FUSE void directory

void.py

#!/usr/bin/env python3
# https://gist.github.com/iTrooz/e1a6e63e0be4efee7863d447b9b72efc/edit
# Creates a "void" directory in selected folder. This directory will absorbs all writes, and always show as empty. Like /dev/null, but as a folder
# Must be run as root
import pyfuse3
import trio
import errno
import stat

class VoidFS(pyfuse3.Operations):
    async def getattr(self, inode, ctx=None):
        entry = pyfuse3.EntryAttributes()
        if inode == pyfuse3.ROOT_INODE:
            entry.st_mode = (stat.S_IFDIR | 0o777)
            entry.st_size = 0
        else:
            entry.st_mode = (stat.S_IFREG | 0o777)
            entry.st_size = 0
        entry.st_atime_ns = 0
        entry.st_mtime_ns = 0
        entry.st_ctime_ns = 0
        entry.st_gid = 0
        entry.st_uid = 0
        entry.st_ino = inode
        return entry

    async def lookup(self, parent_inode, name, ctx=None):
        return await self.getattr(inode=2)  # any file "exists"

    async def opendir(self, inode, ctx):
        return inode

    async def readdir(self, fh, start_id, token):
        return  # always empty

    async def open(self, inode, flags, ctx):
        return pyfuse3.FileInfo(fh=inode)

    async def create(self, parent_inode, name, mode, flags, ctx):
        entry = await self.getattr(inode=2)
        return (pyfuse3.FileInfo(fh=2), entry)

    async def write(self, fh, offset, buf):
        return len(buf)  # discard

    async def setattr(self, inode, attr, fields, fh, ctx):
        return await self.getattr(inode)

if __name__ == '__main__':
    import sys
    if len(sys.argv) != 2:
        print(f"Usage: {sys.argv[0]} <mountpoint>")
        sys.exit(1)

    pyfuse3.init(VoidFS(), sys.argv[1], ['fsname=voidfs', 'allow_other'])
    try:
        trio.run(pyfuse3.main)
    except KeyboardInterrupt:
        pass
    finally:
        pyfuse3.close()