xendapi.py

xen 3.2.2 源码

    @rtype: callable object
    """    
    return lambda *args, **kwargs: \
           _check_ref(lambda r: XendDomain.instance().is_valid_dev('vif', r),
                      'VIF_metrics', func, *args, **kwargs)

def valid_vdi(func):
    """Decorator to verify if vdi_ref is valid before calling method.

    @param func: function with params: (self, session, vdi_ref, ...)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(XendNode.instance().is_valid_vdi,
                      'VDI', func, *args, **kwargs)

def valid_vtpm(func):
    """Decorator to verify if vtpm_ref is valid before calling method.

    @param func: function with params: (self, session, vtpm_ref, ...)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(lambda r: XendDomain.instance().is_valid_dev('vtpm', r),
                      'VTPM', func, *args, **kwargs)


def valid_console(func):
    """Decorator to verify if console_ref is valid before calling method.

    @param func: function with params: (self, session, console_ref, ...)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(lambda r: XendDomain.instance().is_valid_dev('console',
                                                                   r),
                      'console', func, *args, **kwargs)

def valid_sr(func):
    """Decorator to verify if sr_ref is valid before calling method.

    @param func: function with params: (self, session, sr_ref, ...)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(lambda r: XendNode.instance().is_valid_sr,
                      'SR', func, *args, **kwargs)

def valid_task(func):
    """Decorator to verify if task_ref is valid before calling
    method.

    @param func: function with params: (self, session, task_ref)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(XendTaskManager.get_task,
                      'task', func, *args, **kwargs)

def valid_debug(func):
    """Decorator to verify if task_ref is valid before calling
    method.

    @param func: function with params: (self, session, task_ref)
    @rtype: callable object
    """
    return lambda *args, **kwargs: \
           _check_ref(lambda r: r in XendAPI._debug,
                      'debug', func, *args, **kwargs)


def valid_object(class_name):
    """Decorator to verify if object is valid before calling
    method.

    @param func: function with params: (self, session, pif_ref)
    @rtype: callable object
    """
    return lambda func: \
           lambda *args, **kwargs: \
           _check_ref(lambda r: \
                          XendAPIStore.get(r, class_name) is not None,
                      'PIF', func, *args, **kwargs)

# -----------------------------
# Bridge to Legacy XM API calls
# -----------------------------

def do_vm_func(fn_name, vm_ref, *args, **kwargs):
    """Helper wrapper func to abstract away from repetitive code.

    @param fn_name: function name for XendDomain instance
    @type fn_name: string
    @param vm_ref: vm_ref
    @type vm_ref: string
    @param *args: more arguments
    @type *args: tuple
    """
    try:
        xendom = XendDomain.instance()
        fn = getattr(xendom, fn_name)
        xendom.do_legacy_api_with_uuid(fn, vm_ref, *args, **kwargs)
        return xen_api_success_void()
    except VMBadState, exn:
        return xen_api_error(['VM_BAD_POWER_STATE', vm_ref, exn.expected,
                              exn.actual])


classes = {
    'session'      : None,
    'event'        : None,
    'host'         : valid_host,
    'host_cpu'     : valid_host_cpu,
    'host_metrics' : valid_host_metrics,
    'VM'           : valid_vm,
    'VBD'          : valid_vbd,
    'VBD_metrics'  : valid_vbd_metrics,
    'VIF'          : valid_vif,
    'VIF_metrics'  : valid_vif_metrics,
    'VDI'          : valid_vdi,
    'VTPM'         : valid_vtpm,
    'console'      : valid_console,
    'SR'           : valid_sr,
    'task'         : valid_task,
    'XSPolicy'     : valid_object("XSPolicy"),
    'ACMPolicy'    : valid_object("ACMPolicy"),
    'debug'        : valid_debug,
    'network'      : valid_object("network"),
    'PIF'          : valid_object("PIF"),
    'VM_metrics'   : valid_object("VM_metrics"),
    'PBD'          : valid_object("PBD"),
    'PIF_metrics'  : valid_object("PIF_metrics")
}

autoplug_classes = {
    'network'     : XendNetwork,
    'PIF'         : XendPIF,
    'VM_metrics'  : XendVMMetrics,
    'PBD'         : XendPBD,
    'PIF_metrics' : XendPIFMetrics,
    'XSPolicy'    : XendXSPolicy,
    'ACMPolicy'   : XendACMPolicy,
}

class XendAPI(object):
    """Implementation of the Xen-API in Xend. Expects to be
    used via XMLRPCServer.

    All methods that need a valid session are marked with
    a L{session_required} decorator that will
    transparently perform the required session authentication.

    We need to support Python <2.4, so we use the old decorator syntax.

    All XMLRPC accessible methods require an 'api' attribute and
    is set to the XMLRPC function name which the method implements.
    """

    __decorated__ = False
    __init_lock__ = threading.Lock()
    _debug = {}
    
    def __new__(cls, *args, **kwds):
        """ Override __new__ to decorate the class only once.

        Lock to make sure the classes are not decorated twice.
        """
        cls.__init_lock__.acquire()
        try:
            if not cls.__decorated__:
                cls._decorate()
                cls.__decorated__ = True
                
            return object.__new__(cls, *args, **kwds)
        finally:
            cls.__init_lock__.release()
            
    def _decorate(cls):
        """ Decorate all the object methods to have validators
        and appropriate function attributes.

        This should only be executed once for the duration of the
        server.
        """
        global_validators = [session_required, catch_typeerror]


        # Cheat methods
        # -------------
        # Methods that have a trivial implementation for all classes.
        # 1. get_by_uuid == getting by ref, so just return uuid for
        #    all get_by_uuid() methods.
        
        for api_cls in classes.keys():
            # We'll let the autoplug classes implement these functions
            # themselves - its much cleaner to do it in the base class
            if api_cls == 'session' or api_cls in autoplug_classes.keys():
                continue
            
            get_by_uuid = '%s_get_by_uuid' % api_cls
            get_uuid = '%s_get_uuid' % api_cls
            get_all_records = '%s_get_all_records' % api_cls    

            def _get_by_uuid(_1, _2, ref):
                return xen_api_success(ref)

            def _get_uuid(_1, _2, ref):
                return xen_api_success(ref)

            def unpack(v):
                return v.get('Value')

            def _get_all_records(_api_cls):
                return lambda s, session: \
                    xen_api_success(dict([(ref, unpack(getattr(cls, '%s_get_record' % _api_cls)(s, session, ref)))\
                                          for ref in unpack(getattr(cls, '%s_get_all' % _api_cls)(s, session))]))

            setattr(cls, get_by_uuid, _get_by_uuid)
            setattr(cls, get_uuid,    _get_uuid)
            setattr(cls, get_all_records, _get_all_records(api_cls))

        # Autoplugging classes
        # --------------------
        # These have all of their methods grabbed out from the implementation
        # class, and wrapped up to be compatible with the Xen-API.

        def getter(ref, type):
            return XendAPIStore.get(ref, type)
        
        for api_cls, impl_cls in autoplug_classes.items():
            def doit(n):           
                dot_n = '%s.%s' % (api_cls, n)
                full_n = '%s_%s' % (api_cls, n)
                if not hasattr(cls, full_n):
                    f = getattr(impl_cls, n)
                    argcounts[dot_n] = f.func_code.co_argcount + 1
                    g = lambda api_cls: \
                    setattr(cls, full_n, \
                            lambda s, session, ref, *args: \
                               xen_api_success( \
                                   f(getter(ref, api_cls), *args)))
                    g(api_cls) # Force api_cls to be captured
                    
            def doit_func(n):           
                dot_n = '%s.%s' % (api_cls, n)
                full_n = '%s_%s' % (api_cls, n)
                if not hasattr(cls, full_n):
                    f = getattr(impl_cls, n)
                    argcounts[dot_n] = f.func_code.co_argcount
                    setattr(cls, full_n, \
                            lambda s, session, *args: \
                               xen_api_success( \
                                   f(*args)))

            ro_attrs = impl_cls.getAttrRO()
            rw_attrs = impl_cls.getAttrRW()
            methods  = impl_cls.getMethods()
            funcs    = impl_cls.getFuncs()
            
            for attr_name in ro_attrs + rw_attrs:
                doit('get_%s' % attr_name)
            for attr_name in rw_attrs:
                doit('set_%s' % attr_name)
            for method in methods:
                doit('%s' % method)
            for func in funcs:
                doit_func('%s' % func)

        def wrap_method(name, new_f):
            try:
                f = getattr(cls, name)
                wrapped_f = (lambda *args: new_f(f, *args))
                wrapped_f.api = f.api
                wrapped_f.async = f.async
                setattr(cls, name, wrapped_f)
            except AttributeError:
                # Logged below (API call: %s not found)
                pass


        def setter_event_wrapper(api_cls, attr_name):
            setter_name = '%s_set_%s' % (api_cls, attr_name)
            wrap_method(
                setter_name,
                lambda setter, s, session, ref, *args:
                _setter_event_dispatch(s, setter, api_cls, attr_name,
                                       session, ref, args))


        def ctor_event_wrapper(api_cls):
            ctor_name = '%s_create' % api_cls
            wrap_method(
                ctor_name,
                lambda ctor, s, session, *args:
                _ctor_event_dispatch(s, ctor, api_cls, session, args))


        def dtor_event_wrapper(api_cls):
            dtor_name = '%s_destroy' % api_cls
            wrap_method(
                dtor_name,
                lambda dtor, s, session, ref, *args:
                _dtor_event_dispatch(s, dtor, api_cls, session, ref, args))


        # Wrapping validators around XMLRPC calls
        # ---------------------------------------

        for api_cls, validator in classes.items():
            def doit(n, takes_instance, async_support = False,
                     return_type = None):
                n_ = n.replace('.', '_')
                try:
                    f = getattr(cls, n_)
                    if n not in argcounts:
                        argcounts[n] = f.func_code.co_argcount - 1
                    
                    validators = takes_instance and validator and \
                                 [validator] or []

                    validators += global_validators
                    for v in validators:
                        f = v(f)
                        f.api = n
                        f.async = async_support
                        if return_type:
                            f.return_type = return_type
                    
                    setattr(cls, n_, f)
                except AttributeError:
                    log.warn("API call: %s not found" % n)

            if api_cls in autoplug_classes.keys():
                impl_cls = autoplug_classes[api_cls]
                ro_attrs = impl_cls.getAttrRO()
                rw_attrs = impl_cls.getAttrRW()
                methods  = map(lambda x: (x, ""), impl_cls.getMethods())
                funcs    = map(lambda x: (x, ""), impl_cls.getFuncs())
            else:
                ro_attrs = getattr(cls, '%s_attr_ro' % api_cls, []) \
                           + cls.Base_attr_ro
                rw_attrs = getattr(cls, '%s_attr_rw' % api_cls, []) \
                           + cls.Base_attr_rw
                methods  = getattr(cls, '%s_methods' % api_cls, []) \
                           + cls.Base_methods
                funcs    = getattr(cls, '%s_funcs'   % api_cls, []) \
                           + cls.Base_funcs