example_formatter_test.go

Documentation: github.com/go-logr/logr/funcr

     1  /*
     2  Copyright 2021 The logr Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package funcr_test
    18  
    19  import (
    20  	"fmt"
    21  	"strings"
    22  
    23  	"github.com/go-logr/logr"
    24  	"github.com/go-logr/logr/funcr"
    25  )
    26  
    27  // NewStdoutLogger returns a logr.Logger that prints to stdout.
    28  // It demonstrates how to implement a custom With* function which
    29  // controls whether INFO or ERROR are printed in front of the log
    30  // message.
    31  func NewStdoutLogger() logr.Logger {
    32  	l := &stdoutlogger{
    33  		Formatter: funcr.NewFormatter(funcr.Options{}),
    34  	}
    35  	return logr.New(l)
    36  }
    37  
    38  type stdoutlogger struct {
    39  	funcr.Formatter
    40  	logMsgType bool
    41  }
    42  
    43  func (l stdoutlogger) WithName(name string) logr.LogSink {
    44  	l.Formatter.AddName(name)
    45  	return &l
    46  }
    47  
    48  func (l stdoutlogger) WithValues(kvList ...any) logr.LogSink {
    49  	l.Formatter.AddValues(kvList)
    50  	return &l
    51  }
    52  
    53  func (l stdoutlogger) WithCallDepth(depth int) logr.LogSink {
    54  	l.Formatter.AddCallDepth(depth)
    55  	return &l
    56  }
    57  
    58  func (l stdoutlogger) Info(level int, msg string, kvList ...any) {
    59  	prefix, args := l.FormatInfo(level, msg, kvList)
    60  	l.write("INFO", prefix, args)
    61  }
    62  
    63  func (l stdoutlogger) Error(err error, msg string, kvList ...any) {
    64  	prefix, args := l.FormatError(err, msg, kvList)
    65  	l.write("ERROR", prefix, args)
    66  }
    67  
    68  func (l stdoutlogger) write(msgType, prefix, args string) {
    69  	var parts []string
    70  	if l.logMsgType {
    71  		parts = append(parts, msgType)
    72  	}
    73  	if prefix != "" {
    74  		parts = append(parts, prefix)
    75  	}
    76  	parts = append(parts, args)
    77  	fmt.Println(strings.Join(parts, ": "))
    78  }
    79  
    80  // WithLogMsgType returns a copy of the logger with new settings for
    81  // logging the message type. It returns the original logger if the
    82  // underlying LogSink is not a stdoutlogger.
    83  func WithLogMsgType(log logr.Logger, logMsgType bool) logr.Logger {
    84  	if l, ok := log.GetSink().(*stdoutlogger); ok {
    85  		clone := *l
    86  		clone.logMsgType = logMsgType
    87  		log = log.WithSink(&clone)
    88  	}
    89  	return log
    90  }
    91  
    92  // Assert conformance to the interfaces.
    93  var _ logr.LogSink = &stdoutlogger{}
    94  var _ logr.CallDepthLogSink = &stdoutlogger{}
    95  
    96  func ExampleFormatter() {
    97  	l := NewStdoutLogger()
    98  	l.Info("no message type")
    99  	WithLogMsgType(l, true).Info("with message type")
   100  	// Output:
   101  	// "level"=0 "msg"="no message type"
   102  	// INFO: "level"=0 "msg"="with message type"
   103  }
   104
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