python - Opposite of __init__ in thread class -

i understand __init__() called automatically when create class newthread = mythread(property) , run() triggered newthread.start(). looking called automatically before thread terminates, don't have explicitly call self.cleanup() before each return statement.

class mythread(thread):       def __init__(self, property):          thread.__init__(self)         self.property = property      def cleanup(self):         # clean here      def run(self):         # stuff         self.cleanup() # current work around         return 

one way making thread subclass context manager. make __exit__() special method want triggered.

the following shows i'm proposing. note: renamed property argument passing constructor because property name of python built-in.

from threading import thread import time  test_thread_exception = false  # change desired  class mythread(thread):      def __init__(self, attribute):         thread.__init__(self)         self.attribute = attribute      def cleanup(self):         # clean here         print('  cleaning after thread')      def run(self):         if test_thread_exception:             raise runtimeerror('oops!')  # force exception         print('  other thread running...')         time.sleep(2)  # something...      def __enter__(self):         try:             self.run()         except exception exc:             print('error: {} exception raised thread'.format(exc))             raise  # reraise exception         return self      def __exit__(self, *args):         self.cleanup()  print('main thread begins execution') mythread('hello') thread:     print('doing other things in main thread while other thread running') print('main thread continuing...') 

output:

main thread begins execution   other thread running... doing other things in main thread while other thread running   cleaning after thread main thread continuing on... 

if change test_thread_exception true, cleanup() won't called since thread didn't run successfully—although change if wished, may need ensure doesn't called twice. here's code above in case:

main thread begins execution error: oops! exception raised thread traceback (most recent call last):   file "opposite_init.py", line 37, in <module>     mythread('hello') thread:   file "opposite_init.py", line 27, in __enter__     self.run()   file "opposite_init.py", line 21, in run     raise runtimeerror('oops!')  # force exception runtimeerror: oops!