func (c *etcdCtx) SetRing(ring torus.Ring) error {
oldr, etcdver, err := c.getRing()
if err != nil {
return err
}
if oldr.Version() != ring.Version()-1 {
return torus.ErrNonSequentialRing
}
b, err := ring.Marshal()
if err != nil {
return err
}
key := MkKey("meta", "the-one-ring")
txn := c.etcd.Client.Txn(c.getContext()).If(
etcdv3.Compare(etcdv3.Version(key), "=", etcdver),
).Then(
etcdv3.OpPut(key, string(b)),
)
resp, err := txn.Commit()
if err != nil {
return err
}
if resp.Succeeded {
return nil
}
return torus.ErrAgain
}
func (e *Etcd) watchRing(r torus.Ring) {
ctx, cancel := context.WithCancel(e.getContext())
defer cancel()
wch := e.Client.Watch(ctx, MkKey("meta", "the-one-ring"))
for resp := range wch {
if err := resp.Err(); err != nil {
clog.Errorf("error watching ring: %s", err)
return
}
for _, ev := range resp.Events {
newRing, err := ring.Unmarshal(ev.Kv.Value)
if err != nil {
clog.Debugf("corrupted ring: %#v", ev.Kv.Value)
clog.Errorf("Failed to unmarshal ring: %s", err)
clog.Error("corrupted ring? Continuing with current ring")
continue
}
clog.Infof("got new ring")
if r.Version() == newRing.Version() {
clog.Warningf("Same ring version: %d", r.Version())
}
e.mut.RLock()
for _, x := range e.ringListeners {
x <- newRing
}
r = newRing
e.mut.RUnlock()
}
}
}
func setRing(cfg torus.Config, r torus.Ring) error {
client, err := etcdv3.New(etcdv3.Config{Endpoints: []string{cfg.MetadataAddress}, TLS: cfg.TLS})
if err != nil {
return err
}
defer client.Close()
resp, err := client.Get(context.Background(), MkKey("meta", "the-one-ring"))
if err != nil {
return err
}
if len(resp.Kvs) == 0 {
return torus.ErrNoGlobalMetadata
}
oldr, err := ring.Unmarshal(resp.Kvs[0].Value)
if err != nil {
return err
}
if oldr.Version() != r.Version()-1 {
return torus.ErrNonSequentialRing
}
b, err := r.Marshal()
if err != nil {
return err
}
_, err = client.Put(context.Background(), MkKey("meta", "the-one-ring"), string(b))
return err
}
func assignData(blocks []torus.BlockRef, r torus.Ring) ClusterState {
out := make(map[string][]torus.BlockRef)
for _, p := range r.Members() {
out[p] = make([]torus.BlockRef, 0)
}
for _, b := range blocks {
peers, err := r.GetPeers(b)
if err != nil {
fmt.Fprintf(os.Stderr, "error in the ring: %s\n", err)
os.Exit(1)
}
for _, p := range peers.Peers[:peers.Replication] {
out[p] = append(out[p], b)
}
}
return out
}
func (s *Server) SetRing(ring torus.Ring) error {
s.mut.Lock()
defer s.mut.Unlock()
if ring.Version()-1 != s.ring.Version() {
return torus.ErrNonSequentialRing
}
s.ring = ring
for _, c := range s.ringListeners {
c <- s.ring
}
return nil
}
func (c ClusterState) Rebalance(oldRing, newRing torus.Ring) (ClusterState, RebalanceStats) {
var stats RebalanceStats
out := make(map[string][]torus.BlockRef)
for _, p := range newRing.Members() {
out[p] = make([]torus.BlockRef, 0)
}
for p, l := range c {
for _, ref := range l {
newp, err := newRing.GetPeers(ref)
newpeers := newp.Peers[:newp.Replication]
if err != nil {
fmt.Fprintf(os.Stderr, "error in the new ring: %s\n", err)
os.Exit(1)
}
oldp, err := oldRing.GetPeers(ref)
oldpeers := oldp.Peers[:oldp.Replication]
if err != nil {
fmt.Fprintf(os.Stderr, "error in the old ring: %s\n", err)
os.Exit(1)
}
myIndex := oldpeers.IndexAt(p)
if newpeers.Has(p) {
out[p] = append(out[p], ref)
stats.BlocksKept++
}
diffpeers := newpeers.AndNot(oldpeers)
if myIndex >= len(diffpeers) {
// downsizing
continue
}
if myIndex == len(oldpeers)-1 && len(diffpeers) > len(oldpeers) {
for i := myIndex; i < len(diffpeers); i++ {
p := diffpeers[i]
out[p] = append(out[p], ref)
stats.BlocksSent++
}
} else {
p := diffpeers[myIndex]
out[p] = append(out[p], ref)
stats.BlocksSent++
}
}
}
return out, stats
}