blob: 1ff91d47635faa37454bb9baff81d0d5e9e0aafe (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package slog_test
import (
"context"
"log/slog"
"log/slog/internal/slogtest"
"os"
)
// A LevelHandler wraps a Handler with an Enabled method
// that returns false for levels below a minimum.
type LevelHandler struct {
level slog.Leveler
handler slog.Handler
}
// NewLevelHandler returns a LevelHandler with the given level.
// All methods except Enabled delegate to h.
func NewLevelHandler(level slog.Leveler, h slog.Handler) *LevelHandler {
// Optimization: avoid chains of LevelHandlers.
if lh, ok := h.(*LevelHandler); ok {
h = lh.Handler()
}
return &LevelHandler{level, h}
}
// Enabled implements Handler.Enabled by reporting whether
// level is at least as large as h's level.
func (h *LevelHandler) Enabled(_ context.Context, level slog.Level) bool {
return level >= h.level.Level()
}
// Handle implements Handler.Handle.
func (h *LevelHandler) Handle(ctx context.Context, r slog.Record) error {
return h.handler.Handle(ctx, r)
}
// WithAttrs implements Handler.WithAttrs.
func (h *LevelHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
return NewLevelHandler(h.level, h.handler.WithAttrs(attrs))
}
// WithGroup implements Handler.WithGroup.
func (h *LevelHandler) WithGroup(name string) slog.Handler {
return NewLevelHandler(h.level, h.handler.WithGroup(name))
}
// Handler returns the Handler wrapped by h.
func (h *LevelHandler) Handler() slog.Handler {
return h.handler
}
// This example shows how to Use a LevelHandler to change the level of an
// existing Handler while preserving its other behavior.
//
// This example demonstrates increasing the log level to reduce a logger's
// output.
//
// Another typical use would be to decrease the log level (to LevelDebug, say)
// during a part of the program that was suspected of containing a bug.
func ExampleHandler_levelHandler() {
th := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: slogtest.RemoveTime})
logger := slog.New(NewLevelHandler(slog.LevelWarn, th))
logger.Info("not printed")
logger.Warn("printed")
// Output:
// level=WARN msg=printed
}
|
