Block until we are connected to a master

def sync_connect_master(self, timeout=None, failed=False):
        '''
        Block until we are connected to a master
        '''
        self._sync_connect_master_success = False
        log.debug("sync_connect_master")

        def on_connect_master_future_done(future):
            self._sync_connect_master_success = True
            self.io_loop.stop()

        self._connect_master_future = self.connect_master(failed=failed)
        # finish connecting to master
        self._connect_master_future.add_done_callback(on_connect_master_future_done)
        if timeout:
            self.io_loop.call_later(timeout, self.io_loop.stop)
        try:
            self.io_loop.start()
        except KeyboardInterrupt:
            self.destroy()
        # I made the following 3 line oddity to preserve traceback.
        # Please read PR #23978 before changing, hopefully avoiding regressions.
        # Good luck, we're all counting on you.  Thanks.
        if self._connect_master_future.done():
            future_exception = self._connect_master_future.exception()
            if future_exception:
                # This needs to be re-raised to preserve restart_on_error behavior.
                raise six.reraise(*future_exception)
        if timeout and self._sync_connect_master_success is False:
            raise SaltDaemonNotRunning('Failed to connect to the salt-master')