blob: c7bfbb7a9331e0c9bf0c36f0c5893a07e409eb86 [file] [log] [blame]
// 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 {
a.Value = slog.StringValue(filepath.Base(a.Value.String()))
}
return a
}
logger := slog.New(slog.HandlerOptions{AddSource: true, ReplaceAttr: replace}.NewTextHandler(os.Stdout))
Infof(logger, "message, %s", "formatted")
// Output:
// level=INFO source=example_wrap_test.go:43 msg="message, formatted"
}