/
agent_server_read.go
85 lines (68 loc) · 1.98 KB
/
agent_server_read.go
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package agent
import (
"bytes"
"encoding/binary"
"io"
"log"
"net"
"github.com/chrislusf/gleam/util"
)
func (as *AgentServer) handleReadConnection(conn net.Conn, readerName, channelName string) {
log.Printf("on disk %s waits for %s", readerName, channelName)
dsStore := as.storageBackend.WaitForNamedDatasetShard(channelName)
log.Printf("on disk %s starts reading %s", readerName, channelName)
var offset int64
var err error
var size int32
sizeBuf := make([]byte, 4)
sizeReader := bytes.NewReader(sizeBuf)
var count int64
messageBytesCache := make([]byte, util.BUFFER_SIZE)
var messageBytes []byte
messageWriter := util.NewBufferedMessageWriter(conn, util.BUFFER_SIZE)
// loop for every read
for {
_, err = dsStore.ReadAt(sizeBuf, offset)
if err != nil {
// connection is closed
if err != io.EOF {
log.Printf("Read size from %s offset %d: %v", channelName, offset, err)
}
// println("got problem reading", channelName, offset, err.Error())
break
}
sizeReader.Reset(sizeBuf)
binary.Read(sizeReader, binary.LittleEndian, &size)
if size == int32(util.MessageControlEOF) {
break
}
// println("reading", channelName, offset, "size:", size)
offset += 4
if size > util.BUFFER_SIZE {
messageBytes = make([]byte, size)
} else {
messageBytes = messageBytesCache[0:size]
}
_, err = dsStore.ReadAt(messageBytes, offset)
if err != nil {
// connection is closed
if err != io.EOF {
log.Printf("Read data from %s offset %d: %v", channelName, offset, err)
}
break
}
offset += int64(size)
err = messageWriter.WriteMessage(messageBytes)
if err != nil {
log.Printf("%s failed to receive %s at %d: %v", readerName, channelName, offset, err)
break
}
count += int64(size)
}
messageWriter.Flush()
if err != nil {
log.Printf("on disk %s finished reading %s %d bytes error: %v", readerName, channelName, count, err)
} else {
log.Printf("on disk %s finished reading %s %d bytes", readerName, channelName, count)
}
}