diff mbox series

[v10,09/10] qcow2_format.py: collect fields to dump in JSON format

Message ID 1594676203-436999-10-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series iotests: Dump QCOW2 dirty bitmaps metadata | expand

Commit Message

Andrey Shinkevich July 13, 2020, 9:36 p.m. UTC
As __dict__ is being extended with class members we do not want to
print, make a light copy of the initial __dict__ and extend the copy
by adding lists we have to print in the JSON output.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 tests/qemu-iotests/qcow2_format.py | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Vladimir Sementsov-Ogievskiy July 16, 2020, 10:24 a.m. UTC | #1
14.07.2020 00:36, Andrey Shinkevich wrote:
> As __dict__ is being extended with class members we do not want to
> print, make a light copy of the initial __dict__ and extend the copy
> by adding lists we have to print in the JSON output.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   tests/qemu-iotests/qcow2_format.py | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
> index e0e14b5..83c3482 100644
> --- a/tests/qemu-iotests/qcow2_format.py
> +++ b/tests/qemu-iotests/qcow2_format.py
> @@ -109,6 +109,8 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>           self.__dict__ = dict((field[2], values[i])
>                                for i, field in enumerate(self.fields))
>   
> +        self.fields_dict = self.__dict__.copy()

No, I don't like that. Keeping two copies of all the data is bad idea. If you want to select some fields, add a method (dump_json() ?) Which will collect the fields you want in a dict and return that new dict. But don't store object attributes twice.

> +
>       def dump(self, dump_json=None):
>           for f in self.fields:
>               value = self.__dict__[f[2]]
> @@ -144,6 +146,7 @@ class Qcow2BitmapExt(Qcow2Struct):
>           self.bitmap_directory = \
>               [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
>                for _ in range(self.nb_bitmaps)]
> +        self.fields_dict.update(bitmap_directory=self.bitmap_directory)
>   
>       def dump(self, dump_json=None):
>           super().dump(dump_json)
> @@ -189,6 +192,7 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
>           table = [e[0] for e in struct.iter_unpack('>Q', fd.read(table_size))]
>           self.bitmap_table = Qcow2BitmapTable(raw_table=table,
>                                                cluster_size=self.cluster_size)
> +        self.fields_dict.update(bitmap_table=self.bitmap_table)
>   
>       def dump(self, dump_json=None):
>           print(f'{"Bitmap name":<25} {self.name}')
>
Andrey Shinkevich July 16, 2020, 3:34 p.m. UTC | #2
On 16.07.2020 13:24, Vladimir Sementsov-Ogievskiy wrote:
> 14.07.2020 00:36, Andrey Shinkevich wrote:
>> As __dict__ is being extended with class members we do not want to
>> print, make a light copy of the initial __dict__ and extend the copy
>> by adding lists we have to print in the JSON output.
>>
>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>> ---
>>   tests/qemu-iotests/qcow2_format.py | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/tests/qemu-iotests/qcow2_format.py 
>> b/tests/qemu-iotests/qcow2_format.py
>> index e0e14b5..83c3482 100644
>> --- a/tests/qemu-iotests/qcow2_format.py
>> +++ b/tests/qemu-iotests/qcow2_format.py
>> @@ -109,6 +109,8 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>>           self.__dict__ = dict((field[2], values[i])
>>                                for i, field in enumerate(self.fields))
>>   +        self.fields_dict = self.__dict__.copy()
>
> No, I don't like that. Keeping two copies of all the data is bad idea. 
> If you want to select some fields, add a method (dump_json() ?) Which 
> will collect the fields you want in a dict and return that new dict. 
> But don't store object attributes twice.
>

Not really. It makes a light copy that stores only references to the 
desired fields.

Andrey


>> +
>>       def dump(self, dump_json=None):
>>           for f in self.fields:
>>               value = self.__dict__[f[2]]
>> @@ -144,6 +146,7 @@ class Qcow2BitmapExt(Qcow2Struct):
>>           self.bitmap_directory = \
>>               [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
>>                for _ in range(self.nb_bitmaps)]
>> + self.fields_dict.update(bitmap_directory=self.bitmap_directory)
>>         def dump(self, dump_json=None):
>>           super().dump(dump_json)
>> @@ -189,6 +192,7 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
>>           table = [e[0] for e in struct.iter_unpack('>Q', 
>> fd.read(table_size))]
>>           self.bitmap_table = Qcow2BitmapTable(raw_table=table,
>> cluster_size=self.cluster_size)
>> +        self.fields_dict.update(bitmap_table=self.bitmap_table)
>>         def dump(self, dump_json=None):
>>           print(f'{"Bitmap name":<25} {self.name}')
>>
>
>
Vladimir Sementsov-Ogievskiy July 16, 2020, 3:40 p.m. UTC | #3
16.07.2020 18:34, Andrey Shinkevich wrote:
> On 16.07.2020 13:24, Vladimir Sementsov-Ogievskiy wrote:
>> 14.07.2020 00:36, Andrey Shinkevich wrote:
>>> As __dict__ is being extended with class members we do not want to
>>> print, make a light copy of the initial __dict__ and extend the copy
>>> by adding lists we have to print in the JSON output.
>>>
>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>> ---
>>>   tests/qemu-iotests/qcow2_format.py | 4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>> diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
>>> index e0e14b5..83c3482 100644
>>> --- a/tests/qemu-iotests/qcow2_format.py
>>> +++ b/tests/qemu-iotests/qcow2_format.py
>>> @@ -109,6 +109,8 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>>>           self.__dict__ = dict((field[2], values[i])
>>>                                for i, field in enumerate(self.fields))
>>>   +        self.fields_dict = self.__dict__.copy()
>>
>> No, I don't like that. Keeping two copies of all the data is bad idea. If you want to select some fields, add a method (dump_json() ?) Which will collect the fields you want in a dict and return that new dict. But don't store object attributes twice.
>>
> 
> Not really. It makes a light copy that stores only references to the desired fields.
> 

I'm not about memory consumption, I'm about the design. Keeping two representations of same thing is always painful to maintain.

> 
>>> +
>>>       def dump(self, dump_json=None):
>>>           for f in self.fields:
>>>               value = self.__dict__[f[2]]
>>> @@ -144,6 +146,7 @@ class Qcow2BitmapExt(Qcow2Struct):
>>>           self.bitmap_directory = \
>>>               [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
>>>                for _ in range(self.nb_bitmaps)]
>>> + self.fields_dict.update(bitmap_directory=self.bitmap_directory)
>>>         def dump(self, dump_json=None):
>>>           super().dump(dump_json)
>>> @@ -189,6 +192,7 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
>>>           table = [e[0] for e in struct.iter_unpack('>Q', fd.read(table_size))]
>>>           self.bitmap_table = Qcow2BitmapTable(raw_table=table,
>>> cluster_size=self.cluster_size)
>>> +        self.fields_dict.update(bitmap_table=self.bitmap_table)
>>>         def dump(self, dump_json=None):
>>>           print(f'{"Bitmap name":<25} {self.name}')
>>>
>>
>>
Andrey Shinkevich July 16, 2020, 3:52 p.m. UTC | #4
On 16.07.2020 18:40, Vladimir Sementsov-Ogievskiy wrote:
> 16.07.2020 18:34, Andrey Shinkevich wrote:
>> On 16.07.2020 13:24, Vladimir Sementsov-Ogievskiy wrote:
>>> 14.07.2020 00:36, Andrey Shinkevich wrote:
>>>> As __dict__ is being extended with class members we do not want to
>>>> print, make a light copy of the initial __dict__ and extend the copy
>>>> by adding lists we have to print in the JSON output.
>>>>
>>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>>> ---
>>>>   tests/qemu-iotests/qcow2_format.py | 4 ++++
>>>>   1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/tests/qemu-iotests/qcow2_format.py 
>>>> b/tests/qemu-iotests/qcow2_format.py
>>>> index e0e14b5..83c3482 100644
>>>> --- a/tests/qemu-iotests/qcow2_format.py
>>>> +++ b/tests/qemu-iotests/qcow2_format.py
>>>> @@ -109,6 +109,8 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>>>>           self.__dict__ = dict((field[2], values[i])
>>>>                                for i, field in enumerate(self.fields))
>>>>   +        self.fields_dict = self.__dict__.copy()
>>>
>>> No, I don't like that. Keeping two copies of all the data is bad 
>>> idea. If you want to select some fields, add a method (dump_json() 
>>> ?) Which will collect the fields you want in a dict and return that 
>>> new dict. But don't store object attributes twice.


That is what I did in the versions before but it looks clumsy to me. 
Every single class lists almost all the items of the __dict__ again in 
the additional method.

Andrey


>>>
>>
>> Not really. It makes a light copy that stores only references to the 
>> desired fields.
>>
>
> I'm not about memory consumption, I'm about the design. Keeping two 
> representations of same thing is always painful to maintain.
>
>>
>>>> +
>>>>       def dump(self, dump_json=None):
>>>>           for f in self.fields:
>>>>               value = self.__dict__[f[2]]
>>>> @@ -144,6 +146,7 @@ class Qcow2BitmapExt(Qcow2Struct):
>>>>           self.bitmap_directory = \
>>>>               [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
>>>>                for _ in range(self.nb_bitmaps)]
>>>> + self.fields_dict.update(bitmap_directory=self.bitmap_directory)
>>>>         def dump(self, dump_json=None):
>>>>           super().dump(dump_json)
>>>> @@ -189,6 +192,7 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
>>>>           table = [e[0] for e in struct.iter_unpack('>Q', 
>>>> fd.read(table_size))]
>>>>           self.bitmap_table = Qcow2BitmapTable(raw_table=table,
>>>> cluster_size=self.cluster_size)
>>>> + self.fields_dict.update(bitmap_table=self.bitmap_table)
>>>>         def dump(self, dump_json=None):
>>>>           print(f'{"Bitmap name":<25} {self.name}')
>>>>
>>>
>>>
>
>
Vladimir Sementsov-Ogievskiy July 16, 2020, 4:08 p.m. UTC | #5
16.07.2020 18:52, Andrey Shinkevich wrote:
> On 16.07.2020 18:40, Vladimir Sementsov-Ogievskiy wrote:
>> 16.07.2020 18:34, Andrey Shinkevich wrote:
>>> On 16.07.2020 13:24, Vladimir Sementsov-Ogievskiy wrote:
>>>> 14.07.2020 00:36, Andrey Shinkevich wrote:
>>>>> As __dict__ is being extended with class members we do not want to
>>>>> print, make a light copy of the initial __dict__ and extend the copy
>>>>> by adding lists we have to print in the JSON output.
>>>>>
>>>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>>>> ---
>>>>>   tests/qemu-iotests/qcow2_format.py | 4 ++++
>>>>>   1 file changed, 4 insertions(+)
>>>>>
>>>>> diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
>>>>> index e0e14b5..83c3482 100644
>>>>> --- a/tests/qemu-iotests/qcow2_format.py
>>>>> +++ b/tests/qemu-iotests/qcow2_format.py
>>>>> @@ -109,6 +109,8 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>>>>>           self.__dict__ = dict((field[2], values[i])
>>>>>                                for i, field in enumerate(self.fields))
>>>>>   +        self.fields_dict = self.__dict__.copy()
>>>>
>>>> No, I don't like that. Keeping two copies of all the data is bad idea. If you want to select some fields, add a method (dump_json() ?) Which will collect the fields you want in a dict and return that new dict. But don't store object attributes twice.
> 
> 
> That is what I did in the versions before but it looks clumsy to me. Every single class lists almost all the items of the __dict__ again in the additional method.
> 

Most of them should be listed automatically by base class method, which will iterate through .fields

> 
>>>>
>>>
>>> Not really. It makes a light copy that stores only references to the desired fields.
>>>
>>
>> I'm not about memory consumption, I'm about the design. Keeping two representations of same thing is always painful to maintain.
>>
>>>
>>>>> +
>>>>>       def dump(self, dump_json=None):
>>>>>           for f in self.fields:
>>>>>               value = self.__dict__[f[2]]
>>>>> @@ -144,6 +146,7 @@ class Qcow2BitmapExt(Qcow2Struct):
>>>>>           self.bitmap_directory = \
>>>>>               [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
>>>>>                for _ in range(self.nb_bitmaps)]
>>>>> + self.fields_dict.update(bitmap_directory=self.bitmap_directory)
>>>>>         def dump(self, dump_json=None):
>>>>>           super().dump(dump_json)
>>>>> @@ -189,6 +192,7 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
>>>>>           table = [e[0] for e in struct.iter_unpack('>Q', fd.read(table_size))]
>>>>>           self.bitmap_table = Qcow2BitmapTable(raw_table=table,
>>>>> cluster_size=self.cluster_size)
>>>>> + self.fields_dict.update(bitmap_table=self.bitmap_table)
>>>>>         def dump(self, dump_json=None):
>>>>>           print(f'{"Bitmap name":<25} {self.name}')
>>>>>
>>>>
>>>>
>>
>>
diff mbox series

Patch

diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
index e0e14b5..83c3482 100644
--- a/tests/qemu-iotests/qcow2_format.py
+++ b/tests/qemu-iotests/qcow2_format.py
@@ -109,6 +109,8 @@  class Qcow2Struct(metaclass=Qcow2StructMeta):
         self.__dict__ = dict((field[2], values[i])
                              for i, field in enumerate(self.fields))
 
+        self.fields_dict = self.__dict__.copy()
+
     def dump(self, dump_json=None):
         for f in self.fields:
             value = self.__dict__[f[2]]
@@ -144,6 +146,7 @@  class Qcow2BitmapExt(Qcow2Struct):
         self.bitmap_directory = \
             [Qcow2BitmapDirEntry(fd, cluster_size=self.cluster_size)
              for _ in range(self.nb_bitmaps)]
+        self.fields_dict.update(bitmap_directory=self.bitmap_directory)
 
     def dump(self, dump_json=None):
         super().dump(dump_json)
@@ -189,6 +192,7 @@  class Qcow2BitmapDirEntry(Qcow2Struct):
         table = [e[0] for e in struct.iter_unpack('>Q', fd.read(table_size))]
         self.bitmap_table = Qcow2BitmapTable(raw_table=table,
                                              cluster_size=self.cluster_size)
+        self.fields_dict.update(bitmap_table=self.bitmap_table)
 
     def dump(self, dump_json=None):
         print(f'{"Bitmap name":<25} {self.name}')