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Package log

v0.0.9
Latest Go to latest
Published: Jun 24, 2020 | License: Apache-2.0 | Module: github.com/grailbio/base

Overview

Package log provides simple level logging. Log output is implemented by an outputter, which by default outputs to Go's logging package. Alternative implementations (e.g., vlog, glog) can provide their own outputter implementation so that logging output is unified.

The package can be used as a replacement for Go's standard logging package; the behavior of its toplevel functions are identical with the default configuration.

If the application wishes to configure logging levels by standard flags, it should call log.AddFlags before flag.Parse. log.AddFlags.

Note that this package is intended to bridge Go's standard log package with Vanadium's (vlog). As we transition away from vlog, we can simplify this package by removing the Outputter interface.

Index

Package Files

Constants

const (
	Ldate         = golog.Ldate         // the date in the local time zone: 2009/01/23
	Ltime         = golog.Ltime         // the time in the local time zone: 01:23:23
	Lmicroseconds = golog.Lmicroseconds // microsecond resolution: 01:23:23.123123.  assumes Ltime.
	Llongfile     = golog.Llongfile     // full file name and line number: /a/b/c/d.go:23
	Lshortfile    = golog.Lshortfile    // final file name element and line number: d.go:23. overrides Llongfile
	LUTC          = golog.LUTC          // if Ldate or Ltime is set, use UTC rather than the local time zone
	LstdFlags     = Ldate | Ltime       // initial values for the standard logger
)
const (
	// Off never outputs messages.
	Off = Level(-3)
	// Error outputs error messages.
	Error = Level(-2)
	// Info outputs informational messages. This is the standard
	// logging level.
	Info = Level(0)
	// Debug outputs messages intended for debugging and development,
	// not for regular users.
	Debug = Level(1)
)

func AddFlags

func AddFlags()

AddFlags adds a standard log level flags to the flag.CommandLine flag set.

func At

func At(level Level) bool

At returns whether the logger is currently logging at the provided level.

func Fatal

func Fatal(v ...interface{})

Fatal formats a message in the manner of fmt.Sprint, outputs it at the error level to the current outputter and then calls os.Exit(1).

func Fatalf

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

Fatalf formats a message in the manner of fmt.Sprintf, outputs it at the error level to the current outputter and then calls os.Exit(1).

func Output

func Output(calldepth int, level Level, s string) error

Output outputs a log message to the current outputter at the provided level and call depth.

func Outputf

func Outputf(out Outputter, level Level, format string, v ...interface{})

Outputf is formats a message using fmt.Sprintf and outputs it to the provided logger at the provided level.

func Panic

func Panic(v ...interface{})

Panic formats a message in the manner of fmt.Sprint, outputs it at the error level to the current outputter and then panics.

func Panicf

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

Panicf formats a message in the manner of fmt.Sprintf, outputs it at the error level to the current outputter and then panics.

func Print

func Print(v ...interface{})

Print formats a message in the manner of fmt.Sprint and outputs it at the Info level to the current outputter.

func Printf

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

Printf formats a message in the manner of fmt.Sprintf and outputs it at the Info level to the current outputter.

func SetFlags

func SetFlags(flag int)

SetFlags sets the output flags for the Go standard logger.

func SetLevel

func SetLevel(level Level)

SetLevel sets the log level for the Go standard logger. It should be called once at the beginning of a program's main.

func SetOutput

func SetOutput(w io.Writer)

SetOutput sets the output destination for the Go standard logger.

func SetPrefix

func SetPrefix(prefix string)

SetPrefix sets the output prefix for the Go standard logger.

type Level

type Level int

A Level is a log verbosity level. Increasing levels decrease in priority and (usually) increase in verbosity: if the outputter is logging at level L, then all messages with level M <= L are outputted.

func (Level) Print

func (l Level) Print(v ...interface{})

Print formats a message in the manner of fmt.Sprint and outputs it at level l to the current outputter.

func (Level) Printf

func (l Level) Printf(format string, v ...interface{})

Printf formats a message in the manner of fmt.Sprintf and outputs it at level l to the current outputter.

func (Level) Println

func (l Level) Println(v ...interface{})

Printkln formats a message in the manner of fmt.Sprintln and outputs it at level l to the current outputter.

func (Level) String

func (l Level) String() string

String returns the string representation of the level l.

type Logger

type Logger = golog.Logger

Logger is an alternative spelling of "log".Logger.

type Outputter

type Outputter interface {
	// Level returns the level at which the outputter is accepting
	// messages.
	Level() Level

	// Output writes the provided message to the outputter at the
	// provided calldepth and level. The message is dropped by
	// the outputter if it is not logging at the desired level.
	Output(calldepth int, level Level, s string) error
}

An Outputter provides a destination for leveled log output.

func GetOutputter

func GetOutputter() Outputter

GetOutputter returns the current outputter used by the log package.

func SetOutputter

func SetOutputter(newOut Outputter) Outputter

SetOutputter provides a new outputter for use in the log package. SetOutputter should not be called concurrently with any log output, and is thus suitable to be called only upon program initialization. SetOutputter returns the old outputter.

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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