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": [
{
"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": {
"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 | 59 ++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
index 83c3482..a263858 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, 'get_fields_dict'):
+ return obj.get_fields_dict()
+ else:
+ return json.JSONEncoder.default(self, obj)
class Qcow2Field:
@@ -112,6 +121,11 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
self.fields_dict = self.__dict__.copy()
def dump(self, dump_json=None):
+ if dump_json:
+ print(json.dumps(self.get_fields_dict(), indent=4,
+ cls=ComplexEncoder))
+ return
+
for f in self.fields:
value = self.__dict__[f[2]]
if isinstance(f[1], str):
@@ -154,6 +168,9 @@ class Qcow2BitmapExt(Qcow2Struct):
print()
entry.dump()
+ def get_fields_dict(self):
+ return self.fields_dict
+
class Qcow2BitmapDirEntry(Qcow2Struct):
@@ -199,6 +216,11 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
super(Qcow2BitmapDirEntry, self).dump()
self.bitmap_table.dump()
+ def get_fields_dict(self):
+ bmp_name = dict(name=self.name)
+ bme_dict = {**bmp_name, **self.fields_dict}
+ return bme_dict
+
class Qcow2BitmapTableEntry:
@@ -214,6 +236,9 @@ class Qcow2BitmapTableEntry:
else:
self.type = 'all-zeroes'
+ def get_fields_dict(self):
+ return dict(type=self.type, offset=self.offset)
+
class Qcow2BitmapTable:
@@ -230,6 +255,18 @@ class Qcow2BitmapTable:
for i, entry in bitmap_table:
print(f'{i:<14} {entry.type:<15} {entry.offset:<24} {size}')
+ def get_fields_dict(self):
+ return dict(entries=self.entries)
+
+
+class Qcow2HeaderExtensionsDoc:
+
+ def __init__(self, extensions):
+ self.extensions = extensions
+
+ def get_fields_dict(self):
+ return dict(Header_extensions=self.extensions)
+
QCOW2_EXT_MAGIC_BITMAPS = 0x23852875
@@ -245,6 +282,9 @@ class QcowHeaderExtension(Qcow2Struct):
0x44415441: 'Data file'
}
+ def get_fields_dict(self):
+ return self.mapping.get(self.value, "<unknown>")
+
fields = (
('u32', Magic, 'magic'),
('u32', '{}', 'length')
@@ -303,6 +343,16 @@ class QcowHeaderExtension(Qcow2Struct):
else:
self.obj.dump(dump_json)
+ def get_fields_dict(self):
+ ext_name = dict(name=self.Magic(self.magic))
+ he_dict = {**ext_name, **self.fields_dict}
+ if self.obj is not None:
+ he_dict.update(data=self.obj)
+ else:
+ he_dict.update(data_str=self.data_str)
+
+ return he_dict
+
@classmethod
def create(cls, magic, data):
return QcowHeaderExtension(magic, len(data), data)
@@ -401,7 +451,16 @@ class QcowHeader(Qcow2Struct):
fd.write(buf)
def dump_extensions(self, dump_json=None):
+ if dump_json:
+ ext_doc = Qcow2HeaderExtensionsDoc(self.extensions)
+ print(json.dumps(ext_doc.get_fields_dict(), indent=4,
+ cls=ComplexEncoder))
+ return
+
for ex in self.extensions:
print('Header extension:')
ex.dump(dump_json)
print()
+
+ def get_fields_dict(self):
+ return self.fields_dict
--
1.8.3.1
14.07.2020 00:36, 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": [
> {
> "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": {
> "entries": [
> {
> "type": "serialized",
> "offset": 655360
> },
> ...
>
> Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Aha, so you actually do what I imagine in a previous patch, add a method returning dict (I'd call it just "to_dict", but that doesn't really matter). (Stil, I'm against keeping self.fields_dict attribute. Just make correct .to_dict() method for base class (which will utilize .fields), and call super().to_dict() and add some another fields in children classes (like it is done for dump() method)
> ---
> tests/qemu-iotests/qcow2_format.py | 59 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
> diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py
> index 83c3482..a263858 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, 'get_fields_dict'):
> + return obj.get_fields_dict()
> + else:
> + return json.JSONEncoder.default(self, obj)
>
>
> class Qcow2Field:
> @@ -112,6 +121,11 @@ class Qcow2Struct(metaclass=Qcow2StructMeta):
> self.fields_dict = self.__dict__.copy()
>
> def dump(self, dump_json=None):
> + if dump_json:
> + print(json.dumps(self.get_fields_dict(), indent=4,
> + cls=ComplexEncoder))
> + return
Now it is obvious, that this is enough: we can just make it a seprate method dump_json in Qcow2Struct and we'll never need to implement dump_json in other classes (only .to_dict). But really, with dump_json parameter other classes are wrong now: they call super().dump(dump_json) which dumps json, and they they print additional things in a non-json format.
> +
> for f in self.fields:
> value = self.__dict__[f[2]]
> if isinstance(f[1], str):
> @@ -154,6 +168,9 @@ class Qcow2BitmapExt(Qcow2Struct):
> print()
> entry.dump()
>
> + def get_fields_dict(self):
> + return self.fields_dict
> +
>
> class Qcow2BitmapDirEntry(Qcow2Struct):
>
> @@ -199,6 +216,11 @@ class Qcow2BitmapDirEntry(Qcow2Struct):
> super(Qcow2BitmapDirEntry, self).dump()
> self.bitmap_table.dump()
>
> + def get_fields_dict(self):
> + bmp_name = dict(name=self.name)
> + bme_dict = {**bmp_name, **self.fields_dict}
> + return bme_dict
> +
>
> class Qcow2BitmapTableEntry:
>
> @@ -214,6 +236,9 @@ class Qcow2BitmapTableEntry:
> else:
> self.type = 'all-zeroes'
>
> + def get_fields_dict(self):
> + return dict(type=self.type, offset=self.offset)
> +
>
> class Qcow2BitmapTable:
>
> @@ -230,6 +255,18 @@ class Qcow2BitmapTable:
> for i, entry in bitmap_table:
> print(f'{i:<14} {entry.type:<15} {entry.offset:<24} {size}')
>
> + def get_fields_dict(self):
> + return dict(entries=self.entries)
> +
> +
> +class Qcow2HeaderExtensionsDoc:
> +
> + def __init__(self, extensions):
> + self.extensions = extensions
> +
> + def get_fields_dict(self):
> + return dict(Header_extensions=self.extensions)
> +
>
> QCOW2_EXT_MAGIC_BITMAPS = 0x23852875
>
> @@ -245,6 +282,9 @@ class QcowHeaderExtension(Qcow2Struct):
> 0x44415441: 'Data file'
> }
>
> + def get_fields_dict(self):
> + return self.mapping.get(self.value, "<unknown>")
> +
> fields = (
> ('u32', Magic, 'magic'),
> ('u32', '{}', 'length')
> @@ -303,6 +343,16 @@ class QcowHeaderExtension(Qcow2Struct):
> else:
> self.obj.dump(dump_json)
>
> + def get_fields_dict(self):
> + ext_name = dict(name=self.Magic(self.magic))
> + he_dict = {**ext_name, **self.fields_dict}
> + if self.obj is not None:
> + he_dict.update(data=self.obj)
> + else:
> + he_dict.update(data_str=self.data_str)
> +
> + return he_dict
> +
> @classmethod
> def create(cls, magic, data):
> return QcowHeaderExtension(magic, len(data), data)
> @@ -401,7 +451,16 @@ class QcowHeader(Qcow2Struct):
> fd.write(buf)
>
> def dump_extensions(self, dump_json=None):
> + if dump_json:
> + ext_doc = Qcow2HeaderExtensionsDoc(self.extensions)
> + print(json.dumps(ext_doc.get_fields_dict(), indent=4,
> + cls=ComplexEncoder))
> + return
> +
> for ex in self.extensions:
> print('Header extension:')
> ex.dump(dump_json)
> print()
> +
> + def get_fields_dict(self):
> + return self.fields_dict
>
--
Best regards,
Vladimir
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