Files
cellxgene/server/common/data_locator.py
Bruce Martin 8beeb57c96 Use DataLocator consistently on backend (#1208)
* allow DataLocator to accept another locator as init param

* migrate to DataLocator

* migrate to DataLocator

* lint

* migrate to DataLocator

* add check for erroroneous use of remote path and annotations

* lint

* revert default data location - now back go CWD

* remove unused import
2020-03-10 19:12:49 -07:00

119 lines
3.8 KiB
Python

import os
import tempfile
import fsspec
from datetime import datetime
class DataLocator:
"""
DataLocator is a simple wrapper around fsspec functionality, and provides a
set of functions to encapsulate a data location (URI or path), interogate
metadata about the object at that location (size, existance, etc) and
access the underlying data.
https://filesystem-spec.readthedocs.io/en/latest/index.html
Example:
dl = DataLocator("/tmp/foo.h5ad")
if dl.exists():
print(dl.size())
with dl.open() as f:
thecontents = f.read()
DataLocator will accept a URI or native path. Error handling is as defined
in fsspec.
"""
def __init__(self, uri_or_path):
if isinstance(uri_or_path, DataLocator):
locator = uri_or_path
self.uri_or_path = locator.uri_or_path
self.protocol = locator.protocol
self.path = locator.path
self.cname = locator.cname
else:
self.uri_or_path = uri_or_path
self.protocol, self.path = DataLocator._get_protocol_and_path(uri_or_path)
# work-around for LocalFileSystem not treating file: and None as the same scheme/protocol
self.cname = self.path if self.protocol == "file" else self.uri_or_path
# will throw RuntimeError if the protocol is unsupported
self.fs = fsspec.filesystem(self.protocol)
@staticmethod
def _get_protocol_and_path(uri_or_path):
if "://" in uri_or_path:
protocol, path = uri_or_path.split("://", 1)
# windows!!! Ignore single letter drive identifiers,
# eg, G:\foo.txt
if len(protocol) > 1:
return protocol, path
return None, uri_or_path
def exists(self):
return self.fs.exists(self.cname)
def size(self):
return self.fs.size(self.cname)
def lastmodtime(self):
""" return datetime object representing last modification time, or None if unavailable """
info = self.fs.info(self.cname)
if self.islocal() and info is not None:
return datetime.fromtimestamp(info["mtime"])
else:
return getattr(info, "LastModified", None)
def abspath(self):
"""
return the absolute path for the locator - only really does something
for file: protocol, as all others are already absolute
"""
if self.islocal():
return os.path.abspath(self.path)
else:
return self.uri_or_path
def isfile(self):
return self.fs.isfile(self.cname)
def open(self, *args):
return self.fs.open(self.uri_or_path, *args)
def islocal(self):
return self.protocol is None or self.protocol == "file"
def local_handle(self):
if self.islocal():
return LocalFilePath(self.path)
# if not local, create a tmp file system object to contain the data,
# and clean it up when done. If the path has a suffix/extension,
# do our best to create a file with the same.
ext = os.path.splitext(self.path)
suffix = None if ext[1] == "" else ext[1]
with self.open() as src, tempfile.NamedTemporaryFile(prefix="cellxgene_", suffix=suffix, delete=False) as tmp:
tmp.write(src.read())
tmp.close()
src.close()
tmp_path = tmp.name
return LocalFilePath(tmp_path, delete=True)
def ls(self):
paths = self.fs.ls(self.uri_or_path)
return [os.path.basename(p) for p in paths]
class LocalFilePath:
def __init__(self, tmp_path, delete=False):
self.tmp_path = tmp_path
self.delete = delete
def __enter__(self):
return self.tmp_path
def __exit__(self, *args):
if self.delete:
os.unlink(self.tmp_path)