[Kimchi-devel] [PATCH 2/7] add a method to load vms sub collection automatically

[Mark Wu]

On 01/16/2014 11:56 PM, shaohef at linux.vnet.ibm.com wrote:
> From: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
>
> When define a new vms sub collection, we do not need to touch vms module any more.
>
> such as:
> add a ifaces, we can define it as follow in vm/ifaces.py:
>
> from kimchi.control.vm import SubCollection
>
> @SubCollection('ifaces')
> class VmIfaces(Collection):
>      def __init__(self, model, vm):
>          super(VmIfaces, self).__init__(model)
>
> Then access URL: /vms/vm-name/ifaces/mac
> VM resource can dispatch ifaces automatically
>
> Signed-off-by: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
> ---
>   src/kimchi/control/vm/__init__.py | 44 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
>
> diff --git a/src/kimchi/control/vm/__init__.py b/src/kimchi/control/vm/__init__.py
> index f22e568..f3f6e48 100644
> --- a/src/kimchi/control/vm/__init__.py
> +++ b/src/kimchi/control/vm/__init__.py
> @@ -20,3 +20,47 @@
>   # You should have received a copy of the GNU Lesser General Public
>   # License along with this library; if not, write to the Free Software
>   # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
> +
> +import os
> +import imp
> +
> +
> +class SubCollection(object):
> +    def __init__(self, name):
> +        self.name = name
> +
> +    def __call__(self, fun):
> +        fun._sub_collection_name = {"name": self.name}
> +        return fun
> +
> +
> +def _listPathModules(path):
> +    modules = set()
> +    for f in os.listdir(path):
> +        base, ext = os.path.splitext(f)
> +        if ext in ('.py', '.pyc', '.pyo'):
> +            modules.add(base)
> +    return sorted(modules)
> +
> +
> +def _load_sub_collections(path):
> +    for mod_name in _listPathModules(path):
> +        if mod_name.startswith("_"):
> +            continue
> +
> +        mod_fobj, mod_absp, mod_desc = imp.find_module(mod_name, [path])
> +        module = imp.load_module(mod_name, mod_fobj,
> +                                 mod_absp, mod_desc)
> +        sub_collections = {}
> +
> +        for collection in [getattr(module, x) for x in dir(module)]:
> +            if not hasattr(collection, "_sub_collection_name"):
> +                continue
> +
> +            name = collection._sub_collection_name["name"]
> +            sub_collections.update({name: collection})
> +
> +        return sub_collections
> +
> +
> +VmDevices = _load_sub_collections(os.path.dirname(__file__))
I think it should be done as a general facility.    You could write a 
metaclass for resource and load its sub collection in "__new__"