🌐 Mailman 3 July 2019 - Python-list - python.org

Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

eryk sun於 2019年7月7日星期日 UTC+8下午3時51分57秒寫道： > On 7/6/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > > > I turn off the anti-virus and tried v3.6.8, get the same result. Usually the > > anti-virus program will warn me if something was blocked. > > In case the executable is corrupt, clear your browser cache and > download the 32-bit version again: > > https://www.python.org/ftp/python/3.6.8/python-3.6.8.exe > > Try to run the installer from an elevated command prompt. If it fails > to run, check again for log files in your %TEMP% directory, which > typically expands to "C:\Users\<username>\AppData\Local\Temp". > > If the installer is still not running -- not even enough to create a > single log file -- then apparently something is configured incorrectly > or missing on your computer that's causing it to fail hard. I'd have > to run it under a debugger to find the cause. > > Anyway, if you're stuck with ancient 3.4, you can at least install > "pywin32-221.win32-py3.4.exe" from the old SourceForge repo: > > https://sourceforge.net/projects/pywin32/files/pywin32/Build%20221 I had overlooked your suggestion of installing it under elevated command prompt. At the last moment I was noticed and gave it a try. Guess what? I run Python-3.6.8.exe successfully and installed it. A real surprise! Thank you for everything you had done to help. --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

eryk sun於 2019年7月7日星期日 UTC+8下午3時51分57秒寫道： > On 7/6/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > > > I turn off the anti-virus and tried v3.6.8, get the same result. Usually the > > anti-virus program will warn me if something was blocked. > > In case the executable is corrupt, clear your browser cache and > download the 32-bit version again: I have its MD5 checked after each download. > https://www.python.org/ftp/python/3.6.8/python-3.6.8.exe > > Try to run the installer from an elevated command prompt. If it fails > to run, check again for log files in your %TEMP% directory, which > typically expands to "C:\Users\<username>\AppData\Local\Temp". > > If the installer is still not running -- not even enough to create a > single log file -- then apparently something is configured incorrectly > or missing on your computer that's causing it to fail hard. I'd have > to run it under a debugger to find the cause. It's very possible there is some problem in my system. A few months ago suddenly I can't login to my email account through ThunderBird. Now I have to remove my password from its settings and manually type-in every time when I log in. Using a debugger is a big burden to me because I am not familiar with the internal of Windows well. > Anyway, if you're stuck with ancient 3.4, you can at least install > "pywin32-221.win32-py3.4.exe" from the old SourceForge repo: > > https://sourceforge.net/projects/pywin32/files/pywin32/Build%20221 Thank you for the link. I will try it later and hope it will run:-) --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

eryk sun於 2019年7月7日星期日 UTC+8下午12時00分47秒寫道： > On 7/6/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > > > In TEMP, there is only one file "chrome_installer.log" dated at the time of > > doing the upgrade (strange?, why chrome?). No errors in it. > > So the installer doesn't even execute. Do you maybe have an > anti-malware program that's blocking its execution? Definitely try > the 3.6.8 installer. I didn't pay attention to the fact that you were > trying to install a very outdated version of 3.6. There may have been > bugs in the installer that were fixed. Always use the most recent > version possible. I turn off the anti-virus and tried v3.6.8, get the same result. Usually the anti-virus program will warn me if something was blocked. --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

eryk sun於 2019年7月7日星期日 UTC+8上午10時13分34秒寫道： > On 7/6/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > > > According to the info you give, I have done the following steps: > > 1. Upgrade to SP2 first. > > 2. Install the CRT update. > > But the result is still the same, nothing happens after double click the > > file python-3.6.1.exe. > > Did you reboot after installing the updates? Afterward, did you > confirm in the system properties that you're running SP2? Did you > check that "%SystemRoot%\System32\ucrtbase.dll" exists, plus a bunch > of "api-ms-win-crt-*.dll" DLLs in the same directory? > > > I deeply appreciate your help. It looks like that Vista has to live with > > Python 3.4 for its rest of life:-) > > That is not true in general for Vista. It's particular to your > computer. Check the installer logs in your %TEMP% directory for > errors, which will typically be an HRESULT error code that starts with > 0x8, such as 0x80070002. > > Try downloading and installing the 64-bit version: > > https://www.python.org/ftp/python/3.6.8/python-3.6.8-amd64.exe Yes, it's SP2 showing up in Start->Computer->Properities window. Also in System32 directory, there is ucrtbase.dll and a bunch of api-ms-win-crt-*.dll too. In TEMP, there is only one file "chrome_installer.log" dated at the time of doing the upgrade (strange?, why chrome?). No errors in it. I can't. My Vista is 32bit. Anyway I will give v3.6.8 a try later. --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

eryk sun於 2019年7月6日星期六 UTC+8下午6時26分42秒寫道： > On 7/6/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > eryk sun於 2019年7月6日星期六 UTC+8下午2時13分23秒寫道： > > > >> Major versions of Python support Windows versions that have extended > >> support from Microsoft at the time of the first release. For Vista, > >> extended support ended on 2017-04-11. Python 3.6 was released on > >> 2016-12-23, so it supports Vista. Python 3.7, on the other hand, does > >> not because it was released on 2018-06-27. > > > > I tried the python-3.6.1.exe, downloaded from www.python.org. Its > > release date is March 21, 2017. But it doesn't run, Vista has no response at > > all. > > Starting with version 3.5, Python requires the Universal C Runtime, > which is an OS component that was introduced in Windows 10 and > backported to previous versions, including Windows Vista (service pack > 2). Python's installer should attempt to install the CRT update, but > from what I've seen this isn't reliable. > > Ideally, it shouldn't be necessary to manually install the CRT update > since Windows Update includes it. Enable optional updates, and keep > your system updated. That said, if you can't or won't use Windows > Update, then you can download and install standalone updates. > > CRT Update > https://support.microsoft.com/en-us/help/3118401 > > The above requires Vista service pack 2 (SP2). The system properties > dialog should say whether SP1 or SP2 is installed. Your system should > be running SP2 if Windows Update is enabled. If you're not even > running SP1, you'll have to install SP1 and then SP2. The system > properties dialog will tell you whether you're running 32-bit or > 64-bit Windows. > > x86 32-bit SP1 > https://www.microsoft.com/en-us/download/details.aspx?id=30 > x64 64-bit SP2 > https://www.microsoft.com/en-us/download/details.aspx?id=21299 > > x86 32-bit SP2 > https://www.microsoft.com/en-us/download/details.aspx?id=16468 > x64 64-bit SP2 > https://www.microsoft.com/en-us/download/details.aspx?id=17669 According to the info you give, I have done the following steps: 1. Upgrade to SP2 first. 2. Install the CRT update. But the result is still the same, nothing happens after double click the file python-3.6.1.exe. I deeply appreciate your help. It looks like that Vista has to live with Python 3.4 for its rest of life:-) --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 7, 2019

July 7, 2019

Michael Torrie於 2019年7月6日星期六 UTC+8下午12時02分02秒寫道： > On 07/05/2019 09:03 PM, jfong(a)ms4.hinet.net wrote: > > From Vista to Win10? That's a three generation gap! Buy a new PC might be a better solution:-) > > Maybe. Windows 10 would probably run okay on that machine. It might be > 10 years old, but if it's 64-bit, Win 10 should run on it. > > You could also buy a hard drive and download the ISO from Microsoft and > give it a try. If it works you can buy the license for it (sigh). > > Of course there are also other good alternatives too. Thank you for your suggestion. This PC was purchased in year 2006 from Dell. The CPU is AMD Athlon 64 X2 4000+. I doubt Win10 will support such an old CPU:-) and the chipset driver might be a big problem too. --Jach

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Random signal capture when using multiprocessing
by José María Mateos July 6, 2019

July 6, 2019

Hi, This is a minimal proof of concept for something that has been bugging me for a few days: ``` $ cat signal_multiprocessing_poc.py import random import multiprocessing import signal import time def signal_handler(signum, frame): raise Exception(f"Unexpected signal {signum}!") def process_message(args): time.sleep(random.random() / 100.) if __name__ == "__main__": signal.signal(signal.SIGTERM, signal_handler) n_round = 1 while n_round < 10: job_list = [x for x in range(random.randint(100, 400))] print(f"Running round {n_round} with {len(job_list)} jobs") with multiprocessing.Pool(8) as p1: p1.map(process_message, job_list) n_round += 1 ``` So basically I have some subprocesses that don't do anything, just sleep for a few milliseconds, and I capture SIGTERM signals. I don't expect This is the output: ``` $ python signal_multiprocessing_poc.py Running round 1 with 244 jobs Running round 2 with 151 jobs Running round 3 with 173 jobs Running round 4 with 124 jobs Running round 5 with 249 jobs Running round 6 with 359 jobs Process ForkPoolWorker-48: Traceback (most recent call last): File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/process.py", line 297, in _bootstrap self.run() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/process.py", line 99, in run self._target(*self._args, **self._kwargs) File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/pool.py", line 110, in worker task = get() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/queues.py", line 352, in get res = self._reader.recv_bytes() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/synchronize.py", line 98, in __exit__ return self._semlock.__exit__(*args) File "signal_multiprocessing_poc.py", line 7, in signal_handler raise Exception(f"Unexpected signal {signum}!") Exception: Unexpected signal 15! Running round 7 with 185 jobs Running round 8 with 246 jobs Running round 9 with 217 jobs Process ForkPoolWorker-68: Traceback (most recent call last): File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/process.py", line 297, in _bootstrap self.run() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/process.py", line 99, in run self._target(*self._args, **self._kwargs) File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/pool.py", line 110, in worker task = get() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/queues.py", line 352, in get res = self._reader.recv_bytes() File "/home/j_mariamateos/miniconda3/lib/python3.7/multiprocessing/synchronize.py", line 98, in __exit__ return self._semlock.__exit__(*args) File "signal_multiprocessing_poc.py", line 7, in signal_handler raise Exception(f"Unexpected signal {signum}!") Exception: Unexpected signal 15! ``` Can anyone help me understand why the random SIGTERM gets captured? I guess some of the children processes receive the signal for termination and that's why I see it, but I don't understand the randomness of it. Of course, as a coworker just pointed out, this works (telling the children processes to ignore the signal handler): ``` import random import multiprocessing import signal import time def signal_handler(signum, frame): raise Exception(f"Unexpected signal {signum}!") def init_worker(): signal.signal(signal.SIGTERM, signal.SIG_IGN) signal.signal(signal.SIGINT, signal.SIG_IGN) def process_message(args): time.sleep(random.random() / 100.) if __name__ == "__main__": signal.signal(signal.SIGTERM, signal_handler) signal.signal(signal.SIGINT, signal_handler) n_round = 1 while n_round < 20: job_list = [x for x in range(random.randint(100, 400))] print(f"Running round {n_round} with {len(job_list)} jobs") with multiprocessing.Pool(8,init_worker) as p1: p1.map(process_message, job_list) n_round += 1 ``` Thanks for your help, -- José María (Chema) Mateos || https://rinzewind.org

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 6, 2019

July 6, 2019

eryk sun於 2019年7月6日星期六 UTC+8下午2時13分23秒寫道： > On 7/5/19, jfong(a)ms4.hinet.net <jfong(a)ms4.hinet.net> wrote: > > Terry Reedy於 2019年7月5日星期五 UTC+8上午12時13分25秒寫道： > > > >> Upgrade to 3.7 or 3.8 to get hundreds of bug fixes, let alone new > >> features. Both subprocess and multiprocessing have gotten fixes. > > > > I can't because my OS is Vista and v3.4 is the last it can run:-( Also > > the pywin32 can't be installed for it requires v3.5 and up. > > Major versions of Python support Windows versions that have extended > support from Microsoft at the time of the first release. For Vista, > extended support ended on 2017-04-11. Python 3.6 was released on > 2016-12-23, so it supports Vista. Python 3.7, on the other hand, does > not because it was released on 2018-06-27. I tried the python-3.6.1.exe, downloaded from www.python.org. Its release date is March 21, 2017. But it doesn't run, Vista has no response at all. --Jach > Windows 7 has extended support until 2020-01-14, so 3.8 supports it. > However, system update KB2533623 is required for enhancements to the > system loader that 3.8 depends on for loading extension modules and > DLLs. > > > I finally get a solution to switch between two notepads in Python. Here > > is the codes for someone he may be interested. > > If I have time I'll write a better version since the code you have is > fragile. But I think you should take others' advice to use a > cross-platform GUI automation library, so you won't be locked into a > Windows-only solution.

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 6, 2019

July 6, 2019

Terry Reedy於 2019年7月5日星期五 UTC+8上午12時13分25秒寫道： > On 7/3/2019 7:57 PM, jfong(a)ms4.hinet.net wrote: > > I have the test0.py below. I expect to see 'abcd' showing in the notepad window: > > --------- > > import subprocess as sp > > p0 = sp.Popen('notepad.exe', stdin=sp.PIPE) > > p0.communicate(input=b'abcd') > > --------- > > But nothing happens. The notepad is completely empty. What have I missed? > > > > --Jach > > > > PS. I am using python 3.4 on Windows Vista > > Upgrade to 3.7 or 3.8 to get hundreds of bug fixes, let alone new > features. Both subprocess and multiprocessing have gotten fixes. I can't because my OS is Vista and v3.4 is the last it can run:-( Also the pywin32 can't be installed for it requires v3.5 and up. > subprocess is meant for running an external program in batch mode. It > receives the one input byte string, sends output, and closes. For > interaction, try multiprocessing. > > Or do what IDLE does, which is to open a two-way socket to the parent > program. (Managing this is not fun.) IDLE was initially written before > multiprocessing. It has been suggested to me that it should switch to > multiprocessing. (But last I read, multiprocessing and tkinter (tcl/tk) > do not play well together on macOS.) Can multiprocessing make debugging of eventloop app easier? > If the subprocess runs a gui, the user should be able to switch focus by > clicking on a subprocess window. I finally get a solution to switch between two notepads in Python. Here is the codes for someone he may be interested. ----------- import subprocess, time, ctypes user32 = ctypes.windll.user32 p0 = subprocess.Popen('notepad.exe') time.sleep(1) handle0 = user32.GetForegroundWindow() # the handler of foreground window thread0 = user32.GetWindowThreadProcessId(handle0, 0) # get its thread id p1 = subprocess.Popen('notepad.exe') time.sleep(1) handle1 = user32.GetForegroundWindow() thread1 = user32.GetWindowThreadProcessId(handle1, 0) for i in range(3): # suppose the notepad1 is the foreground window time.sleep(5) # delay enough time for typing test user32.AttachThreadInput(thread1, thread0, True) user32.SetForegroundWindow(handle0) time.sleep(5) user32.AttachThreadInput(thread0, thread1, True) user32.SetForegroundWindow(handle1) print('end') --Jach

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Re: What's wrong on using Popen's communicate method?
by jfong＠ms4.hinet.net July 6, 2019

July 6, 2019

Chris Angelico於 2019年7月6日星期六 UTC+8上午10時48分10秒寫道： > On Sat, Jul 6, 2019 at 12:31 PM <jfong(a)ms4.hinet.net> wrote: > > > > Terry Reedy於 2019年7月5日星期五 UTC+8上午12時13分25秒寫道： > > > On 7/3/2019 7:57 PM, jfong(a)ms4.hinet.net wrote: > > > > I have the test0.py below. I expect to see 'abcd' showing in the notepad window: > > > > --------- > > > > import subprocess as sp > > > > p0 = sp.Popen('notepad.exe', stdin=sp.PIPE) > > > > p0.communicate(input=b'abcd') > > > > --------- > > > > But nothing happens. The notepad is completely empty. What have I missed? > > > > > > > > --Jach > > > > > > > > PS. I am using python 3.4 on Windows Vista > > > > > > Upgrade to 3.7 or 3.8 to get hundreds of bug fixes, let alone new > > > features. Both subprocess and multiprocessing have gotten fixes. > > > > I can't because my OS is Vista and v3.4 is the last it can run:-( Also the pywin32 can't be installed for it requires v3.5 and up. > > > > So... upgrade to a better operating system? > > ChrisA From Vista to Win10? That's a three generation gap! Buy a new PC might be a better solution:-) --Jach

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