nanomsg.org/go/mangos/v2@v2.0.9-0.20200203084354-8a092611e461/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/v2"
    37  	"nanomsg.org/go/mangos/v2/protocol/respondent"
    38  	"nanomsg.org/go/mangos/v2/protocol/surveyor"
    39  
    40  	// register transports
    41  	_ "nanomsg.org/go/mangos/v2/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  	var msg []byte
    57  	if sock, err = surveyor.NewSocket(); err != nil {
    58  		die("can't get new surveyor socket: %s", err)
    59  	}
    60  	if err = sock.Listen(url); err != nil {
    61  		die("can't listen on surveyor socket: %s", err.Error())
    62  	}
    63  	err = sock.SetOption(mangos.OptionSurveyTime, time.Second/2)
    64  	if err != nil {
    65  		die("SetOption(): %s", err.Error())
    66  	}
    67  	for {
    68  		time.Sleep(time.Second)
    69  		fmt.Println("SERVER: SENDING DATE SURVEY REQUEST")
    70  		if err = sock.Send([]byte("DATE")); err != nil {
    71  			die("Failed sending survey: %s", err.Error())
    72  		}
    73  		for {
    74  			if msg, err = sock.Recv(); err != nil {
    75  				break
    76  			}
    77  			fmt.Printf("SERVER: RECEIVED \"%s\" SURVEY RESPONSE\n",
    78  				string(msg))
    79  		}
    80  		fmt.Println("SERVER: SURVEY OVER")
    81  	}
    82  }
    83  
    84  func client(url string, name string) {
    85  	var sock mangos.Socket
    86  	var err error
    87  	var msg []byte
    88  
    89  	if sock, err = respondent.NewSocket(); err != nil {
    90  		die("can't get new respondent socket: %s", err.Error())
    91  	}
    92  	if err = sock.Dial(url); err != nil {
    93  		die("can't dial on respondent socket: %s", err.Error())
    94  	}
    95  	for {
    96  		if msg, err = sock.Recv(); err != nil {
    97  			die("Cannot recv: %s", err.Error())
    98  		}
    99  		fmt.Printf("CLIENT(%s): RECEIVED \"%s\" SURVEY REQUEST\n",
   100  			name, string(msg))
   101  
   102  		d := date()
   103  		fmt.Printf("CLIENT(%s): SENDING DATE SURVEY RESPONSE\n", name)
   104  		if err = sock.Send([]byte(d)); err != nil {
   105  			die("Cannot send: %s", err.Error())
   106  		}
   107  	}
   108  }
   109  
   110  func main() {
   111  	if len(os.Args) > 2 && os.Args[1] == "server" {
   112  		server(os.Args[2])
   113  		os.Exit(0)
   114  	}
   115  	if len(os.Args) > 3 && os.Args[1] == "client" {
   116  		client(os.Args[2], os.Args[3])
   117  		os.Exit(0)
   118  	}
   119  	fmt.Fprintf(os.Stderr, "Usage: survey server|client <URL> <ARG>\n")
   120  	os.Exit(1)
   121  }