func activate(st *store.Store, self string, c *doozer.Client) int64 {
w := store.NewWatch(st, calGlob)
for _, base := range store.Getdir(st, calDir) {
p := calDir + "/" + base
v, rev := st.Get(p)
if rev != store.Dir && v[0] == "" {
seqn, err := c.Set(p, rev, []byte(self))
if err != nil {
log.Println(err)
continue
}
w.Stop()
return seqn
}
}
for ev := range w.C {
// TODO ev.IsEmpty()
if ev.IsSet() && ev.Body == "" {
seqn, err := c.Set(ev.Path, ev.Rev, []byte(self))
if err != nil {
log.Println(err)
continue
}
w.Stop()
return seqn
}
}
return 0
}
// Find possible addresses for cluster named name.
func lookup(b *doozer.Client, name string) (as []string) {
info, err := b.Walk("/ctl/ns/"+name+"/*", nil, 0, -1)
if err != nil {
panic(err)
}
for _, e := range info {
as = append(as, string(e.Body))
}
return as
}
// Elect chooses a seed node, and returns a connection to a cal.
// If this process is the seed, returns nil.
func elect(name, id, laddr string, b *doozer.Client) *doozer.Client {
// advertise our presence, since we might become a cal
nspath := "/ctl/ns/" + name + "/" + id
r, err := b.Set(nspath, 0, []byte(laddr))
if err != nil {
panic(err)
}
// fight to be the seed
_, err = b.Set("/ctl/boot/"+name, 0, []byte(id))
switch err {
case doozer.ErrOldRev:
// we lost, lookup addresses again
cl := lookupAndAttach(b, name)
if cl == nil {
panic("failed to attach after losing election")
}
// also delete our entry, since we're not officially a cal yet.
// it gets set again in peer.Main when we become a cal.
err := b.Del(nspath, r)
if err != nil {
panic(err)
}
return cl
case nil:
return nil // we are the seed node -- don't attach
}
panic(err)
}
func Main(clusterName, self, baddr string, cl *doozer.Client, udpConn net.PacketConn, listener, webListener net.Listener, pulseInterval, fillDelay, kickTimeout int64) {
listenAddr := listener.Addr().String()
var activateSeqn int64
useSelf := make(chan bool, 1)
st := store.New()
pr := &proposer{
seqns: make(chan int64, alpha),
props: make(chan *consensus.Prop),
st: st,
}
calSrv := func() {
go gc.Pulse(self, st.Seqns, pr, pulseInterval)
go gc.Clean(st, 360000, time.Tick(1e9))
}
if cl == nil { // we are the only node in a new cluster
set(st, "/ctl/name", clusterName, store.Missing)
set(st, "/ctl/node/"+self+"/addr", listenAddr, store.Missing)
set(st, "/ctl/node/"+self+"/hostname", os.Getenv("HOSTNAME"), store.Missing)
set(st, "/ctl/node/"+self+"/version", Version, store.Missing)
set(st, "/ctl/cal/0", self, store.Missing)
calSrv()
close(useSelf)
} else {
setC(cl, "/ctl/node/"+self+"/addr", listenAddr, store.Clobber)
setC(cl, "/ctl/node/"+self+"/hostname", os.Getenv("HOSTNAME"), store.Clobber)
setC(cl, "/ctl/node/"+self+"/version", Version, store.Clobber)
rev, err := cl.Rev()
if err != nil {
panic(err)
}
walk, err := cl.Walk("/**", &rev, nil, nil)
if err != nil {
panic(err)
}
watch, err := cl.Watch("/**", rev+1)
if err != nil {
panic(err)
}
go follow(st.Ops, watch.C)
follow(st.Ops, walk.C)
st.Flush()
ch, err := st.Wait(rev + 1)
if err == nil {
<-ch
}
go func() {
activateSeqn = activate(st, self, cl)
calSrv()
advanceUntil(cl, st.Seqns, activateSeqn+alpha)
err := watch.Cancel()
if err != nil {
panic(err)
}
close(useSelf)
if baddr != "" {
b := doozer.New("<boot>", baddr)
setC(
b,
"/ctl/ns/"+clusterName+"/"+self,
listenAddr,
store.Missing,
)
}
}()
}
start := <-st.Seqns
cmw := st.Watch(store.Any)
in := make(chan consensus.Packet, 50)
out := make(chan consensus.Packet, 50)
consensus.NewManager(self, start, alpha, in, out, st.Ops, pr.seqns, pr.props, cmw, fillDelay, st)
if cl == nil {
// Skip ahead alpha steps so that the registrar can provide a
// meaningful cluster.
for i := start + 1; i < start+alpha+1; i++ {
st.Ops <- store.Op{i, store.Nop}
}
}
shun := make(chan string, 3) // sufficient for a cluster of 7
go member.Clean(shun, st, pr)
sv := &server.Server{listenAddr, st, pr, self, alpha}
go sv.Serve(listener, useSelf)
if webListener != nil {
web.Store = st
web.ClusterName = clusterName
go web.Serve(webListener)
}
go func() {
for p := range out {
addr, err := net.ResolveUDPAddr(p.Addr)
if err != nil {
log.Println(err)
continue
}
n, err := udpConn.WriteTo(p.Data, addr)
if err != nil {
log.Println(err)
continue
}
if n != len(p.Data) {
log.Println("packet len too long:", len(p.Data))
continue
}
}
}()
lv := liveness{
timeout: kickTimeout,
ival: kickTimeout / 2,
times: make(map[string]int64),
self: self,
shun: shun,
}
for {
t := time.Nanoseconds()
buf := make([]byte, maxUDPLen)
n, addr, err := udpConn.ReadFrom(buf)
if err == os.EINVAL {
return
}
if err != nil {
log.Println(err)
continue
}
buf = buf[:n]
// Update liveness time stamp for this addr
lv.times[addr.String()] = t
lv.check(t)
in <- consensus.Packet{addr.String(), buf}
}
}
func setC(cl *doozer.Client, path, body string, rev int64) {
_, err := cl.Set(path, rev, []byte(body))
if err != nil {
panic(err)
}
}
func advanceUntil(cl *doozer.Client, ver <-chan int64, done int64) {
for <-ver < done {
cl.Nop()
}
}