问题
I have a python script which works well when run in the console.
However, when using pywin32 in order to let it run as a service, the service gets installed and starts okay but the desired output is not produced. So something must be going wrong -- but I can't see what's happening to find out the reason.
The script does the following:
- Searches for *.csv files in a given input dir
- If no such files are found it waits 1 minute. If one is found it uses it as input for step 3. If multiple csv files are found it uses the first one.
- Does some transformation on the order of the columns
- Writes the transformed content into an output csv
- Moves the input csv into a subdirectory and renames it.
Let me first show you the code of the version that is implemented as a service:
#!/usr/bin/env python3
import sys
import os
import csv
from pathlib import Path
import time
import win32service
import win32serviceutil
import win32event
def reorder_AT_csv(ifile, ofile):
"Öffnet die CSV Datei, überführt sie in das neue Format und exportiert sie."
print('[i] Lese aus ' + ifile.name + ' und schreibe in ' +
ofile.name)
with open(
ifile, mode='r') as infile, open(
ofile, mode='w') as outfile:
reader = csv.DictReader(
infile,
fieldnames=[
'Post Nummer', 'Sendungsnummer', 'Referenz1', 'Referenz2',
'Gewicht', 'Empf.Name1', 'Empf.Adresse', 'Empf.PLZ',
'Empf.Ort', 'Kostenstelle', 'Produkt'
],
delimiter=';')
fn = [
'Post Nummer', 'Referenz1', 'Referenz2', 'Sendungsnummer',
'Gewicht', 'Empf.Name1', 'Empf.Adresse', 'Empf.PLZ', 'Empf.Ort',
'Kostenstelle', 'Produkt'
]
writer = csv.DictWriter(
outfile, extrasaction='ignore', fieldnames=fn, delimiter=';')
# reorder the header first
try:
for row in reader:
# writes the reordered rows to the new file
writer.writerow(row)
except Exception as e:
print('[!] Fehler bei der Bearbeitung der CSV Datei:')
print('[!] ' + str(e))
print(
'[!] Bitte ueberpruefen, ob es sich um eine korrekte CSV Datei handelt!'
)
sys.exit(1)
def checkInputFromUser(path):
"Überprüfe ob das Verzeichnis existiert."
if not path.exists():
print(
'[!] Die Eingabe ist kein Verzeichnis. Bitte ein gueltiges Verzeichnis eingeben.'
)
sys.exit(1)
return True
def findCSVFile(path):
"Finde alle CSV Dateien im Verzeichnis path."
all_files = []
all_files.extend(Path(path).glob('*.csv'))
if len(all_files) == 0:
# print('[!] Keine CSV Dateien gefunden. Bitte Pfad überprüfen.')
# sys.exit(1)
return None
elif len(all_files) > 1:
print('[i] Mehrere CSV Dateien gefunden. Nehme ersten Fund:')
return all_files[0]
def moveInputFile(input):
"Verschiebe Input Datei in Unterordner und füge Suffix hinzu."
movepath = Path(input.parent / 'processed')
targetname = input.with_suffix(input.suffix + '.success')
fulltarget = movepath / targetname.name
input.replace(fulltarget)
class CSVConvertSvc(win32serviceutil.ServiceFramework):
# you can NET START/STOP the service by the following name
_svc_name_ = "blub"
# this text shows up as the service name in the Service
# Control Manager (SCM)
_svc_display_name_ = "bar der AT CSV Dateien."
# this text shows up as the description in the SCM
_svc_description_ = "Dieser Dienst öffnet die AT CSV Datei und überführt sie in das DPD Format."
def __init__(self, args):
win32serviceutil.ServiceFramework.__init__(self, args)
# create an event to listen for stop requests on
self.hWaitStop = win32event.CreateEvent(None, 0, 0, None)
# core logic of the service
def SvcDoRun(self):
import servicemanager
rc = None
inputpath = Path(r'C:\Users\Dennis\Documents')
outputpath = Path(r'C:\Users\Dennis\Desktop')
file = None
# if the stop event hasn't been fired keep looping
while rc != win32event.WAIT_OBJECT_0:
checkInputFromUser(inputpath)
while file is None:
file = findCSVFile(inputpath)
if file is None:
time.sleep(60)
inputfile = file
outputfile = outputpath / 'out.csv'
reorder_AT_csv(inputfile, outputfile)
moveInputFile(inputfile)
# block for 5 seconds and listen for a stop event
rc = win32event.WaitForSingleObject(self.hWaitStop, 5000)
# called when we're being shut down
def SvcStop(self):
# tell the SCM we're shutting down
self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
# fire the stop event
win32event.SetEvent(self.hWaitStop)
if __name__ == '__main__':
win32serviceutil.HandleCommandLine(CSVConvertSvc)
This version does not do what it is supposed to do. However, I started with this could as a non-service version, but rather a simple python script, which does what it is supposed to do:
#!/usr/bin/env python3
import sys
import os
import csv
import time
from pathlib import Path
def reorder_AT_csv(ifile, ofile):
"Öffnet die CSV Datei, überführt sie in das neue Format und exportiert sie."
print('[i] Lese aus ' + ifile.name + ' und schreibe in ' +
ofile.name)
with open(
ifile, mode='r') as infile, open(
ofile, mode='w') as outfile:
reader = csv.DictReader(
infile,
fieldnames=[
'Post Nummer', 'Sendungsnummer', 'Referenz1', 'Referenz2',
'Gewicht', 'Empf.Name1', 'Empf.Adresse', 'Empf.PLZ',
'Empf.Ort', 'Kostenstelle', 'Produkt'
],
delimiter=';')
fn = [
'Post Nummer', 'Referenz1', 'Referenz2', 'Sendungsnummer',
'Gewicht', 'Empf.Name1', 'Empf.Adresse', 'Empf.PLZ', 'Empf.Ort',
'Kostenstelle', 'Produkt'
]
writer = csv.DictWriter(
outfile, extrasaction='ignore', fieldnames=fn, delimiter=';')
# reorder the header first
try:
for row in reader:
# writes the reordered rows to the new file
writer.writerow(row)
except Exception as e:
print('[!] Fehler bei der Bearbeitung der CSV Datei:')
print('[!] ' + str(e))
print(
'[!] Bitte ueberpruefen, ob es sich um eine korrekte CSV Datei handelt!'
)
sys.exit(1)
def checkInputFromUser(path):
"Überprüfe ob das Verzeichnis existiert."
if not path.exists():
print(
'[!] Die Eingabe ist kein Verzeichnis. Bitte ein gueltiges Verzeichnis eingeben.'
)
sys.exit(1)
return True
def findCSVFile(path):
"Finde alle CSV Dateien im Verzeichnis path."
all_files = []
all_files.extend(Path(path).glob('*.csv'))
if len(all_files) == 0:
# print('[!] Keine CSV Dateien gefunden. Bitte Pfad überprüfen.')
# sys.exit(1)
return None
elif len(all_files) > 1:
print('[i] Mehrere CSV Dateien gefunden. Nehme ersten Fund:')
return all_files[0]
def moveInputFile(input):
movepath = Path(input.parent / 'processed')
targetname = input.with_suffix(input.suffix + '.success')
fulltarget = movepath / targetname.name
input.replace(fulltarget)
def main():
inputpath = Path(r'C:\Users\Dennis\Documents')
outputpath = Path(r'C:\Users\Dennis\Desktop')
file = None
checkInputFromUser(inputpath)
while file is None:
file = findCSVFile(inputpath)
if file is None:
time.sleep(60)
inputfile = file
outputfile = outputpath / 'out.csv'
reorder_AT_csv(inputfile, outputfile)
moveInputFile(inputfile)
if __name__ == '__main__':
main()
Being very new to Python, I can't figure out what I am missing. The service is installed correctly and also starts without a problem. I am using ActiveState Python 3.6 which is shipped with pywin32 libs.
回答1:
Use logging to report on the program's progress and do debug printing. This way, you'll see what the program is doing and where it's stuck.
(Also note that ServiceFramework has a "debug mode". Running <your_program> debug from the console instructs HandleCommandLine to run your program interactively: you get console output, and Ctrl-C terminates the program. This makes the run-fix iterations take less time but won't reveal the bugs that only manifest when running as a service. So it's helpful but is only a preliminary step, running as a service and logging to a file is the ultimate test.)
Here's how I arrange my scripts that run unatteneded/as a service.
Set up logging ASAP.
Always use a rotating handler so that logs do not grow indefinitely.
Make sure to log any unhandled exceptions.# set up logging ##################################### import sys,logging,logging.handlers,os.path #in this particular case, argv[0] is likely pythonservice.exe deep in python's lib\ # so it makes no sense to write log there log_file=os.path.splitext(__file__)[0]+".log" l = logging.getLogger() l.setLevel(logging.INFO) f = logging.Formatter('%(asctime)s %(process)d:%(thread)d %(name)s %(levelname)-8s %(message)s') h=logging.StreamHandler(sys.stdout) h.setLevel(logging.NOTSET) h.setFormatter(f) l.addHandler(h) h=logging.handlers.RotatingFileHandler(log_file,maxBytes=1024**2,backupCount=1) h.setLevel(logging.NOTSET) h.setFormatter(f) l.addHandler(h) del h,f #hook to log unhandled exceptions def excepthook(type,value,traceback): logging.error("Unhandled exception occured",exc_info=(type,value,traceback)) #Don't need another copy of traceback on stderr if old_excepthook!=sys.__excepthook__: old_excepthook(type,value,traceback) old_excepthook = sys.excepthook sys.excepthook = excepthook del log_file,os # ####################################################Log every program start and stop.
In the case of a service, must also log unhandled exceptions manually atSvcDoRunlevel sincepythonservice.exeseems to swallow all exceptions. Keep thesys.excepthookreplacement anyway just in case.def SvcDoRun(self): #sys.excepthook doesn't seem to work in this routine - # apparently, everything is handled by the ServiceFramework machinery try: l.info("Starting service") main() except Exception,e: excepthook(*sys.exc_info()) else: l.info("Finished successfully") def SvcStop(self): l.info("Stop request received") <...>Log any meaningful step, in user's terms, that the program does. Report trivial or very frequent happenings at higher level of verbosity. Choose the levels in such a way that output with any
l.setLevel()gives a complete picture, with the corresponding level of detail.file_ = findCSVFile(inputpath) if file_: l.info("Processing `%s'", file_) # Note the quotes around the name. # They will help detect any leading/trailing #space in the path. else: l.debug("No more files") <...> l.info("Moving to `%s'",fulltarget) input.replace(fulltarget) <...> l.debug("waiting") rc = win32event.WaitForSingleObject(<...>)
来源：https://stackoverflow.com/questions/51194784/how-to-debug-a-python-program-running-as-a-service