github.com/gdamore/mangos@v1.4.0/examples/survey/survey.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  // survey implements a survey example.  server is a surveyor listening
    16  // socket, and clients are dialing respondent sockets.
    17  //
    18  // To use:
    19  //
    20  //   $ go build .
    21  //   $ url=tcp://127.0.0.1:40899
    22  //   $ ./survey server $url server & server=$!
    23  //   $ ./survey client $url client0 & client0=$!
    24  //   $ ./survey client $url client1 & client1=$!
    25  //   $ ./survey 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  	"nanomsg.org/go-mangos"
    37  	"nanomsg.org/go-mangos/protocol/respondent"
    38  	"nanomsg.org/go-mangos/protocol/surveyor"
    39  	"nanomsg.org/go-mangos/transport/ipc"
    40  	"nanomsg.org/go-mangos/transport/tcp"
    41  )
    42  
    43  func die(format string, v ...interface{}) {
    44  	fmt.Fprintln(os.Stderr, fmt.Sprintf(format, v...))
    45  	os.Exit(1)
    46  }
    47  
    48  func date() string {
    49  	return time.Now().Format(time.ANSIC)
    50  }
    51  
    52  func server(url string) {
    53  	var sock mangos.Socket
    54  	var err error
    55  	var msg []byte
    56  	if sock, err = surveyor.NewSocket(); err != nil {
    57  		die("can't get new surveyor socket: %s", err)
    58  	}
    59  	sock.AddTransport(ipc.NewTransport())
    60  	sock.AddTransport(tcp.NewTransport())
    61  	if err = sock.Listen(url); err != nil {
    62  		die("can't listen on surveyor socket: %s", err.Error())
    63  	}
    64  	err = sock.SetOption(mangos.OptionSurveyTime, time.Second/2)
    65  	if err != nil {
    66  		die("SetOption(): %s", err.Error())
    67  	}
    68  	for {
    69  		time.Sleep(time.Second)
    70  		fmt.Println("SERVER: SENDING DATE SURVEY REQUEST")
    71  		if err = sock.Send([]byte("DATE")); err != nil {
    72  			die("Failed sending survey: %s", err.Error())
    73  		}
    74  		for {
    75  			if msg, err = sock.Recv(); err != nil {
    76  				break
    77  			}
    78  			fmt.Printf("SERVER: RECEIVED \"%s\" SURVEY RESPONSE\n",
    79  				string(msg))
    80  		}
    81  		fmt.Println("SERVER: SURVEY OVER")
    82  	}
    83  }
    84  
    85  func client(url string, name string) {
    86  	var sock mangos.Socket
    87  	var err error
    88  	var msg []byte
    89  
    90  	if sock, err = respondent.NewSocket(); err != nil {
    91  		die("can't get new respondent socket: %s", err.Error())
    92  	}
    93  	sock.AddTransport(ipc.NewTransport())
    94  	sock.AddTransport(tcp.NewTransport())
    95  	if err = sock.Dial(url); err != nil {
    96  		die("can't dial on respondent socket: %s", err.Error())
    97  	}
    98  	for {
    99  		if msg, err = sock.Recv(); err != nil {
   100  			die("Cannot recv: %s", err.Error())
   101  		}
   102  		fmt.Printf("CLIENT(%s): RECEIVED \"%s\" SURVEY REQUEST\n",
   103  			name, string(msg))
   104  
   105  		d := date()
   106  		fmt.Printf("CLIENT(%s): SENDING DATE SURVEY RESPONSE\n", name)
   107  		if err = sock.Send([]byte(d)); err != nil {
   108  			die("Cannot send: %s", err.Error())
   109  		}
   110  	}
   111  }
   112  
   113  func main() {
   114  	if len(os.Args) > 2 && os.Args[1] == "server" {
   115  		server(os.Args[2])
   116  		os.Exit(0)
   117  	}
   118  	if len(os.Args) > 3 && os.Args[1] == "client" {
   119  		client(os.Args[2], os.Args[3])
   120  		os.Exit(0)
   121  	}
   122  	fmt.Fprintf(os.Stderr, "Usage: survey server|client <URL> <ARG>\n")
   123  	os.Exit(1)
   124  }