Files
cellxgene/server/app/util/data_locator.py
Matt Weiden f3015cb9df Makefile modularity, test targets, and auto-formatting (#1070)
* Fix Makefile whitespace and .PHONY use

* Fix Makefile filename

* Modularize Makefile into client and server Makefiles

Part of the reason that the Makefile in the root directory is a bit
complicated is that it tries to handle tasks that can be handled
separately in the client and server modules.

This commit pushes some of the make logic specific to each module into
their own makefiles and calls out to those makefiles from that in the
project root.

* Add auto-formatting to client and server modules

One thing that can make linting faster is auto-formatting. This commit
adds the yapf auto-formatting tool to the server module and uses
eslint's "fix" functionality to speed up the linting/formatting process.

* Add yapf for automatic code formatting

* Add a root test target that calls sub-tests

* Apply yapf to python files

* Do not duplicate npm commands, simply pass through

* Update documentation

* Do not shadow reserved word len

* Add general test target

* Fix make call in dev-env

* Use black instead of yapf

* Run flake8 from the root directory

* Revert "Apply yapf to python files"

This reverts commit cdca128a01.

* Apply black to python code

* Resolve lint errors resulting from black format

* Add explanation of server unit tests in dev guidelines
2019-12-27 14:43:37 -08:00

104 lines
3.2 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):
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.
with self.open() as src, tempfile.NamedTemporaryFile(prefix="cellxgene_", delete=False) as tmp:
tmp.write(src.read())
tmp.close()
src.close()
tmp_path = tmp.name
return LocalFilePath(tmp_path, delete=True)
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)