hello_asyncio.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
'''
hello_asyncio.py - Example file system for pyfuse3 using asyncio.

This program presents a static file system containing a single file.

Copyright © 2015 Nikolaus Rath <Nikolaus.org>
Copyright © 2015 Gerion Entrup.

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''

import asyncio
import errno
import logging
import os
import stat
from argparse import ArgumentParser
from typing import cast

import pyfuse3
import pyfuse3.asyncio
from pyfuse3 import FileHandleT, FileInfo, InodeT

try:
    import faulthandler
except ImportError:
    pass
else:
    faulthandler.enable()

log = logging.getLogger(__name__)
pyfuse3.asyncio.enable()


class TestFs(pyfuse3.Operations):
    def __init__(self):
        super(TestFs, self).__init__()
        self.hello_name = b"message"
        self.hello_inode = cast(InodeT, pyfuse3.ROOT_INODE + 1)
        self.hello_data = b"hello world\n"

    async def getattr(self, inode, ctx=None):
        entry = pyfuse3.EntryAttributes()
        if inode == pyfuse3.ROOT_INODE:
            entry.st_mode = stat.S_IFDIR | 0o755
            entry.st_size = 0
        elif inode == self.hello_inode:
            entry.st_mode = stat.S_IFREG | 0o644
            entry.st_size = len(self.hello_data)
        else:
            raise pyfuse3.FUSEError(errno.ENOENT)

        stamp = int(1438467123.985654 * 1e9)
        entry.st_atime_ns = stamp
        entry.st_ctime_ns = stamp
        entry.st_mtime_ns = stamp
        entry.st_gid = os.getgid()
        entry.st_uid = os.getuid()
        entry.st_ino = inode

        return entry

    async def lookup(self, parent_inode, name, ctx=None):
        if parent_inode != pyfuse3.ROOT_INODE or name != self.hello_name:
            raise pyfuse3.FUSEError(errno.ENOENT)
        return await self.getattr(self.hello_inode)

    async def opendir(self, inode, ctx):
        if inode != pyfuse3.ROOT_INODE:
            raise pyfuse3.FUSEError(errno.ENOENT)
        # For simplicity, we use the inode as file handle
        return FileHandleT(inode)

    async def readdir(self, fh, start_id, token):
        assert fh == pyfuse3.ROOT_INODE

        # only one entry
        if start_id == 0:
            pyfuse3.readdir_reply(token, self.hello_name, await self.getattr(self.hello_inode), 1)
        return

    async def setxattr(self, inode, name, value, ctx):
        if inode != pyfuse3.ROOT_INODE or name != b'command':
            raise pyfuse3.FUSEError(errno.ENOTSUP)

        if value == b'terminate':
            pyfuse3.terminate()
        else:
            raise pyfuse3.FUSEError(errno.EINVAL)

    async def open(self, inode, flags, ctx):
        if inode != self.hello_inode:
            raise pyfuse3.FUSEError(errno.ENOENT)
        if flags & os.O_RDWR or flags & os.O_WRONLY:
            raise pyfuse3.FUSEError(errno.EACCES)
        # For simplicity, we use the inode as file handle
        return FileInfo(fh=FileHandleT(inode))

    async def read(self, fh, off, size):
        assert fh == self.hello_inode
        return self.hello_data[off : off + size]


def init_logging(debug=False):
    formatter = logging.Formatter(
        '%(asctime)s.%(msecs)03d %(threadName)s: [%(name)s] %(message)s',
        datefmt="%Y-%m-%d %H:%M:%S",
    )
    handler = logging.StreamHandler()
    handler.setFormatter(formatter)
    root_logger = logging.getLogger()
    if debug:
        handler.setLevel(logging.DEBUG)
        root_logger.setLevel(logging.DEBUG)
    else:
        handler.setLevel(logging.INFO)
        root_logger.setLevel(logging.INFO)
    root_logger.addHandler(handler)


def parse_args():
    '''Parse command line'''

    parser = ArgumentParser()

    parser.add_argument('mountpoint', type=str, help='Where to mount the file system')
    parser.add_argument(
        '--debug', action='store_true', default=False, help='Enable debugging output'
    )
    parser.add_argument(
        '--debug-fuse', action='store_true', default=False, help='Enable FUSE debugging output'
    )
    return parser.parse_args()


def main():
    options = parse_args()
    init_logging(options.debug)

    testfs = TestFs()
    fuse_options = set(pyfuse3.default_options)
    fuse_options.add('fsname=hello_asyncio')
    if options.debug_fuse:
        fuse_options.add('debug')
    pyfuse3.init(testfs, options.mountpoint, fuse_options)
    try:
        asyncio.run(pyfuse3.main())
    except:
        pyfuse3.close(unmount=False)
        raise

    pyfuse3.close()


if __name__ == '__main__':
    main()