Auto prepend caller when wrapping errors

internal/errwrap/wrap.go

@@ -0,0 +1,43 @@
+// Copyright 2024 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package errwrap
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"strings"
+)
+
+// Wrap wraps the given error using the given message while prepending
+// the name of the calling function, creating a poor man's stack trace
+func Wrap(err error, msg string) error {
+	pc := make([]uintptr, 15)
+	n := runtime.Callers(2, pc)
+	frames := runtime.CallersFrames(pc[:n])
+	frame, _ := frames.Next()
+	// strip full import paths and just use the package name
+	chunks := strings.Split(frame.Function, "/")
+	withCaller := fmt.Sprintf("%s: %s", chunks[len(chunks)-1], msg)
+	if err == nil {
+		return fmt.Errorf(withCaller)
+	}
+	return fmt.Errorf("%s: %w", withCaller, err)
+}
+
+// Unwrap receives an error and returns the last error in the chain of
+// wrapped errors
+func Unwrap(err error) error {
+	if err == nil {
+		return nil
+	}
+	for {
+		u := errors.Unwrap(err)
+		if u == nil {
+			break
+		}
+		err = u
+	}
+	return err
+}