/
confsyncd.go
209 lines (186 loc) · 5.33 KB
/
confsyncd.go
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package main
import (
"os"
"log"
"net"
"flag"
"time"
"runtime"
"strconv"
"io/ioutil"
"encoding/json"
"path/filepath"
zmq "github.com/alecthomas/gozmq"
"github.com/howeyc/fsnotify"
)
type Config struct {
Time int64
Body string
}
type Request struct {
Type string
}
type ConnRequest struct {
Type string
PubAddress string
RepAddress string
}
type ConnReply struct {
PubAddress string
Clients []string
}
// Config actions {{{
func readConfig(filename string) Config {
file, _ := os.Open(filename)
defer file.Close()
content, _ := ioutil.ReadAll(file)
stat, _ := file.Stat()
return Config{stat.ModTime().UnixNano(), string(content)}
}
func writeConfig(filename string, content []byte) {
err := ioutil.WriteFile(filename, content, 0x777)
if err != nil {
log.Fatal(err)
}
}
func publishConfig(config Config, global_pub_socket, local_pub_socket zmq.Socket) {
m, _ := json.Marshal(config)
global_pub_socket.Send(m, 0)
local_pub_socket.Send([]byte(config.Body), 0)
}
// }}}
// Event handlers {{{
func watchConfig(filename string, global_pub_socket, local_pub_socket zmq.Socket) {
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Fatal(err)
}
err = watcher.Watch(filename)
if err != nil {
log.Fatal(err)
}
for {
select {
case _ = <-watcher.Event:
local_config := readConfig(filename)
publishConfig(local_config, global_pub_socket, local_pub_socket)
case err := <-watcher.Error:
log.Println("Watcher error:", err)
}
runtime.Gosched()
}
}
func watchSub(global_sub_socket, global_pub_socket, local_pub_socket zmq.Socket, filename string) {
for {
data, _ := global_sub_socket.Recv(0)
var msg Config
_ = json.Unmarshal(data, &msg)
local_config := readConfig(filename)
if msg.Time > local_config.Time {
body := []byte(msg.Body)
writeConfig(filename, body)
local_pub_socket.Send(body, 0)
} else if msg.Time < local_config.Time {
m, _ := json.Marshal(local_config)
global_pub_socket.Send(m, 0)
}
runtime.Gosched()
}
}
func watchRep(ctx zmq.Context, global_rep_socket, global_sub_socket zmq.Socket, clients *[]string, pub_address string) {
for {
data, _ := global_rep_socket.Recv(0)
var req Request
_ = json.Unmarshal(data, &req)
if req.Type == "connect" {
var creq ConnRequest
json.Unmarshal(data, &creq)
if !strSliceContains(*clients, creq.RepAddress) {
global_sub_socket.Connect(creq.PubAddress)
reply, _ := json.Marshal(ConnReply{pub_address, *clients})
global_rep_socket.Send(reply, 0)
for _, adr := range *clients {
req_socket := openSocket(ctx, zmq.REQ, adr)
req_socket.Send(data, 0)
req_socket.Close()
}
*clients = append(*clients, creq.RepAddress)
log.Printf("Connected: "+creq.RepAddress)
}
}
runtime.Gosched()
}
}
// }}}
// Helper functions {{{
func openSocket(ctx zmq.Context, t zmq.SocketType, url string) zmq.Socket {
socket, _ := ctx.NewSocket(t)
if t == zmq.PUB || t == zmq.REP {
socket.Bind(url)
} else {
socket.Connect(url)
}
return socket
}
func findOpenPort() int {
for i := 1024; i < 65536; i++ {
_, err := net.Dial("tcp", "localhost:"+strconv.Itoa(i))
if err != nil { return i }
}
return 5555 // will never return this unless you use up all the ports
}
func strSliceContains(sl []string, elem string) bool {
for _, v := range sl { if v == elem { return true } }
return false
}
// }}}
var conn_adr = flag.String("connect", "", "address of a confsyncd instance to connect")
var conf_filepath = flag.String("file", "config.json", "config file to sync")
var rep_port = flag.Int("port", 0, "global rep socket port, default is random")
func main() {
flag.Parse()
filename, _ := filepath.Abs(*conf_filepath)
hostname, _ := os.Hostname()
ctx, _ := zmq.NewContext()
defer ctx.Close()
global_pub_port := strconv.Itoa(findOpenPort())
global_pub_socket := openSocket(ctx, zmq.PUB, "tcp://*:"+global_pub_port)
pub_address := "tcp://"+hostname+":"+global_pub_port
defer global_pub_socket.Close()
local_pub_socket := openSocket(ctx, zmq.PUB, "ipc://confsyncd")
defer local_pub_socket.Close()
global_sub_socket, _ := ctx.NewSocket(zmq.SUB)
global_sub_socket.SetSockOptString(zmq.SUBSCRIBE, "")
defer global_sub_socket.Close()
var global_rep_port string
if *rep_port == 0 {
global_rep_port = strconv.Itoa(findOpenPort())
} else {
global_rep_port = strconv.Itoa(*rep_port)
}
global_rep_socket := openSocket(ctx, zmq.REP, "tcp://*:"+global_rep_port)
defer global_rep_socket.Close()
log.Printf("Address: tcp://"+hostname+":"+global_rep_port)
time.Sleep(1e9/2)
local_config := readConfig(filename)
publishConfig(local_config, global_pub_socket, local_pub_socket)
var clients []string
if *conn_adr != "" {
req_socket := openSocket(ctx, zmq.REQ, *conn_adr)
conn_req := ConnRequest{"connect", pub_address, "tcp://"+hostname+":"+global_rep_port}
conn_req_json, _ := json.Marshal(conn_req)
req_socket.Send(conn_req_json, 0)
reply, _ := req_socket.Recv(0)
var conn_reply ConnReply
json.Unmarshal(reply, &conn_reply)
global_sub_socket.Connect(conn_reply.PubAddress)
clients = conn_reply.Clients
clients = append(clients, *conn_adr)
req_socket.Close()
} else {
clients = make([]string, 0)
}
go watchRep(ctx, global_rep_socket, global_sub_socket, &clients, pub_address)
go watchSub(global_sub_socket, global_pub_socket, local_pub_socket, filename)
watchConfig(filename, global_pub_socket, local_pub_socket)
}