7 +160,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      200,
-					valueStr:  "200",
 					labels:     map[string]string{"tag": "value"},
 				},
 			},
@@ -193,37 +170,31 @@ func TestHandlePacket(t *testing.T) {
 				&TimerEvent{
 					metricName: "foo",
 					value:      200,
-					valueStr:  "200",
 					labels:     map[string]string{},
 				},
 				&TimerEvent{
 					metricName: "foo",
 					value:      300,
-					valueStr:  "300",
 					labels:     map[string]string{},
 				},
 				&CounterEvent{
 					metricName: "foo",
 					value:      50,
-					valueStr:  "50",
 					labels:     map[string]string{},
 				},
 				&GaugeEvent{
 					metricName: "foo",
 					value:      6,
-					valueStr:  "6",
 					labels:     map[string]string{},
 				},
 				&CounterEvent{
 					metricName: "bar",
 					value:      1,
-					valueStr:  "1",
 					labels:     map[string]string{},
 				},
 				&TimerEvent{
 					metricName: "bar",
 					value:      5,
-					valueStr:  "5",
 					labels:     map[string]string{},
 				},
 			},
@@ -243,7 +214,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      1,
-					valueStr:  "1",
 					labels:     map[string]string{},
 				},
 			},
@@ -254,7 +224,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "foo",
 					value:      2,
-					valueStr:  "2",
 					labels:     map[string]string{},
 				},
 			},
@@ -281,7 +250,6 @@ func TestHandlePacket(t *testing.T) {
 				&CounterEvent{
 					metricName: "valid_utf8",
 					value:      1,
-					valueStr:  "1",
 					labels:     map[string]string{},
 				},
 			},

exporter.go

@@ -23,7 +23,6 @@ import (
 	"strconv"
 	"strings"
 	"unicode/utf8"
-	"math"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -145,44 +144,38 @@ func (c *SummaryContainer) Get(metricName string, labels prometheus.Labels) prom
 type Event interface {
 	MetricName() string
 	Value() float64
-	ValueStr() string
 	Labels() map[string]string
 }
 
 type CounterEvent struct {
 	metricName string
 	value      float64
-	valueStr   string
 	labels     map[string]string
 }
 
 func (c *CounterEvent) MetricName() string        { return c.metricName }
 func (c *CounterEvent) Value() float64            { return c.value }
-func (c *CounterEvent) ValueStr() string          { return c.valueStr }
 func (c *CounterEvent) Labels() map[string]string { return c.labels }
 
 type GaugeEvent struct {
 	metricName string
 	value      float64
-	valueStr   string
+	relative   bool
 	labels     map[string]string
 }
 
 func (g *GaugeEvent) MetricName() string        { return g.metricName }
 func (g *GaugeEvent) Value() float64            { return g.value }
-func (g *GaugeEvent) ValueStr() string          { return g.valueStr }
 func (c *GaugeEvent) Labels() map[string]string { return c.labels }
 
 type TimerEvent struct {
 	metricName string
 	value      float64
-	valueStr   string
 	labels     map[string]string
 }
 
 func (t *TimerEvent) MetricName() string        { return t.metricName }
 func (t *TimerEvent) Value() float64            { return t.value }
-func (t *TimerEvent) ValueStr() string          { return t.valueStr }
 func (c *TimerEvent) Labels() map[string]string { return c.labels }
 
 type Events []Event
@@ -238,7 +231,7 @@ func (b *Exporter) Listen(e <-chan Events) {
 				metricName = escapeMetricName(event.MetricName())
 			}
 
-			switch event.(type) {
+			switch ev := event.(type) {
 			case *CounterEvent:
 				counter := b.Counters.Get(
 					b.suffix(metricName, "counter"),
@@ -261,11 +254,8 @@ func (b *Exporter) Listen(e <-chan Events) {
 					prometheusLabels,
 				)
 
-				var value = event.ValueStr()
+				if ev.relative {
-				if strings.Index(value, "+") == 0 {
 					gauge.Add(event.Value())
-				} else if strings.Index(value, "-") == 0 {
-					gauge.Sub(math.Abs(event.Value()))
 				} else {
 					gauge.Set(event.Value())
 				}
@@ -303,27 +293,25 @@ type StatsDListener struct {
 	conn *net.UDPConn
 }
 
-func buildEvent(statType, metric string, value float64, valueStr string, labels map[string]string) (Event, error) {
+func buildEvent(statType, metric string, value float64, relative bool, labels map[string]string) (Event, error) {
 	switch statType {
 	case "c":
 		return &CounterEvent{
 			metricName: metric,
 			value:      float64(value),
-			valueStr:   valueStr,
 			labels:     labels,
 		}, nil
 	case "g":
 		return &GaugeEvent{
 			metricName: metric,
 			value:      float64(value),
-			valueStr:   valueStr,
+			relative:   relative,
 			labels:     labels,
 		}, nil
 	case "ms", "h":
 		return &TimerEvent{
 			metricName: metric,
 			value:      float64(value),
-			valueStr:   valueStr,
 			labels:     labels,
 		}, nil
 	case "s":
@@ -395,11 +383,11 @@ func (l *StatsDListener) handlePacket(packet []byte, e chan<- Events) {
 			}
 			valueStr, statType := components[0], components[1]
 
-			var prefix = ""
+			var relative = false
 			if strings.Index(valueStr, "+") == 0 {
-				prefix = "+"
+				relative = true
 			} else if strings.Index(valueStr, "-") == 0 {
-				prefix = "-"
+				relative = true
 			}
 
 			value, err := strconv.ParseFloat(valueStr, 64)
@@ -445,9 +433,7 @@ func (l *StatsDListener) handlePacket(packet []byte, e chan<- Events) {
 				}
 			}
 
-			// convert the (possibly) sampled value to a string and add the operation prefix back on
+			event, err := buildEvent(statType, metric, value, relative, labels)
-			valueStr = prefix + strconv.FormatFloat(math.Abs(value), 'f', -1, 64)
-			event, err := buildEvent(statType, metric, value, valueStr, labels)
 			if err != nil {
 				log.Errorf("Error building event on line %s: %s", line, err)
 				networkStats.WithLabelValues("illegal_event").Inc()