slogerr

slogerr

Attach slog.Attr to an error and have them flatten across the wrap chain.

import (
    "errors"
    "log/slog"

    "github.com/flamingoosesoftwareinc/slogerr"
)

err := slogerr.New(errors.New("not found"), slog.String("resource", "visitor"))
err = slogerr.New(err, slog.String("id", "abc123"))

slog.Error("op failed", "err", err)
// level=ERROR msg="op failed" err.message="not found" err.id=abc123 err.resource=visitor

AnnotatedError implements error, Unwrap, and slog.LogValuer, so a handler renders the error message and accumulated attributes as a group without any call-site plumbing. Attributes are collected from every AnnotatedError in the chain, outermost first.

The group's message field comes from Error(). Top-level annotations named message are omitted from log output; Attrs() still returns them unchanged. Use a named group for contextual message attributes, such as context.message.

func (e *AnnotatedError) Error() string
func (e *AnnotatedError) Unwrap() error
func (e *AnnotatedError) Attrs() []slog.Attr
func (e *AnnotatedError) LogValue() slog.Value

License

MPL-2.0