Python crontab 尝试除 ValueError

Question

我有这个脚本，当我从命令行运行时它工作正常...

#!/usr/bin/python
# -*- coding: utf-8 -*-

import time
from time import sleep
import os
import logging
import glob
import sys
import subprocess
import pymssql
import shutil
import StringIO
from StringIO import StringIO

#Check share mounted
if os.path.ismount("/home/marco/cas01-share/") == 0:

    #logging.info('share not mounted')
    print "share not mounted"
    #mount share
    #logging.info('share now mounted')
    #print "share now mounted"
else:
    print "share mounted"

# File paths
fullpath2Newfile = "/home/marco/cas01-share/New/"
fullpathfiles2Process = "/home/marco/cas01-share/Process/"
fullpathProcessedfiles = "/home/marco/cas01-share/Processed/"

if not os.listdir('/home/marco/cas01-share/New'):
    print "directory empty"
else:
    print "directory not empty"

    # Directory more than one file?
    num_files = len([f for f in os.listdir('/home/marco/cas01-share/New')
                if os.path.isfile(os.path.join('/home/marco/cas01-share/New', f))])
    print "directory has " + str(num_files) + " files"



    num_files = 0

    for filename in os.listdir('/home/marco/cas01-share/New'):
        succesfullRun = 0
        num_files += 1

        print filename
        filename = str(filename)
        batchnumber = filename.strip("['SENSE-extract-ascii--.csv']")[:-9]
        print batchnumber

        newfullpath2Newfile = fullpath2Newfile + filename
        fullpathfiles2Process = "/home/marco/cas01-share/Process/SENSE-extract.csv"
        fullpathProcessedfiles = "/home/marco/cas01-share/Processed/SENSE-extract-" + batchnumber + ".csv"
        print newfullpath2Newfile
        print fullpathfiles2Process
        print fullpathProcessedfiles


        # Execute job
        ExceptionFlag = 0
        while (succesfullRun == 0):

            if ExceptionFlag == 0:
                shutil.move(newfullpath2Newfile, fullpathfiles2Process)

            try:

                # Move to sense check folder
                # Connect to DB
                conn = pymssql.connect(server='IP', user='User', password='password', tds_version='8.0')
                cursor = conn.cursor()
                cursor.execute("EXEC msdb.dbo.sp_start_job @job_name = 'Marco_test'")

            except Exception as e:
                (error_code, error_message) = e

                ExceptionFlag = 1

                #print error_message

                if "does not exist" in error_message:
                    print "ERROR: Job name not found"

                if "job is already running" in error_message:
                    print "ERROR: a Job is already running"

                if "job already has a pending request" in error_message:
                    print "ERROR: pending request"

                time.sleep(0.5)

            else:
                print "Job executed succesfully"
                # Copy file to processed
                shutil.copy(fullpathfiles2Process, fullpathProcessedfiles)

                succesfullRun = 1

            conn.close()
            time.sleep(0.5)

exit()

但是当我尝试在 crontab 上安排时，出现以下错误

# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h  dom mon dow   command

#SENSE
*/5 * * * * /usr/bin/python /home/administrator/Share/scripts/python3 >> /home/administrator/Share/scripts/logs/sense$

我收到这个错误:

Traceback (most recent call last): File "...", line 239, in (error_code, error_message) = e ValueError: need more than 1 value to unpack

我认为这与“cronos 计划执行作业”和它自己的脚本之间没有管道有关，我不知道这是否有意义，就像它不知道从哪里获取信息一样......

本质上是试图捕获 EXECUT a MSSQL JOB 命令的异常。

Answer 1

您的问题是您正在解包异常。不应假定异常是可迭代的，也不应假定它们包含参数。

In [2]: try:
   ...:     assert False
   ...: except Exception as e:
   ...:     c, m = e
   ...:     
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-2-2e0dd0160822> in <module>()
      2     assert False
      3 except Exception as e:
----> 4     c, m = e
      5 

ValueError: need more than 0 values to unpack

如果您将消息传递给 Exception 类，则它具有 1 个值:

In [3]: try:
    assert False, "This is a message"
except Exception as e:
    c, m = e
   ...:     
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-8af2ea044375> in <module>()
      2     assert False, "This is a message"
      3 except Exception as e:
----> 4     c, m = e
      5 

ValueError: need more than 1 value to unpack

您的错误处理固有地会在错误捕获后产生错误。学习使用回溯或 Exception.args 代替:

回溯示例

In [10]: try:
   ....:         assert False, "This is a message"
   ....: except Exception as error:
   ....:     trace = traceback.format_exc()
   ....:     print(trace, file=sys.stderr)
   ....:     
Traceback (most recent call last):
  File "<ipython-input-10-5a56c0f9112a>", line 2, in <module>
    assert False, "This is a message"
AssertionError: This is a message

Exception.args 示例

In [11]: from __future__ import print_function

In [12]: import sys

In [13]: try:
   ....:        assert False, "This is a message"
   ....: except Exception as error:
   ....:        print(error.args, file=sys.stderr)
   ....:     
('This is a message',)