1. 简介
Go 标准包中已经提供了对 RPC 的支持，而且支持三个级别的 RPC：TCP、 HTTP、 JSONRPC。
但 Go 的 RPC 包是独一无二的 RPC，它和传统的 RPC 系统不同，它只支持 Go 开发的服务器与客户端之间的交互，因为在内部，它们采用了 Gob 来编码。
2. 要求
- 函数必须是导出的(首字母大写)
- 必须有两个导出类型的参数
- 第一个参数是接收的参数，第二个参数是返回给客户端的参数，第二个参数必须是指针类型的
- 函数还要有一个返回值 error
- func (t *T) MethodName(argType T1, replyType *T2) error
3. Http RPC
/server/main.go
package main import ( "errors" "fmt" "net/http" "net/rpc" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } type Arith int func (t *Arith) Multiply(args *Args, reply *int) error { *reply = args.A * args.B return nil } func (t *Arith) Divide(args *Args, quo *Quotient) error { if args.B == 0 { return errors.New("divide by zero") } quo.Quo = args.A / args.B quo.Rem = args.A % args.B return nil } func main() { arith := new(Arith) rpc.Register(arith) rpc.HandleHTTP() err := http.ListenAndServe(":1234", nil) if err != nil { fmt.Println(err.Error()) } }
/client/main.go
package main import ( "fmt" "log" "net/rpc" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } func main() { client, err := rpc.DialHTTP("tcp", "localhost:1234") if err != nil { log.Fatal("dialing:", err) } args := Args{17, 8} var reply int err = client.Call("Arith.Multiply", args, &reply) if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d*%d=%d\n", args.A, args.B, reply) var quot Quotient err = client.Call("Arith.Divide", args, ") if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d/%d=%d remainder %d\n", args.A, args.B, quot.Quo, quot.Rem) }
4. TCP RPC
/server/main.go
package main import ( "errors" "fmt" "net" "net/rpc" "os" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } type Arith int func (t *Arith) Multiply(args *Args, reply *int) error { *reply = args.A * args.B return nil } func (t *Arith) Divide(args *Args, quo *Quotient) error { if args.B == 0 { return errors.New("divide by zero") } quo.Quo = args.A / args.B quo.Rem = args.A % args.B return nil } func main() { arith := new(Arith) rpc.Register(arith) tcpAddr, err := net.ResolveTCPAddr("tcp", "localhost:1234") checkError(err) listener, err := net.ListenTCP("tcp", tcpAddr) checkError(err) for { conn, err := listener.Accept() if err != nil { continue } rpc.ServeConn(conn) } } func checkError(err error) { if err != nil { fmt.Println("Fatal error ", err.Error()) os.Exit(1) } }
/client/main.go
package main import ( "fmt" "log" "net/rpc" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } func main() { client, err := rpc.Dial("tcp", "localhost:1234") if err != nil { log.Fatal("dialing:", err) } args := Args{17, 8} var reply int err = client.Call("Arith.Multiply", args, &reply) if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d*%d=%d\n", args.A, args.B, reply) var quot Quotient err = client.Call("Arith.Divide", args, ") if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d/%d=%d remainder %d\n", args.A, args.B, quot.Quo, quot.Rem) }
5. JSON RPC
/server/main.go
package main import ( "errors" "fmt" "net" "net/rpc" "net/rpc/jsonrpc" "os" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } type Arith int func (t *Arith) Multiply(args *Args, reply *int) error { *reply = args.A * args.B return nil } func (t *Arith) Divide(args *Args, quo *Quotient) error { if args.B == 0 { return errors.New("divide by zero") } quo.Quo = args.A / args.B quo.Rem = args.A % args.B return nil } func main() { arith := new(Arith) rpc.Register(arith) tcpAddr, err := net.ResolveTCPAddr("tcp", "localhost:1234") checkError(err) listener, err := net.ListenTCP("tcp", tcpAddr) checkError(err) for { conn, err := listener.Accept() if err != nil { continue } jsonrpc.ServeConn(conn) } } func checkError(err error) { if err != nil { fmt.Println("Fatal error ", err.Error()) os.Exit(1) } }
/client/main.go
package main import ( "fmt" "log" "net/rpc/jsonrpc" ) type Args struct { A, B int } type Quotient struct { Quo, Rem int } func main() { client, err := jsonrpc.Dial("tcp", "localhost:1234") if err != nil { log.Fatal("dialing:", err) } args := Args{17, 8} var reply int err = client.Call("Arith.Multiply", args, &reply) if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d*%d=%d\n", args.A, args.B, reply) var quot Quotient err = client.Call("Arith.Divide", args, ") if err != nil { log.Fatal("arith error:", err) } fmt.Printf("Arith:%d/%d=%d remainder %d\n", args.A, args.B, quot.Quo, quot.Rem) }
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