gearman-go/worker/agent.go
2014-12-10 09:13:49 +08:00

203 lines
3.6 KiB
Go

package worker
import (
"bufio"
"bytes"
"encoding/binary"
"net"
"sync"
"io"
)
// The agent of job server.
type agent struct {
sync.Mutex
conn net.Conn
rw *bufio.ReadWriter
worker *Worker
in chan []byte
net, addr string
}
// Create the agent of job server.
func newAgent(net, addr string, worker *Worker) (a *agent, err error) {
a = &agent{
net: net,
addr: addr,
worker: worker,
in: make(chan []byte, queueSize),
}
return
}
func (a *agent) Connect() (err error) {
a.Lock()
defer a.Unlock()
a.conn, err = net.Dial(a.net, a.addr)
if err != nil {
return
}
a.rw = bufio.NewReadWriter(bufio.NewReader(a.conn),
bufio.NewWriter(a.conn))
go a.work()
return
}
func (a *agent) work() {
defer func() {
if err := recover(); err != nil {
a.worker.err(err.(error))
}
}()
var inpack *inPack
var l int
var err error
var data, leftdata []byte
for {
if data, err = a.read(); err != nil {
if opErr, ok := err.(*net.OpError); ok {
if opErr.Temporary() {
continue
}else{
a.disconnect_error(err)
// else - we're probably dc'ing due to a Close()
break
}
} else if( err == io.EOF ){
a.disconnect_error(err)
break
}
a.worker.err(err)
// If it is unexpected error and the connection wasn't
// closed by Gearmand, the agent should close the conection
// and reconnect to job server.
a.Close()
a.conn, err = net.Dial(a.net, a.addr)
if err != nil {
a.worker.err(err)
break
}
a.rw = bufio.NewReadWriter(bufio.NewReader(a.conn),
bufio.NewWriter(a.conn))
}
if len(leftdata) > 0 { // some data left for processing
data = append(leftdata, data...)
}
if len(data) < minPacketLength { // not enough data
leftdata = data
continue
}
if inpack, l, err = decodeInPack(data); err != nil {
a.worker.err(err)
leftdata = data
continue
}
leftdata = nil
inpack.a = a
a.worker.in <- inpack
if len(data) > l {
leftdata = data[l:]
}
}
}
func (a * agent) disconnect_error( err error ){
if( a.conn != nil ){
err = &WorkerDisconnectError{
err : err,
agent : a,
}
a.worker.err(err)
}
}
func (a *agent) Close() {
a.Lock()
defer a.Unlock()
if a.conn != nil {
a.conn.Close()
a.conn = nil
}
}
func (a *agent) Grab() {
a.Lock()
defer a.Unlock()
a.grab()
}
func (a *agent) grab(){
outpack := getOutPack()
outpack.dataType = dtGrabJobUniq
a.write(outpack)
}
func (a *agent) PreSleep() {
a.Lock()
defer a.Unlock()
outpack := getOutPack()
outpack.dataType = dtPreSleep
a.write(outpack)
}
func (a *agent) reconnect() (error){
a.Lock()
defer a.Unlock()
conn, err := net.Dial(a.net, a.addr)
if err != nil {
return err;
}
a.conn = conn
a.rw = bufio.NewReadWriter(bufio.NewReader(a.conn),
bufio.NewWriter(a.conn))
a.grab()
a.worker.reRegisterFuncsForAgent(a)
go a.work()
return nil
}
// read length bytes from the socket
func (a *agent) read() (data []byte, err error) {
n := 0
tmp := getBuffer(bufferSize)
var buf bytes.Buffer
// read the header so we can get the length of the data
if n, err = a.rw.Read(tmp); err != nil {
return
}
dl := int(binary.BigEndian.Uint32(tmp[8:12]))
// write what we read so far
buf.Write(tmp[:n])
// read until we receive all the data
for buf.Len() < dl+minPacketLength {
if n, err = a.rw.Read(tmp); err != nil {
return buf.Bytes(), err
}
buf.Write(tmp[:n])
}
return buf.Bytes(), err
}
// Internal write the encoded job.
func (a *agent) write(outpack *outPack) (err error) {
var n int
buf := outpack.Encode()
for i := 0; i < len(buf); i += n {
n, err = a.rw.Write(buf[i:])
if err != nil {
return err
}
}
return a.rw.Flush()
}