package main

import (
	"fmt"
	"go.opencensus.io/exporter/stackdriver"
	"go.opencensus.io/trace"
	"log"
)

func main() {
	// Registering the Stackdriver exporter to log sample requests in Stackdriver Trace
	exporter, err := stackdriver.NewExporter(stackdriver.Options{
		ProjectID: os.Getenv("PROJECT_ID"),

		ClientOptions: []option.ClientOption{
			option.WithCredentialsFile(os.Getenv("STACKDRIVER_CREDENTIALS")),
		},
	})
	if err != nil {
		log.Fatalf("error initiating the Stackdriver trace exporter: %s", err)
	}
	trace.RegisterExporter(exporter)
	trace.ApplyConfig(trace.Config{DefaultSampler: trace.ProbabilitySampler(0.01)})

	doSomething()
}

func doSomething() {
	ctx, span := trace.StartSpan(ctx, "main.doSomething")
	defer span.End()

	fmt.Println("Doing something")
}