Luiz Capitulino <lcapitul...@redhat.com> writes:
> On Mon, 14 Feb 2011 13:34:11 -0600
> Anthony Liguori <anth...@codemonkey.ws> wrote:
>
>> On 02/14/2011 12:34 PM, Luiz Capitulino wrote:
>> > On Mon, 14 Feb 2011 08:39:11 -0600
>> > Anthony Liguori<anth...@codemonkey.ws> wrote:
>> >
>> >
>> >> On 02/14/2011 06:45 AM, Luiz Capitulino wrote:
>> >>
>> >>> So the question is: how does the schema based design support extending
>> >>> commands or events? Does it require adding new commands/events?
>> >>>
>> >>>
>> >> Well, let me ask you, how do we do that today?
>> >>
>> >> Let's say that I want to add a new parameter to the `change' function so
>> >> that I can include a salt parameter as part of the password.
>> >>
>> >> The way we'd do this today is by checking for the 'salt' parameter in
>> >> qdict, and if it's not present, use a random salt or something like that.
>> >>
>> > You likely want to do what you did before. Of course that you have to
>> > consider if what you're doing is extending an existing command or badly
>> > overloading it (like change is today), in this case you'll want to add
>> > a new command instead.
>> >
>> > But yes, the use-case here is extending an existing command.
>> >
>> >
>> >> However, if I'm a QMP client, how can I tell whether you're going to
>> >> ignore my salt parameter or actually use it? Nothing in QMP tells me
>> >> this today. If I set the salt parameter in the `change' command, I'll
>> >> just get a success message.
>> >>
>> > I'm sorry?
>> >
>> > { "execute": "change", "arguments": { "device": "vnc", "target":
>> > "password", "arg": "1234", "salt": "r1" } }
>> > {"error": {"class": "InvalidParameter", "desc": "Invalid parameter
>> > 'salt'", "data": {"name": "salt"}}}
>> >
>>
>> So I'm supposed to execute the command, and if execution fails, drop the
>> new parameter? If we add a few optional parameters, does that mean I
>> have to try every possible combination of parameters?
>
> No, of course not, our plan has always been to do this via an schema,
Correct.
> the only reason we don't do this today is lack of time/help.
Disagree on "only". QMP didn't just suffer from lack of pushing power.
On the contrary, it suffered from too much pushing in opposite
directions.
[...]
