def update(self, doc, process=None):
        if process is None:
            pk = 'id'
            id = doc.id
            doc.synced = False
            set = doc
        elif process == UPDATE_PROCESS:
            if self.db.docs.find({'sid': doc.sid}).count() == 0:
                return self.insert(doc, synced=True)
            pk = 'sid'
            id = doc.sid
            doc.synced = not doc.merged() # must be commited if was merged
            doc.merged(False)
            set = {'tid': doc.tid, 'data': doc.data, 'user': doc.user,
                   'public': doc.public, 'synced': doc.synced}
        elif process == COMMIT_PROCESS:
            pk = 'id'
            id = doc.id
            doc.synced = True
            set = {'sid': doc.sid, 'tid': doc.tid, 'synced': doc.synced}
        else:
            raise DatabaseException('Incorrect update process')

        try:
            rs = self.db.docs.update({pk: id}, {'$set': set}, safe=True)
            assert rs['n'] == 1
        except Exception as e:
            raise DatabaseException(e)
        return doc
def log_exception(cls, msg):
        """Try to log an error message to this process's error log and the shared error log.

        NB: Doesn't raise (logs an error instead).
        """
        pid = os.getpid()
        fatal_error_log_entry = cls._format_exception_message(msg, pid)

        # We care more about this log than the shared log, so write to it first.
        try:
            cls._try_write_with_flush(cls._pid_specific_error_fileobj, fatal_error_log_entry)
        except Exception as e:
            logger.error(
                "Error logging the message '{}' to the pid-specific file handle for {} at pid {}:\n{}".format(
                    msg, cls._log_dir, pid, e
                )
            )

        # Write to the shared log.
        try:
            # TODO: we should probably guard this against concurrent modification by other pants
            # subprocesses somehow.
            cls._try_write_with_flush(cls._shared_error_fileobj, fatal_error_log_entry)
        except Exception as e:
            logger.error(
                "Error logging the message '{}' to the shared file handle for {} at pid {}:\n{}".format(
                    msg, cls._log_dir, pid, e
                )
            )