logger

Documentation

Overview

Package logger provides helper functions that can be used in combination with slog to increase functionality or make working with slog easier.

1. Logging in unit tests

To log in unit tests you can create a new slog logger that uses logger.testWriter as its writer. This can be constructed by creating a logger like this: `logger.NewTest(t)`.

2. Creating a new logger with an increased log level based on another logger

You can create a new logger with a new log level by creating a new slog.Logger with the LevelHandler in this package and passing the handler of the other logger. As an example, if you have a slog.Logger named `log` you can create a new logger with an increased log level (here slog.LevelWarn) like this:

slog.New(logger.NewLevelHandler(slog.LevelWarn, log.Handler()))

Index

• Constants
• func GetClientStreamInterceptor(l *slog.Logger) grpc.DialOption
• func GetClientUnaryInterceptor(l *slog.Logger) grpc.DialOption
• func GetServerStreamInterceptor(l *slog.Logger) grpc.ServerOption
• func GetServerUnaryInterceptor(l *slog.Logger) grpc.ServerOption
• func NewJSONLogger(level slog.Level) *slog.Logger
• func NewTest(t *testing.T) *slog.Logger
• func NewTextLogger(level slog.Level) *slog.Logger
• func ReplaceGRPCLogger(l *slog.Logger)
• func VerbosityFromInt(verbosity int) slog.Level
• type LevelHandler
  • func NewLevelHandler(level slog.Leveler, h slog.Handler) *LevelHandler
  • func (h *LevelHandler) Enabled(_ context.Context, level slog.Level) bool
  • func (h *LevelHandler) Handle(ctx context.Context, r slog.Record) error
  • func (h *LevelHandler) Handler() slog.Handler
  • func (h *LevelHandler) WithAttrs(attrs []slog.Attr) slog.Handler
  • func (h *LevelHandler) WithGroup(name string) slog.Handler

Constants

const CmdLineVerbosityDescription = "log verbosity: Use -1 for debug information, 0 for info, 1 for warn, 2 for error"

CmdLineVerbosityDescription explains numeric log levels.

Functions

func GetClientStreamInterceptor

func GetClientStreamInterceptor(l *slog.Logger) grpc.DialOption

GetClientStreamInterceptor returns a gRPC client option for intercepting stream gRPC logs.

func GetClientUnaryInterceptor

func GetClientUnaryInterceptor(l *slog.Logger) grpc.DialOption

GetClientUnaryInterceptor returns a gRPC client option for intercepting unary gRPC logs.

func GetServerStreamInterceptor

func GetServerStreamInterceptor(l *slog.Logger) grpc.ServerOption

GetServerStreamInterceptor returns a gRPC server option for intercepting streaming gRPC logs.

func GetServerUnaryInterceptor

func GetServerUnaryInterceptor(l *slog.Logger) grpc.ServerOption

GetServerUnaryInterceptor returns a gRPC server option for intercepting unary gRPC logs.

func NewJSONLogger

func NewJSONLogger(level slog.Level) *slog.Logger

NewJSONLogger creates a new slog.Logger that writes JSON formatted log messages to os.Stderr.

func NewTest

func NewTest(t *testing.T) *slog.Logger

NewTest creates a new slog.Logger that writes to a testing.T.

func NewTextLogger

func NewTextLogger(level slog.Level) *slog.Logger

NewTextLogger creates a new slog.Logger that writes text formatted log messages to os.Stderr.

func ReplaceGRPCLogger

func ReplaceGRPCLogger(l *slog.Logger)

ReplaceGRPCLogger replaces grpc's internal logger with the given logger.

func VerbosityFromInt

func VerbosityFromInt(verbosity int) slog.Level

VerbosityFromInt converts a verbosity level from an integer to a slog.Level.

Types

type LevelHandler

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

LevelHandler wraps a Handler with an Enabled method that returns false for levels below a minimum.

func NewLevelHandler

func NewLevelHandler(level slog.Leveler, h slog.Handler) *LevelHandler

NewLevelHandler returns a LevelHandler with the given level. All methods except Enabled delegate to h.

func (*LevelHandler) Enabled

func (h *LevelHandler) Enabled(_ context.Context, level slog.Level) bool

Enabled implements Handler.Enabled by reporting whether level is at least as large as h's level.

func (*LevelHandler) Handle

func (h *LevelHandler) Handle(ctx context.Context, r slog.Record) error

Handle implements Handler.Handle.

func (*LevelHandler) Handler

func (h *LevelHandler) Handler() slog.Handler

Handler returns the Handler wrapped by h.

func (*LevelHandler) WithAttrs

func (h *LevelHandler) WithAttrs(attrs []slog.Attr) slog.Handler

WithAttrs implements Handler.WithAttrs.

func (*LevelHandler) WithGroup

func (h *LevelHandler) WithGroup(name string) slog.Handler

WithGroup implements Handler.WithGroup.