Code Examples for bater.io/posts/2023/07/telemetry-in-go-readers/

iteration-1.go

package main

import (
	"context"
	"log"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
	"go.opentelemetry.io/otel/metric"
	metricsdk "go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"
	"go.opentelemetry.io/otel/sdk/resource"
	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
)

var res = resource.NewWithAttributes(
	semconv.SchemaURL,
	semconv.ServiceName("runtime-instrumentation-example"),
)

func main() {
	exp, err := stdoutmetric.New()
	if err != nil {
		log.Fatal(err)
	}

	// Register the exporter with an SDK via a periodic reader.
	//read := metricsdk.NewPeriodicReader(exp, metricsdk.WithInterval(1*time.Second))
	read := metricsdk.NewManualReader()
	provider := metricsdk.NewMeterProvider(metricsdk.WithResource(res), metricsdk.WithReader(read))
	defer func() {
		err := provider.Shutdown(context.Background())
		if err != nil {
			log.Fatal(err)
		}
	}()
	otel.SetMeterProvider(provider)

	log.Print("Starting runtime instrumentation:")
	m := otel.Meter("my.meter.name")

	counter, _ := m.Int64Counter(
		"some.prefix.counter",
		metric.WithDescription("my-counter"),
		metric.WithUnit("calls"),
	)

	counter.Add(context.TODO(), 1, metric.WithAttributes(
		attribute.String("cmd", "root")),
	)

	collectedMetrics := &metricdata.ResourceMetrics{}
	read.Collect(context.TODO(), collectedMetrics)
	exp.Export(context.TODO(), collectedMetrics)
}

// This can also be found at https://github.com/iamkirkbater/opentelemetry-go-examples/blob/000dde799d77ef1f1efa4639c671d4772bd8998a/metric-test.go

iteration-2.go

package main

import (
	"context"
	"log"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
	"go.opentelemetry.io/otel/metric"
	metricsdk "go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"
	"go.opentelemetry.io/otel/sdk/resource"
	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
)

var res = resource.NewWithAttributes(
	semconv.SchemaURL,
	semconv.ServiceName("runtime-instrumentation-example"),
)

var metricReader = metricsdk.NewManualReader()

func setup_metrics() func() {
	provider := metricsdk.NewMeterProvider(metricsdk.WithResource(res), metricsdk.WithReader(metricReader))
	otel.SetMeterProvider(provider)
	return func() {
		err := provider.Shutdown(context.Background())
		if err != nil {
			log.Fatal(err)
		}
	}
}

func closeout_metrics(ctx context.Context) {
	exp, err := stdoutmetric.New()
	if err != nil {
		log.Fatal(err)
	}

	collectedMetrics := &metricdata.ResourceMetrics{}
	metricReader.Collect(ctx, collectedMetrics)
	exp.Export(ctx, collectedMetrics)
}

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

	shutdown := setup_metrics()
	defer shutdown()

	log.Print("Starting runtime instrumentation:")
	m := otel.Meter("my.meter.name")

	counter, _ := m.Int64Counter(
		"some.prefix.counter",
		metric.WithDescription("my-counter"),
		metric.WithUnit("calls"),
	)

	counter.Add(ctx, 1, metric.WithAttributes(
		attribute.String("cmd", "root")),
	)

	closeout_metrics(ctx)
}

// This can also be found at https://github.com/iamkirkbater/opentelemetry-go-examples/blob/b2d4789d3f6ff1b9b9537562ecf4004a41964391/metric-test.go