// Adds a new region to our regions cache.
func (c *Client) discoverRegion(ctx context.Context, metaRow *pb.GetResponse) (*region.Client, *regioninfo.Info, error) {
if metaRow.Result == nil {
return nil, nil, errors.New("table not found")
}
var host string
var port uint16
var reg *regioninfo.Info
for _, cell := range metaRow.Result.Cell {
switch string(cell.Qualifier) {
case "regioninfo":
var err error
reg, err = regioninfo.InfoFromCell(cell)
if err != nil {
return nil, nil, err
}
case "server":
value := cell.Value
if len(value) == 0 {
continue // Empty during NSRE.
}
colon := bytes.IndexByte(value, ':')
if colon < 1 { // Colon can't be at the beginning.
return nil, nil,
fmt.Errorf("broken meta: no colon found in info:server %q", cell)
}
host = string(value[:colon])
portU64, err := strconv.ParseUint(string(value[colon+1:]), 10, 16)
if err != nil {
return nil, nil, err
}
port = uint16(portU64)
default:
// Other kinds of qualifiers: ignore them.
// TODO: If this is the parent of a split region, there are two other
// KVs that could be useful: `info:splitA' and `info:splitB'.
// Need to investigate whether we can use those as a hint to update our
// regions_cache with the daughter regions of the split.
}
}
var res newRegResult
ret := make(chan newRegResult)
go newRegion(ret, host, port, c.rpcQueueSize, c.flushInterval)
select {
case res = <-ret:
case <-ctx.Done():
return nil, nil, ErrDeadline
}
if res.Err != nil {
return nil, nil, res.Err
}
c.addRegionToCache(reg, res.Client)
return res.Client, reg, nil
}
// parseMetaTableResponse parses the contents of a row from the meta table.
// It's guaranteed to return a region info and a host/port OR return an error.
func (c *Client) parseMetaTableResponse(metaRow *pb.GetResponse) (
*regioninfo.Info, string, uint16, error) {
var reg *regioninfo.Info
var host string
var port uint16
for _, cell := range metaRow.Result.Cell {
switch string(cell.Qualifier) {
case "regioninfo":
var err error
reg, err = regioninfo.InfoFromCell(cell)
if err != nil {
return nil, "", 0, err
}
case "server":
value := cell.Value
if len(value) == 0 {
continue // Empty during NSRE.
}
colon := bytes.IndexByte(value, ':')
if colon < 1 { // Colon can't be at the beginning.
return nil, "", 0,
fmt.Errorf("broken meta: no colon found in info:server %q", cell)
}
host = string(value[:colon])
portU64, err := strconv.ParseUint(string(value[colon+1:]), 10, 16)
if err != nil {
return nil, "", 0, err
}
port = uint16(portU64)
default:
// Other kinds of qualifiers: ignore them.
// TODO: If this is the parent of a split region, there are two other
// KVs that could be useful: `info:splitA' and `info:splitB'.
// Need to investigate whether we can use those as a hint to update our
// regions_cache with the daughter regions of the split.
}
}
if reg == nil {
// There was no regioninfo in the row in meta, this is really not
// expected.
err := fmt.Errorf("Meta seems to be broken, there was no regioninfo in %s",
metaRow)
log.Error(err.Error())
return nil, "", 0, err
} else if port == 0 { // Either both `host' and `port' are set, or both aren't.
return nil, "", 0, fmt.Errorf("Meta doesn't have a server location in %s",
metaRow)
}
return reg, host, port, nil
}
