func (ls *libstore) GetList(key string) ([]string, error) {
var args storagerpc.GetArgs
var reply storagerpc.GetListReply
args.Key = key
args.WantLease = false
args.HostPort = ls.hostport
// FIRST CHECK FROM LOCAL CACHE!!!
val, err := ls.leases.Get(key, &args)
if err == nil {
return val.([]string), nil
}
// CHECK IF WE NEED LEASE
if ls.mode == Always {
args.WantLease = true
} else if ls.mode == Never {
args.WantLease = false
}
// pick the right server
cli, err := ls.GetServer(key)
if err != nil {
return nil, err
}
// call rpc to storage server
err = cli.Call("StorageServer.GetList", &args, &reply)
if err != nil {
return nil, err
}
// check reply status
if reply.Status != storagerpc.OK {
err = GetErrorType(reply.Status)
return nil, err
}
// check if allow lease
if reply.Lease.Granted {
ls.leases.Insert(key, reply.Value, reply.Lease)
}
return reply.Value, nil
}
func (ls *libstore) Get(key string) (string, error) {
var args storagerpc.GetArgs
var reply storagerpc.GetReply
//set wantlease to be false
args.Key = key
args.WantLease = false
args.HostPort = ls.hostport
// check if it is in cache
val, err := ls.leases.Get(key, &args)
if err == nil {
return val.(string), nil
}
//CHECK IF WE NEED LEASE
if ls.mode == Always {
args.WantLease = true
} else if ls.mode == Never {
args.WantLease = false
}
// pick the right server
cli, err := ls.GetServer(key)
if err != nil {
return "", err
}
// call rpc
err = cli.Call("StorageServer.Get", &args, &reply)
if err != nil {
return "", err
}
if reply.Status != storagerpc.OK {
err = GetErrorType(reply.Status)
return "", err
}
// insert into cache
if reply.Lease.Granted {
ls.leases.Insert(key, reply.Value, reply.Lease)
}
return reply.Value, nil
}
func (ls *libstore) GetList(key string) ([]string, error) {
var args storagerpc.GetArgs
var reply storagerpc.GetListReply
args.Key = key
args.WantLease = false
args.HostPort = ls.hostport
val, err := ls.localCache.Get(&args)
if err == nil {
return val.([]string), nil
}
if ls.mode == Always {
args.WantLease = true
} else if ls.mode == Never {
args.WantLease = false
}
cli, err := ls.GetServer(key)
if err != nil {
return nil, err
}
err = cli.Call("StorageServer.GetList", &args, &reply)
if err != nil {
return nil, err
}
if reply.Status != storagerpc.OK {
err = GetErrorType(reply.Status)
return nil, err
}
if reply.Lease.Granted {
ls.localCache.Put(key, reply.Value, reply.Lease)
}
return reply.Value, nil
}
func (ls *libstore) GetList(key string) ([]string, error) {
var args storagerpc.GetArgs
var reply storagerpc.GetListReply
current_time := time.Now().Unix()
// Check whether the key is in the cache
// If yes, return directly
ls.list_cache_locker.Lock()
if list_cache_elem, ok := ls.list_cache[key]; ok {
if list_cache_elem.lease_end >= current_time {
ls.list_cache_locker.Unlock()
return list_cache_elem.content, nil
} else {
delete(ls.list_cache, key)
}
}
ls.list_cache_locker.Unlock()
args.Key = key
args.HostPort = ls.host_port
if ls.lease_mode == Normal {
ls.list_cache_locker.Lock()
if query_list, ok := ls.query_record[key]; ok {
query_list.PushBack(current_time)
} else {
new_list := list.New()
new_list.PushBack(current_time)
ls.query_record[key] = new_list
}
if query_list, ok := ls.query_record[key]; ok {
for elem := query_list.Front(); elem != nil; elem = elem.Next() {
if elem.Value.(int64)+storagerpc.QueryCacheSeconds < current_time {
query_list.Remove(elem)
} else {
break
}
}
if query_list.Len() >= storagerpc.QueryCacheThresh {
args.WantLease = true
} else {
args.WantLease = false
}
}
ls.list_cache_locker.Unlock()
} else if ls.lease_mode == Always {
args.WantLease = true
}
target_server := ls.GetServerIndex(key)
ls.rpc_connection[target_server].Call("StorageServer.GetList", args, &reply)
if reply.Status != storagerpc.OK {
return nil, errors.New("Error in Getlist")
}
if reply.Lease.Granted {
ls.list_cache_locker.Lock()
defer ls.list_cache_locker.Unlock()
ls.list_cache[key] = &ListCacheElement{lease_end: time.Now().Unix() + int64(reply.Lease.ValidSeconds), content: reply.Value}
}
return reply.Value, nil
}
