mangos pattern guide
PAIR — Two Way Radio
PAIR connects exactly two peers, each of which can send and receive freely.
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.
pair.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.
// pair implements a pair example. node0 is a listening
// pair socket, and node1 is a dialing pair socket.
//
// To use:
//
// $ go build .
// $ url=tcp://127.0.0.1:40899
// $ ./pair node0 $url & node0=$!
// $ ./pair node1 $url & node1=$!
// $ sleep 3
// $ kill $node0 $node1
//
package main
import (
"fmt"
"os"
"time"
"go.nanomsg.org/mangos/v3"
"go.nanomsg.org/mangos/v3/protocol/pair"
// 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 sendName(sock mangos.Socket, name string) {
fmt.Printf("%s: SENDING \"%s\"\n", name, name)
if err := sock.Send([]byte(name)); err != nil {
die("failed sending: %s", err)
}
}
func recvName(sock mangos.Socket, name string) {
var msg []byte
var err error
if msg, err = sock.Recv(); err == nil {
fmt.Printf("%s: RECEIVED: \"%s\"\n", name, string(msg))
}
}
func sendRecv(sock mangos.Socket, name string) {
for {
sock.SetOption(mangos.OptionRecvDeadline, 100*time.Millisecond)
recvName(sock, name)
time.Sleep(time.Second)
sendName(sock, name)
}
}
func node0(url string) {
var sock mangos.Socket
var err error
if sock, err = pair.NewSocket(); err != nil {
die("can't get new pair socket: %s", err)
}
if err = sock.Listen(url); err != nil {
die("can't listen on pair socket: %s", err.Error())
}
sendRecv(sock, "node0")
}
func node1(url string) {
var sock mangos.Socket
var err error
if sock, err = pair.NewSocket(); err != nil {
die("can't get new pair socket: %s", err.Error())
}
if err = sock.Dial(url); err != nil {
die("can't dial on pair socket: %s", err.Error())
}
sendRecv(sock, "node1")
}
func main() {
if len(os.Args) > 2 && os.Args[1] == "node0" {
node0(os.Args[2])
os.Exit(0)
}
if len(os.Args) > 2 && os.Args[1] == "node1" {
node1(os.Args[2])
os.Exit(0)
}
fmt.Fprintf(os.Stderr, "Usage: pair node0|node1 <URL>\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
./pair node0 $url & node0=$!
sleep 1 # Wait for node0 to start listening
./pair node1 $url & node1=$!
sleep 3
kill $node0 $node1
mangos is pure Go. The blank transport import in the example registers the URL transports it uses.