go.nanomsg.org/mangos/v3@v3.4.3-0.20240217232803-46464076f1f5/examples/reqrep/reqrep.go (about)

     1  // Copyright 2018 The Mangos Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use file except in compliance with the License.
     5  // You may obtain a copy of the license at
     6  //
     7  //    http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // reqprep implements a request/reply example.  node0 is a listening
    16  // rep socket, and node1 is a dialing req socket.
    17  //
    18  // To use:
    19  //
    20  //   $ go build .
    21  //   $ url=tcp://127.0.0.1:40899
    22  //   $ ./reqrep node0 $url & node0=$! && sleep 1
    23  //   $ ./reqrep node1 $url
    24  //   $ kill $node0
    25  //
    26  package main
    27  
    28  import (
    29  	"fmt"
    30  	"os"
    31  	"time"
    32  
    33  	"go.nanomsg.org/mangos/v3"
    34  	"go.nanomsg.org/mangos/v3/protocol/rep"
    35  	"go.nanomsg.org/mangos/v3/protocol/req"
    36  
    37  	// register transports
    38  	_ "go.nanomsg.org/mangos/v3/transport/all"
    39  )
    40  
    41  func die(format string, v ...interface{}) {
    42  	fmt.Fprintln(os.Stderr, fmt.Sprintf(format, v...))
    43  	os.Exit(1)
    44  }
    45  
    46  func date() string {
    47  	return time.Now().Format(time.ANSIC)
    48  }
    49  
    50  func node0(url string) {
    51  	var sock mangos.Socket
    52  	var err error
    53  	var msg []byte
    54  	if sock, err = rep.NewSocket(); err != nil {
    55  		die("can't get new rep socket: %s", err)
    56  	}
    57  	if err = sock.Listen(url); err != nil {
    58  		die("can't listen on rep socket: %s", err.Error())
    59  	}
    60  	for {
    61  		// Could also use sock.RecvMsg to get header
    62  		msg, err = sock.Recv()
    63  		if err != nil {
    64  			die("cannot receive on rep socket: %s", err.Error())
    65  		}
    66  		if string(msg) == "DATE" { // no need to terminate
    67  			fmt.Println("NODE0: RECEIVED DATE REQUEST")
    68  			d := date()
    69  			fmt.Printf("NODE0: SENDING DATE %s\n", d)
    70  			err = sock.Send([]byte(d))
    71  			if err != nil {
    72  				die("can't send reply: %s", err.Error())
    73  			}
    74  		}
    75  	}
    76  }
    77  
    78  func node1(url string) {
    79  	var sock mangos.Socket
    80  	var err error
    81  	var msg []byte
    82  
    83  	if sock, err = req.NewSocket(); err != nil {
    84  		die("can't get new req socket: %s", err.Error())
    85  	}
    86  	if err = sock.Dial(url); err != nil {
    87  		die("can't dial on req socket: %s", err.Error())
    88  	}
    89  	fmt.Printf("NODE1: SENDING DATE REQUEST %s\n", "DATE")
    90  	if err = sock.Send([]byte("DATE")); err != nil {
    91  		die("can't send message on push socket: %s", err.Error())
    92  	}
    93  	if msg, err = sock.Recv(); err != nil {
    94  		die("can't receive date: %s", err.Error())
    95  	}
    96  	fmt.Printf("NODE1: RECEIVED DATE %s\n", string(msg))
    97  	sock.Close()
    98  }
    99  
   100  func main() {
   101  	if len(os.Args) > 2 && os.Args[1] == "node0" {
   102  		node0(os.Args[2])
   103  		os.Exit(0)
   104  	}
   105  	if len(os.Args) > 2 && os.Args[1] == "node1" {
   106  		node1(os.Args[2])
   107  		os.Exit(0)
   108  	}
   109  	fmt.Fprintf(os.Stderr, "Usage: reqrep node0|node1 <URL>\n")
   110  	os.Exit(1)
   111  }