mangos pattern guide
SURVEYOR / RESPONDENT — Everybody Votes
SURVEYOR / RESPONDENT asks connected peers a question and collects their responses.
Start in a Go module and install the current major version: go get go.nanomsg.org/mangos/v3. The complete example below is synchronized with the mangos main branch.
survey.go
// Copyright 2018 The Mangos Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
// You may obtain a copy of the license at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// survey implements a survey example. server is a surveyor listening
// socket, and clients are dialing respondent sockets.
//
// To use:
//
// $ go build .
// $ url=tcp://127.0.0.1:40899
// $ ./survey server $url server & server=$!
// $ ./survey client $url client0 & client0=$!
// $ ./survey client $url client1 & client1=$!
// $ ./survey client $url client2 & client2=$!
// $ sleep 5
// $ kill $server $client0 $client1 $client2
//
package main
import (
"fmt"
"os"
"time"
"go.nanomsg.org/mangos/v3"
"go.nanomsg.org/mangos/v3/protocol/respondent"
"go.nanomsg.org/mangos/v3/protocol/surveyor"
// register transports
_ "go.nanomsg.org/mangos/v3/transport/all"
)
func die(format string, v ...interface{}) {
fmt.Fprintln(os.Stderr, fmt.Sprintf(format, v...))
os.Exit(1)
}
func date() string {
return time.Now().Format(time.ANSIC)
}
func server(url string) {
var sock mangos.Socket
var err error
var msg []byte
if sock, err = surveyor.NewSocket(); err != nil {
die("can't get new surveyor socket: %s", err)
}
if err = sock.Listen(url); err != nil {
die("can't listen on surveyor socket: %s", err.Error())
}
err = sock.SetOption(mangos.OptionSurveyTime, time.Second/2)
if err != nil {
die("SetOption(): %s", err.Error())
}
for {
time.Sleep(time.Second)
fmt.Println("SERVER: SENDING DATE SURVEY REQUEST")
if err = sock.Send([]byte("DATE")); err != nil {
die("Failed sending survey: %s", err.Error())
}
for {
if msg, err = sock.Recv(); err != nil {
break
}
fmt.Printf("SERVER: RECEIVED \"%s\" SURVEY RESPONSE\n",
string(msg))
}
fmt.Println("SERVER: SURVEY OVER")
}
}
func client(url string, name string) {
var sock mangos.Socket
var err error
var msg []byte
if sock, err = respondent.NewSocket(); err != nil {
die("can't get new respondent socket: %s", err.Error())
}
if err = sock.Dial(url); err != nil {
die("can't dial on respondent socket: %s", err.Error())
}
for {
if msg, err = sock.Recv(); err != nil {
die("Cannot recv: %s", err.Error())
}
fmt.Printf("CLIENT(%s): RECEIVED \"%s\" SURVEY REQUEST\n",
name, string(msg))
d := date()
fmt.Printf("CLIENT(%s): SENDING DATE SURVEY RESPONSE\n", name)
if err = sock.Send([]byte(d)); err != nil {
die("Cannot send: %s", err.Error())
}
}
}
func main() {
if len(os.Args) > 2 && os.Args[1] == "server" {
server(os.Args[2])
os.Exit(0)
}
if len(os.Args) > 3 && os.Args[1] == "client" {
client(os.Args[2], os.Args[3])
os.Exit(0)
}
fmt.Fprintf(os.Stderr, "Usage: survey server|client <URL> <ARG>\n")
os.Exit(1)
}
Run it
#!/bin/sh
#
# Copyright 2014 The Mangos Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use file except in compliance with the License.
# You may obtain a copy of the license at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
url=tcp://127.0.0.1:40899
./survey server $url server & server=$!
./survey client $url client0 & client0=$!
./survey client $url client1 & client1=$!
./survey client $url client2 & client2=$!
sleep 5
kill $server $client0 $client1 $client2
mangos is pure Go. The blank transport import in the example registers the URL transports it uses.