1// Copyright The OpenTelemetry Authors
 2// SPDX-License-Identifier: Apache-2.0
 3
 4package otel // import "go.opentelemetry.io/otel"
 5
 6import (
 7	"go.opentelemetry.io/otel/internal/global"
 8	"go.opentelemetry.io/otel/metric"
 9)
10
11// Meter returns a Meter from the global MeterProvider. The name must be the
12// name of the library providing instrumentation. This name may be the same as
13// the instrumented code only if that code provides built-in instrumentation.
14// If the name is empty, then a implementation defined default name will be
15// used instead.
16//
17// If this is called before a global MeterProvider is registered the returned
18// Meter will be a No-op implementation of a Meter. When a global MeterProvider
19// is registered for the first time, the returned Meter, and all the
20// instruments it has created or will create, are recreated automatically from
21// the new MeterProvider.
22//
23// This is short for GetMeterProvider().Meter(name).
24func Meter(name string, opts ...metric.MeterOption) metric.Meter {
25	return GetMeterProvider().Meter(name, opts...)
26}
27
28// GetMeterProvider returns the registered global meter provider.
29//
30// If no global GetMeterProvider has been registered, a No-op GetMeterProvider
31// implementation is returned. When a global GetMeterProvider is registered for
32// the first time, the returned GetMeterProvider, and all the Meters it has
33// created or will create, are recreated automatically from the new
34// GetMeterProvider.
35func GetMeterProvider() metric.MeterProvider {
36	return global.MeterProvider()
37}
38
39// SetMeterProvider registers mp as the global MeterProvider.
40func SetMeterProvider(mp metric.MeterProvider) {
41	global.SetMeterProvider(mp)
42}