Source code for fsspec.implementations.webhdfs

# https://hadoop.apache.org/docs/r1.0.4/webhdfs.html

import logging
import os
import secrets
import shutil
import tempfile
import uuid
from contextlib import suppress
from urllib.parse import quote

import requests

from ..spec import AbstractBufferedFile, AbstractFileSystem
from ..utils import infer_storage_options

logger = logging.getLogger("webhdfs")


[docs]class WebHDFS(AbstractFileSystem): """ Interface to HDFS over HTTP using the WebHDFS API. Supports also HttpFS gateways. Three auth mechanisms are supported: insecure: no auth is done, and the user is assumed to be whoever they say they are (parameter `user`), or a predefined value such as "dr.who" if not given spnego: when kerberos authentication is enabled, auth is negotiated by requests_kerberos https://github.com/requests/requests-kerberos . This establishes a session based on existing kinit login and/or specified principal/password; parameters are passed with ``kerb_kwargs`` token: uses an existing Hadoop delegation token from another secured service. Indeed, this client can also generate such tokens when not insecure. Note that tokens expire, but can be renewed (by a previously specified user) and may allow for proxying. """ tempdir = str(tempfile.gettempdir()) protocol = "webhdfs", "webHDFS"
[docs] def __init__( self, host, port=50070, kerberos=False, token=None, user=None, proxy_to=None, kerb_kwargs=None, data_proxy=None, use_https=False, **kwargs, ): """ Parameters ---------- host: str Name-node address port: int Port for webHDFS kerberos: bool Whether to authenticate with kerberos for this connection token: str or None If given, use this token on every call to authenticate. A user and user-proxy may be encoded in the token and should not be also given user: str or None If given, assert the user name to connect with proxy_to: str or None If given, the user has the authority to proxy, and this value is the user in who's name actions are taken kerb_kwargs: dict Any extra arguments for HTTPKerberosAuth, see `<https://github.com/requests/requests-kerberos/blob/master/requests_kerberos/kerberos_.py>`_ data_proxy: dict, callable or None If given, map data-node addresses. This can be necessary if the HDFS cluster is behind a proxy, running on Docker or otherwise has a mismatch between the host-names given by the name-node and the address by which to refer to them from the client. If a dict, maps host names `host->data_proxy[host]`; if a callable, full URLs are passed, and function must conform to `url->data_proxy(url)`. use_https: bool Whether to connect to the Name-node using HTTPS instead of HTTP kwargs """ if self._cached: return super().__init__(**kwargs) self.url = "{protocol}://{host}:{port}/webhdfs/v1".format( protocol="https" if use_https else "http", host=host, port=port ) self.kerb = kerberos self.kerb_kwargs = kerb_kwargs or {} self.pars = {} self.proxy = data_proxy or {} if token is not None: if user is not None or proxy_to is not None: raise ValueError( "If passing a delegation token, must not set " "user or proxy_to, as these are encoded in the" " token" ) self.pars["delegation"] = token if user is not None: self.pars["user.name"] = user if proxy_to is not None: self.pars["doas"] = proxy_to if kerberos and user is not None: raise ValueError( "If using Kerberos auth, do not specify the " "user, this is handled by kinit." ) self._connect()
def _connect(self): self.session = requests.Session() if self.kerb: from requests_kerberos import HTTPKerberosAuth self.session.auth = HTTPKerberosAuth(**self.kerb_kwargs) def _call(self, op, method="get", path=None, data=None, redirect=True, **kwargs): url = self.url + quote(path or "") args = kwargs.copy() args.update(self.pars) args["op"] = op.upper() logger.debug("sending %s with %s", url, method) out = self.session.request( method=method.upper(), url=url, params=args, data=data, allow_redirects=redirect, ) if out.status_code in [400, 401, 403, 404, 500]: try: err = out.json() msg = err["RemoteException"]["message"] exp = err["RemoteException"]["exception"] except (ValueError, KeyError): pass else: if exp in ["IllegalArgumentException", "UnsupportedOperationException"]: raise ValueError(msg) elif exp in ["SecurityException", "AccessControlException"]: raise PermissionError(msg) elif exp in ["FileNotFoundException"]: raise FileNotFoundError(msg) else: raise RuntimeError(msg) out.raise_for_status() return out def _open( self, path, mode="rb", block_size=None, autocommit=True, replication=None, permissions=None, **kwargs, ): """ Parameters ---------- path: str File location mode: str 'rb', 'wb', etc. block_size: int Client buffer size for read-ahead or write buffer autocommit: bool If False, writes to temporary file that only gets put in final location upon commit replication: int Number of copies of file on the cluster, write mode only permissions: str or int posix permissions, write mode only kwargs Returns ------- WebHDFile instance """ block_size = block_size or self.blocksize return WebHDFile( self, path, mode=mode, block_size=block_size, tempdir=self.tempdir, autocommit=autocommit, replication=replication, permissions=permissions, ) @staticmethod def _process_info(info): info["type"] = info["type"].lower() info["size"] = info["length"] return info @classmethod def _strip_protocol(cls, path): return infer_storage_options(path)["path"] @staticmethod def _get_kwargs_from_urls(urlpath): out = infer_storage_options(urlpath) out.pop("path", None) out.pop("protocol", None) if "username" in out: out["user"] = out.pop("username") return out def info(self, path): out = self._call("GETFILESTATUS", path=path) info = out.json()["FileStatus"] info["name"] = path return self._process_info(info) def ls(self, path, detail=False): out = self._call("LISTSTATUS", path=path) infos = out.json()["FileStatuses"]["FileStatus"] for info in infos: self._process_info(info) info["name"] = path.rstrip("/") + "/" + info["pathSuffix"] if detail: return sorted(infos, key=lambda i: i["name"]) else: return sorted(info["name"] for info in infos) def content_summary(self, path): """Total numbers of files, directories and bytes under path""" out = self._call("GETCONTENTSUMMARY", path=path) return out.json()["ContentSummary"] def ukey(self, path): """Checksum info of file, giving method and result""" out = self._call("GETFILECHECKSUM", path=path, redirect=False) if "Location" in out.headers: location = self._apply_proxy(out.headers["Location"]) out2 = self.session.get(location) out2.raise_for_status() return out2.json()["FileChecksum"] else: out.raise_for_status() return out.json()["FileChecksum"] def home_directory(self): """Get user's home directory""" out = self._call("GETHOMEDIRECTORY") return out.json()["Path"] def get_delegation_token(self, renewer=None): """Retrieve token which can give the same authority to other uses Parameters ---------- renewer: str or None User who may use this token; if None, will be current user """ if renewer: out = self._call("GETDELEGATIONTOKEN", renewer=renewer) else: out = self._call("GETDELEGATIONTOKEN") t = out.json()["Token"] if t is None: raise ValueError("No token available for this user/security context") return t["urlString"] def renew_delegation_token(self, token): """Make token live longer. Returns new expiry time""" out = self._call("RENEWDELEGATIONTOKEN", method="put", token=token) return out.json()["long"] def cancel_delegation_token(self, token): """Stop the token from being useful""" self._call("CANCELDELEGATIONTOKEN", method="put", token=token) def chmod(self, path, mod): """Set the permission at path Parameters ---------- path: str location to set (file or directory) mod: str or int posix epresentation or permission, give as oct string, e.g, '777' or 0o777 """ self._call("SETPERMISSION", method="put", path=path, permission=mod) def chown(self, path, owner=None, group=None): """Change owning user and/or group""" kwargs = {} if owner is not None: kwargs["owner"] = owner if group is not None: kwargs["group"] = group self._call("SETOWNER", method="put", path=path, **kwargs) def set_replication(self, path, replication): """ Set file replication factor Parameters ---------- path: str File location (not for directories) replication: int Number of copies of file on the cluster. Should be smaller than number of data nodes; normally 3 on most systems. """ self._call("SETREPLICATION", path=path, method="put", replication=replication) def mkdir(self, path, **kwargs): self._call("MKDIRS", method="put", path=path) def makedirs(self, path, exist_ok=False): if exist_ok is False and self.exists(path): raise FileExistsError(path) self.mkdir(path) def mv(self, path1, path2, **kwargs): self._call("RENAME", method="put", path=path1, destination=path2) def rm(self, path, recursive=False, **kwargs): self._call( "DELETE", method="delete", path=path, recursive="true" if recursive else "false", ) def rm_file(self, path, **kwargs): self.rm(path) def cp_file(self, lpath, rpath, **kwargs): with self.open(lpath) as lstream: tmp_fname = "/".join([self._parent(rpath), f".tmp.{secrets.token_hex(16)}"]) # Perform an atomic copy (stream to a temporary file and # move it to the actual destination). try: with self.open(tmp_fname, "wb") as rstream: shutil.copyfileobj(lstream, rstream) self.mv(tmp_fname, rpath) except BaseException: # noqa with suppress(FileNotFoundError): self.rm(tmp_fname) raise def _apply_proxy(self, location): if self.proxy and callable(self.proxy): location = self.proxy(location) elif self.proxy: # as a dict for k, v in self.proxy.items(): location = location.replace(k, v, 1) return location
class WebHDFile(AbstractBufferedFile): """A file living in HDFS over webHDFS""" def __init__(self, fs, path, **kwargs): super().__init__(fs, path, **kwargs) kwargs = kwargs.copy() if kwargs.get("permissions", None) is None: kwargs.pop("permissions", None) if kwargs.get("replication", None) is None: kwargs.pop("replication", None) self.permissions = kwargs.pop("permissions", 511) tempdir = kwargs.pop("tempdir") if kwargs.pop("autocommit", False) is False: self.target = self.path self.path = os.path.join(tempdir, str(uuid.uuid4())) def _upload_chunk(self, final=False): """Write one part of a multi-block file upload Parameters ========== final: bool This is the last block, so should complete file, if self.autocommit is True. """ out = self.fs.session.post( self.location, data=self.buffer.getvalue(), headers={"content-type": "application/octet-stream"}, ) out.raise_for_status() return True def _initiate_upload(self): """Create remote file/upload""" kwargs = self.kwargs.copy() if "a" in self.mode: op, method = "APPEND", "POST" else: op, method = "CREATE", "PUT" kwargs["overwrite"] = "true" out = self.fs._call(op, method, self.path, redirect=False, **kwargs) location = self.fs._apply_proxy(out.headers["Location"]) if "w" in self.mode: # create empty file to append to out2 = self.fs.session.put( location, headers={"content-type": "application/octet-stream"} ) out2.raise_for_status() self.location = location.replace("CREATE", "APPEND") def _fetch_range(self, start, end): start = max(start, 0) end = min(self.size, end) if start >= end or start >= self.size: return b"" out = self.fs._call( "OPEN", path=self.path, offset=start, length=end - start, redirect=False ) out.raise_for_status() if "Location" in out.headers: location = out.headers["Location"] out2 = self.fs.session.get(self.fs._apply_proxy(location)) return out2.content else: return out.content def commit(self): self.fs.mv(self.path, self.target) def discard(self): self.fs.rm(self.path)