add etcd

etcd/Note.md

@@ -0,0 +1,28 @@
+## etcd注意事项
+### go.mod
+- 第一步：
+`go mod init`
+- 第二步
+`go mod tidy`时，出现下述错误：
+  `/etcd imports
+  github.com/coreos/etcd/clientv3 tested by
+  github.com/coreos/etcd/clientv3.test imports
+  github.com/coreos/etcd/auth imports
+  github.com/coreos/etcd/mvcc/backend imports
+  github.com/coreos/bbolt: github.com/coreos/bbolt@v1.3.5: parsing go.mod:
+  module declares its path as: go.etcd.io/bbolt
+  but was required as: github.com/coreos/bbolt`
+
+### 解决方案
+- 修改go.mod
+`go mod edit -replace github.com/coreos/bbolt@v1.3.4=go.etcd.io/bbolt@v1.3.4`
+- 运行
+`go mod tidy`
+- 如果出现下述错误
+`imports
+  google.golang.org/grpc/naming: module google.golang.org/grpc@latest found (v1.32.0), but does not contain package google.golang.org/grpc/naming
+  `
+- 解决方案还是要修改go.mod
+`go mod edit -replace google.golang.org/grpc@v1.32.0=google.golang.org/grpc@v1.26.0`
+- 重新下载
+`go mod tidy`

etcd/conf/init.go

@@ -0,0 +1,32 @@
+package conf
+
+import (
+	"fmt"
+	"github.com/coreos/etcd/clientv3"
+	"time"
+)
+
+// etcd - conf
+
+var (
+	etcdCli *clientv3.Client
+)
+
+func Init(address []string) (err error) {
+	etcdCli, err = clientv3.New(clientv3.Config{
+		Endpoints:   address,
+		DialTimeout: 5 * time.Second,
+	})
+	if err != nil {
+		// handle error!
+		fmt.Printf("connect to etcd failed, err:%v\n", err)
+		return
+	}
+	fmt.Println("connect to etcd success")
+
+	return
+}
+
+func GetCli() *clientv3.Client {
+	return etcdCli
+}

etcd/get/get.go

@@ -0,0 +1,26 @@
+package get
+
+import (
+	"context"
+	"fmt"
+	"github.com/coreos/etcd/clientv3"
+	"time"
+)
+
+// etcd - client get示例
+// use etcd/clientv3
+
+func GetInfo(cli *clientv3.Client, key string) (err error) {
+	// get
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	resp, err := cli.Get(ctx, key)
+	cancel()
+	if err != nil {
+		fmt.Printf("get from etcd failed, err:%v\n", err)
+		return
+	}
+	for _, ev := range resp.Kvs {
+		fmt.Printf("%s:%s\n", ev.Key, ev.Value)
+	}
+	return
+}

etcd/go.mod

@@ -0,0 +1,47 @@
+module wing.com/magic-golang/etcd
+
+go 1.17
+
+replace github.com/coreos/bbolt v1.3.4 => go.etcd.io/bbolt v1.3.4
+
+replace (
+	google.golang.org/grpc v1.32.0 => google.golang.org/grpc v1.26.0
+	google.golang.org/grpc v1.43.0 => google.golang.org/grpc v1.26.0
+)
+
+require github.com/coreos/etcd v3.3.27+incompatible
+
+require (
+	github.com/coreos/bbolt v1.3.4 // indirect
+	github.com/coreos/go-semver v0.3.0 // indirect
+	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf // indirect
+	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect
+	github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
+	github.com/dustin/go-humanize v1.0.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/btree v1.0.1 // indirect
+	github.com/google/uuid v1.3.0 // indirect
+	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0 // indirect
+	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0 // indirect
+	github.com/jonboulle/clockwork v0.2.2 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/prometheus/client_golang v1.12.0 // indirect
+	github.com/soheilhy/cmux v0.1.5 // indirect
+	github.com/tmc/grpc-websocket-proxy v0.0.0-20220101234140-673ab2c3ae75 // indirect
+	github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	go.uber.org/multierr v1.6.0 // indirect
+	go.uber.org/zap v1.20.0 // indirect
+	golang.org/x/crypto v0.0.0-20220112180741-5e0467b6c7ce // indirect
+	golang.org/x/net v0.0.0-20220121210141-e204ce36a2ba // indirect
+	golang.org/x/sys v0.0.0-20220114195835-da31bd327af9 // indirect
+	golang.org/x/text v0.3.7 // indirect
+	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11 // indirect
+	google.golang.org/genproto v0.0.0-20220118154757-00ab72f36ad5 // indirect
+	google.golang.org/grpc v1.43.0 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	sigs.k8s.io/yaml v1.3.0 // indirect
+)

etcd/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"wing.com/magic-golang/etcd/conf"
+	"wing.com/magic-golang/etcd/get"
+	"wing.com/magic-golang/etcd/put"
+	"wing.com/magic-golang/etcd/watch"
+)
+
+// etcd 示例
+
+func main() {
+	// 1. 初始化etcd
+	err := conf.Init([]string{"127.0.0.1:2379"})
+	if err != nil {
+		fmt.Printf("Init etcd connection failed, error is %v.\n", err)
+		return
+	}
+
+	// 2. put操作
+	err = put.PutData(conf.GetCli(), "test", "hello")
+	if err != nil {
+		fmt.Printf("etcd put data failed, error is %v.\n", err)
+		return
+	}
+
+	// 3. get操作
+	err = get.GetInfo(conf.GetCli(), "test")
+	if err != nil {
+		fmt.Printf("etcd put data failed, error is %v.\n", err)
+		return
+	}
+
+	// 4. watch操作
+	watch.WatchKey(conf.GetCli(), "test")
+}

etcd/put/put.go

@@ -0,0 +1,22 @@
+package put
+
+import (
+	"context"
+	"fmt"
+	"github.com/coreos/etcd/clientv3"
+	"time"
+)
+
+// etcd - client put示例
+// use etcd/clientv3
+
+func PutData(cli *clientv3.Client, key, value string) (err error) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	_, err = cli.Put(ctx, key, value)
+	cancel()
+	if err != nil {
+		fmt.Printf("put to etcd failed, err:%v\n", err)
+		return
+	}
+	return
+}

etcd/watch/watch.go

@@ -0,0 +1,19 @@
+package watch
+
+import (
+	"context"
+	"fmt"
+	"github.com/coreos/etcd/clientv3"
+)
+
+// watch demo
+
+func WatchKey(cli *clientv3.Client, key string) {
+	// watch key change
+	rch := cli.Watch(context.Background(), key) // <-chan WatchResponse
+	for wresp := range rch {
+		for _, ev := range wresp.Events {
+			fmt.Printf("Type: %s Key:%s Value:%s\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
+		}
+	}
+}

fundamental/29-mapslice.go

@@ -2,7 +2,7 @@ package main
 
 import "fmt"
 
-func main()  {
+func main() {
 	mapSlice1()
 	mapSlice2()
 }
@@ -13,7 +13,7 @@ func mapSlice1() {
 	for index, value := range mapSlice {
 		fmt.Printf("index:%d value:%v\n", index, value)
 	}
-	fmt.Println("after init")
+	fmt.Println("after conf")
 	// 对切片中的map元素进行初始化
 	mapSlice[0] = make(map[string]string, 10)
 	mapSlice[0]["name"] = "小王子"
@@ -29,7 +29,7 @@ func mapSlice2() {
 	// 声明一个键为string，值为string切片的map
 	var sliceMap = make(map[string][]string, 3)
 	fmt.Println(sliceMap)
-	fmt.Println("after init")
+	fmt.Println("after conf")
 	// 键
 	key := "中国"
 	value, ok := sliceMap[key]

mysql/connect/connect.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - 连接示例

mysql/delete/delete.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - Delete删除示例

mysql/injection/injection.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 	"github.com/jmoiron/sqlx"
 )
 

mysql/insert/insert.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - Insert插入示例

mysql/prepare/prepare.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - 预处理

mysql/query/query.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - Query查询示例

mysql/sqlx/sqlx.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 	"github.com/jmoiron/sqlx"
 )
 

mysql/transaction/transaction.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - 事务示例

mysql/update/update.go

@@ -3,7 +3,7 @@ package main
 import (
 	"database/sql"
 	"fmt"
-	_ "github.com/go-sql-driver/mysql" // init()
+	_ "github.com/go-sql-driver/mysql" // conf()
 )
 
 // MySQL - Update更新示例

package/calcdemo.go

@@ -7,9 +7,9 @@ package main
     - 单行导入和多行导入
     - 导入包的时候可以指定别名
     - 导入包不想使用包内部的标识符，需要使用匿名导入
-    - 每个包导入的时候会自动执行一个名为`init()`的函数，它没有参数也没有返回值，不能手动调用
-    - `init()`的执行顺序：变量声明 > init() > main()
- */
+    - 每个包导入的时候会自动执行一个名为`conf()`的函数，它没有参数也没有返回值，不能手动调用
+    - `conf()`的执行顺序：变量声明 > conf() > main()
+*/
 
 import (
 	calc "code.wing.com/package/calc"
@@ -21,16 +21,16 @@ var x int = 20
 
 const pi = 3.1415926
 
-func init()  {
+func init() {
 	fmt.Printf("x = %v, pi = %v.\n", x, pi)
 }
 
-func main()  {
+func main() {
 	ret := calc.Add(50, 80)
 	/*
 		-------------------------Module cals---------------------
 		x = 20, pi = 3.1415926.
 		ret:  130
-	 */
+	*/
 	fmt.Println("ret: ", ret)
 }