lager

README

lager

Lager is a logging library for go

[!NOTE]

This repository should be imported as code.cloudfoundry.org/lager/v3.

Docs

• Usage

Contributing

See the Contributing.md for more information on how to contribute.

Working Group Charter

This repository is maintained by App Runtime Platform under Diego area.

[!IMPORTANT]

Content in this file is managed by the CI task sync-readme and is generated by CI following a convention.

Documentation

Index

• Constants
• func DefaultValuePatterns() []string
• func NewHandler(l Logger) slog.Handler
• type Data
• type JSONRedacter
  • func NewJSONRedacter(keyPatterns []string, valuePatterns []string) (*JSONRedacter, error)
  • func (r JSONRedacter) Redact(data []byte) []byte
• type LogFormat
  • func (log LogFormat) ToJSON() []byte
• type LogLevel
  • func LogLevelFromString(s string) (LogLevel, error)
  • func (l LogLevel) String() string
• type Logger
  • func NewLogger(component string) Logger
• type ReconfigurableSink
  • func NewReconfigurableSink(sink Sink, initialMinLogLevel LogLevel) *ReconfigurableSink
  • func (sink *ReconfigurableSink) GetMinLevel() LogLevel
  • func (sink *ReconfigurableSink) Log(log LogFormat)
  • func (sink *ReconfigurableSink) SetMinLevel(level LogLevel)
• type Sink
  • func NewPrettySink(writer io.Writer, minLogLevel LogLevel) Sink
  • func NewRedactingSink(sink Sink, keyPatterns []string, valuePatterns []string) (Sink, error)
  • func NewSlogSink(l *slog.Logger) Sink
  • func NewTruncatingSink(sink Sink, maxDataStringLength int) Sink
  • func NewWriterSink(writer io.Writer, minLogLevel LogLevel) Sink

Constants

const (
	StackTraceBufferSize = 1024 * 100
	RequestIdHeader      = "X-Vcap-Request-Id"
)

Functions

func DefaultValuePatterns

func DefaultValuePatterns() []string

func NewHandler

func NewHandler(l Logger) slog.Handler

NewHandler wraps the logger as a slog.Handler The supplied Logger must be a lager.logger type created by lager.NewLogger(), otherwise it panics.

Note the following log level conversions:

slog.LevelDebug -> lager.DEBUG
slog.LevelError -> lager.ERROR
slog.LevelError -> lager.FATAL
default         -> lager.INFO

Types

type Data

type Data map[string]interface{}

type JSONRedacter

type JSONRedacter struct {
	// contains filtered or unexported fields
}

func NewJSONRedacter

func NewJSONRedacter(keyPatterns []string, valuePatterns []string) (*JSONRedacter, error)

func (JSONRedacter) Redact

func (r JSONRedacter) Redact(data []byte) []byte

type LogFormat

type LogFormat struct {
	Timestamp string   `json:"timestamp"`
	Source    string   `json:"source"`
	Message   string   `json:"message"`
	LogLevel  LogLevel `json:"log_level"`
	Data      Data     `json:"data"`
	Error     error    `json:"-"`
	// contains filtered or unexported fields
}

func (LogFormat) ToJSON

func (log LogFormat) ToJSON() []byte

type LogLevel

type LogLevel int

const (
	DEBUG LogLevel = iota
	INFO
	ERROR
	FATAL
)

func LogLevelFromString

func LogLevelFromString(s string) (LogLevel, error)

func (LogLevel) String

func (l LogLevel) String() string

type Logger

type Logger interface {
	RegisterSink(Sink)
	Session(task string, data ...Data) Logger
	SessionName() string
	Debug(action string, data ...Data)
	Info(action string, data ...Data)
	Error(action string, err error, data ...Data)
	Fatal(action string, err error, data ...Data)
	WithData(Data) Logger
	WithTraceInfo(*http.Request) Logger
}

func NewLogger

func NewLogger(component string) Logger

type ReconfigurableSink

type ReconfigurableSink struct {
	// contains filtered or unexported fields
}

func NewReconfigurableSink

func NewReconfigurableSink(sink Sink, initialMinLogLevel LogLevel) *ReconfigurableSink

func (*ReconfigurableSink) GetMinLevel

func (sink *ReconfigurableSink) GetMinLevel() LogLevel

func (*ReconfigurableSink) Log

func (sink *ReconfigurableSink) Log(log LogFormat)

func (*ReconfigurableSink) SetMinLevel

func (sink *ReconfigurableSink) SetMinLevel(level LogLevel)

type Sink

type Sink interface {
	//Log to the sink.  Best effort -- no need to worry about errors.
	Log(LogFormat)
}

A Sink represents a write destination for a Logger. It provides a thread-safe interface for writing logs

func NewPrettySink

func NewPrettySink(writer io.Writer, minLogLevel LogLevel) Sink

func NewRedactingSink

func NewRedactingSink(sink Sink, keyPatterns []string, valuePatterns []string) (Sink, error)

NewRedactingSink creates a sink that redacts sensitive information from the data field. The old behavior of NewRedactingWriterSink (which was removed in v2) can be obtained using the following code:

redactingSink, err := NewRedactingSink(
	NewWriterSink(writer, minLogLevel),
	keyPatterns,
	valuePatterns,
)

if err != nil {
	return nil, err
}

return NewReconfigurableSink(
	redactingSink,
	minLogLevel,
), nil

func NewSlogSink

func NewSlogSink(l *slog.Logger) Sink

NewSlogSink wraps a slog.Logger as a lager Sink This allows code using slog to integrate with code that uses lager Note the following log level conversions:

lager.DEBUG -> slog.LevelDebug
lager.ERROR -> slog.LevelError
lager.FATAL -> slog.LevelError
default     -> slog.LevelInfo

func NewTruncatingSink

func NewTruncatingSink(sink Sink, maxDataStringLength int) Sink

NewTruncatingSink returns a sink that truncates strings longer than the max data string length Example:

writerSink := lager.NewWriterSink(os.Stdout, lager.INFO)
sink := lager.NewTruncatingSink(testSink, 20)
logger := lager.NewLogger("test")
logger.RegisterSink(sink)
logger.Info("message", lager.Data{"A": strings.Repeat("a", 25)})

func NewWriterSink

func NewWriterSink(writer io.Writer, minLogLevel LogLevel) Sink