Python crontab try except ValueError

Question

I've got this script than when I run from command line it works fine...

#!/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()

But when I try to schedule on crontab I get the bellow error

# 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$

I get this error:

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

I think its to do with there's no pipeline between the "cronos schedule executed job" and the script it self, I dont know if that makes any sense, like it doesnt know where to get the information from and viceversa...

In essence in trying to catch an exceptions of an EXECUT a MSSQL JOB command.

Answer 1

Your issue is that you are unpacking an Exception. Exceptions should not be assumed to be iterables, nor should you assume they contain arguments.

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

If you pass a message to the Exception class, it then has 1 value:

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

Your error handling inherently produces an error after your error catching. Learn to use traceback or Exception.args instead:

Traceback Example

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 Example

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',)

Answer 2

Updated and working code:

#!/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
import mechanize
from BeautifulSoup import BeautifulSoup
import urllib2

#Configure logging
if os.path.isdir("/home/administrator/Share/scripts/logs/") == 0:
    os.makedirs("/home/administrator/Share/scripts/logs/")

if os.path.isfile("/home/administrator/Share/scripts/logs/sense.log") == 0:
    open("/home/administrator/Share/scripts/logs/sense.log", 'w')

logging.basicConfig(filename='/home/administrator/Share/scripts/logs/sense.log',level=logging.DEBUG,format='%(asctime)s - %(message)s')
logging.info('RUNNING SCRIPT')

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

    logging.info('share not mounted')
    #print "share not mounted"
    #mount share
    os.popen("sudo mount -t cifs \"//path to network share -o username=username,domain=domain,sec=ntlmssp,password=password")
    logging.info('share now mounted')
    #print "share now mounted"

# start Automated browsing
browser = mechanize.Browser()
browser.open("page")
browser.select_form(nr = 0)
browser.form['email'] = "user"
browser.form['password'] = "pass"
browser.submit()

#Open Page (Data)
browser.follow_link(text="Data")

#Find generate button
i = 0
batch = 0
for form in browser.forms():

    browser.form = list(browser.forms())[0]  # use when form is unnamed

    for control in browser.form.controls:
        if control.name == "generate":
            batch = 1
            logging.info('generate detected')
            #print "generate detected"
            #Click button
            browser.submit(nr=i)

    if batch == 0:
        logging.info('nothing to generate')
        #print "nothing to generate"
        #print "*******************"

    i =+ 1
#END Find generate button

#Back to "admin/Dowload" page (Data)
browser.follow_link(text="Data")

# Data Table parsing
html = browser.response().read()
soup = BeautifulSoup(html)

table = soup.find("table")

i = 0
for row in table.findAll("tr")[1:]:

    col = row.findAll("td")

    if not col:
        break

    batch = str(col[0])
    records = col[1]
    generated = col[2]
    downloaded = col[3]
    links = col[4]
    photos = col[5]
    sheet = str(col[6])
    confirmed = col[7]

    if "Not yet downloaded" in confirmed:
        i += 1

        stripbatch = batch.strip("<td></td>")
        stripsheet = sheet.strip("<td><a href=\"download/xls/\">Excel</a></td>")

        url = "website" + stripsheet
        time.strftime("%d/%m/%Y")
        file = "/home/administrator/-share/New/SENSE-extract-ascii-" + stripsheet + "-" + time.strftime("%Y%m%d") + ".csv"

        #Dowload file
        logging.info('File %s Downloaded', stripsheet)
        #print "File " + stripsheet + " Downloaded"
        browser.retrieve(url, file)[0]

    if i < 1:
        logging.info('nothing to dowload')
        #print "nothing to dowload"
        #print "******************"
        break

#END Table parsing

#Reparse table to confirm
browser.follow_link(text="Data") #reload page to see changes

html = browser.response().read()
soup = BeautifulSoup(html)

table = soup.find("table")

browser.select_form(nr = 0)

i=1
while i >= 1:

    browser.follow_link(text="Data") #reload page to see changes

    html = browser.response().read()
    soup = BeautifulSoup(html)
    table = soup.find("table")
    browser.select_form(nr = 0)

    for form in browser.forms():

        for control in browser.form.controls:
            if control.type == "submit":
                i += 1
            else:
                i = 0

    if i == 0:
        logging.info('nothing to confirm')
        #print "nothing to confirm"
        #print "******************"
    else:
        logging.info('%s confirmed', control.name[0])
        #print control.name[0] + "confirmed"

    browser.submit(nr = 0)

logging.info('*** Batch generated and CSV file downloaded from Sense ***')
#print "*** done ***"

#END reparsin table to confirm

#Change mount for access to test, for NEW, processed ...
# Declase File paths

# Scrap file information for naming Naming

# Move and replace from New to sense processed folder

#Execute Job start by job_name

# Copy file to processed


#END Sense file downloading


# File paths
fullpath2Newfile = "/home/administrator/-share/New/"
fullpathfiles2Process = "/home/administrator/-share/"
fullpathProcessedfiles = "/home/administrator/-share/Processed/"

if not os.listdir('/home/administrator/cas01-share/New'):
    # print "directory empty"
        logging.info('No New files to upload')

else:
    #print "directory not empty"

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

    # logging.info('More than one file in New Directory')
    logging.info('Directory has: %s Files', str(num_files))



    num_files = 0

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

        # print filename
        logging.info('File: %s', filename)

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

        newfullpath2Newfile = fullpath2Newfile + filename
        fullpathfiles2Process = "/home/administrator/-share/SENSE-extract.csv"
        fullpathProcessedfiles = "/home/administrator/-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='server', user='domain\user', password='pwd', tds_version='8.0')
                cursor = conn.cursor()
                cursor.execute("EXEC msdb.dbo.sp_start_job @job_name = 'jobname'")

            except Exception as e:
                (error_message) = e
                #print(e)

                ExceptionFlag = 1

                print error_message
                #print error_message


                if "does not exist" in error_message:
                    # print "ERROR: Job name not found"
                    logging.info('ERROR: Job name not found')

                if "job is already running" in error_message:
                     #print "ERROR: a Job is already running"
                    logging.info('ERROR: a Job is already running')

                if "job already has a pending request" in error_message:
                    # print "ERROR: pending request"
                    logging.info('ERROR: pending request')

                if "Unable to connect" in error_message:
                    # print "ERROR: Server unavailable"
                    logging.info('ERROR: Server unavailable')

                time.sleep(0.5)


            else:
                # print "Job executed succesfully"
                logging.info('Job %s Executed', batchnumber)
                # Copy file to processed
                shutil.copy(fullpathfiles2Process, fullpathProcessedfiles)

                succesfullRun = 1

            #conn.close()
            time.sleep(0.5)


logging.info('Finished uploading jobs')
logging.info('END')
exit()

#END script