1//go:build !go1.21
 2// +build !go1.21
 3
 4/*
 5Copyright 2019 The logr Authors.
 6
 7Licensed under the Apache License, Version 2.0 (the "License");
 8you may not use this file except in compliance with the License.
 9You may obtain a copy of the License at
10
11    http://www.apache.org/licenses/LICENSE-2.0
12
13Unless required by applicable law or agreed to in writing, software
14distributed under the License is distributed on an "AS IS" BASIS,
15WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16See the License for the specific language governing permissions and
17limitations under the License.
18*/
19
20package logr
21
22import (
23	"context"
24)
25
26// FromContext returns a Logger from ctx or an error if no Logger is found.
27func FromContext(ctx context.Context) (Logger, error) {
28	if v, ok := ctx.Value(contextKey{}).(Logger); ok {
29		return v, nil
30	}
31
32	return Logger{}, notFoundError{}
33}
34
35// FromContextOrDiscard returns a Logger from ctx.  If no Logger is found, this
36// returns a Logger that discards all log messages.
37func FromContextOrDiscard(ctx context.Context) Logger {
38	if v, ok := ctx.Value(contextKey{}).(Logger); ok {
39		return v
40	}
41
42	return Discard()
43}
44
45// NewContext returns a new Context, derived from ctx, which carries the
46// provided Logger.
47func NewContext(ctx context.Context, logger Logger) context.Context {
48	return context.WithValue(ctx, contextKey{}, logger)
49}