| // 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" |
| "fmt" |
| "os" |
| "path/filepath" |
| "runtime" |
| "time" |
| |
| "golang.org/x/exp/slog" |
| ) |
| |
| // Infof is an example of a user-defined logging function that wraps slog. |
| // The log record contains the source position of the caller of Infof. |
| func Infof(logger *slog.Logger, format string, args ...any) { |
| if !logger.Enabled(context.Background(), slog.LevelInfo) { |
| return |
| } |
| var pcs [1]uintptr |
| runtime.Callers(2, pcs[:]) // skip [Callers, Infof] |
| r := slog.NewRecord(time.Now(), slog.LevelInfo, fmt.Sprintf(format, args...), pcs[0]) |
| _ = logger.Handler().Handle(context.Background(), r) |
| } |
| |
| func Example_wrapping() { |
| replace := func(groups []string, a slog.Attr) slog.Attr { |
| // Remove time. |
| if a.Key == slog.TimeKey && len(groups) == 0 { |
| return slog.Attr{} |
| } |
| // Remove the directory from the source's filename. |
| if a.Key == slog.SourceKey { |
| source := a.Value.Any().(*slog.Source) |
| source.File = filepath.Base(source.File) |
| } |
| return a |
| } |
| logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{AddSource: true, ReplaceAttr: replace})) |
| Infof(logger, "message, %s", "formatted") |
| |
| // Output: |
| // level=INFO source=example_wrap_test.go:44 msg="message, formatted" |
| } |