Move to a more canonicalized output from qemu-img info.

Move to a form that is all lower cased, dashes->underscores, underscores
instead of spaces which allows for better integration with python. Also
make the parser more robust to failures when encountering new fields such
as snapshot lists. Provide a new qemu img info object that can be used
to do the parsing and access the underlying attributes.

Change-Id: Ie098dbd9f06dd4ef966768e2caa128f1d09b019c

nova/tests/test_image_utils.py

@@ -21,7 +21,7 @@
 
 
 class ImageUtilsTestCase(test.TestCase):
-    def test_qemu_info(self):
+    def test_qemu_info_canon(self):
         path = "disk.config"
         example_output = """image: disk.config
 file format: raw
@@ -35,14 +35,35 @@ def test_qemu_info(self):
                       'qemu-img', 'info', path).AndReturn((example_output, ''))
         self.mox.ReplayAll()
         image_info = images.qemu_img_info(path)
-        self.assertEquals('disk.config', image_info['image'])
-        self.assertEquals('raw', image_info['file format'])
-        self.assertEquals('64M (67108864 bytes)', image_info['virtual size'])
-        self.assertEquals('96K', image_info['disk size'])
-        self.assertEquals('bb', image_info['blah blah'])
-        self.assertEquals("65536", image_info['cluster_size'])
+        self.assertEquals('disk.config', image_info.image)
+        self.assertEquals('raw', image_info.file_format)
+        self.assertEquals(67108864, image_info.virtual_size)
+        self.assertEquals(98304, image_info.disk_size)
+        self.assertEquals(65536, image_info.cluster_size)
 
-    def test_qemu_info_snap(self):
+    def test_qemu_info_canon2(self):
+        path = "disk.config"
+        example_output = """image: disk.config
+file format: QCOW2
+virtual size: 67108844
+cluster_size: 65536
+disk size: 963434
+backing file: /var/lib/nova/a328c7998805951a_2
+"""
+        self.mox.StubOutWithMock(utils, 'execute')
+        utils.execute('env', 'LC_ALL=C', 'LANG=C',
+                      'qemu-img', 'info', path).AndReturn((example_output, ''))
+        self.mox.ReplayAll()
+        image_info = images.qemu_img_info(path)
+        self.assertEquals('disk.config', image_info.image)
+        self.assertEquals('qcow2', image_info.file_format)
+        self.assertEquals(67108844, image_info.virtual_size)
+        self.assertEquals(963434, image_info.disk_size)
+        self.assertEquals(65536, image_info.cluster_size)
+        self.assertEquals('/var/lib/nova/a328c7998805951a_2',
+                          image_info.backing_file)
+
+    def test_qemu_backing_file_actual(self):
         path = "disk.config"
         example_output = """image: disk.config
 file format: raw
@@ -52,18 +73,63 @@ def test_qemu_info_snap(self):
 Snapshot list:
 ID        TAG                 VM SIZE                DATE       VM CLOCK
 1     d9a9784a500742a7bb95627bb3aace38      0 2012-08-20 10:52:46 00:00:00.000
+backing file: /var/lib/nova/a328c7998805951a_2 (actual path: /b/3a988059e51a_2)
+"""
+        self.mox.StubOutWithMock(utils, 'execute')
+        utils.execute('env', 'LC_ALL=C', 'LANG=C',
+                      'qemu-img', 'info', path).AndReturn((example_output, ''))
+        self.mox.ReplayAll()
+        image_info = images.qemu_img_info(path)
+        self.assertEquals('disk.config', image_info.image)
+        self.assertEquals('raw', image_info.file_format)
+        self.assertEquals(67108864, image_info.virtual_size)
+        self.assertEquals(98304, image_info.disk_size)
+        self.assertEquals(1, len(image_info.snapshots))
+        self.assertEquals('/b/3a988059e51a_2',
+                          image_info.backing_file)
+
+    def test_qemu_info_convert(self):
+        path = "disk.config"
+        example_output = """image: disk.config
+file format: raw
+virtual size: 64M
+disk size: 96K
+Snapshot list:
+ID        TAG                 VM SIZE                DATE       VM CLOCK
+1        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
+3        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
+4        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
+junk stuff: bbb
+"""
+        self.mox.StubOutWithMock(utils, 'execute')
+        utils.execute('env', 'LC_ALL=C', 'LANG=C',
+                      'qemu-img', 'info', path).AndReturn((example_output, ''))
+        self.mox.ReplayAll()
+        image_info = images.qemu_img_info(path)
+        self.assertEquals('disk.config', image_info.image)
+        self.assertEquals('raw', image_info.file_format)
+        self.assertEquals(67108864, image_info.virtual_size)
+        self.assertEquals(98304, image_info.disk_size)
+
+    def test_qemu_info_snaps(self):
+        path = "disk.config"
+        example_output = """image: disk.config
+file format: raw
+virtual size: 64M (67108864 bytes)
+disk size: 96K
+Snapshot list:
+ID        TAG                 VM SIZE                DATE       VM CLOCK
+1        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
+3        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
+4        d9a9784a500742a7bb95627bb3aace38    0 2012-08-20 10:52:46 00:00:00.000
 """
         self.mox.StubOutWithMock(utils, 'execute')
         utils.execute('env', 'LC_ALL=C', 'LANG=C',
                       'qemu-img', 'info', path).AndReturn((example_output, ''))
         self.mox.ReplayAll()
         image_info = images.qemu_img_info(path)
-        self.assertEquals('disk.config', image_info['image'])
-        self.assertEquals('raw', image_info['file format'])
-        self.assertEquals('64M (67108864 bytes)', image_info['virtual size'])
-        self.assertEquals('96K', image_info['disk size'])
-        self.assertEquals("65536", image_info['cluster_size'])
-        # This would be triggered if the split encountered this section
-        self.assertNotIn('snapshot list', image_info)
-        bad_cap = '1     d9a9784a500742a7bb95627bb3aace38      0 2012-08-20 10'
-        self.assertNotIn(bad_cap, image_info)
+        self.assertEquals('disk.config', image_info.image)
+        self.assertEquals('raw', image_info.file_format)
+        self.assertEquals(67108864, image_info.virtual_size)
+        self.assertEquals(98304, image_info.disk_size)
+        self.assertEquals(3, len(image_info.snapshots))

nova/tests/test_utils.py

@@ -37,6 +37,41 @@
 FLAGS = flags.FLAGS
 
 
+class ByteConversionTest(test.TestCase):
+    def test_string_conversions(self):
+        working_examples = {
+            '1024KB': 1048576,
+            '1024TB': 1125899906842624,
+            '1024K': 1048576,
+            '1024T': 1125899906842624,
+            '1TB': 1099511627776,
+            '1T': 1099511627776,
+            '1KB': 1024,
+            '1K': 1024,
+            '1B': 1,
+            '1B': 1,
+            '1': 1,
+            '1MB': 1048576,
+            '7MB': 7340032,
+            '0MB': 0,
+            '0KB': 0,
+            '0TB': 0,
+            '': 0,
+        }
+        for (in_value, expected_value) in working_examples.items():
+            b_value = utils.to_bytes(in_value)
+            self.assertEquals(expected_value, b_value)
+            if len(in_value):
+                in_value = "-" + in_value
+                b_value = utils.to_bytes(in_value)
+                self.assertEquals(expected_value * -1, b_value)
+        breaking_examples = [
+            'junk1KB', '1023BBBB',
+        ]
+        for v in breaking_examples:
+            self.assertRaises(TypeError, utils.to_bytes, v)
+
+
 class ExecuteTestCase(test.TestCase):
     def test_retry_on_failure(self):
         fd, tmpfilename = tempfile.mkstemp()

nova/utils.py

@@ -63,6 +63,16 @@
     cfg.BoolOpt('disable_process_locking', default=False,
                 help='Whether to disable inter-process locks'))
 
+# Used for looking up extensions of text
+# to their 'multiplied' byte amount
+BYTE_MULTIPLIERS = {
+    '': 1,
+    't': 1024 ** 4,
+    'g': 1024 ** 3,
+    'm': 1024 ** 2,
+    'k': 1024,
+}
+
 
 def vpn_ping(address, port, timeout=0.05, session_id=None):
     """Sends a vpn negotiation packet and returns the server session.
@@ -574,6 +584,34 @@ def utf8(value):
     return value
 
 
+def to_bytes(text, default=0):
+    """Try to turn a string into a number of bytes. Looks at the last
+    characters of the text to determine what conversion is needed to
+    turn the input text into a byte number.
+
+    Supports: B/b, K/k, M/m, G/g, T/t (or the same with b/B on the end)
+
+    """
+    # Take off everything not number 'like' (which should leave
+    # only the byte 'identifier' left)
+    mult_key_org = text.lstrip('-1234567890')
+    mult_key = mult_key_org.lower()
+    mult_key_len = len(mult_key)
+    if mult_key.endswith("b"):
+        mult_key = mult_key[0:-1]
+    try:
+        multiplier = BYTE_MULTIPLIERS[mult_key]
+        if mult_key_len:
+            # Empty cases shouldn't cause text[0:-0]
+            text = text[0:-mult_key_len]
+        return int(text) * multiplier
+    except KeyError:
+        msg = _('Unknown byte multiplier: %s') % mult_key_org
+        raise TypeError(msg)
+    except ValueError:
+        return default
+
+
 def delete_if_exists(pathname):
     """delete a file, but ignore file not found error"""
 

nova/virt/disk/api.py

@@ -112,9 +112,7 @@ def get_disk_size(path):
     :returns: Size (in bytes) of the given disk image as it would be seen
               by a virtual machine.
     """
-    size = images.qemu_img_info(path)['virtual size']
-    size = size.split('(')[1].split()[0]
-    return int(size)
+    return images.qemu_img_info(path).virtual_size
 
 
 def extend(image, size):