1.go-kit 介绍
go-kit是一个分布式的开发工具集,在大型的组织(业务)中可以用来构建微服务,其解决了分布式系统中大多数常见问题,因此,使用者可以将精力集中在业务逻辑上。
他里面有用来帮助我们实现微服务的一些工具包, 和SpringBoot不同, 直接把框架搭好, 而需要手动的搭框架。go-kit 也存在3层架构。
微服务就是一个大项目中的一个小功能块,并且这个功能块可以不计语言差别的和其他功能模块通过API进行通讯和结合。
1.1 go-kit 三层结构
go-kit和SSM中的MVC一样也有三层结构endpoint,service, transport,通过这三层结构来实现,接收一个请求,然后返回一个结果。
Transport
Transport处于该微服务的最上层,主要负责于HTTP, gRPC,thrift等相关的逻辑,负责解析请求,并且调用endpoint来处理请求Endpoint
endpoint属于客户端和服务端的转接器,他定义了request和response的格式,上层给Transport调用来处理请求,下层链接Service将Service所返回的结果转换成request需要的格式Service
最底下的我们这个模块所需要实现的功能了
2.go-kit 实例
service -> endpoint -> transport
service.go
package service
import (
"errors"
"strings"
)
type StringServiceI interface {
GetUppercase(string) (string, error)
PostUppercase(string) (string, error)
GetCount(string) int
}
type StringService struct {
}
func (StringService) GetUppercase(s string) (string, error) {
if s == "" {
return "", errors.New("error")
}
return strings.ToUpper(s), nil
}
func (StringService) PostUppercase(s string) (string, error) {
if s == "" {
return "", errors.New("error")
}
return strings.ToUpper(s), nil
}
func (StringService) GetCount(s string) (int, error) {
if s == "" {
return 0, errors.New("error")
}
return len(s), nil
}
endpoint.go
package endpoint
import (
"context"
"github.com/go-kit/kit/endpoint"
"go-demo06/service"
)
type Endpoints struct {
GetUppercase endpoint.Endpoint
PostUppercase endpoint.Endpoint
GetCount endpoint.Endpoint
}
type UppercaseRequest struct {
S string `json:"s"`
}
type UppercaseResponse struct {
V string `json:"v"`
Err error `json:"err"`
}
type CountRequest struct {
S string `json:"s"`
}
type CountResponse struct {
V int `json:"v"`
}
func MakeEndpoints(svc service.StringService) Endpoints {
return Endpoints{
GetCount: MakeGetCountEndpoint(svc),
GetUppercase: MakeGetUppercaseEndpoint(svc),
PostUppercase: MakePostUppercaseEndpoint(svc),
}
}
func MakeGetUppercaseEndpoint(svc service.StringService) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
req := request.(UppercaseRequest)
v, err := svc.GetUppercase(req.S)
if err != nil {
return UppercaseResponse{v, err}, nil
}
return UppercaseResponse{v, err}, nil
}
}
func MakePostUppercaseEndpoint(svc service.StringService) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
req := request.(UppercaseRequest)
v, err := svc.PostUppercase(req.S)
if err != nil {
return UppercaseResponse{v, err}, nil
}
return UppercaseResponse{v, err}, nil
}
}
func MakeGetCountEndpoint(svc service.StringService) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (response interface{}, err error) {
req := request.(CountRequest)
v, err := svc.GetCount(req.S)
if err != nil {
return CountResponse{v}, nil
}
return CountResponse{v}, nil
}
}
rest.go
package transport
import (
"context"
"encoding/json"
httptransport "github.com/go-kit/kit/transport/http"
"github.com/gorilla/mux"
"go-demo06/endpoint"
"go-demo06/service"
"log"
"net/http"
)
func RestRun() {
svc := service.StringService{}
r := makeHttpHandler(svc)
log.Fatal(http.ListenAndServe(":8080", r))
}
func makeHttpHandler(svc service.StringService) http.Handler {
r := mux.NewRouter()
e := endpoint.MakeEndpoints(svc)
r.Methods("GET").Path("/uppercase").Handler(httptransport.NewServer(e.GetUppercase, DecodeUppercaseRequest, EncodeUppercaseResponse))
r.Methods("GET").Path("/count").Handler(httptransport.NewServer(e.GetCount, DecodeCountRequest, EncodeCountResponse))
return r
}
func DecodeUppercaseRequest(_ context.Context, r *http.Request) (interface{}, error) {
var req endpoint.UppercaseRequest
if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
return nil, err
}
return req, nil
}
func EncodeUppercaseResponse(_ context.Context, w http.ResponseWriter, response interface{}) error {
// transport body to json
w.Header().Set("Content-type", "application/json")
return json.NewEncoder(w).Encode(response)
}
func DecodeCountRequest(_ context.Context, r *http.Request) (interface{}, error) {
var req endpoint.CountRequest
if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
return nil, err
}
return req, nil
}
func EncodeCountResponse(_ context.Context, w http.ResponseWriter, response interface{}) error {
// transport body to json
w.Header().Set("Content-type", "application/json")
return json.NewEncoder(w).Encode(response)
}
main.go
package main
import (
"go-demo06/transport"
)
func main() {
transport.RestRun()
}
go run main.go