File size: 8,864 Bytes
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import logging
import os
import types
import uuid
from stat import S_ISDIR, S_ISLNK
import paramiko
from .. import AbstractFileSystem
from ..utils import infer_storage_options
logger = logging.getLogger("fsspec.sftp")
#: Short names for the missing host key policies built into paramiko, accepted
#: as the ``host_key_policy`` argument of ``SFTPFileSystem``.
HOST_KEY_POLICIES = {
"auto_add": paramiko.AutoAddPolicy,
"reject": paramiko.RejectPolicy,
"warning": paramiko.WarningPolicy,
}
def _resolve_host_key_policy(policy):
"""Turn a ``host_key_policy`` argument into a paramiko policy instance."""
if policy is None:
return paramiko.AutoAddPolicy()
if isinstance(policy, str):
try:
return HOST_KEY_POLICIES[policy]()
except KeyError:
raise ValueError(
f"Unknown host_key_policy {policy!r}; expected one of "
f"{sorted(HOST_KEY_POLICIES)} or a paramiko.MissingHostKeyPolicy"
) from None
if isinstance(policy, type) and issubclass(policy, paramiko.MissingHostKeyPolicy):
return policy()
if isinstance(policy, paramiko.MissingHostKeyPolicy):
return policy
raise TypeError(
"host_key_policy must be one of "
f"{sorted(HOST_KEY_POLICIES)}, a paramiko.MissingHostKeyPolicy subclass "
f"or instance, not {type(policy).__name__}"
)
class SFTPFileSystem(AbstractFileSystem):
"""Files over SFTP/SSH
Peer-to-peer filesystem over SSH using paramiko.
Note: if using this with the ``open`` or ``open_files``, with full URLs,
there is no way to tell if a path is relative, so all paths are assumed
to be absolute.
"""
protocol = "sftp", "ssh"
def __init__(self, host, **ssh_kwargs):
"""
Parameters
----------
host: str
Hostname or IP as a string
temppath: str
Location on the server to put files, when within a transaction
host_key_policy: str or paramiko.MissingHostKeyPolicy, optional
Policy applied when the server presents a host key that is not
known yet, passed to
``paramiko.SSHClient.set_missing_host_key_policy``. Either one of
the strings ``"auto_add"`` (default, ``paramiko.AutoAddPolicy``:
accept and remember any unknown key), ``"warning"``
(``paramiko.WarningPolicy``: log a warning and accept) or
``"reject"`` (``paramiko.RejectPolicy``: refuse to connect), or a
``paramiko.MissingHostKeyPolicy`` subclass or instance.
The default, ``"auto_add"``, trusts any host key presented on the
first connection to a host, so a man-in-the-middle attacker can
impersonate the server. Pass ``"reject"`` to only connect to hosts
whose keys are already in the known hosts of the process.
ssh_kwargs: dict
Parameters passed on to connection. See details in
https://docs.paramiko.org/en/3.3/api/client.html#paramiko.client.SSHClient.connect
May include port, username, password...
"""
if self._cached:
return
super().__init__(**ssh_kwargs)
self.temppath = ssh_kwargs.pop("temppath", "/tmp") # remote temp directory
self.host_key_policy = _resolve_host_key_policy(
ssh_kwargs.pop("host_key_policy", None)
)
self.host = host
self.ssh_kwargs = ssh_kwargs
self._connect()
def _connect(self):
logger.debug("Connecting to SFTP server %s", self.host)
self.client = paramiko.SSHClient()
self.client.set_missing_host_key_policy(self.host_key_policy)
self.client.connect(self.host, **self.ssh_kwargs)
self.ftp = self.client.open_sftp()
@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)
return out
def mkdir(self, path, create_parents=True, mode=511):
path = self._strip_protocol(path)
logger.debug("Creating folder %s", path)
if self.exists(path):
raise FileExistsError(f"File exists: {path}")
if create_parents:
self.makedirs(path)
else:
self.ftp.mkdir(path, mode)
def makedirs(self, path, exist_ok=False, mode=511):
if self.exists(path) and not exist_ok:
raise FileExistsError(f"File exists: {path}")
parts = path.split("/")
new_path = "/" if path[:1] == "/" else ""
for part in parts:
if part:
new_path = f"{new_path}/{part}" if new_path else part
if not self.exists(new_path):
self.ftp.mkdir(new_path, mode)
def rmdir(self, path):
path = self._strip_protocol(path)
logger.debug("Removing folder %s", path)
self.ftp.rmdir(path)
def info(self, path):
path = self._strip_protocol(path)
stat = self._decode_stat(self.ftp.stat(path))
stat["name"] = path
return stat
def created(self, path):
"""Return the created timestamp of a file as a datetime.datetime"""
# The API does not provide creation time, so we use modification time
info = self.info(path)
mtime = info.get("mtime", None)
if mtime is not None:
return mtime
raise RuntimeError("Could not retrieve creation time (modification time).")
def modified(self, path):
"""Return the modified timestamp of a file as a datetime.datetime"""
info = self.info(path)
mtime = info.get("mtime", None)
if mtime is not None:
return mtime
raise RuntimeError("Could not retrieve modification time.")
@staticmethod
def _decode_stat(stat, parent_path=None):
if S_ISDIR(stat.st_mode):
t = "directory"
elif S_ISLNK(stat.st_mode):
t = "link"
else:
t = "file"
out = {
"name": "",
"size": stat.st_size,
"type": t,
"uid": stat.st_uid,
"gid": stat.st_gid,
"time": datetime.datetime.fromtimestamp(
stat.st_atime, tz=datetime.timezone.utc
),
"mtime": datetime.datetime.fromtimestamp(
stat.st_mtime, tz=datetime.timezone.utc
),
}
if parent_path:
out["name"] = "/".join([parent_path.rstrip("/"), stat.filename])
return out
def ls(self, path, detail=False):
path = self._strip_protocol(path)
logger.debug("Listing folder %s", path)
stats = [self._decode_stat(stat, path) for stat in self.ftp.listdir_iter(path)]
if detail:
return stats
else:
paths = [stat["name"] for stat in stats]
return sorted(paths)
def put_file(self, lpath, rpath, callback=None, **kwargs):
self.mkdirs(self._parent(os.fspath(rpath)), exist_ok=True)
logger.debug("Put file %s into %s", lpath, rpath)
self.ftp.put(lpath, rpath)
def get_file(self, rpath, lpath, **kwargs):
if self.isdir(rpath):
os.makedirs(lpath, exist_ok=True)
else:
self.ftp.get(self._strip_protocol(rpath), lpath)
def _open(self, path, mode="rb", block_size=None, **kwargs):
"""
block_size: int or None
If 0, no buffering, if 1, line buffering, if >1, buffer that many
bytes, if None use default from paramiko.
"""
logger.debug("Opening file %s", path)
if kwargs.get("autocommit", True) is False:
# writes to temporary file, move on commit
path2 = "/".join([self.temppath, str(uuid.uuid4())])
f = self.ftp.open(path2, mode, bufsize=block_size if block_size else -1)
f.temppath = path2
f.targetpath = path
f.fs = self
f.commit = types.MethodType(commit_a_file, f)
f.discard = types.MethodType(discard_a_file, f)
else:
f = self.ftp.open(path, mode, bufsize=block_size if block_size else -1)
return f
def _rm(self, path):
if self.isdir(path):
self.ftp.rmdir(path)
else:
self.ftp.remove(path)
def mv(self, old, new):
new = self._strip_protocol(new)
old = self._strip_protocol(old)
logger.debug("Renaming %s into %s", old, new)
self.ftp.posix_rename(old, new)
def commit_a_file(self):
self.fs.mv(self.temppath, self.targetpath)
def discard_a_file(self):
self.fs._rm(self.temppath)
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