[Freeipa-devel] [PATCH 424] install: Introduce installer framework ipapython.install

[Jan Cholasta]

Dne 6.5.2015 v 08:11 Martin Kosek napsal(a):
> On 04/29/2015 06:25 PM, Jan Cholasta wrote:
>> Dne 20.4.2015 v 16:56 Jan Cholasta napsal(a):
>>> Dne 20.4.2015 v 15:14 Martin Basti napsal(a):
>>>> On 17/04/15 16:15, Jan Cholasta wrote:
>>>>> Dne 16.4.2015 v 16:46 Jan Cholasta napsal(a):
>>>>>> Hi,
>>>>>>
>>>>>> the attached patch adds the basics of the new installer framework.
>>>>>>
>>>>>> As a next step, I plan to convert the install scripts to use the
>>>>>> framework with their old code (the old code will be gradually ported to
>>>>>> the framework later).
>>>>>>
>>>>>> (Note I didn't manage to write docstrings today, expect update
>>>>>> tomorrow.)
>>>>>
>>>>> Added some docstrings.
>>>>>
>>>>> Also updated the patch to reflect little brainstorming David and I had
>>>>> this morning.
>>>>>
>>>>>>
>>>>>> Honza
>>>>>
>>>>>
>>>>>
>>>> Hello, see comments bellow:
>>>>
>>>> 1) We started using new shorter License header in files:
>>>> #
>>>> # Copyright (C) 2015  FreeIPA Contributors see COPYING for license
>>>> #
>>>
>>> OK.
>>>
>>>>
>>>> 2) IMO this will not work, NoneType has no 'obj' attribute
>>>> +        else:
>>>> +            if isinstance(value, from_):
>>>> +                value = None
>>>> +                stack.append(value.obj)
>>>> +                continue
>>>
>>> Right.
>>>
>>>>
>>>> 3) Multiple inheritance. I do not like it much.
>>>> +class CompositeInstaller(Installer, CompositeConfigurator):
>>>
>>> I guess you are antagonistic to multiple inheritance because of how
>>> other languages (like C++) do it. In Python it can be pretty elegant and
>>> is basis for e.g. the mixin design pattern.
>>>
>>>>
>>>> Installer and CompositeConfigurator inherites from Configurator class,
>>>> and all of them implements _generator method.
>>>
>>> Both of them call super()._generator(), so it's no problem (same for
>>> other methods).
>>>
>>>>
>>>> If I understand correctly
>>>> (https://www.python.org/download/releases/2.3/mro/) the
>>>> Installer._generator method will be used in this case.
>>>> However in case when CompositeConfigurator has more levels (respectively
>>>> it is more specialized) of inheritance, it could take precedence and its
>>>> _generator method may be used instead.
>>>
>>> The order of precedence is defined by the order of base classes in the
>>> class definition.
>>>
>>>>
>>>> I'm afraid this may suddenly stop working.
>>>> Maybe I'm wrong, please fix me.
>>>
>>> As long as you call the super class, it will work fine.
>>>
>>>>
>>>> And Multiple inheritance is not easily readable, this is even a diamond
>>>> inheritance model.
>>>
>>> Cooperative inheritance is used by design and IMHO is easily readable if
>>> you know how to read it. Every class defines a single bit of behavior.
>>> Without cooperative inheritance, it would have to be hardcoded and/or
>>> hacked around, which I wanted to avoid.
>>>
>>> This blog post explains it nicely:
>>> <https://rhettinger.wordpress.com/2011/05/26/super-considered-super/>.
>>>
>>
>> Updated patch attached.
>>
>> Also attached is patch 425 which migrates ipa-server-install to the install
>> framework.
>
> Good job there. I am just curious, will this framework and new option
> processing be friendly to other types of option passing than just via options?
> I mean tickets
>
> https://fedorahosted.org/freeipa/ticket/4517
> https://fedorahosted.org/freeipa/ticket/4468
>
> Especially 4517 is important, we need to be able to run
>
> # cat install.conf
> ds_password=Secret123
> admin_password=Secret456
> ip_address=123456
> setup_dns=False
>
> # ipa-server-install --unattended --conf install.conf
>
> I assume yes, but I am just making sure.

Yes, definitely.

-- 
Jan Cholasta