- // Copyright 2011 Xing Xing <mikespook@gmail.com> All rights reserved.
- // Use of this source code is governed by a MIT
- // license that can be found in the LICENSE file.
-
- package worker
-
- import (
- "fmt"
- "time"
- "sync"
- "encoding/binary"
- )
-
- const (
- Unlimited = 0
- OneByOne = 1
-
- Immediately = 0
- )
-
- /*
- Worker side api for gearman
-
- usage:
- w = worker.New(worker.Unlimited)
- w.AddFunction("foobar", foobar)
- w.AddServer("127.0.0.1:4730")
- w.Work() // Enter the worker's main loop
-
- The definition of the callback function 'foobar' should suit for the type 'JobFunction'.
- It looks like this:
-
- func foobar(job *Job) (data []byte, err os.Error) {
- //sth. here
- //plaplapla...
- return
- }
- */
- type Worker struct {
- agents map[string]*agent
- funcs JobFuncs
- in chan *Response
- running bool
- limit chan bool
-
- Id string
- // assign a ErrFunc to handle errors
- ErrorHandler ErrorHandler
- JobHandler JobHandler
- mutex sync.Mutex
- }
-
- // Get a new worker
- func New(l int) (worker *Worker) {
- worker = &Worker{
- agents: make(map[string]*agent, QUEUE_SIZE),
- funcs: make(JobFuncs),
- in: make(chan *Response, QUEUE_SIZE),
- }
- if l != Unlimited {
- worker.limit = make(chan bool, l)
- }
- return
- }
-
- //
- func (worker *Worker) err(e error) {
- if worker.ErrorHandler != nil {
- worker.ErrorHandler(e)
- }
- }
-
- // Add a server. The addr should be 'host:port' format.
- // The connection is established at this time.
- func (worker *Worker) AddServer(net, addr string) (err error) {
- // Create a new job server's client as a agent of server
- a, err := newAgent(net, addr, worker)
- if err != nil {
- return err
- }
- worker.agents[net + addr] = a
- return
- }
-
- // Write a job to job server.
- // Here, the job's mean is not the oraginal mean.
- // Just looks like a network package for job's result or tell job server, there was a fail.
- func (worker *Worker) broadcast(req *request) {
- for _, v := range worker.agents {
- v.write(req)
- }
- }
-
- // Add a function.
- // Plz added job servers first, then functions.
- // The API will tell every connected job server that 'I can do this'
- func (worker *Worker) AddFunc(funcname string,
- f JobFunc, timeout uint32) (err error) {
- worker.mutex.Lock()
- defer worker.mutex.Unlock()
- if _, ok := worker.funcs[funcname]; ok {
- return fmt.Errorf("The function already exists: %s", funcname)
- }
- worker.funcs[funcname] = &jobFunc{f: f, timeout: timeout}
- if worker.running {
- worker.addFunc(funcname, timeout)
- }
- return
- }
-
- // inner add function
- func (worker *Worker) addFunc(funcname string, timeout uint32) {
- req := getRequest()
- if timeout == 0 {
- req.DataType = CAN_DO
- req.Data = []byte(funcname)
- } else {
- req.DataType = CAN_DO_TIMEOUT
- l := len(funcname)
- req.Data = getBuffer(l + 5)
- copy(req.Data, []byte(funcname))
- req.Data[l] = '\x00'
- binary.BigEndian.PutUint32(req.Data[l + 1:], timeout)
- }
- worker.broadcast(req)
- }
-
- // Remove a function.
- func (worker *Worker) RemoveFunc(funcname string) (err error) {
- worker.mutex.Lock()
- defer worker.mutex.Unlock()
- if _, ok := worker.funcs[funcname]; !ok {
- return fmt.Errorf("The function does not exist: %s", funcname)
- }
- delete(worker.funcs, funcname)
- if worker.running {
- worker.removeFunc(funcname)
- }
- return
- }
-
- // inner remove function
- func (worker *Worker) removeFunc(funcname string) {
- req := getRequest()
- req.DataType = CANT_DO
- req.Data = []byte(funcname)
- worker.broadcast(req)
- }
-
- func (worker *Worker) dealResp(resp *Response) {
- defer func() {
- if worker.running && worker.limit != nil {
- <-worker.limit
- }
- }()
- switch resp.DataType {
- case ERROR:
- worker.err(GetError(resp.Data))
- case JOB_ASSIGN, JOB_ASSIGN_UNIQ:
- if err := worker.exec(resp); err != nil {
- worker.err(err)
- }
- default:
- worker.handleResponse(resp)
- }
- }
-
- // Main loop
- func (worker *Worker) Work() {
- defer func() {
- for _, v := range worker.agents {
- v.Close()
- }
- }()
- worker.running = true
- for _, v := range worker.agents {
- v.Connect()
- go v.Work()
- }
- worker.Reset()
- for funcname, f := range worker.funcs {
- worker.addFunc(funcname, f.timeout)
- }
- var resp *Response
- for resp = range worker.in {
- go worker.dealResp(resp)
- }
- }
-
- // job handler
- func (worker *Worker) handleResponse(resp *Response) {
- if worker.JobHandler != nil {
- job := getJob()
- job.a = worker.agents[resp.agentId]
- job.Handle = resp.Handle
- if resp.DataType == ECHO_RES {
- job.data = resp.Data
- }
- if err := worker.JobHandler(job); err != nil {
- worker.err(err)
- }
- }
- }
-
- // Close.
- func (worker *Worker) Close() {
- worker.running = false
- close(worker.in)
- if worker.limit != nil {
- close(worker.limit)
- }
- }
-
- // Send a something out, get the samething back.
- func (worker *Worker) Echo(data []byte) {
- req := getRequest()
- req.DataType = ECHO_REQ
- req.Data = data
- worker.broadcast(req)
- }
-
- // Remove all of functions.
- // Both from the worker or job servers.
- func (worker *Worker) Reset() {
- req := getRequest()
- req.DataType = RESET_ABILITIES
- worker.broadcast(req)
- worker.funcs = make(JobFuncs)
- }
-
- // Set the worker's unique id.
- func (worker *Worker) SetId(id string) {
- worker.Id = id
- req := getRequest()
- req.DataType = SET_CLIENT_ID
- req.Data = []byte(id)
- worker.broadcast(req)
- }
-
- // Execute the job. And send back the result.
- func (worker *Worker) exec(resp *Response) (err error) {
- defer func() {
- if r := recover(); r != nil {
- if e, ok := r.(error); ok {
- err = e
- } else {
- err = ErrUnknown
- }
- }
- }()
- f, ok := worker.funcs[resp.Fn]
- if !ok {
- return fmt.Errorf("The function does not exist: %s", resp.Fn)
- }
- var r *result
- job := getJob()
- job.a = worker.agents[resp.agentId]
- job.Handle = resp.Handle
- if f.timeout == 0 {
- d, e := f.f(job)
- r = &result{data: d, err: e}
- } else {
- r = execTimeout(f.f, job, time.Duration(f.timeout)*time.Second)
- }
- req := getRequest()
- if r.err == nil {
- req.DataType = WORK_COMPLETE
- } else {
- if r.data == nil {
- req.DataType = WORK_FAIL
- } else {
- req.DataType = WORK_EXCEPTION
- }
- err = r.err
- }
- req.Data = r.data
- if worker.running {
- job.a.write(req)
- }
- return
- }
-
- type result struct {
- data []byte
- err error
- }
-
- func execTimeout(f JobFunc, job Job, timeout time.Duration) (r *result) {
- rslt := make(chan *result)
- defer close(rslt)
- go func() {
- defer func() { recover() }()
- d, e := f(job)
- rslt <- &result{data: d, err: e}
- }()
- select {
- case r = <-rslt:
- case <-time.After(timeout):
- return &result{err: ErrTimeOut}
- }
- return r
- }
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