Inspect GFE Latency in Spanner Go Client - 2

main.go

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// [START spanner_quickstart]

// Sample spanner_quickstart is a basic program that uses Cloud Spanner.
package main

import (
	"context"
	"fmt"
	"log"
	"strconv"
	"strings"
	"time"

	spanner "cloud.google.com/go/spanner/apiv1"
	gax "github.com/googleapis/gax-go/v2"
	sppb "google.golang.org/genproto/googleapis/spanner/v1"
	"google.golang.org/grpc"
	"google.golang.org/grpc/metadata"

	"contrib.go.opencensus.io/exporter/jaeger"
	"go.opencensus.io/trace"
)

func main() {
	ctx := context.Background()

	// This database must exist.
	databaseName := "projects/testing/instances/test-instance/databases/test-db"

	client, err := spanner.NewClient(ctx)
	if err != nil {
		log.Fatalf("Failed to create client %v", err)
	}
	defer client.Close()

	setupOpenCensus()

	req := &sppb.CreateSessionRequest{Database: databaseName}
	session, err := client.CreateSession(ctx, req)
	if err != nil {
		log.Fatalf("CreateSession failed with %v", err)
	}

	req2 := &sppb.ExecuteSqlRequest{
		Session:   session.Name,
		Sql:       "SELECT * FROM Test ORDER BY ID ASC",
		QueryMode: sppb.ExecuteSqlRequest_PROFILE,
	}

	for i := 0; i < 20; i++ {
		ctx, span := trace.StartSpan(ctx, "demo/ExecuteSql")
		var md metadata.MD
		resultSet, err := client.ExecuteSql(ctx, req2, gax.WithGRPCOptions(grpc.Header(&md)))
		if err != nil {
			log.Fatalf("ExecuteSql failed with %v", err)
		}
		fmt.Println("Row", resultSet.GetRows())
		gfeLatency := getGFELatency(md)
		span.AddAttributes(trace.Int64Attribute("GFE Latency", gfeLatency))
		span.End()
		time.Sleep(10 * time.Second)
	}
}

func setupOpenCensus() {
	// Configure 100% sample rate, otherwise, few traces will be sampled.
	trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})

	agentEndpointURI := "localhost:6831"
	collectorEndpointURI := "http://localhost:14268/api/traces"

	je, err := jaeger.NewExporter(jaeger.Options{
		AgentEndpoint:     agentEndpointURI,
		CollectorEndpoint: collectorEndpointURI,
		ServiceName:       "demo",
	})
	if err != nil {
		log.Fatalf("Failed to create the Jaeger exporter: %v", err)
	}

	// And now finally register it as a Trace Exporter
	trace.RegisterExporter(je)
}

func getGFELatency(md metadata.MD) int64 {
	srvTiming := md.Get("server-timing")[0]
	gfeLtcy, _ := strconv.Atoi(strings.TrimPrefix(srvTiming, "gfet4t7; dur="))
	return int64(gfeLtcy)
}

// [END spanner_quickstart]