Getting a Process.start() error pickle.PicklingError: Can't pickle <type 'module'>: it's not found as __builtin__.module with Python 2.7

[marc nicole]

Hello,

I am using Python 2.7 on Windows 10 and I want to launch a process
independently of the rest of the code so that the execution continues while
the started process proceeds. I am using Process().start() from Python 2.7
as follows:

from multiprocessing import Process
def do_something(text):
print(text)
if __name__ == "__main__":
q = Process(target=do_something,args=("somecmd") )
q.start()
# following code should execute right after the q.start() call (not
until it returns)
.....


But getting the error at the call of Process().start():
pickle.PicklingError: Can't pickle <type 'module'>: it's not found as
__builtin__.module

anybody could provide an alternative to call the function do_something() in
a separate thread ?

[Barry Scott]

Post by marc nicole
I am using Python 2.7 on Windows 10

Why? Install Python 3.12 and it will be easier to get help and support.
If you have legacy that still needs porting then you can install 3.12 along side
the unsupported 3.12.


Barry

[geodandw]

Post by Barry Scott

Post by marc nicole
I am using Python 2.7 on Windows 10

Why? Install Python 3.12 and it will be easier to get help and support.
If you have legacy that still needs porting then you can install 3.12 along side
the unsupported 3.12.
Barry

I think you mean alongside the unsupported 2.7.

[Stefan Ram]

Post by marc nicole
pickle.PicklingError: Can't pickle <type 'module'>: it's not found as
__builtin__.module

I'm not exactly dialed in on Python 2, but threading might be
less of a headache when it comes to pickling and could still
check the box for parallelism.

[marc nicole]

Hello Alan,

Thanks for the reply, Here's the code I tested for the debug:

import time
from multiprocessing import Process

def do_Something():
print('hello world!')

def start(fn):
p = Process(target=fn, args=())
p.start()

def ghello():
print ("hello world g")

def fhello():
print('hello world f')

if __name__ == "__main__":
start(do_something)
print("executed")
exit(0)

but neither "Hello World" or "Executed" are displayed in the console which
finishes normally without returning any message.

Module naming is OK and don't think it is a problem related to that.

Now the question, when to use Process/Multiprocess and when to use
Threading in Python?.Thread is there a distinctive use case that can
showcase when to use either? are they interchangeable? to note that using
Threading the console DID display the messages correctly!

Thanks.

Post by marc nicole
Hello,
I am using Python 2.7 on Windows 10

Others have pointed out that 2.7 is unsupported and has
been for many years now. Its also inferior in most
respects including its error reporting.
If possible you should upgrade to 3.X

Post by marc nicole
from multiprocessing import Process
print(text)
q = Process(target=do_something,args=("somecmd") )
q.start()
# following code should execute right after the q.start() call

So what does happen? If you put a print statement here does it execute
before or after the error message? It might make things easier to
debug(clearer error traceback) if you put the code to create the thread
into a separate function?
def do_Something(text)...
q = Process....
q.start()
if __name_....
start(do_something)
print('Something here')

Post by marc nicole
pickle.PicklingError: Can't pickle <type 'module'>: it's not found as
__builtin__.module

But please show us the full error trace even if its not much.
Also check your module naming, is there a possibility
you've named your file do_something.py or similar?
(I'm guessing the function is what is being pickled?)

Post by marc nicole
anybody could provide an alternative to call the function do_something()

in

Post by marc nicole
a separate thread ?

Why not just use the Threading module?
If it's as simple as just running something in a
thread multiprocessing is probably not needed.
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
http://www.flickr.com/photos/alangauldphotos
_______________________________________________
https://mail.python.org/mailman/listinfo/tutor

[Stefan Ram]

Post by marc nicole
print("executed")
but neither "Hello World" or "Executed" are displayed in the console which

It shouldn't spit out "Executed" 'cause there's a lowercase
"e" in the mix. Talk about sweating the small stuff!

That 'if __name__ == "__main__"' jazz? It's barking up the wrong
tree here, just muddying the waters. I'd 86 that clause for now.

In your start() function call, you're rockin' "do_something()",
but the actual function's defined as "do_Something()" with a
capital "S". Python's all about that case sensitivity.

Dropping that "exit(0)" bomb right after firing up the process?
That's like bailing on a gnarly wave before you even catch it.
It might pull the plug on the main process before the kid process
has a chance to strut its stuff.

Those "ghello" and "fhello" functions? They're just chillin'
there, not pulling their weight!

Post by marc nicole
Now the question, when to use Process/Multiprocess and when to use
Threading in Python?

When it comes to processes vs. threads, it's like choosing
between a burrito and a taco.

Use processes for those CPU-heavy tasks to get that real
parallel action across multiple cores, dodging Python's GIL
like it's rush hour on the 405.

Processes are also tougher than a two-dollar steak and perfect
for memory hogs.

On the flip side, threading's your go-to for I/O-bound tasks
where the GIL takes a breather during I/O ops, letting you
multitask like a boss. Threads are as light as a surfer's
board, play nice with shared memory, and are the bee's knees
for juggling a ton of tasks without breaking a sweat.

[Keith Thompson]

Post by Stefan Ram

Post by marc nicole
print("executed")
but neither "Hello World" or "Executed" are displayed in the console which

It shouldn't spit out "Executed" 'cause there's a lowercase
"e" in the mix. Talk about sweating the small stuff!
That 'if __name__ == "__main__"' jazz? It's barking up the wrong
tree here, just muddying the waters. I'd 86 that clause for now.
In your start() function call, you're rockin' "do_something()",
but the actual function's defined as "do_Something()" with a
capital "S". Python's all about that case sensitivity.
Dropping that "exit(0)" bomb right after firing up the process?
That's like bailing on a gnarly wave before you even catch it.
It might pull the plug on the main process before the kid process
has a chance to strut its stuff.
Those "ghello" and "fhello" functions? They're just chillin'
there, not pulling their weight!

[...]

Stefan, you've recently started using a lot of slang in your posts.
I suggest that this is counterproductive. For me, it makes your
posts more difficult to read. I can imagine that it would be even
more difficult for readers whose first language is not English.

You also indent your own new text, which is exactly the opposite of
common Usenet conventions. (You've been doing this for a long time.)

Please consider prioritizing your readers' convenience over whatever
benefit you derive from your unconventional posting style.

[a***@gmail.com]

Unfortunately, Alan, even though 2.7 was considered pickled, people keep
taking it back out of the bottle and wondering why it does not work so well!

There are companies like Microsoft and Samsung that let people know their OS
on their devices will no longer be supported with updates and some apps may
no longer work if downloaded. And, yet, I bet for years afterwards, people
will refuse to upgrade because they don't want to replace equipment or even
learn a new slightly different interface.

Having said that, I understand many people are stuck for various reasons and
are required to use whatever version is officially allowed. For some
questions, answers may still be provided. There are some workarounds or even
newer packages designed to do what is not otherwise available.

But many of us here may not be answering the questions as we have no reason
to be able to access the old software or interest.

-----Original Message-----
From: Tutor <tutor-bounces+avi.e.gross=***@python.org> On Behalf Of
Alan Gauld via Tutor
Sent: Tuesday, September 3, 2024 4:41 AM
To: ***@python.org
Cc: python-***@python.org
Subject: Re: [Tutor] Getting a Process.start() error pickle.PicklingError:
Can't pickle <type 'module'>: it's not found as __builtin__.module with
Python 2.7

Post by marc nicole
Hello,
I am using Python 2.7 on Windows 10

Others have pointed out that 2.7 is unsupported and has
been for many years now. Its also inferior in most
respects including its error reporting.
If possible you should upgrade to 3.X

Post by marc nicole
from multiprocessing import Process
print(text)
q = Process(target=do_something,args=("somecmd") )
q.start()
# following code should execute right after the q.start() call

So what does happen? If you put a print statement here does it execute
before or after the error message? It might make things easier to
debug(clearer error traceback) if you put the code to create the thread
into a separate function?

def do_Something(text)...

def start(fn):
q = Process....
q.start()

if __name_....
start(do_something)
print('Something here')

Post by marc nicole
pickle.PicklingError: Can't pickle <type 'module'>: it's not found as
__builtin__.module

But please show us the full error trace even if its not much.

Also check your module naming, is there a possibility
you've named your file do_something.py or similar?
(I'm guessing the function is what is being pickled?)

Post by marc nicole
anybody could provide an alternative to call the function do_something()

in

Post by marc nicole
a separate thread ?

Why not just use the Threading module?
If it's as simple as just running something in a
thread multiprocessing is probably not needed.
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos



_______________________________________________
Tutor maillist - ***@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor