[Freeipa-devel] CLI parameter: TextFile, BinaryFile and mutually exclusive group

[Christian Heimes]

Hello,

While I was working on the ticket
https://fedorahosted.org/freeipa/ticket/5155, I noticed a couple of
additional places that may raise an IOError. Instead of a File()
paramaeter, the vault plugin uses Str() paramater in combination with
open() to read files.

For passwords I can mostly replace the Str() parameter with File().
There is only one minor issue. The File() class has no encoding flag.
ipalib.cli.cli.load_files() uses the encoding of sys.stdin to
determinate the encoding. In some cases the encoding of sys.stdin can be
ASCII. For that reason I like to add an encoding parameter to File().

For public and private key file I can't use File(). File() is a subclass
of Str(), which requires unicode text. The vault code treats public and
private key data as bytes. I assume it wants to support DER encoded key
data, too. I like to introduce a new BinaryFile() parameter, which
subclasses Bytes(). It might make sense to alias File as TextFile and
deprecate the File name.

Finally the vault plugin has several mutually exclusive paramater, e.g.
passsword and password-file. The plugin has seven distinct checks for
mutual exclusion. IMHO this should be better handled by the parameter
parsing code. Python's argparse module has a similar feature:
https://docs.python.org/2/library/argparse.html#mutual-exclusion

I like to handle the case with a mutually_exclusive flag such as:

    Str(
        'password?',
        cli_name='password',
        doc=_('Vault password'),
	mutually_exclusive='password',
    ),
    File(
        'password_file?',
        cli_name='password_file',
        doc=_('File containing the vault password'),
	mutually_exclusive='password',
    ),

If more than one parameter with the same mutually_exclusive group name
is given, then a MutuallyExclusiveError is raised.

Christian

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