From 2ea4545db77bfbfdb35cd63d42a592ad9a2673fc Mon Sep 17 00:00:00 2001
From: zionjxyu <zionjxyu@tencent.com>
Date: Mon, 16 May 2022 16:54:34 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=B0=81=E8=A3=85=E5=AD=97=E7=AC=A6?=
 =?UTF-8?q?=E4=B8=B2=E7=9B=B8=E5=85=B3=E5=87=BD=E6=95=B0=EF=BC=8Cetcd?=
 =?UTF-8?q?=E9=80=89=E4=B8=BE=E5=8A=9F=E8=83=BD?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 client/elect.go      | 71 ++++++++++++++++++++++++++++++++++++++++++
 constant/constant.go | 16 ++++++++--
 strings/string.go    | 73 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+), 2 deletions(-)
 create mode 100644 client/elect.go

diff --git a/client/elect.go b/client/elect.go
new file mode 100644
index 0000000..11db203
--- /dev/null
+++ b/client/elect.go
@@ -0,0 +1,71 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/client/v3/concurrency"
+)
+
+// Node 表示参与选举的节点。
+type Node struct {
+	elect     *concurrency.Election
+	prefix    string
+	session   *concurrency.Session
+	leaderKey string
+}
+
+// New 返回一个新创建的Node对象。
+func New(client *clientv3.Client, service string, leaderKey string, ttl int) (*Node, error) {
+	if client == nil {
+		return nil, fmt.Errorf("unexpected client, nil")
+	}
+
+	prefix := fmt.Sprintf("/m/elect/%s/", service)
+	session, err := concurrency.NewSession(client, concurrency.WithTTL(ttl))
+	if err != nil {
+		err = fmt.Errorf("new session error, %w", err)
+		return nil, err
+	}
+
+	elect := concurrency.NewElection(session, prefix)
+	return &Node{
+		elect:     elect,
+		prefix:    prefix,
+		session:   session,
+		leaderKey: leaderKey,
+	}, nil
+}
+
+// WaitToBeLeader 阻塞等待成为leader。
+func (n *Node) WaitToBeLeader(timeout time.Duration) error {
+	ctx := context.Background()
+	if timeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+		defer cancel()
+	}
+	return n.elect.Campaign(ctx, n.leaderKey)
+}
+
+// ObserverDone 将session断开、过期事件关联上回调事件。例如：leader断开服务器连接了，丢失leadership，则os.Exit(1)。
+func (n *Node) ObserverDone(cb func()) {
+	ch := n.session.Done()
+	for {
+		_, ok := <-ch
+		if !ok {
+			break
+		}
+	}
+
+	if cb != nil {
+		cb()
+	}
+}
+
+// Close 关闭内部session。
+func (n *Node) Close() error {
+	return n.session.Close()
+}
diff --git a/constant/constant.go b/constant/constant.go
index bde1217..34f2bf7 100644
--- a/constant/constant.go
+++ b/constant/constant.go
@@ -9,8 +9,20 @@ const (
 )
 
 const (
-	TrueFlag  = 1 // 真值
-	FalseFlag = 0 // 假值
+	// SepFlag 竖线分割符
+	SepFlag = "|"
+	// Comma 逗号
+	Comma = ","
+	// Hyphen 连字符
+	Hyphen = "-"
+	// Colon 冒号
+	Colon = ":"
+	// CommConfigPath 通用配置文件路径
+	CommConfigPath = "comm.yaml"
+	// TrueFlag 表示真的数值
+	TrueFlag = 1
+	// FalseFlag 表示假的数值
+	FalseFlag = 0
 )
 
 const (
diff --git a/strings/string.go b/strings/string.go
index 284175b..3baa594 100644
--- a/strings/string.go
+++ b/strings/string.go
@@ -7,10 +7,13 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"fmt"
+	"math"
 	"math/big"
 	"math/rand"
+	"reflect"
 	"strings"
 	"time"
+	"unsafe"
 )
 
 // NullStringToString nullstring转换成string
@@ -24,6 +27,15 @@ func NullStringToString(nullStrings []sql.NullString) []string {
 	return strings
 }
 
+// TrimSpaceSlice 将src中元素逐个调用strings.TrimSpace。
+func TrimSpaceSlice(src []string) []string {
+	dest := make([]string, 0, len(src))
+	for _, s := range src {
+		dest = append(dest, strings.TrimSpace(s))
+	}
+	return dest
+}
+
 // SplitString 返回以partition分割的字符串数组
 func SplitString(str, partition string) []string {
 	splitStr := strings.Split(str, partition)
@@ -83,3 +95,64 @@ func GetUniqueID() string {
 	uniqueID := fmt.Sprintf("%d", seqNo)
 	return uniqueID
 }
+
+// IsStringSliceEqual 返回两个字符串列表是否相等。都为nil，返回true。其中之一为nil，返回false。
+// 都不是nil，则长度内容顺序都一致才返回true。
+func IsStringSliceEqual(lh, rh []string) bool {
+	if lh == nil && rh == nil {
+		return true
+	}
+
+	if lh == nil || rh == nil {
+		return false
+	}
+
+	if len(lh) != len(rh) {
+		return false
+	}
+
+	for k, v := range lh {
+		if v != rh[k] {
+			return false
+		}
+	}
+	return true
+}
+
+// SplitSlice 将slice按长度batchSize分成多段
+// batchHandler 返回false，表示退出执行
+func SplitSlice(slice interface{}, batchSize int, batchHandler func(batch interface{}) bool) {
+	if batchHandler == nil {
+		return
+	}
+
+	rv := reflect.ValueOf(slice)
+	if rv.Kind() != reflect.Slice {
+		panic("argument not a slice")
+	}
+
+	blocks := int(math.Ceil(float64(rv.Len()) / float64(batchSize)))
+	for i := 0; i < blocks; i++ {
+		begin := i * batchSize
+		end := begin + batchSize
+		if end > rv.Len() {
+			end = rv.Len()
+		}
+
+		batch := rv.Slice(begin, end)
+		isContinue := batchHandler(batch.Interface())
+		if !isContinue {
+			break
+		}
+	}
+}
+
+// BytesToString copy-free的[]byte转string，但注意使用场景限制，不可滥用。
+func BytesToString(bytes []byte) string {
+	var s string
+	sliceHeader := (*reflect.SliceHeader)(unsafe.Pointer(&bytes))
+	stringHeader := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	stringHeader.Data = sliceHeader.Data
+	stringHeader.Len = sliceHeader.Len
+	return s
+}