[Engine-devel] "wipe after delete" Matching defaults from GUI to Backend

[Ravi Nori]

On 10/11/2012 07:50 PM, Itamar Heim wrote:
> On 10/11/2012 05:28 PM, Daniel Erez wrote:
>>
>>
>> ----- Original Message -----
>>> From: "Ravi Nori" <rnori at redhat.com>
>>> To: "Daniel Erez" <derez at redhat.com>
>>> Cc: engine-devel at ovirt.org
>>> Sent: Thursday, October 11, 2012 3:21:05 PM
>>> Subject: Re: [Engine-devel] "wipe after delete" Matching defaults 
>>> from GUI to    Backend
>>>
>>> On 10/10/2012 01:17 AM, Daniel Erez wrote:
>>>>
>>>> ----- Original Message -----
>>>>> From: "Ravi Nori" <rnori at redhat.com>
>>>>> To: engine-devel at ovirt.org
>>>>> Sent: Tuesday, October 9, 2012 6:40:56 PM
>>>>> Subject: [Engine-devel] "wipe after delete" Matching defaults from
>>>>> GUI to    Backend
>>>>>
>>>>> I am working on the bug where the defaults values in the GUI for
>>>>> disk
>>>>> actions don't correspond to the default values in the API/Backend.
>>>>> For
>>>>> example the "wipe after delete" flag defaults to true in the GUI
>>>>> but
>>>>> false in the backend code. Default values are not sent from the
>>>>> frontend
>>>>> to the backend. Please refer to the bugzilla link
>>>>>
>>>>> https://bugzilla.redhat.com/show_bug.cgi?id=845466
>>>>>
>>>>> After discussing with Michael as to how to approach fixing this,
>>>>> we
>>>>> think the best way to do it would be to fix it in the Backend
>>>>> class
>>>>> businessentities.Disk by replacing primitives with reference types
>>>>> and
>>>>> forcing business logic in the class to set the default values to
>>>>> match
>>>>> the default values in the client.
>>>>>
>>>>> I would appreciate some feedback on this and also on what the
>>>>> default
>>>>> values are for Disk operations on the GUI.
>>>> GUI behavior is as follows:
>>>> For File storage domains - WipeAfterDelete check-box is
>>>> unchangeable and unchecked (false).
>>>> For Block storage domains - WipeAfterDelete check-box is changeable
>>>> and
>>>> the default value is according to 'SANWipeAfterDelete'
>>>> configuration value.
>>>>
>>>> I think you should simply utilize the same configuration value in
>>>> REST or backend when creating a new disk.
>>>>
>>>>> Thanks
>>>>>
>>>>> Ravi
>>>>> _______________________________________________
>>>>> Engine-devel mailing list
>>>>> Engine-devel at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/engine-devel
>>>>>
>>> Thanks for the reply.
>>>
>>> Here is my current implementation
>>>
>>> I modified businessentities.BaseDisk class to change wipeAfterDelete
>>> to
>>> wrapper class (reference class) for boolean
>>>
>>>       private Boolean wipeAfterDelete;
>>>
>>> I also added default values for File and block storages
>>>       private boolean wipeAfterDeleteFileStorageDomain = false;
>>>       private boolean wipeAfterDeleteBlockStorageDomain =
>>> Config.<Boolean>GetValue(ConfigValues.SANWipeAfterDelete);
>>>
>>> The storage type determines which of the two default values is
>>> returned
>>> by BaseDisk when wipeAfterDelete is not set (is null)
>>>       StorageType storageType = StorageType.UNKNOWN;
>>>
>>> So isWipeAfterDeleteMethodLooks like this
>>>
>>>       public boolean isWipeAfterDelete() {
>>>           if (wipeAfterDelete == null) {
>>>               return getDefaultIsWipeAfterDelete();
>>>           }
>>>           return wipeAfterDelete;
>>>       }
>>>
>>>       private boolean getDefaultIsWipeAfterDelete() {
>>>           if(storageType.equals(StorageType.UNKNOWN)) {
>>>               return false;
>>>           }
>>>           switch (storageType) {
>>>               case ISCSI:
>>>               case FCP:
>>>                   return wipeAfterDeleteBlockStorageDomain;
>>>               default:
>>>                   return wipeAfterDeleteFileStorageDomain;
>>>           }
>>>       }
>>>
>>> There is a new method isWipeAfterDeleteSet that will be used by
>>> commands
>>> to set the storage type to get the default wipeAfterDeleteFlag if
>>> wipeAfterDelete was not set.
>>>
>>>       public boolean isWipeAfterDeleteSet() {
>>>           return wipeAfterDelete != null;
>>>       }
>>>
>>> Now in bll.AddDiskCommand I modified executeVmCommand to add the
>>> following
>>>
>>> if(!getParameters().getDiskInfo().isWipeAfterDeleteSet()) {
>>>               StorageType storageType =
>>> getStorageDomain().getstorage_type();
>>> getParameters().getDiskInfo().setStorageType(storageType);
>>>           }
>>>
>>> This approach minimizes the impact of changes. So all commands
>>> interested in wipeAfterDelete flag based on storage type if
>>> wipeAfterDelete has not been set need to set the storageType before
>>> calling isWipeAfterDelete.
>>>
>>> Please let me know if this is the solution conflicts with something
>>> you
>>> have been working on. All the existing code will work as it has been
>>> working, if wipeAfterDelete has not been set and storageType has not
>>> been set the method isWipeAfterDelete return false (like it was
>>> earlier)
>>>
>>
>>
>> Calling 'Config.<?> GetValue' in a business entity could be 
>> problematic in the UI since
>> only the backend can invoke it (business entities are common for the 
>> backend and the UI
>> which means that both may instantiate/manipulate them).
>> We use GWT RPC for serializing/deserializing these business entities,
>> thus we usually can't reference non plain java objects (or use some 
>> tweaks/tricks if applicable).
>> Try to check the UI behavior after the new changes and let me know...
>> [as an alternative, you can probably get 'SANWipeAfterDelete' config 
>> value from REST code (or backend)].
>
> clients (UI/API) can only call the ConfigurationValues enum, and 
> should use the query for it (gui has this already of course, just look 
> it up)
Yes it is going to be a problem with the UI, I will work on an 
alternative. Since this method will be called from both backend and 
frontend code, I think it is best not to have the logic to extract the 
default value in the BaseDisk class. I am leaning towards the following 
implementation, please let me know your thoughts. I also took a look at 
ConfigurationValues but I thinks the below works best

The only change in the BaseDisk class is changing the reference type for 
wipeAfterDelete flag and the addition of a new method

     public boolean isWipeAfterDeleteSet() {
         return wipeAfterDelete != null;
     }

and change in isWipeAfterDelete method

     public boolean isWipeAfterDelete() {
         if (isWipeAfterDeleteSet()) {
             return wipeAfterDelete;
         }
         return false;
     }

The backend handles the logic when wipeAfterDelete flag is not set. So 
in AddDiskCommand executeVmCommand method we check if the flag is set, 
otherwise we get the storage type and get the default value using the 
new Utility class WipeAfterDeleteUtils

        if(!getParameters().getDiskInfo().isWipeAfterDeleteSet()) {
             StorageType storageType = getStorageDomain().getstorage_type();
getParameters().getDiskInfo().setWipeAfterDelete(WipeAfterDeleteUtils.getDefaultWipeAfterDeleteFlag(storageType));
         }

and the Utility class is a very simple class that extracts the default 
value based on the storagetype

public class WipeAfterDeleteUtils {

     static Boolean wipeAfterDeleteBlockStorageDomain;

     static boolean wipeAfterDeleteFileStorageDomain = false;

     public static synchronized boolean 
getDefaultWipeAfterDeleteFlag(final StorageType storageType) {
         if(storageType.isBlockDomain()) {
             if(wipeAfterDeleteBlockStorageDomain == null) {
                     wipeAfterDeleteBlockStorageDomain =
Config.<Boolean>GetValue(ConfigValues.SANWipeAfterDelete);
             }
             return wipeAfterDeleteBlockStorageDomain;
         }
         if(storageType.isFileDomain()) {
             return wipeAfterDeleteFileStorageDomain;
         }
         return false;
     }
}