go.nanomsg.org/mangos/v3@v3.4.3-0.20240217232803-46464076f1f5/examples/pubsub/pubsub.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  // pubsub implements a publish/subscribe example.  server is a listening
    16  // pub socket, and clients are dialing sub sockets.
    17  //
    18  // To use:
    19  //
    20  //   $ go build .
    21  //   $ url=tcp://127.0.0.1:40899
    22  //   $ ./pubsub server $url server & server=$! && sleep 1
    23  //   $ ./pubsub client $url client0 & client0=$!
    24  //   $ ./pubsub client $url client1 & client1=$!
    25  //   $ ./pubsub client $url client2 & client2=$!
    26  //   $ sleep 5
    27  //   $ kill $server $client0 $client1 $client2
    28  //
    29  package main
    30  
    31  import (
    32  	"fmt"
    33  	"os"
    34  	"time"
    35  
    36  	"go.nanomsg.org/mangos/v3"
    37  	"go.nanomsg.org/mangos/v3/protocol/pub"
    38  	"go.nanomsg.org/mangos/v3/protocol/sub"
    39  
    40  	// register transports
    41  	_ "go.nanomsg.org/mangos/v3/transport/all"
    42  )
    43  
    44  func die(format string, v ...interface{}) {
    45  	fmt.Fprintln(os.Stderr, fmt.Sprintf(format, v...))
    46  	os.Exit(1)
    47  }
    48  
    49  func date() string {
    50  	return time.Now().Format(time.ANSIC)
    51  }
    52  
    53  func server(url string) {
    54  	var sock mangos.Socket
    55  	var err error
    56  	if sock, err = pub.NewSocket(); err != nil {
    57  		die("can't get new pub socket: %s", err)
    58  	}
    59  	if err = sock.Listen(url); err != nil {
    60  		die("can't listen on pub socket: %s", err.Error())
    61  	}
    62  	for {
    63  		// Could also use sock.RecvMsg to get header
    64  		d := date()
    65  		fmt.Printf("SERVER: PUBLISHING DATE %s\n", d)
    66  		if err = sock.Send([]byte(d)); err != nil {
    67  			die("Failed publishing: %s", err.Error())
    68  		}
    69  		time.Sleep(time.Second)
    70  	}
    71  }
    72  
    73  func client(url string, name string) {
    74  	var sock mangos.Socket
    75  	var err error
    76  	var msg []byte
    77  
    78  	if sock, err = sub.NewSocket(); err != nil {
    79  		die("can't get new sub socket: %s", err.Error())
    80  	}
    81  	if err = sock.Dial(url); err != nil {
    82  		die("can't dial on sub socket: %s", err.Error())
    83  	}
    84  	// Empty byte array effectively subscribes to everything
    85  	err = sock.SetOption(mangos.OptionSubscribe, []byte(""))
    86  	if err != nil {
    87  		die("cannot subscribe: %s", err.Error())
    88  	}
    89  	for {
    90  		if msg, err = sock.Recv(); err != nil {
    91  			die("Cannot recv: %s", err.Error())
    92  		}
    93  		fmt.Printf("CLIENT(%s): RECEIVED %s\n", name, string(msg))
    94  	}
    95  }
    96  
    97  func main() {
    98  	if len(os.Args) > 2 && os.Args[1] == "server" {
    99  		server(os.Args[2])
   100  		os.Exit(0)
   101  	}
   102  	if len(os.Args) > 3 && os.Args[1] == "client" {
   103  		client(os.Args[2], os.Args[3])
   104  		os.Exit(0)
   105  	}
   106  	fmt.Fprintf(os.Stderr, "Usage: pubsub server|client <URL> <ARG>\n")
   107  	os.Exit(1)
   108  }