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Diffstat (limited to 'src/buildstream/_messenger.py')
| -rw-r--r-- | src/buildstream/_messenger.py | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/src/buildstream/_messenger.py b/src/buildstream/_messenger.py index 7dec93994..d83b464ff 100644 --- a/src/buildstream/_messenger.py +++ b/src/buildstream/_messenger.py @@ -283,3 +283,32 @@ class Messenger(): # Write to the open log file self._log_handle.write('{}\n'.format(text)) self._log_handle.flush() + + # get_state_for_child_job_pickling(self) + # + # Return data necessary to reconstruct this object in a child job process. + # + # This should be implemented the same as __getstate__(). We define this + # method instead as it is child job specific. + # + # Returns: + # (dict): This `state` is what we want `self.__dict__` to be restored to + # after instantiation in the child process. + # + def get_state_for_child_job_pickling(self): + state = self.__dict__.copy() + + # When pickling a Messenger over to the ChildJob, we don't want to bring + # the whole _message_handler over with it. We also don't want to remove it + # in the main process. If we remove it in the child process then we will + # already be too late. The only time that seems just right is here, when + # preparing the child process' copy of the Messenger. + # + # Another approach might be to use a context manager on the Messenger, + # which removes and restores the _message_handler. This wouldn't require + # access to private details of Messenger, but it would open up a window + # where messagesw wouldn't be handled as expected. + # + del state['_message_handler'] + + return state |