// mustParseStmt parses a single statement or panics.
func mustParseStmt(stmt string) influxql.Statement {
q, err := influxql.ParseQuery(stmt)
if err != nil {
panic(err)
} else if len(q.Statements) != 1 {
panic(fmt.Sprintf("expected 1 statement but got %d", len(q.Statements)))
}
return q.Statements[0]
}
func (s *Service) processMapShardRequest(w io.Writer, buf []byte) error {
// Decode request
var req MapShardRequest
if err := req.UnmarshalBinary(buf); err != nil {
return err
}
// Parse the statement.
q, err := influxql.ParseQuery(req.Query())
if err != nil {
return fmt.Errorf("processing map shard: %s", err)
} else if len(q.Statements) != 1 {
return fmt.Errorf("processing map shard: expected 1 statement but got %d", len(q.Statements))
}
m, err := s.TSDBStore.CreateMapper(req.ShardID(), q.Statements[0], int(req.ChunkSize()))
if err != nil {
return fmt.Errorf("create mapper: %s", err)
}
if m == nil {
return writeMapShardResponseMessage(w, NewMapShardResponse(0, ""))
}
if err := m.Open(); err != nil {
return fmt.Errorf("mapper open: %s", err)
}
defer m.Close()
var metaSent bool
for {
var resp MapShardResponse
if !metaSent {
resp.SetTagSets(m.TagSets())
resp.SetFields(m.Fields())
metaSent = true
}
chunk, err := m.NextChunk()
if err != nil {
return fmt.Errorf("next chunk: %s", err)
}
// NOTE: Even if the chunk is nil, we still need to send one
// empty response to let the other side know we're out of data.
if chunk != nil {
b, err := json.Marshal(chunk)
if err != nil {
return fmt.Errorf("encoding: %s", err)
}
resp.SetData(b)
}
// Write to connection.
resp.SetCode(0)
if err := writeMapShardResponseMessage(w, &resp); err != nil {
return err
}
if chunk == nil {
// All mapper data sent.
return nil
}
}
}