log

README

Log

Provides a high level abstraction for structured logging.

Interface

This is an interface for structured logging. It provides a simple way of creating logs messages with metadata with the ability to send to multiple outputs.

// A structure log interface which can
// output to multiple backends.
type Log interface {
	Init(opts ...Option) error
	Options() Options
	Logger
	String() string
}

type Logger interface {
	// Logger interface
	Debug(args ...interface{})
	Info(args ...interface{})
	Error(args ...interface{})
	Fatal(args ...interface{})
	// Formatted logger
	Debugf(format string, args ...interface{})
	Infof(format string, args ...interface{})
	Errorf(format string, args ...interface{})
	Fatalf(format string, args ...interface{})
	// Specify your own levels
	Log(l Level, args ...interface{})
	Logf(l Level, format string, args ...interface{})
	// Returns with extra fields
	WithFields(f Fields) Logger
}

// Event represents a single log event
type Event struct {
	Level     Level  `json:"level"`
	Fields    Fields `json:"fields"`
	Timestamp int64  `json:"timestamp"`
	Message   string `json:"message"`
}

// An output represents a file, indexer, syslog, etc
type Output interface {
	// Send an event
	Send(*Event) error
	// Flush any buffered events
	Flush() error
	// Discard the output
	Close() error
	// Name of output
	String() string
}

func NewLog(opts ...Option) Log {
	return newOS(opts...)
}

Supported Backends

• File

Documentation

Overview

Package log is an interface for structured logging.

Index

• Variables
• func NewContext(ctx context.Context, c Log) context.Context
• type Event
  • func (e *Event) MarshalJSON() ([]byte, error)
• type Fields
• type Level
• type Log
  • func FromContext(ctx context.Context) (Log, bool)
  • func NewLog(opts ...Option) Log
• type Logger
• type Option
  • func WithFields(f Fields) Option
  • func WithLevel(l Level) Option
  • func WithOutput(ot Output) Option
• type Options
• type Output
  • func NewOutput(opts ...OutputOption) Output
• type OutputOption
  • func OutputName(name string) OutputOption
• type OutputOptions

Variables

var (
	DefaultLevel      Level = InfoLevel
	DefaultOutputName       = "log.json"

	Levels = map[Level]string{
		DebugLevel: "debug",
		InfoLevel:  "info",
		WarnLevel:  "warn",
		ErrorLevel: "error",
		FatalLevel: "fatal",
	}
)

Functions

func NewContext

func NewContext(ctx context.Context, c Log) context.Context

Types

type Event

type Event struct {
	Level     Level  `json:"level"`
	Fields    Fields `json:"fields"`
	Timestamp int64  `json:"timestamp"`
	Message   string `json:"message"`
}

Event represents a single log event

func (*Event) MarshalJSON

func (e *Event) MarshalJSON() ([]byte, error)

type Fields

type Fields map[string]string

type Level

type Level int32

const (
	DebugLevel Level = 0
	InfoLevel  Level = 1
	WarnLevel  Level = 2
	ErrorLevel Level = 3
	FatalLevel Level = 4
)

type Log

type Log interface {
	Init(opts ...Option) error
	Options() Options
	Logger
	String() string
}

A structure log interface which can output to multiple backends.

func FromContext

func FromContext(ctx context.Context) (Log, bool)

func NewLog

func NewLog(opts ...Option) Log

type Logger

type Logger interface {
	// Logger interface
	Debug(args ...interface{})
	Info(args ...interface{})
	Error(args ...interface{})
	Fatal(args ...interface{})
	// Formatted logger
	Debugf(format string, args ...interface{})
	Infof(format string, args ...interface{})
	Errorf(format string, args ...interface{})
	Fatalf(format string, args ...interface{})
	// Specify your own levels
	Log(l Level, args ...interface{})
	Logf(l Level, format string, args ...interface{})
	// Returns with extra fields
	WithFields(f Fields) Logger
}

type Option

type Option func(o *Options)

func WithFields

func WithFields(f Fields) Option

func WithLevel

func WithLevel(l Level) Option

func WithOutput

func WithOutput(ot Output) Option

type Options

type Options struct {
	// the current log level
	Level Level
	// the output to write to
	Outputs []Output
	// include a set of fields
	Fields Fields

	// Alternative options
	Context context.Context
}

type Output

type Output interface {
	// Send an event
	Send(*Event) error
	// Flush any buffered events
	Flush() error
	// Discard the output
	Close() error
	// Name of output
	String() string
}

An output represents a file, indexer, syslog, etc

func NewOutput

func NewOutput(opts ...OutputOption) Output

type OutputOption

type OutputOption func(o *OutputOptions)

func OutputName

func OutputName(name string) OutputOption

type OutputOptions

type OutputOptions struct {
	// filepath, url, etc
	Name string
}