[Engine-devel] Disk BE very small refactoring
Hi All, Please express your opinion if you have any - Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after. Appreciate any input, Vered
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device" and have isPlugged method called "device.isPlugged()" ? Then you can also add the readOnly property which is not represented at VmDevice. Does this sound logical to you? ----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device" and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
Vered, I forgot sharable disk may be associated with two VMs, hence having a field of VmDevice may be problematic. However, maybe we need some interface (i.e - Device) which BothVmDevice and your class (or maybe an object of some class that will be contained in your class) will implement?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device" and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
Vered, I forgot sharable disk may be associated with two VMs, hence having a field of VmDevice may be problematic.
In this case there will be 2 VmDevice entities for the same disk, IIUC. Why not just rely on the field there? Why does it need to be "flattened" on the Disk BE?
However, maybe we need some interface (i.e - Device) which BothVmDevice and your class (or maybe an object of some class that will be contained in your class) will implement?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes. I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come. I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy. The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future. Regards, Maor On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
I had a problem, didn't see all the replies till now. I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks. So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first. Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go. The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system. I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame. If there is any other/unanswered issue or objection to the design change please share. I appreciate your inputs, Vered ----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Omer Frenkel" <ofrenkel@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 8:40:38 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I had a problem, didn't see all the replies till now.
I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks.
please explain why you think plugged is a hack? what is wrong with it?
So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first.
Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go.
The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system.
I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame.
If there is any other/unanswered issue or objection to the design change please share.
I appreciate your inputs, Vered
sorry i didnt understand why the current disk object isnt good enough, you get a disk, some of its properties are valid only in some situations. i think its easier to use instead of couple of different objects representing the same entity in different situations.
----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Omer Frenkel" <ofrenkel@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Thursday, May 30, 2013 11:29:40 AM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Omer Frenkel" <ofrenkel@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 8:40:38 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I had a problem, didn't see all the replies till now.
I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks.
please explain why you think plugged is a hack? what is wrong with it?
You have is_readonly and is_plugged in the device level , this is far from being a hack and managed in the correct place since both may apply to multiple device types (disk, nics ....)
So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first.
Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go.
The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system.
I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame.
If there is any other/unanswered issue or objection to the design change please share.
I appreciate your inputs, Vered
sorry i didnt understand why the current disk object isnt good enough, you get a disk, some of its properties are valid only in some situations. i think its easier to use instead of couple of different objects representing the same entity in different situations.
I totally agree with Omer, please specify what is impossible or hard to achieve with the current schema
----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Eli Mesika" <emesika@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Thursday, May 30, 2013 12:57:26 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Omer Frenkel" <ofrenkel@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Thursday, May 30, 2013 11:29:40 AM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Omer Frenkel" <ofrenkel@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 8:40:38 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I had a problem, didn't see all the replies till now.
I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks.
please explain why you think plugged is a hack? what is wrong with it?
You have is_readonly and is_plugged in the device level , this is far from being a hack and managed in the correct place since both may apply to multiple device types (disk, nics ....) There's no problem with device level, only I can't use VmDevice (which is where this naturally belongs) in UI since it will cause a major change we don't want right now. Not only that, VmDevice does hold this info, but not other relevant info used in UI and available in Disk, so using VmDevice on it's own is not only to extensive a change, but also by far will not end there.
So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first.
Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go.
The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system.
I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame.
If there is any other/unanswered issue or objection to the design change please share.
I appreciate your inputs, Vered
sorry i didnt understand why the current disk object isnt good enough, you get a disk, some of its properties are valid only in some situations. i think its easier to use instead of couple of different objects representing the same entity in different situations.
I totally agree with Omer, please specify what is impossible or hard to achieve with the current schema
No problem with DB schema, please see my answer in engine-devel, I'm not sure you're directly cc'ed.
----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message ----- > From: "Vered Volansky" <vered@redhat.com> > To: engine-devel@ovirt.org > Sent: Monday, May 27, 2013 6:18:58 PM > Subject: [Engine-devel] Disk BE very small refactoring > > Hi All, > > Please express your opinion if you have any - > > Currently Disk BE has a plugged property, which should be a > property > of > the > relationship between vm(or template) and a disk. > I plan to remove this property from the Disk entity, and add new > entity, > called DeviceDisk. > This should inherit from Disk and contain the vm/template guid and > the > plugged property at first round. > At second round it'll also contain the readOnly property, for RO > disks, > TBD > right after. > > Appreciate any input, > Vered > _______________________________________________ > Engine-devel mailing list > Engine-devel@ovirt.org > http://lists.ovirt.org/mailman/listinfo/engine-devel > _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
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----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Eli Mesika" <emesika@redhat.com> Cc: engine-devel@ovirt.org Sent: Sunday, June 2, 2013 12:02:55 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Eli Mesika" <emesika@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Thursday, May 30, 2013 12:57:26 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Omer Frenkel" <ofrenkel@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Thursday, May 30, 2013 11:29:40 AM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Omer Frenkel" <ofrenkel@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 8:40:38 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I had a problem, didn't see all the replies till now.
I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks.
please explain why you think plugged is a hack? what is wrong with it?
You have is_readonly and is_plugged in the device level , this is far from being a hack and managed in the correct place since both may apply to multiple device types (disk, nics ....) There's no problem with device level, only I can't use VmDevice (which is where this naturally belongs) in UI since it will cause a major change we don't want right now. Not only that, VmDevice does hold this info, but not other relevant info used in UI and available in Disk, so using VmDevice on it's own is not only to extensive a change, but also by far will not end there.
So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first.
Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go.
The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system.
I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame.
If there is any other/unanswered issue or objection to the design change please share.
I appreciate your inputs, Vered
sorry i didnt understand why the current disk object isnt good enough, you get a disk, some of its properties are valid only in some situations. i think its easier to use instead of couple of different objects representing the same entity in different situations.
I totally agree with Omer, please specify what is impossible or hard to achieve with the current schema
No problem with DB schema, please see my answer in engine-devel, I'm not sure you're directly cc'ed. The way I see it, it's a design issue. A disk is different from other devices as it can be attached to multiple VMs. I.e., the same Disk record in the database is associated with either 0 device records (a floating disk), 1 device record (a normal disk) or multiple device records (shared disk). The java object has a few properties that really belong to the disk (e.g., alias, size, wipeAfterDelete), some that belong to the device (plugged, readOnly in the near future) and some the belong to ALL the VMs it's attached to (e.g., vmNames).
This way, the object is unusable - depending on which query you use to load it, you'll have a different set of properties set to null, which is unacceptable in modular code. The suggestion here is simple - instead of needing to comment or somehow no what properties a function is allowed to use, make it explicit my moving these properties to a sensible object.
----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message ----- > From: "Yair Zaslavsky" <yzaslavs@redhat.com> > To: "Vered Volansky" <vered@redhat.com> > Cc: engine-devel@ovirt.org > Sent: Monday, May 27, 2013 6:22:58 PM > Subject: Re: [Engine-devel] Disk BE very small refactoring > > Vered, > VmDevice has "isPlugged" field, > Why not have somehow in your inheritence (either Disk or a > subclass) > a > field > : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
> and have isPlugged method called "device.isPlugged()" ? > > Then you can also add the readOnly property which is not > represented > at > VmDevice. > > > Does this sound logical to you? > > ----- Original Message ----- >> From: "Vered Volansky" <vered@redhat.com> >> To: engine-devel@ovirt.org >> Sent: Monday, May 27, 2013 6:18:58 PM >> Subject: [Engine-devel] Disk BE very small refactoring >> >> Hi All, >> >> Please express your opinion if you have any - >> >> Currently Disk BE has a plugged property, which should be a >> property >> of >> the >> relationship between vm(or template) and a disk. >> I plan to remove this property from the Disk entity, and add new >> entity, >> called DeviceDisk. >> This should inherit from Disk and contain the vm/template guid >> and >> the >> plugged property at first round. >> At second round it'll also contain the readOnly property, for RO >> disks, >> TBD >> right after. >> >> Appreciate any input, >> Vered >> _______________________________________________ >> Engine-devel mailing list >> Engine-devel@ovirt.org >> http://lists.ovirt.org/mailman/listinfo/engine-devel >> > _______________________________________________ > Engine-devel mailing list > Engine-devel@ovirt.org > http://lists.ovirt.org/mailman/listinfo/engine-devel > _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
----- Original Message -----
From: "Omer Frenkel" <ofrenkel@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com>, engine-devel@ovirt.org Sent: Thursday, May 30, 2013 11:29:40 AM Subject: Re: [Engine-devel] Disk BE very small refactoring
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: "Maor Lipchuk" <mlipchuk@redhat.com>, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Omer Frenkel" <ofrenkel@redhat.com>, "Mike Kolesnik" <mkolesni@redhat.com>, "Allon Mureinik" <amureini@redhat.com>, "Daniel Erez" <derez@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 8:40:38 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I had a problem, didn't see all the replies till now.
I'll add some more info as to why we want to do this like we do. It all started from adding the readOnly property to disks. It should have been handled like plugged is handled, yet plugged is a hack, and if we don't change that now, we'll only keep on adding unreasonable hacks.
please explain why you think plugged is a hack? what is wrong with it? Plugged is a property of a disk-vm. Were the disk only be able to be plugged to one VM, there would be no problem with that. But since the disk can be plugged to several VMs, the plugged property should be on the relationship between the two, and not selectively on disk. Since this is the current case, there's a query that fills in this data in disk under the VM's context, which can be changed when the VM's context is different, which is a hack.
So from the start - Disk currently: - Sometimes represents a disk in a vm context and sometimes not. - Holds plugged property, which is only relevant when a disk is in a vm context, which already suggests this is not the natural place for it. - Also holds bootable and interface, which cause limitations of use, but are not so obviously related to the relationship between Disk and Vm as plugged. - Can be shared between several vm's, to some plugged and to some not plugged. - Will soon be optionally RO in one VM and RW in another, which is exactly the same as plugged, and therefore plugged issue should be fixed first.
Every column in that shows a disk in the UI receives a Disk entity, and show its contents, while plugged/unplugged is ignored when not in a VM context. The way things are now, using a VmDevice in the where we need it to show plug status, we'll also have to use it in all other columns, which is irrelevant and just totally not related. So using VmDevice in UI is a no go.
The UI is the main limitation forcing us to use something that extends Disk, and what I described below is the easiest thing to implement in the time restrictions we have without changing the entire system.
I think this answers all the questions not already answered by others. Regarding Maor suggestion - might be a good idea, but not in this scope or time-frame.
If there is any other/unanswered issue or objection to the design change please share.
I appreciate your inputs, Vered
sorry i didnt understand why the current disk object isnt good enough, you get a disk, some of its properties are valid only in some situations. i think its easier to use instead of couple of different objects representing the same entity in different situations.
This just doesn't belong there, there's a workaround to make it work when it's indeed needed - by the GetAllDisksByVmIdQuery. In between the value there means nothing, the fact that we successfully avoid falling into that pitfall doesn't mean it should remain this way. More importantly, this is not done here, we're adding other properties (currently RO) that face the same handling onless this is resolved now. This is the best resolution we came up with under the circumstances. Are you putting you foot down on this?
----- Original Message -----
From: "Maor Lipchuk" <mlipchuk@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, May 28, 2013 1:49:46 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
I think the main problem is that we abuse the business entity to act as an O/R mapping class to the DB and also to be used as a business entity for presentation purposes.
I understand how Yair thought isPlugged could be fetched from vmDevice, this is a confusing design, and it is just one example and more to come.
I suggest that if we already thinking of changing the class hierarchy, we can start by implementing a package for presentation classes for transient classes such as this instead enforcing complex hierarchy.
The query class will fetch all the data from the DB and initialized the transient class and send it to the client. I think it could be a good start and will solve many issues we might encounter in the future.
Regards, Maor
On 05/28/2013 11:24 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Vered Volansky" <vered@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:22:58 PM Subject: Re: [Engine-devel] Disk BE very small refactoring
Vered, VmDevice has "isPlugged" field, Why not have somehow in your inheritence (either Disk or a subclass) a field : "VmDevice device"
disk id is the device id, no need for field to represent the relation. the combination of disk-id and a specific entity (vm/template) will get you the other info
and have isPlugged method called "device.isPlugged()" ?
Then you can also add the readOnly property which is not represented at VmDevice.
Does this sound logical to you?
----- Original Message -----
From: "Vered Volansky" <vered@redhat.com> To: engine-devel@ovirt.org Sent: Monday, May 27, 2013 6:18:58 PM Subject: [Engine-devel] Disk BE very small refactoring
Hi All,
Please express your opinion if you have any -
Currently Disk BE has a plugged property, which should be a property of the relationship between vm(or template) and a disk. I plan to remove this property from the Disk entity, and add new entity, called DeviceDisk. This should inherit from Disk and contain the vm/template guid and the plugged property at first round. At second round it'll also contain the readOnly property, for RO disks, TBD right after.
Appreciate any input, Vered _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
participants (7)
-
Allon Mureinik -
Eli Mesika -
Maor Lipchuk -
Mike Kolesnik -
Omer Frenkel -
Vered Volansky -
Yair Zaslavsky