Why a python method not returning?

Question

I have a destroy() method which is called before my thread is coming down.

def destroy(self):
    self.logger.debug("Instance is being destroyed")
    //do stuff
    self.logger.debug("Instance has been destroyed")

This is the code from where it is called:

if (__name__ == '__main__'):
try:        
    instance = device_instance()             
        while True:
            //do stuff
            if input_string == 'destroy':
                instance.destroy()
                logger.debug("Back in main after destroying")
                break
            else:
                //do stuff
            time.sleep(.100)
except Exception, ex:
    logger.debug("Exception occurred" + str(ex))
except:
    logger.debug("Unhandled exception occurred")

Now when I run it, the problem is I see logging statements "Instance is being destroyed" and "Instance has been destroyed" and I don't see "Back in main after destroying". That means my destroy() is never returning. I tried adding explicit return statement, still the same problem. If I add sys.exit(0) to destroy() at the end, it does raise exception which is eventually caught in main. What could be the issue?

Answer 1

您是否在查看同一记录器？

Answer 2

Is your log level above to debug? Try with print

Also, try adding a log before the call.

Answer 3

I think we'll need a bit more information than this -- probably about the context of 'do something' and input_string

I put this into a piece of code:

import logging                                                                                          
import time                                                                                             

logger = logging.getLogger('')                                                                          

class device_instance(object):                                                                          

    def destroy(self):                                                                                  
        self.logger.warning('Instance is being destroyed')                                              
        # do stuff                                                                                      
        self.logger.warning('Instance is destroyed')                                                    

input_strings = ['one', 'two', 'destroy']                                                               

if (__name__ == '__main__'):                                                                            
    logging.basicConfig()                                                                               
    try:                                                                                                
        instance = device_instance()                                                                    
        instance.logger = logger                                                                        

        gen = input_strings.__iter__()                                                                  

        while True:                                                                                     
            #do stuff                                                                                   
            try:                                                                                        
                input_string = gen.next()                                                               
            except StopIteration:                                                                       
                input_string = 'destroy'                                                                

            if input_string == 'destroy':                                                               
                instance.destroy()                                                                      
                logger.warning("Back in main after destroying")                                         
                break                                                                                   
            else:                                                                                       
                time.sleep(.100)                                                                        
    except:                                                                                             
        logger.exception("Unhandled exception occurred")

This outputs what you'd expect:

WARNING:root:Instance is being destroyed                                                                    
WARNING:root:Instance is destroyed                                                                          
WARNING:root:Back in main after destroying

So something else is at play, I think.