git.sr.ht/~pingoo/stdx@v0.0.0-20240218134121-094174641f6e/cron/logger.go (about)

     1  package cron
     2  
     3  import (
     4  	"io/ioutil"
     5  	"log"
     6  	"os"
     7  	"strings"
     8  	"time"
     9  )
    10  
    11  // DefaultLogger is used by Cron if none is specified.
    12  var DefaultLogger Logger = PrintfLogger(log.New(os.Stdout, "cron: ", log.LstdFlags))
    13  
    14  // DiscardLogger can be used by callers to discard all log messages.
    15  var DiscardLogger Logger = PrintfLogger(log.New(ioutil.Discard, "", 0))
    16  
    17  // Logger is the interface used in this package for logging, so that any backend
    18  // can be plugged in. It is a subset of the github.com/go-logr/logr interface.
    19  type Logger interface {
    20  	// Info logs routine messages about cron's operation.
    21  	Info(msg string, keysAndValues ...interface{})
    22  	// Error logs an error condition.
    23  	Error(err error, msg string, keysAndValues ...interface{})
    24  }
    25  
    26  // PrintfLogger wraps a Printf-based logger (such as the standard library "log")
    27  // into an implementation of the Logger interface which logs errors only.
    28  func PrintfLogger(l interface{ Printf(string, ...interface{}) }) Logger {
    29  	return printfLogger{l, false}
    30  }
    31  
    32  // VerbosePrintfLogger wraps a Printf-based logger (such as the standard library
    33  // "log") into an implementation of the Logger interface which logs everything.
    34  func VerbosePrintfLogger(l interface{ Printf(string, ...interface{}) }) Logger {
    35  	return printfLogger{l, true}
    36  }
    37  
    38  type printfLogger struct {
    39  	logger  interface{ Printf(string, ...interface{}) }
    40  	logInfo bool
    41  }
    42  
    43  func (pl printfLogger) Info(msg string, keysAndValues ...interface{}) {
    44  	if pl.logInfo {
    45  		keysAndValues = formatTimes(keysAndValues)
    46  		pl.logger.Printf(
    47  			formatString(len(keysAndValues)),
    48  			append([]interface{}{msg}, keysAndValues...)...)
    49  	}
    50  }
    51  
    52  func (pl printfLogger) Error(err error, msg string, keysAndValues ...interface{}) {
    53  	keysAndValues = formatTimes(keysAndValues)
    54  	pl.logger.Printf(
    55  		formatString(len(keysAndValues)+2),
    56  		append([]interface{}{msg, "error", err}, keysAndValues...)...)
    57  }
    58  
    59  // formatString returns a logfmt-like format string for the number of
    60  // key/values.
    61  func formatString(numKeysAndValues int) string {
    62  	var sb strings.Builder
    63  	sb.WriteString("%s")
    64  	if numKeysAndValues > 0 {
    65  		sb.WriteString(", ")
    66  	}
    67  	for i := 0; i < numKeysAndValues/2; i++ {
    68  		if i > 0 {
    69  			sb.WriteString(", ")
    70  		}
    71  		sb.WriteString("%v=%v")
    72  	}
    73  	return sb.String()
    74  }
    75  
    76  // formatTimes formats any time.Time values as RFC3339.
    77  func formatTimes(keysAndValues []interface{}) []interface{} {
    78  	var formattedArgs []interface{}
    79  	for _, arg := range keysAndValues {
    80  		if t, ok := arg.(time.Time); ok {
    81  			arg = t.Format(time.RFC3339)
    82  		}
    83  		formattedArgs = append(formattedArgs, arg)
    84  	}
    85  	return formattedArgs
    86  }