stack/libs/go-libs/otlp/cli.go

package otlp

import (
	"fmt"
	"strings"
	"sync"

	flag "github.com/spf13/pflag"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/sdk/resource"
	"go.uber.org/fx"
)

var (
	onceInitOTLPFlags sync.Once
	OnceLoadResources sync.Once
)

const (
	OtelResourceAttributes = "otel-resource-attributes"
	OtelServiceName        = "otel-service-name"
)

func InitOTLPFlags(flags *flag.FlagSet) {
	onceInitOTLPFlags.Do(func() {
		flags.String(OtelServiceName, "", "OpenTelemetry service name")
		flags.StringSlice(OtelResourceAttributes, []string{}, "Additional OTLP resource attributes")
	})
}

func LoadResource(serviceName string, resourceAttributes []string) fx.Option {
	options := make([]fx.Option, 0)
	OnceLoadResources.Do(func() {
		options = append(options,
			fx.Provide(func() (*resource.Resource, error) {
				defaultResource := resource.Default()
				attributes := make([]attribute.KeyValue, 0)
				if serviceName != "" {
					attributes = append(attributes, attribute.String("service.name", serviceName))
				}
				for _, ra := range resourceAttributes {
					parts := strings.SplitN(ra, "=", 2)
					if len(parts) < 2 {
						return nil, fmt.Errorf("malformed otlp attribute: %s", ra)
					}
					attributes = append(attributes, attribute.String(parts[0], parts[1]))
				}
				return resource.Merge(defaultResource, resource.NewSchemaless(attributes...))
			}),
		)
	})

	return fx.Options(options...)
}