func Connect(target string) (Client, error) {
conn, err := net.Dial("tcp", target)
if err != nil {
return nil, err
}
// hanshake
_, cmd, _, err := network.Receive(conn)
if err != nil {
return nil, err
}
ch := make(chan PendingOperation)
c := &NetworkClient{connectionId: *cmd.Header.ConnectionID,
userId: USER_ID,
secret: CLIENT_SECRET,
sequence: 1,
conn: conn,
closed: false,
error: nil,
notifier: ch}
go c.listen(ch)
return c, nil
}
func (self *NetworkClient) listen(notifications <-chan PendingOperation) {
pending := make(map[int64]PendingOperation) // pendings
for {
_, cmd, value, err := network.Receive(self.conn)
if err != nil {
if !self.closed {
self.error = err
// TODO: try closing socket
}
break
}
var response error
if *cmd.Status.Code != kproto.Command_Status_SUCCESS {
response = RemoteError{status: *cmd.Status}
}
// Notify caller
// Seems more complicated than it should, but we are optimizing
// for when we receive in order
for {
op := <-notifications
// Chances are, it's in order
if op.sequence == *cmd.Header.AckSequence {
if *cmd.Status.Code == kproto.Command_Status_SUCCESS {
// Status SUCCESS
switch *cmd.Header.MessageType {
case kproto.Command_GET_RESPONSE:
// GET
op.value <- value
case kproto.Command_GETVERSION_RESPONSE:
// Get Version
op.value <- cmd.Body.KeyValue.DbVersion
case kproto.Command_GETNEXT_RESPONSE:
// Get Next
op.value <- cmd.Body.KeyValue.Key
case kproto.Command_GETPREVIOUS_RESPONSE:
// Get Previous
op.value <- cmd.Body.KeyValue.Key
case kproto.Command_GETKEYRANGE_RESPONSE:
// Get Key Range
op.array <- cmd.Body.Range.Keys
default:
// PUT, DELETE
op.receiver <- response // TODO: send back the actual response
}
} else {
// Status FAILURE
op.receiver <- response // TODO: send back the actual response
}
break
} else {
// Either we missed it or it hasnt arrived yet.
pending[op.sequence] = op
op, ok := pending[*cmd.Header.AckSequence]
if ok { // this is the case where we missed it
op.receiver <- response
delete(pending, op.sequence)
break
}
}
}
}
// Notify all pendings that we are closed for business
}