path: root/api/examples/gfapi.py

#!/usr/bin/python

from ctypes import *
from ctypes.util import find_library
import os
import sys
import time
import types

# Looks like ctypes is having trouble with dependencies, so just force them to
# load with RTLD_GLOBAL until I figure that out.
glfs = CDLL(find_library("glusterfs"),RTLD_GLOBAL)
xdr = CDLL(find_library("gfxdr"),RTLD_GLOBAL)
api = CDLL(find_library("gfapi"),RTLD_GLOBAL)

# Wow, the Linux kernel folks really play nasty games with this structure.  If
# you look at the man page for stat(2) and then at this definition you'll note
# two discrepancies.  First, we seem to have st_nlink and st_mode reversed.  In
# fact that's exactly how they're defined *for 64-bit systems*; for 32-bit
# they're in the man-page order.  Even uglier, the man page makes no mention of
# the *nsec fields, but they are very much present and if they're not included
# then we get memory corruption because libgfapi has a structure definition
# that's longer than ours and they overwrite some random bit of memory after
# the space we allocated.  Yes, that's all very disgusting, and I'm still not
# sure this will really work on 32-bit because all of the field types are so
# obfuscated behind macros and feature checks.
class Stat (Structure):
        _fields_ = [
                ("st_dev",              c_ulong),
                ("st_ino",              c_ulong),
                ("st_nlink",            c_ulong),
                ("st_mode",             c_uint),
                ("st_uid",              c_uint),
                ("st_gid",              c_uint),
                ("st_rdev",             c_ulong),
                ("st_size",             c_ulong),
                ("st_blksize",          c_ulong),
                ("st_blocks",           c_ulong),
                ("st_atime",            c_ulong),
                ("st_atimensec",        c_ulong),
                ("st_mtime",            c_ulong),
                ("st_mtimensec",        c_ulong),
                ("st_ctime",            c_ulong),
                ("st_ctimensec",        c_ulong),
        ]
api.glfs_creat.restype = c_void_p
api.glfs_open.restype = c_void_p
api.glfs_lstat.restype = c_int
api.glfs_lstat.argtypes = [c_void_p, c_char_p, POINTER(Stat)]

class Dirent (Structure):
        _fields_ = [
                ("d_ino",       c_ulong),
                ("d_off",       c_ulong),
                ("d_reclen",    c_ushort),
                ("d_type",      c_char),
                ("d_name",      c_char * 256),
        ]
api.glfs_opendir.restype = c_void_p
api.glfs_readdir_r.restype = c_int
api.glfs_readdir_r.argtypes = [c_void_p, POINTER(Dirent),
                               POINTER(POINTER(Dirent))]

# There's a bit of ctypes glitchiness around __del__ functions and module-level
# variables.  If we unload the module while we still have references to File or
# Volume objects, the module-level variables might have disappeared by the time
# __del__ gets called.  Therefore the objects hold references which they
# release when __del__ is done.  We only actually use the object-local values
# in __del__; for clarity, we just use the simpler module-level form elsewhere.

class File(object):

        def __init__ (self, fd):
                # Add a reference so the module-level variable "api" doesn't
                # get yanked out from under us (see comment above File def'n).
                self._api = api
                self.fd = fd

        def __del__ (self):
                self._api.glfs_close(self.fd)
                self._api = None

        # File operations, in alphabetical order.

        def fsync (self):
                return api.glfs_fsync(self.fd)

        def read (self, buflen, flags=0):
                rbuf = create_string_buffer(buflen)
                rc = api.glfs_read(self.fd,rbuf,buflen,flags)
                if rc > 0:
                        return rbuf.value[:rc]
                else:
                        return rc

        def read_buffer (self, buf, flags=0):
                return api.glfs_read(self.fd,buf,len(buf),flags)

        def write (self, data, flags=0):
                return api.glfs_write(self.fd,data,len(data),flags)


class Dir(object):

        def __init__ (self, fd):
                # Add a reference so the module-level variable "api" doesn't
                # get yanked out from under us (see comment above File def'n).
                self._api = api
                self.fd = fd
                self.cursor = POINTER(Dirent)()

        def __del__ (self):
                self._api.glfs_closedir(self.fd)
                self._api = None

        def next (self):
                entry = Dirent()
                entry.d_reclen = 256
                rc = api.glfs_readdir_r(self.fd,byref(entry),byref(self.cursor))
                if (rc < 0) or (not self.cursor) or (not self.cursor.contents):
                        return rc
                return entry

class Volume(object):

        # Housekeeping functions.

        def __init__ (self, host, volid, proto="tcp", port=24007):
                # Add a reference so the module-level variable "api" doesn't
                # get yanked out from under us (see comment above File def'n).
                self._api = api
                self.fs = api.glfs_new(volid)
                api.glfs_set_volfile_server(self.fs,proto,host,port)

        def __del__ (self):
                self._api.glfs_fini(self.fs)
                self._api = None

        def set_logging (self, path, level):
                api.glfs_set_logging(self.fs,path,level)

        def mount (self):
                api.glfs_init(self.fs)

        # File operations, in alphabetical order.

        def creat (self, path, flags, mode):
                fd = api.glfs_creat(self.fs,path,flags,mode)
                if not fd:
                        return fd
                return File(fd)

        def getxattr (self, path, key, maxlen):
                buf = create_string_buffer(maxlen)
                rc = api.glfs_getxattr(self.fs,path,key,buf,maxlen)
                if rc < 0:
                        return rc
                return buf.value[:rc]

        def listxattr (self, path):
                buf = create_string_buffer(512)
                rc = api.glfs_listxattr(self.fs,path,buf,512)
                if rc < 0:
                        return rc
                xattrs = []
                # Parsing character by character is ugly, but it seems like the
                # easiest way to deal with the "strings separated by NUL in one
                # buffer" format.
                i = 0
                while i < rc:
                        new_xa = buf.raw[i]
                        i += 1
                        while i < rc:
                                next_char = buf.raw[i]
                                i += 1
                                if next_char == '\0':
                                        xattrs.append(new_xa)
                                        break
                                new_xa += next_char
                xattrs.sort()
                return xattrs

        def lstat (self, path):
                x = Stat()
                rc = api.glfs_lstat(self.fs,path,byref(x))
                if rc >= 0:
                        return x
                else:
                        return rc

        def mkdir (self, path):
                return api.glfs_mkdir(self.fs,path)

        def open (self, path, flags):
                fd = api.glfs_open(self.fs,path,flags)
                if not fd:
                        return fd
                return File(fd)

        def opendir (self, path):
                fd = api.glfs_opendir(self.fs,path)
                if not fd:
                        return fd
                return Dir(fd)

        def rename (self, opath, npath):
                return api.glfs_rename(self.fs,opath,npath)

        def rmdir (self, path):
                return api.glfs_rmdir(self.fs,path)

        def setxattr (self, path, key, value, vlen):
                return api.glfs_setxattr(self.fs,path,key,value,vlen,0)

        def unlink (self, path):
                return api.glfs_unlink(self.fs,path)

if __name__ == "__main__":
        def test_create_write (vol, path, data):
                mypath = path + ".io"
                fd = vol.creat(mypath,os.O_WRONLY|os.O_EXCL,0644)
                if not fd:
                        return False, "creat error"
                rc = fd.write(data)
                if rc != len(data):
                        return False, "wrote %d/%d bytes" % (rc, len(data))
                return True, "wrote %d bytes" % rc

        # TBD: this test fails if we do create, open, write, read
        def test_open_read (vol, path, data):
                mypath = path + ".io"
                fd = vol.open(mypath,os.O_RDONLY)
                if not fd:
                        return False, "open error"
                dlen = len(data) * 2
                buf = fd.read(dlen)
                if type(buf) == types.IntType:
                        return False, "read error %d" % buf
                if len(buf) != len(data):
                        return False, "read %d/%d bytes" % (len(buf), len(data))
                return True, "read '%s'" % buf

        def test_lstat (vol, path, data):
                mypath = path + ".io"
                sb = vol.lstat(mypath)
                if type(sb) == types.IntType:
                        return False, "lstat error %d" % sb
                if sb.st_size != len(data):
                        return False, "lstat size is %d, expected %d" % (
                                sb.st_size, len(data))
                return True, "lstat got correct size %d" % sb.st_size

        def test_rename (vol, path, data):
                opath = path + ".io"
                npath = path + ".tmp"
                rc = vol.rename(opath,npath)
                if rc < 0:
                        return False, "rename error %d" % rc
                ofd = vol.open(opath,os.O_RDWR)
                if isinstance(ofd,File):
                        return False, "old path working after rename"
                nfd = vol.open(npath,os.O_RDWR)
                if isinstance(nfd,File):
                        return False, "new path not working after rename"
                return True, "rename worked"

        def test_unlink (vol, path, data):
                mypath = path + ".tmp"
                rc = vol.unlink(mypath)
                if rc < 0:
                        return False, "unlink error %d" % fd
                fd = vol.open(mypath,os.O_RDWR)
                if isinstance(fd,File):
                        return False, "path still usable after unlink"
                return True, "unlink worked"

        def test_mkdir (vol, path, data):
                mypath = path + ".dir"
                rc = vol.mkdir(mypath)
                if rc < 0:
                        return False, "mkdir error %d" % rc
                return True, "mkdir worked"

        def test_create_in_dir (vol, path, data):
                mypath = path + ".dir/probe"
                fd = vol.creat(mypath,os.O_RDWR,0644)
                if not isinstance(fd,File):
                        return False, "create (in dir) error"
                return True, "create (in dir) worked"

        def test_dir_listing (vol, path, data):
                mypath = path + ".dir"
                fd = vol.opendir(mypath)
                if not isinstance(fd,Dir):
                        return False, "opendir error %d" % fd
                files = []
                while True:
                        ent = fd.next()
                        if not isinstance(ent,Dirent):
                                break
                        name = ent.d_name[:ent.d_reclen]
                        files.append(name)
                if files != [".", "..", "probe"]:
                        return False, "wrong directory contents"
                return True, "directory listing worked"

        def test_unlink_in_dir (vol, path, data):
                mypath = path + ".dir/probe"
                rc = vol.unlink(mypath)
                if rc < 0:
                        return False, "unlink (in dir) error %d" % rc
                return True, "unlink (in dir) worked"

        def test_rmdir (vol, path, data):
                mypath = path + ".dir"
                rc = vol.rmdir(mypath)
                if rc < 0:
                        return False, "rmdir error %d" % rc
                sb = vol.lstat(mypath)
                if not isinstance(sb,Stat):
                        return False, "dir still there after rmdir"
                return True, "rmdir worked"

        def test_setxattr (vol, path, data):
                mypath = path + ".xa"
                fd = vol.creat(mypath,os.O_RDWR|os.O_EXCL,0644)
                if not fd:
                        return False, "creat (xattr test) error"
                key1, key2 = "hello", "goodbye"
                if vol.setxattr(mypath,"trusted.key1",key1,len(key1)) < 0:
                        return False, "setxattr (key1) error"
                if vol.setxattr(mypath,"trusted.key2",key2,len(key2)) < 0:
                        return False, "setxattr (key2) error"
                return True, "setxattr worked"

        def test_getxattr (vol, path, data):
                mypath = path + ".xa"
                buf = vol.getxattr(mypath,"trusted.key1",32)
                if type(buf) == types.IntType:
                        return False, "getxattr error"
                if buf != "hello":
                        return False, "wrong getxattr value %s" % buf
                return True, "getxattr worked"

        def test_listxattr (vol, path, data):
                mypath = path + ".xa"
                xattrs = vol.listxattr(mypath)
                if type(xattrs) == types.IntType:
                        return False, "listxattr error"
                if xattrs != ["trusted.key1","trusted.key2"]:
                        return False, "wrong listxattr value %s" % repr(xattrs)
                return True, "listxattr worked"

        test_list = (
                test_create_write,
                test_open_read,
                test_lstat,
                test_rename,
                test_unlink,
                test_mkdir,
                test_create_in_dir,
                test_dir_listing,
                test_unlink_in_dir,
                test_rmdir,
                test_setxattr,
                test_getxattr,
                test_listxattr,
        )

        ok_to_fail = (
                # TBD: this fails opening the new file, even though the file
                # did get renamed.  Looks like a gfapi bug, not ours.
                (test_rename, "new path not working after rename"),
                # TBD: similar, call returns error even though it worked
                (test_rmdir, "dir still there after rmdir"),
        )

        volid, path = sys.argv[1:3]
        data = "fubar"
        vol = Volume("localhost",volid)
        vol.set_logging("/dev/null",7)
        #vol.set_logging("/dev/stderr",7)
        vol.mount()

        failures = 0
        expected = 0
        for t in test_list:
                rc, msg = t(vol,path,data)
                if rc:
                        print "PASS: %s" % msg
                else:
                        print "FAIL: %s" % msg
                        failures += 1
                        for otf in ok_to_fail:
                                if (t == otf[0]) and (msg == otf[1]):
                                        print "  (skipping known failure)"
                                        expected += 1
                                        break # from the *inner* for loop
                        else:
                                break # from the *outer* for loop

        print "%d failures (%d expected)" % (failures, expected)