Metadata-Version: 1.1
Name: SizeFS
Version: 0.4.0
Summary: SizeFS is a mock filesystem for creating files of particular sizes with specified contents.
Home-page: http://pypi.python.org/pypi/SizeFS/
Author: Sohonet
Author-email: dev@sohonet.com
License: LICENSE.txt
Download-URL: https://github.com/sohonetlabs/sizefs
Description: SizeFS
        ======
        
        A mock Filesystem that exists in memory only and allows for the creation of
        files of a size specified by the filename.
        
        For example, reading a file named 128M+1B will return a file of 128 Megabytes
        plus 1 byte, reading a file named 128M-1B will return a file of 128 Megabytes
        minus 1 byte
        
        Within the filesystem one level of folders may be created. Each of these folders
        can have its extended attributes set to determine the default contents of each
        file within the folder. The attributes of individual files may be overridden,
        and, when mounted as a filesystem using fuse, should be set using 'xattr' for
        OS X, or 'attr' for Linux. The attributes are described below in the 'Extended Usage'
        section.
        
        Files may only be created within the folders and can only be named with a valid
        size descriptor. The names of the files should be a number followed by one of the
        letters B, K, M, G, T, P or E (to mean bytes, kilobytes, megabytes ...). Optionally
        an addition or subtraction may be specified to modify the base size of the file.
        
        Examples of valid filenames:
        
            100K     - A 100 kilobyte file.
            4M       - A 4 megabyte file.
            2G-1B    - A file 1 byte smaller than 2 gigabytes.
            100K+10K - A file 10 kilobytes larger than 100 kilobytes.
            10E      - A ten exabyte file (yes really!)
        
        File contents are generated as they are read, so it is entirely possible to 'create'
        files that are larger than any available RAM or HD storage. This can be very useful
        for testing large external storage systems, and the +/- operations are useful for
        exploring file size limitations without having to specify a file size as a huge
        number of bytes. The contents of each file are specified by a set of regular
        expressions that are initially inherited from the containing folder.
        
        Example Usage - SizeFS
        ----------------------
        
        Create Size File objects in memory:
        
            from sizefs import SizeFS
            sfs = SizeFS()
            sfs.open('/1B').read()
            sfs.open('/20B').read(20)
            sfs.open('/2K').read(1024)
            sfs.open('/128K').read(1024*128)
            sfs.open('/4G').read(4*1024*1024)
        
        The folder structure can be used to determine the content of the files:
        
            sfs.open('/zeros/5B').read(5)
            out> 00000
        
            sfs.open('/ones/5B').read(5)
            out> 11111
        
            sfs.open('/alpha_num/5B').read(5)
            out> TMdEv
        
        
        Extended Usage - SizefsFuse
        ---------------------------
        
        The folders 'ones', 'zeros' and 'alpha\_num' are always present, but new
        folders can also be created. When files are created in a folder, the
        xattrs of the folder determine that file's content until the file's
        xattrs are updated:
        
        
            from sizefs.sizefsFuse import SizefsFuse
            sfs = SizefsFuse()
            sfs.mkdir('/regex1', None)
            sfs.setxattr('/regex1', 'generator', 'regex', None)
            sfs.setxattr('/regex1', 'filler', 'regex', None)
            print sfs.read('/regex1/5B', 5, 0, None)
        
            out> regex
        
            sfs.setxattr('/regex1/5B', 'filler', 'string', None)
            print sfs.read('/regex1/5B', 5, 0, None)
        
            out> string
        
            sfs.setxattr('/regex1/5B', 'filler', 'a{2}b{2}c', None)
            print sfs.read('/regex1/5B', 5, 0, None)
        
            out> aabbc
        
        Files can also be added to SizeFS without reading their contents using
        sfs.create():
        
        
            sfs.mkdir('/folder', None)
            sfs.create('/folder/5B', None)
            print sfs.read('/folder/5B', 5, 0, None)
        
            out> 11111
        
        And as discussed above, the name of the file determines its size:
        
        
        
            # Try to read more contents than the files contains
            print len(sfs.read('/regex3/128K', 256*1000, 0, None))
        
            out> 128000
        
            # Try to read more contents than the files contains
            print len(sfs.read('/regex3/128K-1B', 256*1000, 0, None))
        
            out> 127999
        
            # Try to read more contents than the files contains
            print len(sfs.read('/alphanum/128K+1B', 256*1000, 0, None))
        
            out> 128001
        
        
        The 'generator' xattr property defines the file content and can be set to one
        of:
        
            ones       - files are filled with ones
            zeros      - files are filled with zeros
            alpha_num  - files are filled with alpha numeric characters
            regex      - files are filled according to a collection of regular expression patterns
        
        We can set up to 5 properties to control the regular expression patterns:
        
            prefix     - defined pattern for the start of a file (default = "")
            suffix     - defined pattern for the end of a file (default = "")
            filler     - repeating pattern to fill file content (default = 0)
            padder     - single character to fill between content and footer (default = 0)
            max_random - the largest number a + or * will resolve to
        
        Where 'prefix', 'suffix', 'filler', and 'padder' conform to the following
        grammar:
        
            <Regex> ::= <Pattern>
        
            <Pattern> ::= <Expression>
                    | <Expression> <Pattern>
        
            <Expression> ::= <Char> [<Multiplier>]
                       | "(" <Pattern> ")" [<Multiplier>]
                       | "[" <Set> "]" [<Multiplier>]
        
            <Multiplier> ::= "*"
                       | "+"
                       | "?"
                       | '{' <Num> '}'
        
            <Set> ::= <Char>
                  | <Char> "-" <Char>
                  | <Set> <Set>
        
        If the requested file sizes are too small for the combination of header, footer
        and some padding, then a warning will be logged, but the file will still
        return as much content as possible to fill the exact file size requested.
        
        The file contents will always match the following pattern:
        
            ^prefix(filler)*(padder)*suffix$
        
        The generator will always produce a string containing the prefix and suffix if a
        file of sufficient size is requested. Following that, the generator will fill
        the remaining space with 'filler' generated as many times as can be contained.
        If a filler pattern is generated that does not fit within the remaining space
        the remainder is filled using the (possibly incomplete) padder pattern. The
        padder pattern will only be used if a complete filler pattern will not fit in
        the space remaining.
        
        'max_random' is used to define the largest random repeat factor of any + or *
        operators.
        
        Random seeks within a file may produce inconsistent results for general file
        contents, however prefix and suffix will always be consistent with the requested
        pattern.
        
        Testing
        ------------------------
        
        Single test run requires pytest
        
        From the command line:
        
            pytest
        
        Full test run requires tox
        
        From the command line:
        
            tox
        
        Mounting as a filesystem
        ------------------------
        
        Mac Mounting - http://osxfuse.github.com/
        
            Usage:
              sizefs.py [--debug] <mount_pount>
              sizefs.py --version
        
              Options:
                --debug           Debug
                -h --help         Show this screen.
                --version         Show version.
        
Keywords: testing,files,size
Platform: UNKNOWN
