Errors

errs provides structured errors. An error can carry a code, parameters, a cause, and stack information, making it suitable for route error rendering.

Install

go get github.com/duxweb/runa

errs belongs to the core module. Import it directly:

import "github.com/duxweb/runa/errs"

Create an error

err := errs.New("user not found",
    errs.Code("USER_NOT_FOUND"),
    errs.Params(errs.Map{"id": "1"}),
)

Wrap an error

if err != nil {
    return errs.Wrap(err)
}

Wrap converts a regular error into *errs.Error, preserves the cause, and records the call stack.

Read an error

if item := errs.As(err); item != nil {
    code := item.Code
    params := item.Params
    _ = code
    _ = params
}

Use with HTTP errors

route.Default().Get("/users/{id}", func(ctx *route.Context) error {
    return ctx.Error(404, errs.New("user not found", errs.Code("USER_NOT_FOUND")))
})

Route error rendering reads the error message, code, and parameters.

Common mistakes

Mixing error code and message

Use stable codes such as user.not_found; use messages for human-readable text.

Exposing underlying errors directly

Database, filesystem, and third-party errors should usually be logged and wrapped before returning to external callers.

Forgetting to keep the cause

Use errs.Wrap(err) when converting lower-level errors so logs can still show the original cause.

API quick reference

• errs.New(message, options...) creates a structured error.
• errs.Wrap(err) wraps a regular error.
• errs.As(err) converts to *errs.Error.
• errs.Code(code) sets the error code.
• errs.Params(map) sets parameters.
• errs.Attr(key, value) sets a single parameter.
• errs.Cause(err) sets the cause.