// serveShardMapping maps the requested shard and streams data back to the client.
func (h *Handler) serveShardMapping(w http.ResponseWriter, r *http.Request) {
w.Header().Add("content-type", "application/json")
var err error
// Pull out shard ID, query statement, and chunking size.
q := r.URL.Query()
pretty := q.Get("pretty") == "true"
id, s, cs := q.Get("shard"), q.Get("q"), q.Get("chunksize")
var chunkSize int
if id == "" {
httpError(w, `no shard ID specified`, pretty, http.StatusBadRequest)
return
}
shardID, err := strconv.Atoi(id)
if err != nil {
httpError(w, `shard ID is not valid`, pretty, http.StatusBadRequest)
return
}
if s == "" {
httpError(w, `no query specified`, pretty, http.StatusBadRequest)
return
}
if cs == "" {
chunkSize = 0
} else {
chunkSize, err = strconv.Atoi(cs)
if err != nil {
httpError(w, `chunk size is not valid`, pretty, http.StatusBadRequest)
return
}
}
mapper, err := h.TSDBStore.CreateMapper(uint64(shardID), s, chunkSize)
if err != nil {
httpError(w, fmt.Sprintf("mapper create: %s", err), pretty, http.StatusInternalServerError)
}
if mapper == nil {
b := MarshalJSON(&tsdb.MapperResponse{}, pretty)
w.Write(b)
w.(http.Flusher).Flush()
return
}
if err := mapper.Open(); err != nil {
httpError(w, fmt.Sprintf("mapper open: %s", err), pretty, http.StatusInternalServerError)
}
defer mapper.Close()
var tagSetsSent bool
for {
var r tsdb.MapperResponse
if !tagSetsSent {
r.TagSets = mapper.TagSets()
tagSetsSent = true
}
chunk, err := mapper.NextChunk()
if err != nil {
httpError(w, fmt.Sprintf("next chunk: %s", err), pretty, http.StatusInternalServerError)
return
}
if chunk != nil {
data := MarshalJSON(&chunk, pretty)
r.Data = data
}
b := MarshalJSON(&r, pretty)
w.Write(b)
w.(http.Flusher).Flush()
if chunk == nil {
return
}
}
}