Middleware wrapper for log output
package Services
import (
"context"
"fmt"
"github.com/go-kit/kit/endpoint"
"github.com/go-kit/kit/log"
"golang.org/x/time/rate"
"gomicro/utils"
"strconv"
)
type UserRequest struct { //封装User请求结构体
Uid int `json:"uid"`
Method string
}
type UserResponse struct {
Result string `json:"result"`
}
//日志中间件,每一个service都应该有自己的日志中间件
func UserServiceLogMiddleware(logger log.Logger) endpoint.Middleware { //Middleware type Middleware func(Endpoint) Endpoint
return func(next endpoint.Endpoint) endpoint.Endpoint { //Endpoint type Endpoint func(ctx context.Context, request interface{}) (response interface{}, err error)
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
r := request.(UserRequest) //通过类型断言获取请求结构体
logger.Log("method", r.Method, "event", "get user", "userid", r.Uid)
return next(ctx, request)
}
}
}
//加入限流功能中间件
func RateLimit(limit *rate.Limiter) endpoint.Middleware { //Middleware type Middleware func(Endpoint) Endpoint
return func(next endpoint.Endpoint) endpoint.Endpoint { //Endpoint type Endpoint func(ctx context.Context, request interface{}) (response interface{}, err error)
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
if !limit.Allow() {
return nil, utils.NewMyError(429, "toot many request")
}
return next(ctx, request)
}
}
}
func GenUserEnPoint(userService IUserService) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
r := request.(UserRequest) //通过类型断言获取请求结构体
result := "nothings"
if r.Method == "GET" {
result = userService.GetName(r.Uid) + strconv.Itoa(utils.ServicePort)
} else if r.Method == "DELETE" {
err := userService.DelUser(r.Uid)
if err != nil {
result = err.Error()
} else {
result = fmt.Sprintf("userid为%d的用户已删除", r.Uid)
}
}
return UserResponse{Result: result}, nil
}
}
Call log Middleware
package main
import (
"flag"
"fmt"
kitlog "github.com/go-kit/kit/log"
httptransport "github.com/go-kit/kit/transport/http"
mymux "github.com/gorilla/mux"
"golang.org/x/time/rate"
"gomicro/Services"
"gomicro/utils"
"log"
"net/http"
"os"
"os/signal"
"strconv"
"syscall"
)
func main() {
go func() {}()
go (func() {})()
name := flag.String("name", "", "服务名称")
port := flag.Int("port", 0, "服务端口")
flag.Parse()
if *name == "" {
log.Fatal("请指定服务名")
}
if *port == 0 {
log.Fatal("请指定端口")
}
var logger kitlog.Logger
{
logger = kitlog.NewLogfmtLogger(os.Stdout)
logger = kitlog.WithPrefix(logger, "mykit", "1.0")
logger = kitlog.WithPrefix(logger, "time", kitlog.DefaultTimestampUTC) //加上前缀时间
logger = kitlog.WithPrefix(logger, "caller", kitlog.DefaultCaller) //加上前缀，日志输出时的文件和第几行代码
}
utils.SetServiceNameAndPort(*name, *port) //设置服务名和端口
user := Services.UserService{}
limit := rate.NewLimiter(1, 5)
endp := Services.RateLimit(limit)(Services.UserServiceLogMiddleware(logger)(Services.GenUserEnPoint(user)))
/*我们分析一下上面这段代码Services.RateLimit(limit)返回一个Middware，type Middleware func(Endpoint) Endpoint
也就是说这段代码的返回值必须是Endpoint类型
type Endpoint func(ctx context.Context, request interface{}) (response interface{}, err error)
才可以传入Middware (Services.UserServiceLogMiddleware(logger)(Services.GenUserEnPoint(user)))
再拆分Services.UserServiceLogMiddleware(logger)也返回一个Middware，同理Services.GenUserEnPoint(user)必然是返回一个EndPoint，这里GenUserEnPoint(user)返回值是\
func(ctx context.Context, request interface{}) (response interface{}, err error)所以是EndPoint类型
那么(Services.UserServiceLogMiddleware(logger)是middleware,Services.GenUserEnPoint(user))值作为参数是Endpoint，返回值依然是一个Endpoint，这个返回值作为参数传递给了Services.RateLimit(limit)，Services.RateLimit(limit)也是一个Middware，所以这样写是成立的
*/
options := []httptransport.ServerOption{
httptransport.ServerErrorEncoder(Services.MyErrorEncoder),
}
serverHandler := httptransport.NewServer(endp, Services.DecodeUserRequest, Services.EncodeUserResponse, options...) //使用go kit创建server传入我们之前定义的两个解析函数
r := mymux.NewRouter()
//r.Handle(`/user/{uid:\d+}`, serverHandler) //这种写法支持多种请求方式
r.Methods("GET", "DELETE").Path(`/user/{uid:\d+}`).Handler(serverHandler) //这种写法仅支持Get，限定只能Get请求
r.Methods("GET").Path("/health").HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
writer.Header().Set("Content-type", "application/json")
writer.Write([]byte(`{"status":"ok"}`))
})
errChan := make(chan error)
go func() {
utils.RegService() //调用注册服务程序
err := http.ListenAndServe(":"+strconv.Itoa(utils.ServicePort), r) //启动http服务
if err != nil {
log.Println(err)
errChan <- err
}
}()
go func() {
sigChan := make(chan os.Signal)
signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
errChan <- fmt.Errorf("%s", <-sigChan)
}()
getErr := <-errChan
utils.UnRegService()
log.Println(getErr)
}