errorset.go

/*******************************************************************************
*
* Copyright 2023 SAP SE
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You should have received a copy of the License along with this
* program. If not, you may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*******************************************************************************/

package errext

import (
	"fmt"
	"os"
	"strings"

	"github.com/sapcc/go-bits/logg"
)

// ErrorSet replaces the "error" return value in functions that can return
// multiple errors. It provides convenience functions for easily adding errors
// to the set.
type ErrorSet []error

// Add adds the given error to the set if it is non-nil.
func (errs *ErrorSet) Add(err error) {
	if err != nil {
		*errs = append(*errs, err)
	}
}

// Addf is a shorthand for errs.Add(fmt.Errorf(...)).
func (errs *ErrorSet) Addf(msg string, args ...any) {
	*errs = append(*errs, fmt.Errorf(msg, args...))
}

// Append adds all errors from the `other` ErrorSet to this one.
func (errs *ErrorSet) Append(other ErrorSet) {
	*errs = append(*errs, other...)
}

// IsEmpty returns true if no errors are in the set.
func (errs ErrorSet) IsEmpty() bool {
	return len(errs) == 0
}

// Join joins the messages of all errors in this set using the provided separator.
// If the set is empty, an empty string is returned.
func (errs ErrorSet) Join(sep string) string {
	msgs := make([]string, len(errs))
	for idx, err := range errs {
		msgs[idx] = err.Error()
	}
	return strings.Join(msgs, sep)
}

// LogFatalIfError reports all errors in this set on level FATAL, thus dying if
// there are any errors.
func (errs ErrorSet) LogFatalIfError() {
	hasErrors := false
	for _, err := range errs {
		hasErrors = true
		logg.Other("FATAL", err.Error())
	}
	if hasErrors {
		os.Exit(1)
	}
}