software/pynsfs
Python Namespace File System
- Author
Bryan Newbold
- Date
July 2008
- URL
This is an experimental implementation of a python namespace as a virtual file system, implemented using the python bindings for fusefs on unix.
At this point only the global namespace of the filesystem instance itself is accessible, and only limited access is available to that. If anything goes wrong it can cause a hard lock and system crash; don't leave it running and don't try to write anything substantial.
The source code can be checked out from the above URL.
Features
An example session goes like:
snark# ls /mnt/python/
snark# python nsfs.py /mnt/python/
*** init complete
let's go!
snark# cd /mnt/python/
snark# ls -l
total 6
-r--r--r-- 1 root wheel 30 Dec 31 1969 DefaultStat
-r--r--r-- 1 root wheel 33 Dec 31 1969 DefaultStatVfs
-r--r--r-- 1 root wheel 19 Dec 31 1969 Fuse
-r--r--r-- 1 root wheel 30 Dec 31 1969 NamespaceFS
-r--r--r-- 1 root wheel 27 Dec 31 1969 NsfsFile
-r--r--r-- 1 root wheel 17 Dec 31 1969 StringIO
drwxr-xr-x 2 root wheel 0 Dec 31 1969 __builtins__
-r--r--r-- 1 root wheel 4 Dec 31 1969 __doc__
-r--r--r-- 1 root wheel 7 Dec 31 1969 __file__
-r--r--r-- 1 root wheel 8 Dec 31 1969 __name__
drwxr-xr-x 2 root wheel 0 Dec 31 1969 _find_fuse_parts
drwxr-xr-x 2 root wheel 0 Dec 31 1969 errno
drwxr-xr-x 2 root wheel 0 Dec 31 1969 fuse
-r--r--r-- 1 root wheel 29 Dec 31 1969 main
drwxr-xr-x 2 root wheel 0 Dec 31 1969 os
drwxr-xr-x 2 root wheel 0 Dec 31 1969 stat
-r--r--r-- 1 root wheel 24 Dec 31 1969 time
snark# ls stat/
ST_ATIME S_ENFMT S_IMODE S_ISDIR S_IWRITE
ST_CTIME S_IEXEC S_IREAD S_ISFIFO S_IWUSR
ST_DEV S_IFBLK S_IRGRP S_ISGID S_IXGRP
ST_GID S_IFCHR S_IROTH S_ISLNK S_IXOTH
ST_INO S_IFDIR S_IRUSR S_ISREG S_IXUSR
ST_MODE S_IFIFO S_IRWXG S_ISSOCK __builtins__
ST_MTIME S_IFLNK S_IRWXO S_ISUID __doc__
ST_NLINK S_IFMT S_IRWXU S_ISVTX __file__
ST_SIZE S_IFREG S_ISBLK S_IWGRP __name__
ST_UID S_IFSOCK S_ISCHR S_IWOTH
snark# cat time
<built-in function time>
snark# echo " Hello Python" >> os/__name__
snark# cat os/__name__
os Hello Python
snark# rm time
snark# ls
DefaultStat __builtins__ fuse
DefaultStatVfs __doc__ main
Fuse __file__ os
NamespaceFS __name__ stat
NsfsFile _find_fuse_parts
StringIO errno
snark# ln __nameofos__ os/__name__
ln: __nameofos__: No such file or directory
snark# ln os/__name__ __nameofos__
snark# cat __nameofos__
os Hello Python
snark# cd ..
snark# umount /mnt/python/The root directory is the global namespace; modules are available as subdirectories and all other objects are accessible as files. Strings can be appended to; all other "files" are readonly and return their string representation. "Files" can be deleted; "directories" can not. Hard links to files are possible.
Requirements
This was developed and has only been tested on FreeBSD 7.0 with Python 2.5.1 version 0.2 of the python-fuse bindings.
- FUSE Filesystem installed and configured on a compatible operating system
- Recent version of Python
- FUSE Python Bindings
Once everything is installed and configured, the script can just be run as root; no installation necessary.
Usage
Try # python nsfs.py -h to get a list of general FUSE options. A simple mount command would look like:
# python nsfs.py /mnt/pythonTo unmount:
# umount /mnt/pythonI like to run in foreground, single threaded, with debug info:
# python nsfs.py -dsf /mnt/pythonReally only basic command line tools work because they don't check for many attributes; try echo "blah" >> file, cat file, df -h, ls -l etc.
TODO
Functions taking simple arguments (or no arguments) could be implemented as character devices; function_name.doc, function_name.repr, etc could give meta-information.
File of the form __thing__ should be renamed .thing.
New files should be allowed and saved as strings.
CHANGELOG
- July 28, 2008
First implementation
