Re: [Libguestfs] [Bug 1046905] New: RFE: add argument to virt-sysprep to disable individual default operations
On Tuesday 07 January 2014 12:12:43 Richard W.M. Jones wrote:
On Tue, Jan 07, 2014 at 11:16:08AM +0100, Pino Toscano wrote:
> On Friday 27 December 2013 10:58:15 you wrote:
> > virt-sysprep either runs with all default operations or a selected
> > list of operations with the --enable argument. A few times I've
> > found I'd like to use the default list, but minus one or two
> > operations in particular, however there's no easy way to specify
> > this.
> >
> > A --disable argument that took the default operation list and
> > skipped
> > selected operations would be useful.
>
> A rough idea I had about this is adding a new --operations
> parameter,
> which would take a a comma-separated list of operations (just like
> the current --enable), but with the following differences:
> - a leading minus would disable the specified operation
> - it would recognize the meta-keywords "all" (for all the available
>
> operations) and "defaults" (for the ones enabled by default)
>
> Processing the list of operations would add/remove them from the
> current set of operations, bailing out whether the resulting set is
> empty (just like right now --enable rejects an empty string).
>
> This way, you could write e.g.:
> - --operations defaults,-hostname,user-account
>
> runs the default ones but not "hostname", and the non-default
> "user-account"
>
> - --operations all
>
> easy shortcut to run all the available operations
>
> and so on.
>
> --enable could just be an alias for --operations, or this new syntax
> could be added directly to --enable directly.
>
> Maybe I'm over-engineering, but IMHO seems a better way than
> potentially adding a --disable argument and deal with the order of
> --enable & --disable and their interactions.
Seems reasonable.
I guess only one --operations opt is allowed?
Or would we allow multiple and concatenate them together? So that
--operations foo,bar --operations -baz
would be equivalent to
--operations foo,bar,-baz
?
Multiple --operations could be useful for scripting, ie. it would let
shell users write:
opts="--operations all -a disk.img"
if [ $disable_foo ]; then opts="$opts --operations -foo"; fi
I agree, allowing multiple --operations is a good thing. After all,
given the proposed behaviour, every --operation would alter the existing
set of operations (empty at the first --operation invocation, as with
--enable), instead of starting from scratch every time.
Another thing to test is whether the OCaml argument parser[1] can
handle '--operations -foo' without thinking that -foo is a separate
arg.
Ah yes, I read about the unsupported --foo=arg syntax.
OTOH, it seems that "--foo --foo", with --foo taking an Arg.String,
gives "--foo" as value for it, so should be safe for us.
--
Pino Toscano