getting a thread out of sleep

M

mark

Right now I have a thread that sleeps for sometime and check if an
event has happened and go back to sleep. Now instead I want the thread
to sleep until the event has occured process the event and go back to
sleep. How to do this?
thanks
mark


class eventhndler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)

def run(self):
while True:
time.sleep(SLEEPTIME)
''''do event stuff'''
 
P

placid

Right now I have a thread that sleeps for sometime and check if an
event has happened and go back to sleep. Now instead I want the thread
to sleep until the event has occured process the event and go back to
sleep. How to do this?
thanks
mark

class eventhndler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)

def run(self):
while True:
time.sleep(SLEEPTIME)
''''do event stuff'''
Click to expand...

The way i would do this is by using an threading.Event (
http://docs.python.org/lib/event-objects.html )

<code>

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.event = threading.Event()

def run:
while True:
# block until some event happens
self.event.wait()
""" do stuff here """
self.event.clear()

</code>

the way to use this is to get the main/separate thread to set() the
event object.


Cheers
 
M

mark

The way i would do this is by using an threading.Event (
http://docs.python.org/lib/event-objects.html )

<code>

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.event = threading.Event()
def run:
while True:
# block until some event happens
self.event.wait()
""" do stuff here """
self.event.clear()
</code>

the way to use this is to get the main/separate thread to set() the
event object.
Click to expand...
Can you give an example of how to get the main threead to set teh event object?
this is exactly what i wanted to do!
thanks a lot!
mark
 
P

placid

Can you give an example of how to get the main threead to set teh event object?
this is exactly what i wanted to do!
thanks a lot!
mark
Click to expand...

To set the event object

<code>

if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandler.start()

# do something here #
evtHandler.event.set()

# do more stuff here #
evtHandler.event.set()

</code>

Hope thats what your looking for.


Cheers
 
P

placid

To set the event object

<code>

if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandler.start()

# do something here #
evtHandler.event.set()

# do more stuff here #
evtHandler.event.set()

</code>

Hope thats what your looking for.

Cheers
Click to expand...

oops I've miss-typed the thread variable name the following should
work

<code>

if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()

# do something here #
evtHandlerThread.event.set()

# do more stuff here #
evtHandlerThread.event.set()

</code>
 
M

mark

oops I've miss-typed the thread variable name the following should
work

<code>
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()

# do something here #
evtHandlerThread.event.set()

# do more stuff here #
evtHandlerThread.event.set()

</code>
Click to expand...


Can I have the same thread process two or more events? Can you tell
how to do this? The code you gave is waiting on one event right. How
can I do it for more events?
thanks a lot!
mark
 
P

placid

Can I have the same thread process two or more events? Can you tell
how to do this? The code you gave is waiting on one event right. How
can I do it for more events?
thanks a lot!
mark
Click to expand...

I don't think a thread can block on more than one event at a time. But
you can make it block on more then one event one at a time.

<code>

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.events = [threading.Event(), threading.Event()]
self.currentEvent = None
def run:
while True:
for event in self.events:
self.currentEvent = event
# block until some event happens
self.currentEvent.wait()
""" do stuff here """
self.currentEvent.clear()

if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()

# do something here #
evtHandlerThread.currentEvent.set()

# do more stuff here #
evtHandlerThread.currentEvent.set()

</code>

what the thread does is sequentially waits for two events to happen
and then execute the same code. You could change this code to perform
different functions for different event objects.

Cheers
 
M

mark

Can I have the same thread process two or more events? Can you tell
how to do this? The code you gave is waiting on one event right. How
can I do it for more events?
thanks a lot!
mark
Click to expand...

I don't think a thread can block on more than one event at a time. But
you can make it block on more then one event one at a time.

<code>

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.events = [threading.Event(), threading.Event()]
self.currentEvent = None
def run:
while True:
for event in self.events:
self.currentEvent = event
# block until some event happens
self.currentEvent.wait()
""" do stuff here """
self.currentEvent.clear()

if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()

# do something here #
evtHandlerThread.currentEvent.set()

# do more stuff here #
evtHandlerThread.currentEvent.set()

</code>

what the thread does is sequentially waits for two events to happen
and then execute the same code. You could change this code to perform
different functions for different event objects.
Click to expand...

Once the thread starts it is going to wait on the event that is the
first element of the list right? This would mean :
evtHandlerThread.currentEvent.set(): that I have only one event right?
Can you explain how I can have different event objects. I dont see how
I can do different functinos for same event.

Thanks a lot!

mark
 
P

placid

I don't think a thread can block on more than one event at a time. But
you can make it block on more then one event one at a time.
<code>
Click to expand...

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.events = [threading.Event(), threading.Event()]
self.currentEvent = None
def run:
while True:
for event in self.events:
self.currentEvent = event
# block until some event happens
self.currentEvent.wait()
""" do stuff here """
self.currentEvent.clear()
Click to expand...
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()
Click to expand...
# do something here #
evtHandlerThread.currentEvent.set()
Click to expand...
# do more stuff here #
evtHandlerThread.currentEvent.set()

what the thread does is sequentially waits for two events to happen
and then execute the same code. You could change this code to perform
different functions for different event objects.
Click to expand...

Once the thread starts it is going to wait on the event that is the
first element of the list right? This would mean :
Click to expand...

This is correct.
evtHandlerThread.currentEvent.set(): that I have only one event right?
Click to expand...

this means that the current event occurred.
Can you explain how I can have different event objects. I dont see how
I can do different functinos for same event.

Thanks a lot!

mark
Click to expand...

To run different functions for the same event is easy, just write a
wrapper class around threading.event() and include some method that
you will run and assign this to different functions for each
EventWrapper.

<code>

class EventWrapper():
def __init__(self,work ):
self.event = threading.Event()
self.eventWork = work

def wait(self):
self.event.wait()

def clear(self)
self.event.clear()

def eventWork(self):
print "no work"

class eventhandler(threading.Thread):
def __init__(self, events = None):
threading.Thread.__init__(self)
self.events = events
self.currentEvent = None
def run:
while True:
if self.events:
for event in self.events:
self.currentEvent = event
# block until the current event happens
self.currentEvent.wait()
self.currentEvent.eventWork()
self.currentEvent.clear()

def eventOneWork():
# do some event 1 specific work here

def eventTwoWork():
# do some event 2 specific work here

if __name__ == "__main__":
events = [EventWrapper(eventOneWork),EventWrapper(eventTwoWork)]

evtHandlerThread = eventhandler(events)
evtHandlerThread.start()

# do something here #
evtHandlerThread.currentEvent.set()
# do more stuff here #
evtHandlerThread.currentEvent.set()

</code>

So you have a EventWrapper class that now contains the Event object
and a workEvent() method which is assigned to a function you create.

Hope this helps.

Cheers
 
M

mark

On 20 Feb 2007 21:26:18 -0800, placid <[email protected]> wrote:
Click to expand...
Right now I have a thread that sleeps for sometime and check if an
event has happened and go back to sleep. Now instead I want the thread
to sleep until the event has occured process the event and go back to sleep
Click to expand...
class eventhndler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
while True:
time.sleep(SLEEPTIME)
''''do event stuff'''
Click to expand...
The way i would do this is by using an threading.Event (
http://docs.python.org/lib/event-objects.html)

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.event = threading.Event()
def run:
while True:
# block until some event happens
self.event.wait()
""" do stuff here """
self.event.clear()
</code>
Click to expand...
the way to use this is to get the main/separate thread to set() the
event object.
Click to expand...
Can you give an example of how to get the main threead to set teh event object?
this is exactly what i wanted to do!
thanks a lot!
mark>
oops I've miss-typed the thread variable name the following should
work
Click to expand...
<code>
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()
Click to expand...
# do something here #
evtHandlerThread.event.set()
Click to expand...
# do more stuff here #
evtHandlerThread.event.set()

Can I have the same thread process two or more events? Can you tell
how to do this? The code you gave is waiting on one event right. How
can I do it for more events?
thanks a lot!
mark
Click to expand...
I don't think a thread can block on more than one event at a time. But
you can make it block on more then one event one at a time.
<code>
Click to expand...

class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.events = [threading.Event(), threading.Event()]
self.currentEvent = None
def run:
while True:
for event in self.events:
self.currentEvent = event
# block until some event happens
self.currentEvent.wait()
""" do stuff here """
self.currentEvent.clear()
Click to expand...
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()
Click to expand...
# do something here #
evtHandlerThread.currentEvent.set()
Click to expand...
# do more stuff here #
evtHandlerThread.currentEvent.set()

what the thread does is sequentially waits for two events to happen
and then execute the same code. You could change this code to perform
different functions for different event objects.
Click to expand...

Once the thread starts it is going to wait on the event that is the
first element of the list right? This would mean :
Click to expand...

This is correct.
evtHandlerThread.currentEvent.set(): that I have only one event right?
Click to expand...

this means that the current event occurred.
Can you explain how I can have different event objects. I dont see how
I can do different functinos for same event.

Thanks a lot!

mark
Click to expand...

To run different functions for the same event is easy, just write a
wrapper class around threading.event() and include some method that
you will run and assign this to different functions for each
EventWrapper.

<code>

class EventWrapper():
def __init__(self,work ):
self.event = threading.Event()
self.eventWork = work

def wait(self):
self.event.wait()

def clear(self)
self.event.clear()

def eventWork(self):
print "no work"

class eventhandler(threading.Thread):
def __init__(self, events = None):
threading.Thread.__init__(self)
self.events = events
self.currentEvent = None
def run:
while True:
if self.events:
for event in self.events:
self.currentEvent = event
# block until the current event happens
self.currentEvent.wait()
self.currentEvent.eventWork()
self.currentEvent.clear()

def eventOneWork():
# do some event 1 specific work here

def eventTwoWork():
# do some event 2 specific work here

if __name__ == "__main__":
events = [EventWrapper(eventOneWork),EventWrapper(eventTwoWork)]

evtHandlerThread = eventhandler(events)
evtHandlerThread.start()

# do something here #
evtHandlerThread.currentEvent.set()
# do more stuff here #
evtHandlerThread.currentEvent.set()

</code>

So you have a EventWrapper class that now contains the Event object
and a workEvent() method which is assigned to a function you create.
Click to expand...
THanks a lot! Does this have to have event1 and event2 occur in
sequence? Will this still work even if only event2 occurs and event1
never occurs?
thanks
mark
 
P

placid

Right now I have a thread that sleeps for sometime and check if an
event has happened and go back to sleep. Now instead I want the thread
to sleep until the event has occured process the event and go back to sleep
class eventhndler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
while True:
time.sleep(SLEEPTIME)
''''do event stuff'''
The way i would do this is by using an threading.Event (
http://docs.python.org/lib/event-objects.html)
<code>
class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.event = threading.Event()
def run:
while True:
# block until some event happens
self.event.wait()
""" do stuff here """
self.event.clear()
</code>
the way to use this is to get the main/separate thread to set() the
event object.
Can you give an example of how to get the main threead to set teh event object?
this is exactly what i wanted to do!
thanks a lot!
mark>
oops I've miss-typed the thread variable name the following should
work
<code>
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()
# do something here #
evtHandlerThread.event.set()
# do more stuff here #
evtHandlerThread.event.set()
</code>
Can I have the same thread process two or more events? Can you tell
how to do this? The code you gave is waiting on one event right. How
can I do it for more events?
thanks a lot!
mark
I don't think a thread can block on more than one event at a time. But
you can make it block on more then one event one at a time.
<code>
class eventhandler(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.events = [threading.Event(), threading.Event()]
self.currentEvent = None
def run:
while True:
for event in self.events:
self.currentEvent = event
# block until some event happens
self.currentEvent.wait()
""" do stuff here """
self.currentEvent.clear()
if __name__ == "__main__":
evtHandlerThread = eventhandler()
evtHandlerThread.start()
# do something here #
evtHandlerThread.currentEvent.set()
# do more stuff here #
evtHandlerThread.currentEvent.set()
</code>
what the thread does is sequentially waits for two events to happen
and then execute the same code. You could change this code to perform
different functions for different event objects.
Once the thread starts it is going to wait on the event that is the
first element of the list right? This would mean :
Click to expand...
Click to expand...
This is correct.
Click to expand...
this means that the current event occurred.
Click to expand...
To run different functions for the same event is easy, just write a
wrapper class around threading.event() and include some method that
you will run and assign this to different functions for each
EventWrapper.

class EventWrapper():
def __init__(self,work ):
self.event = threading.Event()
self.eventWork = work
Click to expand...
def wait(self):
self.event.wait()
Click to expand...
def clear(self)
self.event.clear()
Click to expand...
def eventWork(self):
print "no work"
Click to expand...
class eventhandler(threading.Thread):
def __init__(self, events = None):
threading.Thread.__init__(self)
self.events = events
self.currentEvent = None
def run:
while True:
if self.events:
for event in self.events:
self.currentEvent = event
# block until the current event happens
self.currentEvent.wait()
self.currentEvent.eventWork()
self.currentEvent.clear()
Click to expand...
def eventOneWork():
# do some event 1 specific work here
Click to expand...
def eventTwoWork():
# do some event 2 specific work here
Click to expand...
if __name__ == "__main__":
events = [EventWrapper(eventOneWork),EventWrapper(eventTwoWork)]
Click to expand...
evtHandlerThread = eventhandler(events)
evtHandlerThread.start()
Click to expand...
# do something here #
evtHandlerThread.currentEvent.set()
# do more stuff here #
evtHandlerThread.currentEvent.set()

So you have a EventWrapper class that now contains the Event object
and a workEvent() method which is assigned to a function you create.
Click to expand...

THanks a lot! Does this have to have event1 and event2 occur in
sequence? Will this still work even if only event2 occurs and event1
never occurs?
thanks
mark
Click to expand...

well if event1 never occurs then it will block/wait until forever and
even if event2 has occurred you never know about it until event1
occurs. You can introduce a timeout to the wait() call on the event
object which says, "block X seconds or until event happens (someone
calls the set method)" so even if event1 doesnt occur you will execute
event1.eventWork() because the timeout occurred. The way to fix this
is before you call the eventWork() method check if the event has
occurred via the isSet() method of Event objects.

http://docs.python.org/lib/event-objects.html

Cheers
 
D

Dennis Lee Bieber

THanks a lot! Does this have to have event1 and event2 occur in
sequence? Will this still work even if only event2 occurs and event1
never occurs?
thanks
mark
Click to expand...

I begin to think you'd be better off just using a Queue to pass the
events in...

Thread:
while True:
evnt = evtQueue.get()
do something with evnt (allows one to pass an identifier and
data)


Other:
evtQueue.put("EVENTx")



As I recall, threading Event() is more targeted at having multiple
threads waiting for notification, and one thread signalling.
--
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/
 

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