custom metric 추가

client/custom_exporter.go

@@ -0,0 +1,83 @@
+package client
+
+import (
+	"math"
+	_ "net/http/pprof"
+	"sync/atomic"
+	"unsafe"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"repositories.action2quare.com/ayo/gocommon/metric"
+)
+
+type metricDesc struct {
+	*prometheus.Desc
+	val       *uint64
+	valueType prometheus.ValueType
+}
+
+type exporterForPrometheus struct {
+	metricPtr unsafe.Pointer // []metricDesc
+}
+
+func newExporterForPrometheus() *exporterForPrometheus {
+	return &exporterForPrometheus{
+		metricPtr: unsafe.Pointer(new([]metricDesc)),
+	}
+}
+
+type metricValueAccessor struct {
+	ptr *uint64
+}
+
+func (va metricValueAccessor) set(val float64) {
+	atomic.StoreUint64(va.ptr, math.Float64bits(val))
+}
+
+func convertValueType(in metric.MetricType) prometheus.ValueType {
+	switch in {
+	case metric.MetricCounter:
+		return prometheus.CounterValue
+
+	case metric.MetricGuage:
+		return prometheus.GaugeValue
+	}
+
+	return prometheus.UntypedValue
+}
+
+func (e *exporterForPrometheus) registMetric(namespace string, desc metric.MetricDescription) metricValueAccessor {
+	ptr := atomic.LoadPointer(&e.metricPtr)
+	container := *(*[]metricDesc)(ptr)
+
+	newcont := make([]metricDesc, len(container)+1)
+	copy(newcont, container)
+
+	newval := new(uint64)
+	newcont[len(container)] = metricDesc{
+		Desc:      prometheus.NewDesc(prometheus.BuildFQName(namespace, "", desc.Name), desc.Help, nil, desc.ConstLabels),
+		val:       newval,
+		valueType: convertValueType(desc.Type),
+	}
+
+	atomic.StorePointer(&e.metricPtr, unsafe.Pointer(&newcont))
+	return metricValueAccessor{
+		ptr: newval,
+	}
+}
+
+func (e *exporterForPrometheus) Describe(ch chan<- *prometheus.Desc) {
+	ptr := atomic.LoadPointer(&e.metricPtr)
+	container := *(*[]metricDesc)(ptr)
+	for _, v := range container {
+		ch <- v.Desc
+	}
+}
+
+func (e *exporterForPrometheus) Collect(ch chan<- prometheus.Metric) {
+	ptr := atomic.LoadPointer(&e.metricPtr)
+	container := *(*[]metricDesc)(ptr)
+	for _, v := range container {
+		ch <- prometheus.MustNewConstMetric(v.Desc, v.valueType, math.Float64frombits(atomic.LoadUint64(v.val)))
+	}
+}