/
clonesrv4.go
91 lines (80 loc) · 2.15 KB
/
clonesrv4.go
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//
// Clone server Model Four
//
package main
import (
zmq "github.com/pebbe/zmq4"
"github.com/pebbe/zmq4/examples/kvsimple"
"fmt"
"strings"
"time"
)
// The main task is identical to clonesrv3 except for where it
// handles subtrees.
func main() {
snapshot, _ := zmq.NewSocket(zmq.ROUTER)
snapshot.Bind("tcp://*:5556")
publisher, _ := zmq.NewSocket(zmq.PUB)
publisher.Bind("tcp://*:5557")
collector, _ := zmq.NewSocket(zmq.PULL)
collector.Bind("tcp://*:5558")
// The body of the main task collects updates from clients and
// publishes them back out to clients:
sequence := int64(0)
kvmap := make(map[string]*kvsimple.Kvmsg)
poller := zmq.NewPoller()
poller.Add(collector, zmq.POLLIN)
poller.Add(snapshot, zmq.POLLIN)
LOOP:
for {
polled, err := poller.Poll(1000 * time.Millisecond)
if err != nil {
break
}
for _, item := range polled {
switch socket := item.Socket; socket {
case collector:
// Apply state update sent from client
kvmsg, err := kvsimple.RecvKvmsg(collector)
if err != nil {
break LOOP // Interrupted
}
sequence++
kvmsg.SetSequence(sequence)
kvmsg.Send(publisher)
kvmsg.Store(kvmap)
fmt.Println("I: publishing update", sequence)
case snapshot:
// Execute state snapshot request
msg, err := snapshot.RecvMessage(0)
if err != nil {
break LOOP
}
identity := msg[0]
// Request is in second frame of message
request := msg[1]
if request != "ICANHAZ?" {
fmt.Println("E: bad request, aborting")
break LOOP
}
subtree := msg[2]
// Send state snapshot to client
// For each entry in kvmap, send kvmsg to client
for _, kvmsg := range kvmap {
if key, _ := kvmsg.GetKey(); strings.HasPrefix(key, subtree) {
snapshot.Send(identity, zmq.SNDMORE)
kvmsg.Send(snapshot)
}
}
// Now send END message with sequence number
fmt.Println("I: sending shapshot =", sequence)
snapshot.Send(identity, zmq.SNDMORE)
kvmsg := kvsimple.NewKvmsg(sequence)
kvmsg.SetKey("KTHXBAI")
kvmsg.SetBody(subtree)
kvmsg.Send(snapshot)
}
}
}
fmt.Printf("Interrupted\n%d messages handled\n", sequence)
}