# 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, tokenize
logger = logging.getLogger("webhdfs")
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"
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()
self._fsid = "webhdfs_" + tokenize(host, port)
@property
def fsid(self):
return self._fsid
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()
# after creating empty file, change location to append to
out2 = self.fs._call("APPEND", "POST", self.path, redirect=False, **kwargs)
self.location = self.fs._apply_proxy(out2.headers["Location"])
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)