Inter process signalling

[Dale Strickland-Clark]

In Linux this is easy with 'signal' and 'kill' but how can I get one Python
process to signal another (possibly running as a service)?

All I need is a simple prod with no other data being sent and none being
returned - except that the signal was delivered.

Receiving a signal should generate an interrupt. I'm not looking for a
solution the involves polling.

Thanks

 

[Dale Strickland-Clark]

In Linux this is easy with 'signal' and 'kill' but how can I get one
Python process to signal another (possibly running as a service)?

All I need is a simple prod with no other data being sent and none being
returned - except that the signal was delivered.

Receiving a signal should generate an interrupt. I'm not looking for a
solution the involves polling.

Thanks

The essential bit of information missing from this is: on Windows.

I want to signal between processes running *on Windows*.

That's what happens when you try to rush a post before going home.
Thank you for your tolerance.

 

[Dennis Lee Bieber]

The essential bit of information missing from this is: on Windows.

I want to signal between processes running *on Windows*.

Unfortunately... You are on Windows...

I think your choices become: Block, or Poll

Check the Win32Api modules...

win32event may be a candidate...
CreateEvent()
OpenEvent()
PulseEvent()
SetEvent()
ResetEvent()
WaitForSingleObject() or WaitForMultipleObjects()
--
Wulfraed Dennis Lee Bieber KD6MOG
(e-mail address removed) (e-mail address removed)
HTTP://wlfraed.home.netcom.com/
(Bestiaria Support Staff: (e-mail address removed))
HTTP://www.bestiaria.com/

 

[Dale Strickland-Clark]

Unfortunately... You are on Windows...

I think your choices become: Block, or Poll

Check the Win32Api modules...

win32event may be a candidate...
CreateEvent()
OpenEvent()
PulseEvent()
SetEvent()
ResetEvent()
WaitForSingleObject() or WaitForMultipleObjects()

Thanks. We'll look into those.

 

[Duncan Booth]

In Linux this is easy with 'signal' and 'kill' but how can I get one
Python process to signal another (possibly running as a service)?

All I need is a simple prod with no other data being sent and none
being returned - except that the signal was delivered.

Receiving a signal should generate an interrupt. I'm not looking for a
solution the involves polling.

Lots of ways. Basically all involving creating a thread which waits on an
event and then calls your code when the event is generated.

You can use semaphores, named pipes &c.; you could create a windows message
queue and simply send the process a message when you want to alert it; you
could create a COM server and call a method on it; you could use
asynchronous procedure calls (APCs) (but you still need to ensure that
there is a thread in an alertable wait state).

If the code you want to signal is running as a service then the easiest way
to signal it is to call win32service.ControlService with a user defined
service code. That gives you 127 signals to play with, and Python's win32
library will simply call the SvcOther method within your service code
(although not of course using the same thread as the actual service is
running on).

 

[Dale Strickland-Clark]

Lots of ways. Basically all involving creating a thread which waits on an
event and then calls your code when the event is generated.

You can use semaphores, named pipes &c.; you could create a windows
message queue and simply send the process a message when you want to alert
it; you could create a COM server and call a method on it; you could use
asynchronous procedure calls (APCs) (but you still need to ensure that
there is a thread in an alertable wait state).

If the code you want to signal is running as a service then the easiest
way to signal it is to call win32service.ControlService with a user
defined service code. That gives you 127 signals to play with, and
Python's win32 library will simply call the SvcOther method within your
service code (although not of course using the same thread as the actual
service is running on).

Thanks Duncan.