Thrift python常见错误分析

来源：互联网发布：数据建模是什么编辑：程序博客网时间：2024/05/01 08:11

使用Thrift经常碰到错误提示“No handlers could be found for logger "thrift.server.TServer"”，这句话其实很坑人，尤其是使用thrift的新手。因为，看到这句话也许会认为，应该是自己编写的server程序框架有问题。也就是如下部分：

<span style="font-size:12px;">handler = XXFilterSpamTextServiceHandler()processor = XXFilterSpamTextService.Processor(handler)transport = TSocket.TServerSocket(port=9090)tfactory = TTransport.TBufferedTransportFactory()pfactory = TBinaryProtocol.TBinaryProtocolFactory()server = TServer.TSimpleServer(processor, transport, tfactory, pfactory)print "starting serve"server.serve()print "done!"</span>

当然，有在这部分出错的，也有在其他地方出错的。下面我们详细分析。

一.程序框架出错

此类错误易犯人群：小白、程序刚刚写完第一次调试阶段。这个错误解法相当简单。比照模版看看出错在那里，官网模版地址http://thrift.apache.org/tutorial/py。server程序代码如下：

import sys, globsys.path.append('gen-py')sys.path.insert(0, glob.glob('../../lib/py/build/lib.*')[0])from tutorial import Calculatorfrom tutorial.ttypes import *from shared.ttypes import SharedStructfrom thrift.transport import TSocketfrom thrift.transport import TTransportfrom thrift.protocol import TBinaryProtocolfrom thrift.server import TServerclass CalculatorHandler:  def __init__(self):    self.log = {}  def ping(self):    print 'ping()'  def add(self, n1, n2):    print 'add(%d,%d)' % (n1, n2)    return n1+n2  def calculate(self, logid, work):    print 'calculate(%d, %r)' % (logid, work)    if work.op == Operation.ADD:      val = work.num1 + work.num2    elif work.op == Operation.SUBTRACT:      val = work.num1 - work.num2    elif work.op == Operation.MULTIPLY:      val = work.num1 * work.num2    elif work.op == Operation.DIVIDE:      if work.num2 == 0:        x = InvalidOperation()        x.what = work.op        x.why = 'Cannot divide by 0'        raise x      val = work.num1 / work.num2    else:      x = InvalidOperation()      x.what = work.op      x.why = 'Invalid operation'      raise x    log = SharedStruct()    log.key = logid    log.value = '%d' % (val)    self.log[logid] = log    return val  def getStruct(self, key):    print 'getStruct(%d)' % (key)    return self.log[key]  def zip(self):    print 'zip()'handler = CalculatorHandler()processor = Calculator.Processor(handler)transport = TSocket.TServerSocket(port=9090)tfactory = TTransport.TBufferedTransportFactory()pfactory = TBinaryProtocol.TBinaryProtocolFactory()server = TServer.TSimpleServer(processor, transport, tfactory, pfactory)# You could do one of these for a multithreaded server#server = TServer.TThreadedServer(processor, transport, tfactory, pfactory)#server = TServer.TThreadPoolServer(processor, transport, tfactory, pfactory)print 'Starting the server...'server.serve()print 'done.'

接下来，我们需要说的是：CalculatorHandler，这个类名需要根据实际情况构造，比如这里他们的名字thrift中的服务类的名字Calculator，然后加上一个Handler就可以构造为服务类了，这种类我们统称为Handler类。

二.编写的Handler类中小错误

thrift框架做的很好，封装的也很好，不仅仅有代码生成功能，而且还有错误处理机制。这种错误处理机制处理过程是：当Handler类中的出现错误时，一律提示：“No handlers could be found for logger "thrift.server.TServer"”。换句话说，当变量拼写错误时，不会提示某个变量未命名，而提示“No handlers could be found for logger "thrift.server.TServer"”，这样无疑增加了改错难度，坑啊！！！

对于此，比较好的解决方案是：使用try....except Exception as e:模块来手动打印错误。try模块代码示例如下：

try：    a=bexcept Exception as  e:    print e

这样出错时候，就会报出哪里出错了！！！！

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