/
string.go
107 lines (93 loc) · 2.71 KB
/
string.go
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// Copyright 2017 The Cockroach Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// 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 settings
import (
"sync/atomic"
"github.com/pkg/errors"
)
// StringSetting is the interface of a setting variable that will be
// updated automatically when the corresponding cluster-wide setting
// of type "string" is updated.
type StringSetting struct {
defaultValue string
v atomic.Value
validateFn func(string) error
}
var _ Setting = &StringSetting{}
func (s *StringSetting) String() string {
return s.Get()
}
// Typ returns the short (1 char) string denoting the type of setting.
func (*StringSetting) Typ() string {
return "s"
}
// Get retrieves the string value in the setting.
func (s *StringSetting) Get() string {
return s.v.Load().(string)
}
// Validate that a value conforms with the validation function.
func (s *StringSetting) Validate(v string) error {
if s.validateFn != nil {
if err := s.validateFn(v); err != nil {
return err
}
}
return nil
}
func (s *StringSetting) set(v string) error {
if err := s.Validate(v); err != nil {
return err
}
s.v.Store(v)
return nil
}
func (s *StringSetting) setToDefault() {
if err := s.set(s.defaultValue); err != nil {
panic(err)
}
}
// RegisterStringSetting defines a new setting with type string.
func RegisterStringSetting(key, desc string, defaultValue string) *StringSetting {
return RegisterValidatedStringSetting(key, desc, defaultValue, nil)
}
// RegisterValidatedStringSetting defines a new setting with type string with a
// validation function.
func RegisterValidatedStringSetting(
key, desc string, defaultValue string, validateFn func(string) error,
) *StringSetting {
if validateFn != nil {
if err := validateFn(defaultValue); err != nil {
panic(errors.Wrap(err, "invalid default"))
}
}
setting := &StringSetting{
defaultValue: defaultValue,
validateFn: validateFn,
}
register(key, desc, setting)
return setting
}
// TestingSetString returns a mock, unregistered string setting for testing. See
// TestingSetBool for more details.
func TestingSetString(s **StringSetting, v string) func() {
saved := *s
tmp := &StringSetting{}
if err := tmp.set(v); err != nil {
panic(err)
}
*s = tmp
return func() {
*s = saved
}
}