flash

README

flash

Creates an opinionated zap logger.

Adapting it as a logr.Logger instance

Shall you at some point need to pass a logr.Logger instance in your code, e.g. while writing code that uses the Kubernetes client library etc., you can use go-logr/zapr to wrap the logger, as follows:

package main

import (
	"github.com/go-logr/zapr"
	"github.com/postfinance/flash"
)

func main() {
	l := flash.New()
	z := zapr.NewLogger(l.Desugar())
        z.V(0).Info("I'm a zap logger complying with logr.Logger interface !")
}

Logger Without Stacktrace

New Logger

Debug / Info / Error

2020-10-09T09:29:06.363+0200    INFO    test/main.go:26 message {"StackTrace": "off", "debug": false}
2020-10-09T09:29:06.364+0200    ERROR   test/main.go:27 message {"StackTrace": "off", "debug": false}

Enable Debug

Debug / Info / Error

2020-10-09T09:29:06.364+0200    DEBUG   test/main.go:33 message {"StackTrace": "off", "debug": true}
2020-10-09T09:29:06.364+0200    INFO    test/main.go:34 message {"StackTrace": "off", "debug": true}
2020-10-09T09:29:06.364+0200    ERROR   test/main.go:35 message {"StackTrace": "off", "debug": true}

Disable Debug

Debug / Info / Error

2020-10-09T09:29:06.364+0200    INFO    test/main.go:42 message {"StackTrace": "off", "debug": false}
2020-10-09T09:29:06.364+0200    ERROR   test/main.go:43 message {"StackTrace": "off", "debug": false}

Fatal

2020-10-09T09:29:06.364+0200    FATAL   test/main.go:47 message {"StackTrace": "on", "debug": false}
exit status 1

Logger With Stacktrace

New Logger

Debug / Info / Error

2020-10-09T09:29:11.889+0200    INFO    test/main.go:26 message {"StackTrace": "off", "debug": false}
2020-10-09T09:29:11.889+0200    ERROR   test/main.go:27 message {"StackTrace": "off", "debug": false}

Enable Debug (Stacktrace on Error or above)

Debug / Info / Error

2020-10-09T09:29:11.889+0200    DEBUG   test/main.go:33 message {"StackTrace": "off", "debug": true}
2020-10-09T09:29:11.889+0200    INFO    test/main.go:34 message {"StackTrace": "off", "debug": true}
2020-10-09T09:29:11.889+0200    ERROR   test/main.go:35 message {"StackTrace": "off", "debug": true}
main.main
        /export/home/sauterm/tmp/test/main.go:35
runtime.main
        /export/home/sauterm/.gimme/versions/go1.15.2.linux.amd64/src/runtime/proc.go:204

Disable Debug (Stacktrace on Fatal only)

Debug / Info / Error

2020-10-09T09:29:11.889+0200    INFO    test/main.go:42 message {"StackTrace": "off", "debug": false}
2020-10-09T09:29:11.889+0200    ERROR   test/main.go:43 message {"StackTrace": "off", "debug": false}

Fatal

2020-10-09T09:29:11.889+0200    FATAL   test/main.go:47 message {"StackTrace": "on", "debug": false}
main.main
        /export/home/sauterm/tmp/test/main.go:47
runtime.main
        /export/home/sauterm/.gimme/versions/go1.15.2.linux.amd64/src/runtime/proc.go:204
exit status 1

Documentation

Overview

Package flash configures an opinionated zap logger.

Index

• type EncoderType
• type FileConfig
• type Logger
  • func New(opts ...Option) *Logger
  • func (l *Logger) Disable()
  • func (l *Logger) Get() *zap.SugaredLogger
  • func (l *Logger) SetDebug(d bool)
  • func (l *Logger) SetLevel(level zapcore.Level)
• type Option
  • func WithColor() Option
  • func WithDebug(debug bool) Option
  • func WithEncoder(e EncoderType) Option
  • func WithFile(cfg FileConfig) Option
  • func WithPrometheus(appName string, registry prometheus.Registerer) Option
  • func WithSinks(sinks ...string) Option
  • func WithStacktrace() Option
  • func WithoutCaller() Option
  • func WithoutTimestamps() Option

Types

type EncoderType

type EncoderType int

EncoderType is a zap encoder.

const (
	Console EncoderType = iota
	JSON
	LogFmt
)

All supported encoder types.

type FileConfig

type FileConfig struct {
	Path       string
	MaxSize    int
	MaxBackups int
	MaxAge     int
	Compress   bool
}

FileConfig holds the configuration for logging into a file. The size is in Megabytes and MaxAge is in days. If compress is true the rotated files are compressed.

type Logger

type Logger struct {
	*zap.SugaredLogger
	// contains filtered or unexported fields
}

Logger is the flash logger which embeds a `zap.SugaredLogger`.

func New

func New(opts ...Option) *Logger

New creates a new Logger. If no options are specified, stacktraces and color output are disabled and the confgured level is `InfoLevel`.

func (*Logger) Disable

func (l *Logger) Disable()

Disable disables (nearly) all output. Only `FatalLevel` errors are logged.

func (*Logger) Get

func (l *Logger) Get() *zap.SugaredLogger

Get returns the embedded zap.Logger

func (*Logger) SetDebug

func (l *Logger) SetDebug(d bool)

SetDebug enables or disables `DebugLevel`.

func (*Logger) SetLevel

func (l *Logger) SetLevel(level zapcore.Level)

SetLevel sets the chosen level. If stacktraces are enabled, it adjusts stacktrace levels accordingly.

type Option

type Option func(c *config)

Option configures zap.Config.

func WithColor

func WithColor() Option

WithColor enables color output.

func WithDebug

func WithDebug(debug bool) Option

WithDebug enables or disables `DebugLevel`.

func WithEncoder

func WithEncoder(e EncoderType) Option

WithEncoder configures the zap encoder.

func WithFile

func WithFile(cfg FileConfig) Option

WithFile configures the logger to log output into a file.

func WithPrometheus

func WithPrometheus(appName string, registry prometheus.Registerer) Option

WithPrometheus registers a prometheus log message counter.

The created metrics are of the form:

<appName>_log_messages_total{level="info"} 4

If appName is an empty string `flash` is used.

func WithSinks

func WithSinks(sinks ...string) Option

WithSinks changes the default zap `stderr` sink.

func WithStacktrace

func WithStacktrace() Option

WithStacktrace completely enables automatic stacktrace capturing. Stacktraces are captured on `ErrorLevel` and above when in debug mode. When not in debug mode, only `FatalLevel` messages contain stacktraces.

func WithoutCaller

func WithoutCaller() Option

WithoutCaller stops annotating logs with the calling function's file name and line number.

func WithoutTimestamps

func WithoutTimestamps() Option

WithoutTimestamps configures the logger to log without timestamps.