使用Twisted中的反应器持续扫描数据库表时出错

Question

经过几个小时的成功运行后，我得到以下错误。在

Traceback (most recent call last): 
  File "/usr/lib/python2.6/threading.py", line 484, in run 
    self.__target(*self.__args, **self.__kwargs) 
  File "/usr/lib/python2.6/dist-packages/twisted/python/threadpool.py", line 210, in _worker 
    result = context.call(ctx, function, *args, **kwargs) 
  File "/usr/lib/python2.6/dist-packages/twisted/python/context.py", line 59, in callWithContext 
    return self.currentContext().callWithContext(ctx, func, *args, **kw) 
  File "/usr/lib/python2.6/dist-packages/twisted/python/context.py", line 37, in callWithContext 
    return func(*args,**kw) 
--- <exception caught here> --- 
  File "/usr/lib/python2.6/dist-packages/twisted/enterprise/adbapi.py", line 436, in _runInteraction 
    conn.rollback() 
  File "/usr/lib/python2.6/dist-packages/twisted/enterprise/adbapi.py", line 52, in rollback 
    self._connection.rollback() 
_mysql_exceptions.OperationalError: (2006, 'MySQL server has gone away') 

我的代码是这样的。。。在

^{pr2}$

有人能告诉我为什么会出错吗？在

Answer 1

在Matt的所有建议和帮助之后，我有以下代码成功运行：

#!usr/bin/python
# Using the "dbmodule" from the previous example, create a ConnectionPool
from twisted.internet import reactor
from twisted.enterprise import adbapi
from twisted.internet import reactor, defer,threads
from twisted.python.threadpool import ThreadPool
import itertools
from twisted.internet.threads import deferToThread
from twisted.internet import reactor, defer, task
from tools.printTime import *
from tools.getVersion import *
from sh_log import *


concurrent = 30
finished=itertools.count(1)
reactor.suggestThreadPoolSize(concurrent)


#Creating Global Instance variables
path="tools"
lo=Log()

class ToolsBuilder:

  def build(self,txn,tool,asset_id):
    if tool:
        print "\n"
        try:
            sql="select tool_filename from tool_master where tool_id = %s" %(tool,)
            sql_asset="select asset_url from asset_master where asset_id = %s" %(asset_id,)
            txn.execute(sql_asset)
            asset_url = txn.fetchall()
            log_date=lo.log_date()
            txn.execute(sql)
            result = txn.fetchall()

            log='\n'+log_date+"::"+str(result[0][0])+ " tool object is created......\n"
            lo.wfile(log)
            temp=(path +'/' + str(result[0][0]))

            if result:
                if temp:
                    f=open(temp).read()
                    obj_tool=compile(f, 'a_filename', 'exec')
                    return obj_tool
        except:
            lo.wfile("Error in creating executable tool object......")
tb=ToolsBuilder()

class ToolsVectorGenerator:

  def generate(self,txn,res_set={}):

    v1=[]
    for asset_id in res_set.iterkeys():
        try:
            obj_tools=[]
            if asset_id:
                print "asset_id..............................",asset_id
                log_date=lo.log_date()
                log=log_date+"::"+" \nVector generation for the asset number...:"+str(asset_id)
                lo.wfile(log)
                vector=[]
                tools_arr=[]
                obj_tools=[]
                for tool in res_set[asset_id]:
                    if tool:
                        print "tool..............",tool
                        temp_tool=tb.build(txn,tool,asset_id)
                        print "temp_tool..........",temp_tool

                        #fetch data of tool setting.....
                        sql_tool_setting="select * from tool_asset_settings where tool_id =%s" %(tool,)
                        txn.execute(sql_tool_setting)
                        result_tool_setting = txn.fetchall()
                        tool_id=result_tool_setting[0][1]
                        t_id=int(tool_id)
                        tool_id_arr=[]
                        tool_id_arr.append(t_id)
                        tool_id_arr.append(result_tool_setting)
                        tool_id_arr.append(temp_tool)
                        tools_arr.append(tool_id_arr)

                #fetch data from asset master
                sql_asset="select asset_name from asset_master where asset_id=%s" %(asset_id,)
                txn.execute(sql_asset)
                result_asset = txn.fetchall()
                vector.append(result_asset)
                vector.append(tools_arr)
        except:
            lo.wfile("\nError in getting asset,please check your database or network connection......")
        tvm.executeVector(vector)
tvg=ToolsVectorGenerator()

class Tool:

  def exectool(self,tool):
      exec tool
      return

  def getResult(self,tool):
      return deferToThread(self.exectool, tool)

to=Tool()

class StateMachine:

  def setPriority(self,txn,tup):
        temp=[]
        arr=[]
        for li in tup:
            sql2="select tool_dependency from tool_asset_settings where tool_id =%s" %(li[1],)
            txn.execute(sql2)
            result12 = txn.fetchall()
            arr=[]
            if result12[0][0]!=None:
                tup12=result12[0][0]
                arr=(li[0],tup12)
    #                print "arr.........",arr
                if arr in tup:
                    print "This element is already exist......."
                else:
                    temp.append(arr)
        temp.extend(tup)
        return tuple(temp)

st=StateMachine()

class ToolsVectorExecutionManager(object):

    def executeVector(self,toolsvector):
        print "toolsvector================>",toolsvector
        if toolsvector:
            for tools in toolsvector[1]:
                if tools[2] != None:
                    to.getResult(tools[2])

tvm=ToolsVectorExecutionManager()

class ToolsToExecuteAnalyzer:

  def __init__(self,dbpool=None):
    self.dbpool = dbpool
    self.loopCall = task.LoopingCall(self.myQuery)

  def start(self):
    print "Started scanner"
    self.loopCall.start(3)

  def stop(self):
    print "Stopping scanner"
    self.loopCall.stop()

  def myQuery(self):

    def interact(txn):
      sql="SELECT tool_asset_id,tool_execute_id FROM tool_to_execute where status='0'"
      txn.execute(sql)
      result=txn.fetchall()
      if result:
            tool_asset_id=tuple([int(e[0]) for e in result])
            tool_execute_id=tuple([int(e[1]) for e in result])
            if len(tool_asset_id)>1:
                sql1="SELECT asset_id,tool_id FROM tool_in_assets WHERE tool_asset_id IN %s"%(tool_asset_id,)
            else:
                sql1="SELECT asset_id,tool_id FROM tool_in_assets WHERE tool_asset_id = (%s)"%(tool_asset_id)
            txn.execute(sql1)
            tup = txn.fetchall()

#dependency check for the selected tool
            asset_tool=st.setPriority(txn,tup)

            log_date=lo.log_date()
            log=log_date+"::priority have been set for the tools......\n"
            lo.wfile(log)

#creating group of asset with their tools
            res={}
            for element in asset_tool:
                if element[0] in res:
                    res[element[0]].append(int(element[1]))
                else:
                    res[int(element[0])] = [int(element[1])]
#Recored deletion from tool_to_execute table
            if res!=None and res.keys()!=[]:
                for asset_id in res.iterkeys():
                    if len(tool_execute_id)>1:
                        sql_del="delete from tool_to_execute where tool_execute_id in %s " %(tool_execute_id,)
                    else:
                        sql_del="delete from tool_to_execute where tool_execute_id = %s" %(tool_execute_id)
                txn.execute(sql_del)

#New Addition of vector
            tvg.generate(txn,res)
#            return res

    d = self.dbpool.runInteraction(interact)
    d.addCallbacks(self.printResult,self.printError)

  def printResult(self,res):

    print "In printResult after generate...."

  def printError(self,error):

    print "Got Error: %r" % error
    error.printTraceback()

ToolsToExecuteAnalyzer()


if __name__ == '__main__':

  from twisted.internet import reactor

  dbpool = adbapi.ConnectionPool("MySQLdb", 'localhost', 'test', 'test','test')
  s = ToolsToExecuteAnalyzer(dbpool)
  reactor.callWhenRunning(s.start)
  reactor.addSystemEventTrigger('before','shutdown',s.stop)
  reactor.run()

这是我的全部代码，我只想知道有多少线程在运行，意味着每个工具都有新的线程？
无论如何，谢谢马特的帮助……）

Answer 2

can anyone tell me why I am getting this error..因为你做错了。在

runInteraction使用游标参数运行提供的函数，该函数指向在线程中运行的事务。你不应该打电话给reactor.callInThread(Scanner().deferExecute)。在

• 最好使用twisted.internet.task.LoopingCall，它将确保在激发下一个调用之前完成调用。在
• 您只是在示例中运行一个查询，因此可以使用ConnectionPool.runQuery而不是ConnectionPool.runInteraction. 在
• 使用errorBack函数报告异常。在

在尝试更正格式错误的代码时，我认为您得到了以下信息：

from twisted.internet import reactor, defer,threads
from twisted.enterprise import adbapi

dbpool = adbapi.ConnectionPool("MySQLdb", '192.168.1.102','test', 'test', 'test')

class Scanner:
  def _execQuery(self,txn):
    sql="SELECT tool_id,tool_name FROM tool_master"
    txn.execute(sql)
    result = txn.fetchall()
    return result

  def objCursor(self):
    return dbpool.runInteraction(self._execQuery)

  def printResult(self,result):
    print "resssssssssssssssssss",result
    reactor.callLater(3,self.deferExecute)

  def deferExecute(self):
    self.objCursor().addCallback(self.printResult)

Scanner()

class MyApp(object):
  reactor.callInThread(Scanner().deferExecute)
  reactor.run()

MyApp()

当你可能需要像下面这样的东西。如果您计划编写一个twisted Application将很容易修改这个Scanner类以从twisted.application.service.Service继承。在

^{pr2}$

Answer 3

您可能还想看看这个片段，它提供了一个ConnectionPool子类，它在“MySQL server has going away”上重新连接。在

http://www.gelens.org/2009/09/13/twisted-connectionpool-revisited/