nanomsg.org/go/mangos/v2@v2.0.9-0.20200203084354-8a092611e461/examples/bus/bus.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  // bus implements a bus example.
    16  //
    17  // To use:
    18  //
    19  //   $ go build .
    20  //   $ url0=tcp://127.0.0.1:40890
    21  //   $ url1=tcp://127.0.0.1:40891
    22  //   $ url2=tcp://127.0.0.1:40892
    23  //   $ url3=tcp://127.0.0.1:40893
    24  //   $ ./bus node0 $url0 $url1 $url2 & node0=$!
    25  //   $ ./bus node1 $url1 $url2 $url3 & node1=$!
    26  //   $ ./bus node2 $url2 $url3 & node2=$!
    27  //   $ ./bus node3 $url3 $url0 & node3=$!
    28  //   $ sleep 5
    29  //   $ kill $node0 $node1 $node2 $node3
    30  //
    31  package main
    32  
    33  import (
    34  	"fmt"
    35  	"os"
    36  	"time"
    37  
    38  	"nanomsg.org/go/mangos/v2"
    39  	"nanomsg.org/go/mangos/v2/protocol/bus"
    40  
    41  	// register transports
    42  	_ "nanomsg.org/go/mangos/v2/transport/all"
    43  )
    44  
    45  func die(format string, v ...interface{}) {
    46  	fmt.Fprintln(os.Stderr, fmt.Sprintf(format, v...))
    47  	os.Exit(1)
    48  }
    49  
    50  func node(args []string) {
    51  	var sock mangos.Socket
    52  	var err error
    53  	var msg []byte
    54  	var x int
    55  
    56  	if sock, err = bus.NewSocket(); err != nil {
    57  		die("bus.NewSocket: %s", err)
    58  	}
    59  	if err = sock.Listen(args[2]); err != nil {
    60  		die("sock.Listen: %s", err.Error())
    61  	}
    62  
    63  	// wait for everyone to start listening
    64  	time.Sleep(time.Second)
    65  	for x = 3; x < len(args); x++ {
    66  		if err = sock.Dial(args[x]); err != nil {
    67  			die("socket.Dial: %s", err.Error())
    68  		}
    69  	}
    70  
    71  	// wait for everyone to join
    72  	time.Sleep(time.Second)
    73  
    74  	fmt.Printf("%s: SENDING '%s' ONTO BUS\n", args[1], args[1])
    75  	if err = sock.Send([]byte(args[1])); err != nil {
    76  		die("sock.Send: %s", err.Error())
    77  	}
    78  	for {
    79  		if msg, err = sock.Recv(); err != nil {
    80  			die("sock.Recv: %s", err.Error())
    81  		}
    82  		fmt.Printf("%s: RECEIVED \"%s\" FROM BUS\n", args[1],
    83  			string(msg))
    84  
    85  	}
    86  }
    87  
    88  func main() {
    89  	if len(os.Args) > 3 {
    90  		node(os.Args)
    91  		os.Exit(0)
    92  	}
    93  	fmt.Fprintf(os.Stderr, "Usage: bus <NODENAME> <URL> <URL>... \n")
    94  	os.Exit(1)
    95  }