gearman-go/worker/request.go

// 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 (
	"bytes"
	"strconv"
)

// Worker side job
type Job struct {
	Data                 []byte
	Handle, UniqueId, Fn string
	agent                *agent
	magicCode, DataType  uint32
	c                    chan bool
}

// Create a new job
func newJob(magiccode, datatype uint32, data []byte) (job *Job) {
	return &Job{magicCode: magiccode,
		DataType: datatype,
		Data:     data,
		c:        make(chan bool)}
}

// Decode job from byte slice
func decodeJob(data []byte) (job *Job, err error) {
	if len(data) < 12 {
		return nil, common.Errorf("Invalid data: %V", data)
	}
	datatype := common.BytesToUint32([4]byte{data[4], data[5], data[6], data[7]})
	l := common.BytesToUint32([4]byte{data[8], data[9], data[10], data[11]})
	if len(data[12:]) != int(l) {
		return nil, common.Errorf("Invalid data: %V", data)
	}
	data = data[12:]
	job = &Job{magicCode: common.RES, DataType: datatype, c: make(chan bool)}
	switch datatype {
	case common.JOB_ASSIGN:
		s := bytes.SplitN(data, []byte{'\x00'}, 3)
		if len(s) == 3 {
			job.Handle = string(s[0])
			job.Fn = string(s[1])
			data = s[2]
		}
	case common.JOB_ASSIGN_UNIQ:
		s := bytes.SplitN(data, []byte{'\x00'}, 4)
		if len(s) == 4 {
			job.Handle = string(s[0])
			job.Fn = string(s[1])
			job.UniqueId = string(s[2])
			data = s[3]
		}
	}
	job.Data = data
	return
}

// Encode a job to byte slice
func (job *Job) Encode() (data []byte) {
	var l int
	if job.DataType == common.WORK_FAIL {
		l = len(job.Handle)
	} else {
		l = len(job.Data)
		if job.Handle != "" {
			l += len(job.Handle) + 1
		}
	}
	data = make([]byte, 0, l+12)

	magiccode := common.Uint32ToBytes(job.magicCode)
	datatype := common.Uint32ToBytes(job.DataType)
	datalength := common.Uint32ToBytes(uint32(l))

	data = append(data, magiccode[:]...)
	data = append(data, datatype[:]...)
	data = append(data, datalength[:]...)
	if job.Handle != "" {
		data = append(data, []byte(job.Handle)...)
		if job.DataType != common.WORK_FAIL {
			data = append(data, 0)
		}
	}
	data = append(data, job.Data...)
	return
}

// Send some datas to client.
// Using this in a job's executing.
func (job *Job) UpdateData(data []byte, iswarning bool) {
	result := append([]byte(job.Handle), 0)
	result = append(result, data...)
	var datatype uint32
	if iswarning {
		datatype = common.WORK_WARNING
	} else {
		datatype = common.WORK_DATA
	}
	job.agent.WriteJob(newJob(common.REQ, datatype, result))
}

// Update status.
// Tall client how many percent job has been executed.
func (job *Job) UpdateStatus(numerator, denominator int) {
	n := []byte(strconv.Itoa(numerator))
	d := []byte(strconv.Itoa(denominator))
	result := append([]byte(job.Handle), '\x00')
	result = append(result, n...)
	result = append(result, '\x00')
	result = append(result, d...)
	job.agent.WriteJob(newJob(common.REQ, common.WORK_STATUS, result))
}

// close the job
func (job *Job) Close() {
	close(job.c)
}

// cancel the job executing
func (job *Job) cancel() {
	defer func() { recover() }()
	job.c <- true
}

// When a job was canceled, return a true form a channel
func (job *Job) Canceled() <-chan bool {
	return job.c
}