Re: [PATCH v11 11/11] qcow2_format.py: support dumping metadata in JSON format

[Vladimir Sementsov-Ogievskiy]

17.07.2020 11:14, Andrey Shinkevich wrote:
> Implementation of dumping QCOW2 image metadata.
> The sample output:
> {
>      "Header_extensions": [
>          {
>              "name": "Feature table",
>              "magic": 1745090647,
>              "length": 192,
>              "data_str": "<binary>"
>          },
>          {
>              "name": "Bitmaps",
>              "magic": 595929205,
>              "length": 24,
>              "data": {
>                  "nb_bitmaps": 2,
>                  "reserved32": 0,
>                  "bitmap_directory_size": 64,
>                  "bitmap_directory_offset": 1048576,
>                  "bitmap_directory": [

bitmap_directy is just a list of dicts..

>                      {
>                          "name": "bitmap-1",
>                          "bitmap_table_offset": 589824,
>                          "bitmap_table_size": 1,
>                          "flags": 2,
>                          "type": 1,
>                          "granularity_bits": 15,
>                          "name_size": 8,
>                          "extra_data_size": 0,
>                          "bitmap_table": {

.. can bitmap_table be just a list of dicts as well, not {entries: <list of 
dicts>} ?
>                              "entries": [
>                                  {
>                                      "type": "serialized",
>                                      "offset": 655360
>                                  },
>                                  ...
>
> Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   tests/qemu-iotests/qcow2_format.py | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
>
> diff --git a/tests/qemu-iotests/qcow2_format.py 
> b/tests/qemu-iotests/qcow2_format.py
> index d2a8659..d40eb49 100644
> --- a/tests/qemu-iotests/qcow2_format.py
> +++ b/tests/qemu-iotests/qcow2_format.py
> @@ -19,6 +19,15 @@
>   
>   import struct
>   import string
> +import json
> +
> +
> +class ComplexEncoder(json.JSONEncoder):
> +    def default(self, obj):
> +        if hasattr(obj, 'to_dict'):
> +            return obj.to_dict()
> +        else:
> +            return json.JSONEncoder.default(self, obj)
>   
>   
>   class Qcow2Field:
> @@ -110,6 +119,11 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
>                                for i, field in enumerate(self.fields))
>   
>       def dump(self, is_json=False):
> +        if is_json:
> +            print(json.dumps(self.to_dict(), indent=4,
> +                             cls=ComplexEncoder))
> +            return
> +
>           for f in self.fields:
>               value = self.__dict__[f[2]]
>               if isinstance(f[1], str):
> @@ -445,6 +459,12 @@ class QcowHeader(Qcow2Struct):
>           fd.write(buf)
>   
>       def dump_extensions(self, is_json=False):
> +        if is_json:
> +            ext_doc = Qcow2HeaderExtensionsDoc(self.extensions)
> +            print(json.dumps(ext_doc.to_dict(), indent=4,
> +                             cls=ComplexEncoder))
> +            return

I'd prefer to get rid of Qcow2HeaderExtensionsDoc.

Could we just do something like json.dumps(self.extensions, indent=4, 
cls=ComplexEncoder) ?


> +
>           for ex in self.extensions:
>               print('Header extension:')
>               ex.dump()


--
Best regards,
Vladimir