utility for reporting runtime stats

telemetry/doc.go

@@ -0,0 +1,2 @@
+// Package telemetry provides monitoring utilities.
+package telemetry

telemetry/runtime.go

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+package telemetry
+
+import (
+	"runtime"
+
+	"github.com/uber-go/tally"
+)
+
+// Runtime reports goroutine and memory statistics exposed by the runtime package.
+type Runtime struct {
+	numGoroutines tally.Gauge
+	heapAlloc     tally.Gauge
+	heapIdle      tally.Gauge
+	heapInuse     tally.Gauge
+	heapObjects   tally.Gauge
+	stackInuse    tally.Gauge
+}
+
+// NewRuntime constructs runtime metrics from the given scope.
+func NewRuntime(scope tally.Scope) *Runtime {
+	sub := scope.SubScope("runtime")
+	memStat := func(name string) tally.Gauge {
+		return sub.Tagged(map[string]string{"stat": name}).Gauge("memory")
+	}
+	return &Runtime{
+		numGoroutines: sub.Gauge("goroutines"),
+		heapAlloc:     memStat("heap_alloc"),
+		heapIdle:      memStat("heap_idle"),
+		heapInuse:     memStat("heap_inuse"),
+		heapObjects:   memStat("heap_objects"),
+		stackInuse:    memStat("stack_inuse"),
+	}
+}
+
+// Update updates runtime stats.
+func (r Runtime) Update() {
+	var mem runtime.MemStats
+	runtime.ReadMemStats(&mem)
+
+	r.heapAlloc.Update(float64(mem.HeapAlloc))
+	r.heapIdle.Update(float64(mem.HeapIdle))
+	r.heapInuse.Update(float64(mem.HeapInuse))
+	r.heapObjects.Update(float64(mem.HeapObjects))
+	r.stackInuse.Update(float64(mem.StackInuse))
+
+	r.numGoroutines.Update(float64(runtime.NumGoroutine()))
+}