log

Documentation

Overview

Package log provides a wrapper around the slog package (might change implementation later). It provides an opinionated interface for logging structured data always with context.

Index

• Constants
• Variables
• func BindFlags(flags *pflag.FlagSet, cfg *Config)
• func Debug(ctx context.Context, msg string, attrs ...any)
• func DebugErr(ctx context.Context, msg string, err error, attrs ...any)
• func Error(ctx context.Context, msg string, err error, attrs ...any)
• func Hex7(key string, value []byte) slog.Attr
• func Info(ctx context.Context, msg string, attrs ...any)
• func InfoErr(ctx context.Context, msg string, err error, attrs ...any)
• func Init(ctx context.Context, cfg Config) (context.Context, error)
• func Warn(ctx context.Context, msg string, err error, attrs ...any)
• func WithCLILogger(ctx context.Context) context.Context
• func WithCtx(ctx context.Context, attrs ...any) context.Context
• func WithLogger(ctx context.Context, logger *slog.Logger) context.Context
• func WithNoopLogger(ctx context.Context) context.Context
• func WithSkip(ctx context.Context, skip int) context.Context
• func WithTestLogger(ctx context.Context, t *testing.T) context.Context
• type Config
  • func DefaultConfig() Config

Constants

const (
	FormatCLI     = "cli"
	FormatConsole = "console"
	FormatJSON    = "json"
	FormatLogfmt  = "logfmt"

	ColorForce   = "force"
	ColorDisable = "disable"
	ColorAuto    = "auto"
)

Variables

var (
	LevelDebug = strings.ToLower(slog.LevelDebug.String())
	LevelInfo  = strings.ToLower(slog.LevelInfo.String())
)

Functions

func BindFlags

func BindFlags(flags *pflag.FlagSet, cfg *Config)

BindFlags binds the standard flags to provide logging config at runtime.

func Debug

func Debug(ctx context.Context, msg string, attrs ...any)

Debug logs the message and attributes at default level.

func DebugErr

func DebugErr(ctx context.Context, msg string, err error, attrs ...any)

DebugErr logs the message and error and attributes at debug level. If err is nil, it will not be logged, but rather use Debug in that case.

func Error

func Error(ctx context.Context, msg string, err error, attrs ...any)

Error logs the message and error and arguments at error level. If err is nil, it will not be logged.

func Hex7

func Hex7(key string, value []byte) slog.Attr

Hex7 is a convenience function for a hex-encoded log attribute limited to first 7 chars for brevity. Note this is NOT 0x prefixed.

func Info

func Info(ctx context.Context, msg string, attrs ...any)

Info logs the message and attributes at info level.

func InfoErr

func InfoErr(ctx context.Context, msg string, err error, attrs ...any)

InfoErr logs the message and error and attributes at info level. If err is nil, it will not be logged, but rather use Info in that case.

func Init

func Init(ctx context.Context, cfg Config) (context.Context, error)

Init initializes the global logger with the given config. It also returns a copy of the context with the logger attached, see WithLogger. It returns an error if the config is invalid.

func Warn

func Warn(ctx context.Context, msg string, err error, attrs ...any)

Warn logs the message and error and attributes at warning level. If err is nil, it will not be logged.

func WithCLILogger

func WithCLILogger(ctx context.Context) context.Context

WithCLILogger returns a copy of the context with a cli logger.

func WithCtx

func WithCtx(ctx context.Context, attrs ...any) context.Context

WithCtx returns a copy of the context with which the logging attributes are associated. Usage:

ctx := log.WithCtx(ctx, "height", 1234)
...
log.Info(ctx, "Height processed") // Will contain attribute: height=1234

func WithLogger

func WithLogger(ctx context.Context, logger *slog.Logger) context.Context

WithLogger returns a copy of the context with which the logger is associated replacing the default global logger when logging with this context.

func WithNoopLogger

func WithNoopLogger(ctx context.Context) context.Context

WithNoopLogger returns a copy of the context with a noop logger which discards all logs.

func WithSkip

func WithSkip(ctx context.Context, skip int) context.Context

WithSkip returns a copy of the context with the skip value set. This is used to control the number of stack frames to skip when `source` is calculated.

func WithTestLogger

func WithTestLogger(ctx context.Context, t *testing.T) context.Context

WithTestLogger returns a copy of the context with a test logger. It ensures that logs are only logged when the `go test -v` is provided or if the test fails. It also ensures that parallel test logs are grouped separately. This is useful for e2e/test/* that runs many tests in parallel, and aims to avoid log flooding in the test output.

Types

type Config

type Config struct {
	Level  string
	Color  string
	Format string
	Writer io.Writer // Optional writer, defaults to os.Stderr.
}

func DefaultConfig

func DefaultConfig() Config

DefaultConfig returns a default config.