Initializing multiple file systems only runs the last one

[florpe]

Hi,

I'm trying to run multiple FUSE mounts from the same process - only the last call to pyfuse3.init() takes effect. Here's an example adapted from hello_asyncio.py:

Code from hello_asyncio.py

'''
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 os
import sys

# If we are running from the pyfuse3 source directory, try
# to load the module from there first.
basedir = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '..'))
if (os.path.exists(os.path.join(basedir, 'setup.py')) and
    os.path.exists(os.path.join(basedir, 'src', 'pyfuse3.pyx'))):
    sys.path.insert(0, os.path.join(basedir, 'src'))

from argparse import ArgumentParser
import asyncio
import stat
import logging
import errno
import pyfuse3
import pyfuse3_asyncio

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 = 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)
        return 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)
        return pyfuse3.FileInfo(fh=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():
    init_logging(True)

    testfs = TestFs()
    testfs2 = TestFs()
    fuse_options = set(pyfuse3.default_options)
    fuse_options.add('fsname=hello_asyncio')
    fuse_options.add('debug')
    pyfuse3.init(testfs, './mnt', fuse_options)
    print('INIT ONE COMPLETE')
    pyfuse3.init(testfs, './mnt2', fuse_options)
    print('INIT TWO COMPLETE')
    loop = asyncio.get_event_loop()
    try:
        print('RUNNING EVENT LOOP')
        loop.run_until_complete(pyfuse3.main())
        # Try `ls ./mnt` and `ls ./mnt2` here
    except:
        pyfuse3.close(unmount=False)
        raise
    finally:
        loop.close()

    pyfuse3.close()

if __name__ == '__main__':
    main()

It seems to me that the globals in pyfuse3.pyx are responsible for this behaviour. A quick-and-dirty fix would be to add to each function using the globals an optional context argument taking a dict of no-longer-global values. The entire init-run-close functionality could also be made part of the Operations class, but I'm not sure whether that is possible in a reasonably backwards compatible way.

I'm not super familiar with FUSE, and definitely unfamiliar with trio - would it nevertheless make sense for me to throw together a pull request, considering the lack of maintainers here?