driver.py 文件源码

def _start_snapshot_request(self):
        """
        Issues the HTTP request to etcd to load the snapshot but only
        loads it as far as the headers.
        :return: tuple of response and snapshot's etcd index.
        :raises HTTPException
        :raises HTTPError
        :raises socket.error
        :raises DriverShutdown if the etcd cluster ID changes.
        """
        _log.info("Loading snapshot headers...")
        resp = self._etcd_request(self._resync_http_pool,
                                  VERSION_DIR,
                                  recursive=True,
                                  timeout=120,
                                  preload_content=False)
        snapshot_index = int(resp.getheader("x-etcd-index", 1))
        if not self._cluster_id:
            _log.error("Snapshot response did not contain cluster ID, "
                       "resyncing to avoid inconsistency")
            raise ResyncRequired()
        _log.info("Got snapshot headers, snapshot index is %s; starting "
                  "watcher...", snapshot_index)
        return resp, snapshot_index