[PATCH-next v2 0/1] Differentiate between physical, soft and virtual devices

From: Christos Sfakianakis <csfakian(a)redhat.com&gt;

Hi,

this is version 2 of the patch. The difference with respect to the
first version is the transfer of the cover letter's use case description
into the commit's message.

Christos

Christos Sfakianakis (1):
  lnst.Devices.Device: customize instance checks to support
    categorization

 lnst/Devices/Device.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

-- 
2.17.1

[PATCH-next v2 1/1] lnst.Devices.Device: customize instance checks to support categorization

From: Christos Sfakianakis <csfakian(a)redhat.com&gt;

Define a custom __instancecheck__ method that does special handling
for RemoteDevice instances defined on the controller. For such instances,
route the check via the _dev_cls attribute of the instance. For all
other cases, the handling remains the same as before.

The result is the ability to differentiate between physical, soft and virtual
devices on the tester's side. A use case follows.

 #==============================================================
 #Controller
 #==============================================================

 from lnst.Devices import VlanDevice
 from lnst.Devices.Device import Device as Dev
 from lnst.Devices.VlanDevice import VlanDevice as VlanDev
 from lnst.Devices.BridgeDevice import BridgeDevice as BridgeDev
 from lnst.Devices.SoftDevice import SoftDevice as SoftDev
 from lnst.Devices.VirtualDevice import VirtualDevice as VirtDev
 ...
        host1.eth0 = DeviceReq(label="net1",
driver=RecipeParam("driver"))
        host1.vlan0 = VlanDevice(realdev=host1.eth0, vlan_id=10)
        x = host1.vlan0

        # Class hierarchy: Device >> SoftDevice >> VlanDevice
        #                  Device >> SoftDevice >> MasterDevice >>
BridgeDevice
                                            #  Before | After
                                            #------------------
        isinstance(x, Dev)                  #  True   |  True
        isinstance(x, SoftDev)              #  False  |  True
        isinstance(x, VlanDev)              #  False  |  True
        isinstance(x, BridgeDev)            #  False  |  False

        isinstance(host1.eth0, VirtDev)     #  True   |  True
        isinstance(x, VirtDev)              #  False  |  False
                                            #         |
 #====================================================|=======
 #Slave                                               |
 #====================================================|=======
        isinstance(dev, Dev)                #  True   |  True
        isinstance(dev, SoftDev)            #  True   |  True
        isinstance(dev, VlanDev)            #  True   |  True
        isinstance(dev, BridgeDev)          #  False  |  False

The result on the slave hasn't changed. The result on the controller
is now in agreement with that on the slave.

Signed-off-by: Christos Sfakianakis <csfakian(a)redhat.com&gt;
---
 lnst/Devices/Device.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lnst/Devices/Device.py b/lnst/Devices/Device.py
index 30deb25..39d1dd2 100644
--- a/lnst/Devices/Device.py
+++ b/lnst/Devices/Device.py
@@ -30,7 +30,14 @@ from pyroute2.netlink.rtnl import RTM_NEWLINK
 from pyroute2.netlink.rtnl import RTM_NEWADDR
 from pyroute2.netlink.rtnl import RTM_DELADDR
 
-class Device(object, metaclass=ABCMeta):
+class DeviceMeta(ABCMeta):
+    def __instancecheck__(self, other):
+        try:
+            return issubclass(other._dev_cls, self)
+        except AttributeError:
+            return super(DeviceMeta, self).__instancecheck__(other)
+
+class Device(object, metaclass=DeviceMeta):
     """The base Device class
 
     Implemented using the pyroute2 package to access different attributes of
-- 
2.17.1

[PATCH-next v2 1/1] lnst.Devices.Device: customize instance checks to support categorization

[Ondrej Lichtner]

On Fri, Jun 07, 2019 at 09:42:50AM +0200, csfakian(a)redhat.com wrote:
>  From: Christos Sfakianakis <csfakian(a)redhat.com&gt;
>  
>  Define a custom __instancecheck__ method that does special handling
>  for RemoteDevice instances defined on the controller. For such instances,
>  route the check via the _dev_cls attribute of the instance. For all
>  other cases, the handling remains the same as before.
>  
>  The result is the ability to differentiate between physical, soft and virtual
>  devices on the tester's side. A use case follows.
>  
>   #==============================================================
>   #Controller
>   #==============================================================
>  
>   from lnst.Devices import VlanDevice
>   from lnst.Devices.Device import Device as Dev
>   from lnst.Devices.VlanDevice import VlanDevice as VlanDev
>   from lnst.Devices.BridgeDevice import BridgeDevice as BridgeDev
>   from lnst.Devices.SoftDevice import SoftDevice as SoftDev
>   from lnst.Devices.VirtualDevice import VirtualDevice as VirtDev
>   ...
>          host1.eth0 = DeviceReq(label="net1",
> driver=RecipeParam("driver"))
>          host1.vlan0 = VlanDevice(realdev=host1.eth0, vlan_id=10)
>          x = host1.vlan0
>  
>          # Class hierarchy: Device >> SoftDevice >> VlanDevice
>          #                  Device >> SoftDevice >> MasterDevice >>
> BridgeDevice
>                                              #  Before | After
>                                              #------------------
>          isinstance(x, Dev)                  #  True   |  True
>          isinstance(x, SoftDev)              #  False  |  True
>          isinstance(x, VlanDev)              #  False  |  True
>          isinstance(x, BridgeDev)            #  False  |  False
>  
>          isinstance(host1.eth0, VirtDev)     #  True   |  True
>          isinstance(x, VirtDev)              #  False  |  False
>                                              #         |
>   #====================================================|=======
>   #Slave                                               |
>   #====================================================|=======
>          isinstance(dev, Dev)                #  True   |  True
>          isinstance(dev, SoftDev)            #  True   |  True
>          isinstance(dev, VlanDev)            #  True   |  True
>          isinstance(dev, BridgeDev)          #  False  |  False
>  
>  The result on the slave hasn't changed. The result on the controller
>  is now in agreement with that on the slave.
>  
>  Signed-off-by: Christos Sfakianakis <csfakian(a)redhat.com&gt;
>  ---
>   lnst/Devices/Device.py | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
>  
>  diff --git a/lnst/Devices/Device.py b/lnst/Devices/Device.py
>  index 30deb25..39d1dd2 100644
>  --- a/lnst/Devices/Device.py
>  +++ b/lnst/Devices/Device.py
>  @@ -30,7 +30,14 @@ from pyroute2.netlink.rtnl import RTM_NEWLINK
>   from pyroute2.netlink.rtnl import RTM_NEWADDR
>   from pyroute2.netlink.rtnl import RTM_DELADDR
>   
>  -class Device(object, metaclass=ABCMeta):
>  +class DeviceMeta(ABCMeta):
>  +    def __instancecheck__(self, other):
>  +        try:
>  +            return issubclass(other._dev_cls, self)
>  +        except AttributeError:
>  +            return super(DeviceMeta, self).__instancecheck__(other)
>  +
>  +class Device(object, metaclass=DeviceMeta):
>       """The base Device class
>   
>       Implemented using the pyroute2 package to access different attributes of
>  -- 
>  2.17.1
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This looks ok, pushed.

-Ondrej