Merge pull request #12 from performancecopilot/string-type-support

add string type support for metrics, closes #4

examples/simple_string_metric/main.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"flag"
+	"time"
+
+	"github.com/performancecopilot/speed"
+)
+
+var timelimit = flag.Int("time", 60, "number of seconds to run for")
+
+func main() {
+	flag.Parse()
+
+	w, err := speed.NewPCPWriter("stringtest", speed.ProcessFlag)
+	if err != nil {
+		panic(err)
+	}
+
+	names := []string{
+		"Batman",
+		"Robin",
+		"Nightwing",
+		"Batgirl",
+		"Red Robin",
+		"Red Hood",
+	}
+
+	m, err := w.RegisterString("bat.names", names[0], speed.InstantSemantics, speed.StringType, speed.OneUnit)
+	if err != nil {
+		panic(err)
+	}
+
+	w.Start()
+	defer w.Stop()
+
+	metric := m.(speed.SingletonMetric)
+	for i := 0; i < *timelimit; i++ {
+		metric.Set(names[i%len(names)])
+		time.Sleep(time.Second)
+	}
+}

metrics.go

@@ -76,6 +76,8 @@ func (m MetricType) IsCompatible(val interface{}) bool {
 		return m == FloatType
 	case float64:
 		return m.isCompatibleFloat(val.(float64))
+	case string:
+		return m == StringType
 	default:
 		return false
 	}
@@ -110,6 +112,13 @@ func (m MetricType) resolveFloat(val interface{}) interface{} {
 }
 
 func (m MetricType) resolve(val interface{}) interface{} {
+	if sval, isString := val.(string); isString {
+		if len(sval) > StringLength {
+			sval = sval[:StringLength]
+		}
+		return NewPCPString(sval)
+	}
+
 	val = m.resolveInt(val)
 	val = m.resolveFloat(val)
 
@@ -138,6 +147,11 @@ func (m MetricType) WriteVal(val interface{}, b bytebuffer.Buffer) error {
 		return b.WriteFloat32(val.(float32))
 	case float64:
 		return b.WriteFloat64(val.(float64))
+	case *PCPString:
+		pos := b.Pos()
+		b.Write(make([]byte, StringLength))
+		b.SetPos(pos)
+		return b.WriteString(val.(*PCPString).val)
 	}
 
 	return errors.New("Invalid Type")

registry.go

@@ -188,10 +188,14 @@ func (r *PCPRegistry) AddMetric(m Metric) error {
 
 	r.metrics[m.Name()] = pcpm
 
+	currentValues := 1
 	if pcpm.Indom() != nil {
-		r.valueCount += pcpm.Indom().InstanceCount()
-	} else {
-		r.valueCount++
+		currentValues = pcpm.Indom().InstanceCount()
+	}
+
+	r.valueCount += currentValues
+	if pcpm.Type() == StringType {
+		r.stringcount += currentValues
 	}
 
 	if pcpm.ShortDescription().String() != "" {

writer.go

@@ -383,29 +383,39 @@ func (w *PCPWriter) writeMetricDesc(m PCPMetric, pos int) {
 	}
 }
 
-func (w *PCPWriter) writeSingletonMetric(m *PCPSingletonMetric) {
-	w.writeMetricDesc(m, m.descoffset)
+func (w *PCPWriter) writeInstance(t MetricType, val interface{}, valueoffset int) updateClosure {
+	offset := valueoffset
+
+	if t == StringType {
+		w.buffer.SetPos(offset)
+		w.buffer.WriteUint64(StringLength - 1)
+		offset = val.(*PCPString).offset
+		w.buffer.WriteUint64(uint64(offset))
+	}
 
-	m.update = newupdateClosure(m.valueoffset, w.buffer, m.t)
-	m.update(m.val)
+	update := newupdateClosure(offset, w.buffer, t)
+	update(val)
 
-	w.buffer.MustSetPos(m.valueoffset + MaxDataValueSize)
-	w.buffer.MustWriteInt64(int64(m.descoffset))
-	w.buffer.MustWriteInt64(0)
+	w.buffer.SetPos(valueoffset + MaxDataValueSize)
+
+	return update
+}
+
+func (w *PCPWriter) writeSingletonMetric(m *PCPSingletonMetric) {
+	w.writeMetricDesc(m, m.descoffset)
+	m.update = w.writeInstance(m.t, m.val, m.valueoffset)
+	w.buffer.WriteInt64(int64(m.descoffset))
+	w.buffer.WriteInt64(0)
 }
 
 func (w *PCPWriter) writeInstanceMetric(m *PCPInstanceMetric) {
 	w.writeMetricDesc(m, m.descoffset)
 
 	for name, i := range m.indom.instances {
 		ival := m.vals[name]
-
-		ival.update = newupdateClosure(ival.offset, w.buffer, m.t)
-		ival.update(ival.val)
-
-		w.buffer.MustSetPos(ival.offset + MaxDataValueSize)
-		w.buffer.MustWriteInt64(int64(m.descoffset))
-		w.buffer.MustWriteInt64(int64(i.offset))
+		ival.update = w.writeInstance(m.t, ival.val, ival.offset)
+		w.buffer.WriteInt64(int64(m.descoffset))
+		w.buffer.WriteInt64(int64(i.offset))
 	}
 }