From: Zooko O'Whielacronx Date: Fri, 10 Sep 2010 16:35:20 +0000 (-0800) Subject: fileutil: copy in the get_disk_stats() and get_available_space() functions from stora... X-Git-Tag: allmydata-tahoe-1.8.2b1~99 X-Git-Url: https://git.rkrishnan.org/?a=commitdiff_plain;h=d5e71c29408bab67de9359446b7ad0c1c6100e0d;p=tahoe-lafs%2Ftahoe-lafs.git fileutil: copy in the get_disk_stats() and get_available_space() functions from storage/server.py --- diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py index 4ebcb1b9..54ef2551 100644 --- a/src/allmydata/test/test_util.py +++ b/src/allmydata/test/test_util.py @@ -503,6 +503,24 @@ class FileUtil(unittest.TestCase): finally: os.chdir(saved_cwd) + def test_disk_stats(self): + avail = fileutil.get_available_space('.', 2**14) + if avail == 0: + raise unittest.SkipTest("This test will spuriously fail there is no disk space left.") + + disk = fileutil.get_disk_stats('.', 2**13) + self.failUnless(disk['total'] > 0, disk['total']) + self.failUnless(disk['used'] > 0, disk['used']) + self.failUnless(disk['free_for_root'] > 0, disk['free_for_root']) + self.failUnless(disk['free_for_nonroot'] > 0, disk['free_for_nonroot']) + self.failUnless(disk['avail'] > 0, disk['avail']) + + def test_disk_stats_avail_nonnegative(self): + # This test will spuriously fail if you have more than 2^128 + # bytes of available space on your filesystem. + disk = fileutil.get_disk_stats('.', 2**128) + self.failUnlessEqual(disk['avail'], 0) + class PollMixinTests(unittest.TestCase): def setUp(self): self.pm = pollmixin.PollMixin() diff --git a/src/allmydata/util/fileutil.py b/src/allmydata/util/fileutil.py index 5a5179c1..9a41c237 100644 --- a/src/allmydata/util/fileutil.py +++ b/src/allmydata/util/fileutil.py @@ -304,3 +304,94 @@ def abspath_expanduser_unicode(path): # We won't hit because # there is always at least one Unicode path component. return os.path.normpath(path) + +windows = False +try: + import win32api, win32con +except ImportError: + pass +else: + windows = True + # + win32api.SetErrorMode(win32con.SEM_FAILCRITICALERRORS | + win32con.SEM_NOOPENFILEERRORBOX) + +def get_disk_stats(whichdir, reserved_space=0): + """Return disk statistics for the storage disk, in the form of a dict + with the following fields. + total: total bytes on disk + free_for_root: bytes actually free on disk + free_for_nonroot: bytes free for "a non-privileged user" [Unix] or + the current user [Windows]; might take into + account quotas depending on platform + used: bytes used on disk + avail: bytes available excluding reserved space + An AttributeError can occur if the OS has no API to get disk information. + An EnvironmentError can occur if the OS call fails. + + whichdir is a directory on the filesystem in question -- the + answer is about the filesystem, not about the directory, so the + directory is used only to specify which filesystem. + + reserved_space is how many bytes to subtract from the answer, so + you can pass how many bytes you would like to leave unused on this + filesystem as reserved_space. + """ + + if windows: + # For Windows systems, where os.statvfs is not available, use GetDiskFreeSpaceEx. + # + # + # Although the docs say that the argument should be the root directory + # of a disk, GetDiskFreeSpaceEx actually accepts any path on that disk + # (like its Win32 equivalent). + + (free_for_nonroot, total, free_for_root) = win32api.GetDiskFreeSpaceEx(whichdir) + else: + # For Unix-like systems. + # + # + # + s = os.statvfs(whichdir) + + # on my mac laptop: + # statvfs(2) is a wrapper around statfs(2). + # statvfs.f_frsize = statfs.f_bsize : + # "minimum unit of allocation" (statvfs) + # "fundamental file system block size" (statfs) + # statvfs.f_bsize = statfs.f_iosize = stat.st_blocks : preferred IO size + # on an encrypted home directory ("FileVault"), it gets f_blocks + # wrong, and s.f_blocks*s.f_frsize is twice the size of my disk, + # but s.f_bavail*s.f_frsize is correct + + total = s.f_frsize * s.f_blocks + free_for_root = s.f_frsize * s.f_bfree + free_for_nonroot = s.f_frsize * s.f_bavail + + # valid for all platforms: + used = total - free_for_root + avail = max(free_for_nonroot - reserved_space, 0) + + return { 'total': total, 'free_for_root': free_for_root, + 'free_for_nonroot': free_for_nonroot, + 'used': used, 'avail': avail, } + +def get_available_space(whichdir, reserved_space): + """Returns available space for share storage in bytes, or None if no + API to get this information is available. + + whichdir is a directory on the filesystem in question -- the + answer is about the filesystem, not about the directory, so the + directory is used only to specify which filesystem. + + reserved_space is how many bytes to subtract from the answer, so + you can pass how many bytes you would like to leave unused on this + filesystem as reserved_space. + """ + try: + return get_disk_stats(whichdir, reserved_space)['avail'] + except AttributeError: + return None + except EnvironmentError: + log.msg("OS call to get disk statistics failed") + return 0