observe-server/common/opentelemetry/metrics.go

package opentelemetry

import (
	"context"
	"time"

	extConfig "go-admin/config"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
	"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
	"go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/resource"
)

func initMeter(res *resource.Resource) (provider *metric.MeterProvider, err error) {
	otelConfig := extConfig.ExtConfig.Otel
	endpoint := otelConfig.Common.Endpoint
	grpcEndpoint := otelConfig.Common.GrpcEndpoint
	interval := otelConfig.Metrics.Interval
	exporter := new(metric.Exporter)
	if endpoint == "" && grpcEndpoint == "" {
		*exporter, err = stdoutmetric.New(stdoutmetric.WithPrettyPrint())
	} else if grpcEndpoint != "" {
		options := []otlpmetricgrpc.Option{
			otlpmetricgrpc.WithEndpoint(grpcEndpoint),
			otlpmetricgrpc.WithInsecure(),
		}
		*exporter, err = otlpmetricgrpc.New(context.TODO(), options...)
	} else {
		*exporter, err = otlpmetrichttp.New(context.TODO(), otlpmetrichttp.WithEndpoint(endpoint), otlpmetrichttp.WithInsecure())
	}
	if interval == 0 {
		interval = 60
	}
	if err != nil {
		return nil, err
	}

	provider = metric.NewMeterProvider(
		metric.WithResource(res),
		metric.WithReader(metric.NewPeriodicReader(*exporter, metric.WithInterval(time.Duration(interval)*time.Second))),
	)
	otel.SetMeterProvider(provider)
	return provider, nil
}