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[Hengqing Hu <hudayou@xxxxxxxxxxx>]

Hi,

These days I was working on a nova-scheduler translated to erlang(update 
database, rpc messaging all in erlang).
Currently it can responds to the following commands the same as the 
nova-scheduler in python:
euca-run-instances -n N -t m1.tiny ami-00000003
euca-run-instances -t m1.tiny ami-00000003

It is still a work in progress and code need to be beautified, functions
needs to be completed, bugs need to be fixed.

Since what I see openstack now is a complete python stack, What I like 
to know is:
Is it possible to have a non python sub project in openstack?
How to make a non python project a sub project of openstack?
Will mixed language projects in openstack be helpfull or messfull?

Best Regards, Hengqing Hu

Attached some code snippet to show some of the ideas:

-module(compute_filter).

%% api
-export([host_passes/2]).

%%%-------------------------------------------------------------------
%%% api
%%%-------------------------------------------------------------------

host_passes({_, State}, FilterProperties) ->
    InstanceType = proplists:get_value(<<"instance_type">>,
                                       FilterProperties),
    Topic = proplists:get_value(<<"topic">>,
                                State),
    ((Topic =/= <<"compute">>) or
     (InstanceType =:= undefined) or
     (InstanceType =:= null)) orelse
    begin
        Capabilities = proplists:get_value(<<"capabilities">>,
                                           State),
        Service = proplists:get_value(<<"service">>,
                                      State),
        CapabilitiesEnabled = proplists:get_value(<<"enabled">>,
                                                  Capabilities,
                                                  1),
        is_service_up(Service) and
        is_capabilities_enabled(CapabilitiesEnabled) and
        satisfies_extra_specs(Capabilities, InstanceType)
    end.

%%%-------------------------------------------------------------------
%%% internal functions
%%%-------------------------------------------------------------------

is_service_up(Service) ->
    Disabled = proplists:get_value(<<"disabled">>,
                                   Service),
    is_service_enabled(Disabled) and
    ensched_lib:service_is_up(Service).

is_capabilities_enabled(1) ->
   true;
is_capabilities_enabled(0) ->
   false.

is_service_enabled(1) ->
    false;
is_service_enabled(0) ->
    true.

satisfies_extra_specs(Capabilities, InstanceType) ->
    (not lists:keymember(<<"extra_specs">>, 1, InstanceType)) orelse
    begin
        ExtraSpecs = proplists:get_value(<<"extra_specs">>, InstanceType),
        lists:all(
            fun({Key, Value})->
                    Value =:= proplists:get_value(Key, Capabilities)
            end,
            ExtraSpecs)
    end.