[Python-Dev] [Python-checkins] cpython (3.2): logging: Added locking in flush() and close() handler methods. Thanks to Fayaz

[Gregory P. Smith]

On Thu, Feb 23, 2012 at 5:51 PM, Gregory P. Smith <greg at krypto.org> wrote:
> On Thu, Feb 23, 2012 at 12:04 PM, vinay.sajip
> <python-checkins at python.org> wrote:
>> http://hg.python.org/cpython/rev/b2adcd90e656
>> changeset:   75211:b2adcd90e656
>> branch:      3.2
>> parent:      75200:85d08a1ba74e
>> user:        Vinay Sajip <vinay_sajip at yahoo.co.uk>
>> date:        Thu Feb 23 19:45:52 2012 +0000
>> summary:
>>  logging: Added locking in flush() and close() handler methods. Thanks to Fayaz Yusuf Khan for the suggestion.
>>
>> files:
>>  Lib/logging/__init__.py |  24 +++++++++-------
>>  Lib/logging/handlers.py |  40 +++++++++++++++-------------
>>  2 files changed, 35 insertions(+), 29 deletions(-)
>>
>>
>> diff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
>> --- a/Lib/logging/__init__.py
>> +++ b/Lib/logging/__init__.py
>> @@ -1,4 +1,4 @@
>> -# Copyright 2001-2010 by Vinay Sajip. All Rights Reserved.
>> +# Copyright 2001-2012 by Vinay Sajip. All Rights Reserved.
>>  #
>>  # Permission to use, copy, modify, and distribute this software and its
>>  # documentation for any purpose and without fee is hereby granted,
>> @@ -16,9 +16,9 @@
>>
>>  """
>>  Logging package for Python. Based on PEP 282 and comments thereto in
>> -comp.lang.python, and influenced by Apache's log4j system.
>> +comp.lang.python.
>>
>> -Copyright (C) 2001-2011 Vinay Sajip. All Rights Reserved.
>> +Copyright (C) 2001-2012 Vinay Sajip. All Rights Reserved.
>>
>>  To use, simply 'import logging' and log away!
>>  """
>> @@ -917,8 +917,9 @@
>>         """
>>         Flushes the stream.
>>         """
>> -        if self.stream and hasattr(self.stream, "flush"):
>> -            self.stream.flush()
>> +        with self.lock:
>> +            if self.stream and hasattr(self.stream, "flush"):
>> +                self.stream.flush()
>
> I don't know if anyone actually builds Python without thread support
> anymore, but if so, self.lock will be set to None and these "with
> self.lock"s will fail.
>
> Perhaps change lock = None to self.lock = some dummy duck typed lock
> that supports use as a context manager and acquire/release calls?

whoops.  once again there I go reading the commit log in order.  Looks
like you already fixed this in
http://hg.python.org/cpython/rev/2ab3a97d544c.  thanks! :)


>
>>
>>     def emit(self, record):
>>         """
>> @@ -969,12 +970,13 @@
>>         """
>>         Closes the stream.
>>         """
>> -        if self.stream:
>> -            self.flush()
>> -            if hasattr(self.stream, "close"):
>> -                self.stream.close()
>> -            StreamHandler.close(self)
>> -            self.stream = None
>> +        with self.lock:
>> +            if self.stream:
>> +                self.flush()
>> +                if hasattr(self.stream, "close"):
>> +                    self.stream.close()
>> +                StreamHandler.close(self)
>> +                self.stream = None
>>
>>     def _open(self):
>>         """
>> diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py
>> --- a/Lib/logging/handlers.py
>> +++ b/Lib/logging/handlers.py
>> @@ -1,4 +1,4 @@
>> -# Copyright 2001-2010 by Vinay Sajip. All Rights Reserved.
>> +# Copyright 2001-2012 by Vinay Sajip. All Rights Reserved.
>>  #
>>  # Permission to use, copy, modify, and distribute this software and its
>>  # documentation for any purpose and without fee is hereby granted,
>> @@ -16,10 +16,9 @@
>>
>>  """
>>  Additional handlers for the logging package for Python. The core package is
>> -based on PEP 282 and comments thereto in comp.lang.python, and influenced by
>> -Apache's log4j system.
>> +based on PEP 282 and comments thereto in comp.lang.python.
>>
>> -Copyright (C) 2001-2010 Vinay Sajip. All Rights Reserved.
>> +Copyright (C) 2001-2012 Vinay Sajip. All Rights Reserved.
>>
>>  To use, simply 'import logging.handlers' and log away!
>>  """
>> @@ -554,10 +553,11 @@
>>         """
>>         Closes the socket.
>>         """
>> -        if self.sock:
>> -            self.sock.close()
>> -            self.sock = None
>> -        logging.Handler.close(self)
>> +        with self.lock:
>> +            if self.sock:
>> +                self.sock.close()
>> +                self.sock = None
>> +            logging.Handler.close(self)
>>
>>  class DatagramHandler(SocketHandler):
>>     """
>> @@ -752,9 +752,10 @@
>>         """
>>         Closes the socket.
>>         """
>> -        if self.unixsocket:
>> -            self.socket.close()
>> -        logging.Handler.close(self)
>> +        with self.lock:
>> +            if self.unixsocket:
>> +                self.socket.close()
>> +            logging.Handler.close(self)
>>
>>     def mapPriority(self, levelName):
>>         """
>> @@ -1095,7 +1096,8 @@
>>
>>         This version just zaps the buffer to empty.
>>         """
>> -        self.buffer = []
>> +        with self.lock:
>> +            self.buffer = []
>>
>>     def close(self):
>>         """
>> @@ -1145,18 +1147,20 @@
>>
>>         The record buffer is also cleared by this operation.
>>         """
>> -        if self.target:
>> -            for record in self.buffer:
>> -                self.target.handle(record)
>> -            self.buffer = []
>> +        with self.lock:
>> +            if self.target:
>> +                for record in self.buffer:
>> +                    self.target.handle(record)
>> +                self.buffer = []
>>
>>     def close(self):
>>         """
>>         Flush, set the target to None and lose the buffer.
>>         """
>>         self.flush()
>> -        self.target = None
>> -        BufferingHandler.close(self)
>> +        with self.lock:
>> +            self.target = None
>> +            BufferingHandler.close(self)
>>
>>
>>  class QueueHandler(logging.Handler):
>>
>> --
>> Repository URL: http://hg.python.org/cpython
>>
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