Example of three types of ad-hoc metric

examples/ad-hoc/main.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/zvelo/go-signalfx"
+)
+
+func main() {
+	config := signalfx.NewConfig()
+	//config.AuthToken = "<YOUR_SIGNALFX_API_TOKEN>" // if $SFX_API_TOKEN is set, this is unnecessary
+	hostname, err := os.Hostname()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "no hostname:", err)
+		os.Exit(1)
+	}
+	hostname += "-" + os.Args[1]
+
+	reporter := signalfx.NewReporter(config, map[string]string{
+		"process":  "ad-hoc",
+		"hostname": hostname,
+	})
+
+	// a gauge is a point-in-time value; it can positive or negative
+	gaugeWalker := newRandomWalker(0, 256)
+	gauge := signalfx.NewInt64(0)
+	g := reporter.NewGauge("test-gauge", gauge,
+		map[string]string{
+			"hostname": hostname,
+			"process":  "ad-hoc",
+		})
+	_ = g
+	cancelFunc := reporter.RunInBackground(time.Second)
+
+	// a cumulative counter is a good choice to wrap an internal value
+	var requestCount = signalfx.Uint64(0)
+	reporter.NewCumulative("test-cumulative-counter",
+		&requestCount,
+		map[string]string{
+			"hostname": hostname,
+		})
+
+	// a counter is a good choice for a value we want to create, then report
+
+	maxInc := big.NewInt(1024)
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := int64(0); i < 288; i++ {
+			inc, err := rand.Int(rand.Reader, maxInc)
+			if err != nil {
+				fmt.Fprintln(os.Stderr, "failed to generate random increment:", err)
+			} else {
+				reporter.Inc("test-counter", map[string]string{"hostname": hostname}, inc.Int64())
+				inc.Add(inc, big.NewInt(int64(requestCount)))
+				requestCount.Set(inc.Uint64())
+			}
+			time.Sleep(time.Second * 2)
+		}
+	}()
+
+	go func() {
+		for {
+			gaugeWalker.inc()
+			gauge.Set(gaugeWalker.value.Int64())
+			time.Sleep(time.Second * 2)
+		}
+	}()
+
+	wg.Wait()
+	cancelFunc()
+}
+
+type randomWalker struct {
+	value        *big.Int
+	maxIncrement *big.Int
+	halfMax      *big.Int
+}
+
+func newRandomWalker(initial, maxIncrement int64) randomWalker {
+	m := big.NewInt(maxIncrement)
+	hm := &big.Int{}
+	hm.Div(m, big.NewInt(2))
+	return randomWalker{
+		value:        big.NewInt(initial),
+		maxIncrement: m,
+		halfMax:      hm,
+	}
+}
+
+func (r randomWalker) inc() {
+	inc, err := rand.Int(rand.Reader, r.maxIncrement)
+	if err != nil {
+		panic(fmt.Sprint("error generating random data: ", err))
+	}
+	inc.Sub(inc, r.halfMax)
+	r.value.Add(r.value, inc)
+}