mangos pattern guide
BUS — Routing
BUS lets peers exchange messages in a simple mesh.
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.
bus.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.
// bus implements a bus example.
//
// To use:
//
// $ go build .
// $ url0=tcp://127.0.0.1:40890
// $ url1=tcp://127.0.0.1:40891
// $ url2=tcp://127.0.0.1:40892
// $ url3=tcp://127.0.0.1:40893
// $ ./bus node0 $url0 $url1 $url2 & node0=$!
// $ ./bus node1 $url1 $url2 $url3 & node1=$!
// $ ./bus node2 $url2 $url3 & node2=$!
// $ ./bus node3 $url3 $url0 & node3=$!
// $ sleep 5
// $ kill $node0 $node1 $node2 $node3
//
package main
import (
"fmt"
"os"
"time"
"go.nanomsg.org/mangos/v3"
"go.nanomsg.org/mangos/v3/protocol/bus"
// 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 node(args []string) {
var sock mangos.Socket
var err error
var msg []byte
var x int
if sock, err = bus.NewSocket(); err != nil {
die("bus.NewSocket: %s", err)
}
if err = sock.Listen(args[2]); err != nil {
die("sock.Listen: %s", err.Error())
}
// wait for everyone to start listening
time.Sleep(time.Second)
for x = 3; x < len(args); x++ {
if err = sock.Dial(args[x]); err != nil {
die("socket.Dial: %s", err.Error())
}
}
// wait for everyone to join
time.Sleep(time.Second)
fmt.Printf("%s: SENDING '%s' ONTO BUS\n", args[1], args[1])
if err = sock.Send([]byte(args[1])); err != nil {
die("sock.Send: %s", err.Error())
}
for {
if msg, err = sock.Recv(); err != nil {
die("sock.Recv: %s", err.Error())
}
fmt.Printf("%s: RECEIVED \"%s\" FROM BUS\n", args[1],
string(msg))
}
}
func main() {
if len(os.Args) > 3 {
node(os.Args)
os.Exit(0)
}
fmt.Fprintf(os.Stderr, "Usage: bus <NODENAME> <URL> <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.
url0=tcp://127.0.0.1:40890
url1=tcp://127.0.0.1:40891
url2=tcp://127.0.0.1:40892
url3=tcp://127.0.0.1:40893
./bus node0 $url0 $url1 $url2 & node0=$!
./bus node1 $url1 $url2 $url3 & node1=$!
./bus node2 $url2 $url3 & node2=$!
./bus node3 $url3 $url0 & node3=$!
sleep 5
kill $node0 $node1 $node2 $node3
mangos is pure Go. The blank transport import in the example registers the URL transports it uses.