slogsink.go

Documentation: github.com/go-logr/logr

     1  //go:build go1.21
     2  // +build go1.21
     3  
     4  /*
     5  Copyright 2023 The logr Authors.
     6  
     7  Licensed under the Apache License, Version 2.0 (the "License");
     8  you may not use this file except in compliance with the License.
     9  You may obtain a copy of the License at
    10  
    11      http://www.apache.org/licenses/LICENSE-2.0
    12  
    13  Unless required by applicable law or agreed to in writing, software
    14  distributed under the License is distributed on an "AS IS" BASIS,
    15  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    16  See the License for the specific language governing permissions and
    17  limitations under the License.
    18  */
    19  
    20  package logr
    21  
    22  import (
    23  	"context"
    24  	"log/slog"
    25  	"runtime"
    26  	"time"
    27  )
    28  
    29  var (
    30  	_ LogSink          = &slogSink{}
    31  	_ CallDepthLogSink = &slogSink{}
    32  	_ Underlier        = &slogSink{}
    33  )
    34  
    35  // Underlier is implemented by the LogSink returned by NewFromLogHandler.
    36  type Underlier interface {
    37  	// GetUnderlying returns the Handler used by the LogSink.
    38  	GetUnderlying() slog.Handler
    39  }
    40  
    41  const (
    42  	// nameKey is used to log the `WithName` values as an additional attribute.
    43  	nameKey = "logger"
    44  
    45  	// errKey is used to log the error parameter of Error as an additional attribute.
    46  	errKey = "err"
    47  )
    48  
    49  type slogSink struct {
    50  	callDepth int
    51  	name      string
    52  	handler   slog.Handler
    53  }
    54  
    55  func (l *slogSink) Init(info RuntimeInfo) {
    56  	l.callDepth = info.CallDepth
    57  }
    58  
    59  func (l *slogSink) GetUnderlying() slog.Handler {
    60  	return l.handler
    61  }
    62  
    63  func (l *slogSink) WithCallDepth(depth int) LogSink {
    64  	newLogger := *l
    65  	newLogger.callDepth += depth
    66  	return &newLogger
    67  }
    68  
    69  func (l *slogSink) Enabled(level int) bool {
    70  	return l.handler.Enabled(context.Background(), slog.Level(-level))
    71  }
    72  
    73  func (l *slogSink) Info(level int, msg string, kvList ...interface{}) {
    74  	l.log(nil, msg, slog.Level(-level), kvList...)
    75  }
    76  
    77  func (l *slogSink) Error(err error, msg string, kvList ...interface{}) {
    78  	l.log(err, msg, slog.LevelError, kvList...)
    79  }
    80  
    81  func (l *slogSink) log(err error, msg string, level slog.Level, kvList ...interface{}) {
    82  	var pcs [1]uintptr
    83  	// skip runtime.Callers, this function, Info/Error, and all helper functions above that.
    84  	runtime.Callers(3+l.callDepth, pcs[:])
    85  
    86  	record := slog.NewRecord(time.Now(), level, msg, pcs[0])
    87  	if l.name != "" {
    88  		record.AddAttrs(slog.String(nameKey, l.name))
    89  	}
    90  	if err != nil {
    91  		record.AddAttrs(slog.Any(errKey, err))
    92  	}
    93  	record.Add(kvList...)
    94  	_ = l.handler.Handle(context.Background(), record)
    95  }
    96  
    97  func (l slogSink) WithName(name string) LogSink {
    98  	if l.name != "" {
    99  		l.name += "/"
   100  	}
   101  	l.name += name
   102  	return &l
   103  }
   104  
   105  func (l slogSink) WithValues(kvList ...interface{}) LogSink {
   106  	l.handler = l.handler.WithAttrs(kvListToAttrs(kvList...))
   107  	return &l
   108  }
   109  
   110  func kvListToAttrs(kvList ...interface{}) []slog.Attr {
   111  	// We don't need the record itself, only its Add method.
   112  	record := slog.NewRecord(time.Time{}, 0, "", 0)
   113  	record.Add(kvList...)
   114  	attrs := make([]slog.Attr, 0, record.NumAttrs())
   115  	record.Attrs(func(attr slog.Attr) bool {
   116  		attrs = append(attrs, attr)
   117  		return true
   118  	})
   119  	return attrs
   120  }
   121
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