add Age Gauge and Monotonic Counter meter types

spectator/meter/age_gauge.go

@@ -0,0 +1,43 @@
+package meter
+
+import (
+	"fmt"
+	"github.com/Netflix/spectator-go/spectator/writer"
+)
+
+// AgeGauge represents a value that is the time in seconds since the epoch at which an event
+// has successfully occurred, or 0 to use the current time in epoch seconds. After an Age Gauge
+// has been set, it will continue reporting the number of seconds since the last time recorded,
+// for as long as the spectatord process runs. The purpose of this metric type is to enable users
+// to more easily implement the Time Since Last Success alerting pattern.
+//
+// To set `now()` as the last success, set a value of 0.
+type AgeGauge struct {
+	id              *Id
+	writer          writer.Writer
+	meterTypeSymbol string
+}
+
+// NewAgeGauge generates a new gauge, using the provided meter identifier.
+func NewAgeGauge(id *Id, writer writer.Writer) *AgeGauge {
+	return &AgeGauge{id, writer, "A"}
+}
+
+// MeterId returns the meter identifier.
+func (g *AgeGauge) MeterId() *Id {
+	return g.id
+}
+
+// Set records the current value.
+func (g *AgeGauge) Set(value int64) {
+	if value >= 0 {
+		var line = fmt.Sprintf("%s:%s:%d", g.meterTypeSymbol, g.id.spectatordId, value)
+		g.writer.Write(line)
+	}
+}
+
+// Now records the current time in epoch seconds in spectatord.
+func (g *AgeGauge) Now() {
+	var line = fmt.Sprintf("%s:%s:0", g.meterTypeSymbol, g.id.spectatordId)
+	g.writer.Write(line)
+}

spectator/meter/age_gauge_test.go

@@ -0,0 +1,69 @@
+package meter
+
+import (
+	"github.com/Netflix/spectator-go/spectator/writer"
+	"testing"
+)
+
+func TestAgeGauge_Set(t *testing.T) {
+	id := NewId("set", nil)
+	w := writer.MemoryWriter{}
+	g := NewAgeGauge(id, &w)
+	g.Set(100)
+
+	expected := "A:set:100"
+	if w.Lines[0] != expected {
+		t.Errorf("Expected line to be %s, got %s", expected, w.Lines[0])
+	}
+}
+
+func TestAgeGauge_SetZero(t *testing.T) {
+	id := NewId("setZero", nil)
+	w := writer.MemoryWriter{}
+	g := NewAgeGauge(id, &w)
+	g.Set(0)
+
+	expected := "A:setZero:0"
+	if w.Lines[0] != expected {
+		t.Errorf("Expected line to be %s, got %s", expected, w.Lines[0])
+	}
+}
+
+func TestAgeGauge_Now(t *testing.T) {
+	id := NewId("now", nil)
+	w := writer.MemoryWriter{}
+	g := NewAgeGauge(id, &w)
+	g.Now()
+
+	expected := "A:now:0"
+	if w.Lines[0] != expected {
+		t.Errorf("Expected line to be %s, got %s", expected, w.Lines[0])
+	}
+}
+
+func TestAgeGauge_SetNegative(t *testing.T) {
+	id := NewId("setNegative", nil)
+	w := writer.MemoryWriter{}
+	g := NewAgeGauge(id, &w)
+	g.Set(-100)
+
+	if len(w.Lines) != 0 {
+		t.Error("Negative values should be ignored")
+	}
+}
+
+func TestAgeGauge_SetMultipleValues(t *testing.T) {
+	id := NewId("setMultiple", nil)
+	w := writer.MemoryWriter{}
+	g := NewAgeGauge(id, &w)
+	g.Set(100)
+	g.Set(200)
+	g.Set(300)
+
+	expectedLines := []string{"A:setMultiple:100", "A:setMultiple:200", "A:setMultiple:300"}
+	for i, line := range w.Lines {
+		if line != expectedLines[i] {
+			t.Errorf("Expected line to be %s, got %s", expectedLines[i], line)
+		}
+	}
+}

spectator/meter/counter.go

@@ -15,12 +15,12 @@ import (
 type Counter struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 // NewCounter generates a new counter, using the provided meter identifier.
 func NewCounter(id *Id, writer writer.Writer) *Counter {
-	return &Counter{id, writer, 'c'}
+	return &Counter{id, writer, "c"}
 }
 
 // MeterId returns the meter identifier.
@@ -30,22 +30,22 @@ func (c *Counter) MeterId() *Id {
 
 // Increment increments the counter.
 func (c *Counter) Increment() {
-	var line = fmt.Sprintf("%c:%s:%d", c.meterTypeSymbol, c.id.spectatordId, 1)
+	var line = fmt.Sprintf("%s:%s:%d", c.meterTypeSymbol, c.id.spectatordId, 1)
 	c.writer.Write(line)
 }
 
 // AddFloat adds a specific float64 delta to the current measurement.
 func (c *Counter) AddFloat(delta float64) {
 	if delta > 0.0 {
-		var line = fmt.Sprintf("%c:%s:%f", c.meterTypeSymbol, c.id.spectatordId, delta)
+		var line = fmt.Sprintf("%s:%s:%f", c.meterTypeSymbol, c.id.spectatordId, delta)
 		c.writer.Write(line)
 	}
 }
 
 // Add is to add a specific int64 delta to the current measurement.
 func (c *Counter) Add(delta int64) {
 	if delta > 0 {
-		var line = fmt.Sprintf("%c:%s:%d", c.meterTypeSymbol, c.id.spectatordId, delta)
+		var line = fmt.Sprintf("%s:%s:%d", c.meterTypeSymbol, c.id.spectatordId, delta)
 		c.writer.Write(line)
 	}
 }

spectator/meter/dist_summary.go

@@ -15,13 +15,13 @@ import (
 type DistributionSummary struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 // NewDistributionSummary generates a new distribution summary, using the
 // provided meter identifier.
 func NewDistributionSummary(id *Id, writer writer.Writer) *DistributionSummary {
-	return &DistributionSummary{id, writer, 'd'}
+	return &DistributionSummary{id, writer, "d"}
 }
 
 // MeterId returns the meter identifier.
@@ -32,7 +32,7 @@ func (d *DistributionSummary) MeterId() *Id {
 // Record records a new value to track within the distribution.
 func (d *DistributionSummary) Record(amount int64) {
 	if amount >= 0 {
-		var line = fmt.Sprintf("%c:%s:%d", d.meterTypeSymbol, d.id.spectatordId, amount)
+		var line = fmt.Sprintf("%s:%s:%d", d.meterTypeSymbol, d.id.spectatordId, amount)
 		d.writer.Write(line)
 	}
 }

spectator/meter/max_gauge.go

@@ -16,12 +16,12 @@ import (
 type MaxGauge struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 // NewMaxGauge generates a new gauge, using the provided meter identifier.
 func NewMaxGauge(id *Id, writer writer.Writer) *MaxGauge {
-	return &MaxGauge{id, writer, 'm'}
+	return &MaxGauge{id, writer, "m"}
 }
 
 // MeterId returns the meter identifier.
@@ -31,6 +31,6 @@ func (g *MaxGauge) MeterId() *Id {
 
 // Set records the current value.
 func (g *MaxGauge) Set(value float64) {
-	var line = fmt.Sprintf("%c:%s:%f", g.meterTypeSymbol, g.id.spectatordId, value)
+	var line = fmt.Sprintf("%s:%s:%f", g.meterTypeSymbol, g.id.spectatordId, value)
 	g.writer.Write(line)
 }

spectator/meter/monotonic_counter.go

@@ -0,0 +1,38 @@
+package meter
+
+import (
+	"fmt"
+	"github.com/Netflix/spectator-go/spectator/writer"
+)
+
+// MonotonicCounter is used to measure the rate at which some event is occurring. This
+// type is safe for concurrent use.
+//
+// The value is a monotonically increasing number. A minimum of two samples must be received
+// in order for spectatord to calculate a delta value and report it to the backend.
+//
+// A variety of networking metrics may be reported monotonically and this metric type provides a
+// convenient means of recording these values, at the expense of a slower time-to-first metric.
+type MonotonicCounter struct {
+	id              *Id
+	writer          writer.Writer
+	meterTypeSymbol string
+}
+
+// NewMonotonicCounter generates a new counter, using the provided meter identifier.
+func NewMonotonicCounter(id *Id, writer writer.Writer) *MonotonicCounter {
+	return &MonotonicCounter{id, writer, "C"}
+}
+
+// MeterId returns the meter identifier.
+func (c *MonotonicCounter) MeterId() *Id {
+	return c.id
+}
+
+// Set is to set a specific int64 delta as the current measurement.
+func (c *MonotonicCounter) Set(delta int64) {
+	if delta > 0 {
+		var line = fmt.Sprintf("%s:%s:%d", c.meterTypeSymbol, c.id.spectatordId, delta)
+		c.writer.Write(line)
+	}
+}

spectator/meter/monotonic_counter_test.go

@@ -0,0 +1,24 @@
+package meter
+
+import (
+	"github.com/Netflix/spectator-go/spectator/writer"
+	"testing"
+)
+
+func TestMonotonicCounter_Set(t *testing.T) {
+	w := writer.MemoryWriter{}
+	id := NewId("add", nil)
+	c := NewMonotonicCounter(id, &w)
+
+	c.Set(4)
+
+	expected := "C:add:4"
+	if w.Lines[0] != expected {
+		t.Error("Expected ", expected, " got ", w.Lines[0])
+	}
+
+	c.Set(-1)
+	if len(w.Lines) != 1 {
+		t.Error("Negative deltas should be ignored")
+	}
+}

spectator/meter/percentile_distsummary.go

@@ -10,7 +10,7 @@ import (
 type PercentileDistributionSummary struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 func (p *PercentileDistributionSummary) MeterId() *Id {
@@ -19,13 +19,13 @@ func (p *PercentileDistributionSummary) MeterId() *Id {
 
 // NewPercentileDistributionSummary creates a new *PercentileDistributionSummary using the meter identifier.
 func NewPercentileDistributionSummary(id *Id, writer writer.Writer) *PercentileDistributionSummary {
-	return &PercentileDistributionSummary{id, writer, 'D'}
+	return &PercentileDistributionSummary{id, writer, "D"}
 }
 
 // Record records a new value to track within the distribution.
 func (p *PercentileDistributionSummary) Record(amount int64) {
 	if amount >= 0 {
-		var line = fmt.Sprintf("%c:%s:%d", p.meterTypeSymbol, p.id.spectatordId, amount)
+		var line = fmt.Sprintf("%s:%s:%d", p.meterTypeSymbol, p.id.spectatordId, amount)
 		p.writer.Write(line)
 	}
 }

spectator/meter/percentile_timer.go

@@ -11,14 +11,14 @@ import (
 type PercentileTimer struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 func NewPercentileTimer(
 	id *Id,
 	writer writer.Writer,
 ) *PercentileTimer {
-	return &PercentileTimer{id, writer, 'T'}
+	return &PercentileTimer{id, writer, "T"}
 }
 
 func (t *PercentileTimer) MeterId() *Id {
@@ -28,7 +28,7 @@ func (t *PercentileTimer) MeterId() *Id {
 // Record records the value for a single event.
 func (t *PercentileTimer) Record(amount time.Duration) {
 	if amount >= 0 {
-		var line = fmt.Sprintf("%c:%s:%f", t.meterTypeSymbol, t.id.spectatordId, amount.Seconds())
+		var line = fmt.Sprintf("%s:%s:%f", t.meterTypeSymbol, t.id.spectatordId, amount.Seconds())
 		t.writer.Write(line)
 	}
 }

spectator/meter/timer.go

@@ -11,12 +11,12 @@ import (
 type Timer struct {
 	id              *Id
 	writer          writer.Writer
-	meterTypeSymbol rune
+	meterTypeSymbol string
 }
 
 // NewTimer generates a new timer, using the provided meter identifier.
 func NewTimer(id *Id, writer writer.Writer) *Timer {
-	return &Timer{id, writer, 't'}
+	return &Timer{id, writer, "t"}
 }
 
 // MeterId returns the meter identifier.
@@ -27,7 +27,7 @@ func (t *Timer) MeterId() *Id {
 // Record records the duration this specific event took.
 func (t *Timer) Record(amount time.Duration) {
 	if amount >= 0 {
-		var line = fmt.Sprintf("%c:%s:%f", t.meterTypeSymbol, t.id.spectatordId, amount.Seconds())
+		var line = fmt.Sprintf("%s:%s:%f", t.meterTypeSymbol, t.id.spectatordId, amount.Seconds())
 		t.writer.Write(line)
 	}
 }