log

Documentation

Overview

Package log implements a library for logging.

This is separate from the standard logging package because logging may be a high-impact activity, and therefore we wanted to provide as much flexibility as possible in the underlying implementation.

Index

• func CopyStandardLogTo(l Level) error
• func Debugf(format string, v ...interface{})
• func Infof(format string, v ...interface{})
• func IsLogging(level Level) bool
• func SetLevel(newLevel Level)
• func SetTarget(target Emitter)
• func Stacks(all bool) []byte
• func Traceback(format string, v ...interface{})
• func TracebackAll(format string, v ...interface{})
• func Warningf(format string, v ...interface{})
• type BasicLogger
  • func Log() *BasicLogger
  • func (l *BasicLogger) Debugf(format string, v ...interface{})
  • func (l *BasicLogger) Infof(format string, v ...interface{})
  • func (l *BasicLogger) IsLogging(level Level) bool
  • func (l *BasicLogger) SetLevel(level Level)
  • func (l *BasicLogger) Warningf(format string, v ...interface{})
• type Emitter
• type GoogleEmitter
  • func (g GoogleEmitter) Emit(level Level, timestamp time.Time, format string, args ...interface{})
• type JSONEmitter
  • func (e JSONEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})
• type K8sJSONEmitter
  • func (e K8sJSONEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})
• type Level
  • func (lv Level) MarshalJSON() ([]byte, error)
  • func (l Level) String() string
  • func (lv *Level) UnmarshalJSON(b []byte) error
• type Logger
• type MultiEmitter
  • func (m MultiEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})
• type TestEmitter
  • func (t TestEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})
• type TestLogger
• type Writer
  • func (l *Writer) Emit(level Level, timestamp time.Time, format string, args ...interface{})
  • func (l *Writer) Write(data []byte) (int, error)

Functions

func CopyStandardLogTo

func CopyStandardLogTo(l Level) error

CopyStandardLogTo redirects the stdlib log package global output to the global logger for the specified level.

func Debugf

func Debugf(format string, v ...interface{})

Debugf logs to the global logger.

func Infof

func Infof(format string, v ...interface{})

Infof logs to the global logger.

func IsLogging

func IsLogging(level Level) bool

IsLogging returns whether the global logger is logging.

func SetLevel

func SetLevel(newLevel Level)

SetLevel sets the log level.

func SetTarget

func SetTarget(target Emitter)

SetTarget sets the log target.

This is not thread safe and shouldn't be called concurrently with any logging calls.

func Stacks

func Stacks(all bool) []byte

Stacks returns goroutine stacks, like panic.

func Traceback

func Traceback(format string, v ...interface{})

Traceback logs the given message and dumps a stacktrace of the current goroutine.

This will be print a traceback, tb, as Warningf(format+":\n%s", v..., tb).

func TracebackAll

func TracebackAll(format string, v ...interface{})

TracebackAll logs the given message and dumps a stacktrace of all goroutines.

This will be print a traceback, tb, as Warningf(format+":\n%s", v..., tb).

func Warningf

func Warningf(format string, v ...interface{})

Warningf logs to the global logger.

Types

type BasicLogger

type BasicLogger struct {
	Level
	Emitter
}

BasicLogger is the default implementation of Logger.

func Log

func Log() *BasicLogger

Log retrieves the global logger.

func (*BasicLogger) Debugf

func (l *BasicLogger) Debugf(format string, v ...interface{})

Debugf implements logger.Debugf.

func (*BasicLogger) Infof

func (l *BasicLogger) Infof(format string, v ...interface{})

Infof implements logger.Infof.

func (*BasicLogger) IsLogging

func (l *BasicLogger) IsLogging(level Level) bool

IsLogging implements logger.IsLogging.

func (*BasicLogger) SetLevel

func (l *BasicLogger) SetLevel(level Level)

SetLevel sets the logging level.

func (*BasicLogger) Warningf

func (l *BasicLogger) Warningf(format string, v ...interface{})

Warningf implements logger.Warningf.

type Emitter

type Emitter interface {
	// Emit emits the given log statement. This allows for control over the
	// timestamp used for logging.
	Emit(level Level, timestamp time.Time, format string, v ...interface{})
}

Emitter is the final destination for logs.

type GoogleEmitter

type GoogleEmitter struct {
	// Emitter is the underlying emitter.
	Emitter
}

GoogleEmitter is a wrapper that emits logs in a format compatible with package github.com/golang/glog.

func (GoogleEmitter) Emit

func (g GoogleEmitter) Emit(level Level, timestamp time.Time, format string, args ...interface{})

Emit emits the message, google-style.

type JSONEmitter

type JSONEmitter struct {
	Writer
}

JSONEmitter logs messages in json format.

func (JSONEmitter) Emit

func (e JSONEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})

Emit implements Emitter.Emit.

type K8sJSONEmitter

type K8sJSONEmitter struct {
	Writer
}

K8sJSONEmitter logs messages in json format that is compatible with Kubernetes fluent configuration.

func (K8sJSONEmitter) Emit

func (e K8sJSONEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})

Emit implements Emitter.Emit.

type Level

type Level uint32

Level is the log level.

const (
	// Warning indicates that output should always be emitted.
	Warning Level = iota

	// Info indicates that output should normally be emitted.
	Info

	// Debug indicates that output should not normally be emitted.
	Debug
)

The following levels are fixed, and can never be changed. Since some control RPCs allow for changing the level as an integer, it is only possible to add additional levels, and the existing one cannot be removed.

func (Level) MarshalJSON

func (lv Level) MarshalJSON() ([]byte, error)

MarshalJSON implements json.Marshaler.MarashalJSON.

func (Level) String

func (l Level) String() string

func (*Level) UnmarshalJSON

func (lv *Level) UnmarshalJSON(b []byte) error

UnmarshalJSON implements json.Unmarshaler.UnmarshalJSON. It can unmarshal from both string names and integers.

type Logger

type Logger interface {
	// Debugf logs a debug statement.
	Debugf(format string, v ...interface{})

	// Infof logs at an info level.
	Infof(format string, v ...interface{})

	// Warningf logs at a warning level.
	Warningf(format string, v ...interface{})

	// IsLogging returns true iff this level is being logged. This may be
	// used to short-circuit expensive operations for debugging calls.
	IsLogging(level Level) bool
}

Logger is a high-level logging interface. It is in fact, not used within the log package. Rather it is provided for others to provide contextual loggers that may append some addition information to log statement. BasicLogger satisfies this interface, and may be passed around as a Logger.

type MultiEmitter

type MultiEmitter []Emitter

MultiEmitter is an emitter that emits to multiple Emitters.

func (MultiEmitter) Emit

func (m MultiEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})

Emit emits to all emitters.

type TestEmitter

type TestEmitter struct {
	TestLogger
}

TestEmitter may be used for wrapping tests.

func (TestEmitter) Emit

func (t TestEmitter) Emit(level Level, timestamp time.Time, format string, v ...interface{})

Emit emits to the TestLogger.

type TestLogger

type TestLogger interface {
	Logf(format string, v ...interface{})
}

TestLogger is implemented by testing.T and testing.B.

type Writer

type Writer struct {
	// Next is where output is written.
	Next io.Writer
	// contains filtered or unexported fields
}

Writer writes the output to the given writer.

func (*Writer) Emit

func (l *Writer) Emit(level Level, timestamp time.Time, format string, args ...interface{})

Emit emits the message.

func (*Writer) Write

func (l *Writer) Write(data []byte) (int, error)

Write writes out the given bytes, handling non-blocking sockets.