forked from pingcap/tidb
/
config_util.go
134 lines (122 loc) · 3.93 KB
/
config_util.go
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// Copyright 2020 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package config
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"reflect"
"time"
"github.com/BurntSushi/toml"
"github.com/pingcap/errors"
)
// CloneConf deeply clones this config.
func CloneConf(conf *Config) (*Config, error) {
content, err := json.Marshal(conf)
if err != nil {
return nil, err
}
var clonedConf Config
if err := json.Unmarshal(content, &clonedConf); err != nil {
return nil, err
}
return &clonedConf, nil
}
var (
// dynamicConfigItems contains all config items that can be changed during runtime.
dynamicConfigItems = map[string]struct{}{
"Performance.MaxProcs": {},
"Performance.MaxMemory": {},
"Performance.CrossJoin": {},
"Performance.FeedbackProbability": {},
"Performance.QueryFeedbackLimit": {},
"Performance.PseudoEstimateRatio": {},
"Performance.StmtCountLimit": {},
"Performance.TCPKeepAlive": {},
"OOMAction": {},
"MemQuotaQuery": {},
"TiKVClient.StoreLimit": {},
"Log.Level": {},
"Log.SlowThreshold": {},
"Log.QueryLogMaxLen": {},
"Log.ExpensiveThreshold": {},
"CheckMb4ValueInUTF8": {},
"EnableStreaming": {},
"TxnLocalLatches.Capacity": {},
"CompatibleKillQuery": {},
"TreatOldVersionUTF8AsUTF8MB4": {},
"OpenTracing.Enable": {},
"PreparedPlanCache.Enabled": {},
}
)
// MergeConfigItems overwrites the dynamic config items and leaves the other items unchanged.
func MergeConfigItems(dstConf, newConf *Config) (acceptedItems, rejectedItems []string) {
return mergeConfigItems(reflect.ValueOf(dstConf), reflect.ValueOf(newConf), "")
}
func mergeConfigItems(dstConf, newConf reflect.Value, fieldPath string) (acceptedItems, rejectedItems []string) {
t := dstConf.Type()
if t.Kind() == reflect.Ptr {
t = t.Elem()
dstConf = dstConf.Elem()
newConf = newConf.Elem()
}
if t.Kind() != reflect.Struct {
if reflect.DeepEqual(dstConf.Interface(), newConf.Interface()) {
return
}
if _, ok := dynamicConfigItems[fieldPath]; ok {
dstConf.Set(newConf)
return []string{fieldPath}, nil
}
return nil, []string{fieldPath}
}
for i := 0; i < t.NumField(); i++ {
fieldName := t.Field(i).Name
if fieldPath != "" {
fieldName = fieldPath + "." + fieldName
}
as, rs := mergeConfigItems(dstConf.Field(i), newConf.Field(i), fieldName)
acceptedItems = append(acceptedItems, as...)
rejectedItems = append(rejectedItems, rs...)
}
return
}
func atomicWriteConfig(c *Config, confPath string) (err error) {
content, err := encodeConfig(c)
if err != nil {
return err
}
tmpConfPath := filepath.Join(os.TempDir(), fmt.Sprintf("tmp_conf_%v.toml", time.Now().Format("20060102150405")))
if err := ioutil.WriteFile(tmpConfPath, []byte(content), 0666); err != nil {
return errors.Trace(err)
}
return errors.Trace(os.Rename(tmpConfPath, confPath))
}
// ConfReloadFunc is used to reload the config to make it work.
type ConfReloadFunc func(oldConf, newConf *Config)
func encodeConfig(conf *Config) (string, error) {
confBuf := bytes.NewBuffer(nil)
te := toml.NewEncoder(confBuf)
if err := te.Encode(conf); err != nil {
return "", errors.New("encode config error=" + err.Error())
}
return confBuf.String(), nil
}
func decodeConfig(content string) (*Config, error) {
c := new(Config)
_, err := toml.Decode(content, c)
return c, err
}