To display image size in human friendly format

Include option '--human-readable' to 'image show' command.
This option displays image size in human readable format
(such as K, M, G, T,..)

(Re-submitted as the original https://review.openstack.org/#/c/399982/ had
a parent commit not present in Gerrit, was proposed by "OpenStack
Proposal Bot")

Change-Id: I0ef74c2ec978483fe49156c88acf5c369a8fa5c2
Closes-Bug: #1640086
Co-Authored-By: Badhmapriya Boopalan <Badhmapriya.Boopalan@cognizant.com>

osc_lib/tests/test_utils.py

@@ -310,6 +310,18 @@ class TestUtils(test_utils.TestCase):
     def test_is_ascii_string(self):
         self.assertFalse(utils.is_ascii(u'\u2665'))
 
+    def test_format_size(self):
+        self.assertEqual("999", utils.format_size(999))
+        self.assertEqual("100K", utils.format_size(100000))
+        self.assertEqual("2M", utils.format_size(2000000))
+        self.assertEqual(
+            "16.4M", utils.format_size(16361280)
+        )
+        self.assertEqual(
+            "1.6G", utils.format_size(1576395005)
+        )
+        self.assertEqual("0", utils.format_size(None))
+
 
 class NoUniqueMatch(Exception):
     pass

osc_lib/utils.py

@@ -489,3 +489,33 @@ def wait_for_status(status_f,
             callback(progress)
         time.sleep(sleep_time)
     return retval
+
+
+def format_size(size):
+    """Display size of a resource in a human readable format
+
+    :param string size:
+        The size of the resource in bytes.
+
+    :returns:
+        Returns the size in human-friendly format
+    :rtype string:
+
+    This function converts the size (provided in bytes) of a resource
+    into a human-friendly format such as K, M, G, T, P, E, Z
+    """
+
+    suffix = ['', 'K', 'M', 'G', 'T', 'P', 'E', 'Z']
+    base = 1000.0
+    index = 0
+
+    if size is None:
+        size = 0
+    while size >= base:
+        index = index + 1
+        size = size / base
+
+    padded = '%.1f' % size
+    stripped = padded.rstrip('0').rstrip('.')
+
+    return '%s%s' % (stripped, suffix[index])