Istio OpenCensus

gistfile1.go

package main

import (
	"bufio"
	"contrib.go.opencensus.io/exporter/prometheus"
	"fmt"
	"go.opencensus.io/stats/view"
	"io"
	"istio.io/pkg/monitoring"
	"log"
	"net/http"
	"os"
)

var (
	RequestType = monitoring.MustCreateLabel("request_type")

	outgoingLatency = monitoring.NewSum(
		"outgoing_latency",
		"The latency of "+
				"outgoing requests (e.g. to a token exchange server, CA, etc.) in milliseconds.",
				monitoring.WithLabels(RequestType),
		)
)

func main() {
	monitoring.MustRegister(outgoingLatency)

	// Create the Prometheus exporter.
	pe, err := prometheus.NewExporter(prometheus.Options{
		Namespace: "ocmetricstutorial",
	})
	if err != nil {
		log.Fatalf("Failed to create the Prometheus stats exporter: %v", err)
	}
	// Register the Prometheus exporter.
	// This step is needed so that metrics can be exported.
	view.RegisterExporter(pe)

	// Now finally run the Prometheus exporter as a scrape endpoint.
	// We'll run the server on port 8888.
	go func() {
		mux := http.NewServeMux()
		mux.Handle("/metrics", pe)
		if err := http.ListenAndServe(":8888", mux); err != nil {
			log.Fatalf("Failed to run Prometheus scrape endpoint: %v", err)
		}
	}()

	// In a REPL:
	//   1. Read input
	//   2. process input
	br := bufio.NewReader(os.Stdin)

	// repl is the read, evaluate, print, loop
	for {
		foo()
		if err := readEvaluateProcess(br); err != nil {
			if err == io.EOF {
				return
			}
			log.Fatal(err)
		}
	}
}

func foo() {
	outgoingLatency.With(RequestType.Value("foo")).Increment()
	rows, err := view.RetrieveData("outgoing_latency")
	if err != nil {
		fmt.Println(err.Error())
	}
	for _, row := range rows {
		fmt.Printf("TAGS: %v\n", row.Tags)
		fmt.Printf("DATA: %v\n", row.Data)
	}
}


// readEvaluateProcess reads a line from the input reader and
// then processes it. It returns an error if any was encountered.
func readEvaluateProcess(br *bufio.Reader) (terr error) {
	fmt.Printf("> ")
	line, _, err := br.ReadLine()
	if err != nil {
		if err != io.EOF {
			return err
		}
		log.Fatal(err)
	}

	out := line
	fmt.Printf("< %s\n\n", out)
	return nil
}