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 <vsement...@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkev...@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
