ceph-volume: human_readable_size() refactor

This commit refactors the `human_readable_size()` function.

The current implementation has a couple of issues:

in a 'human readable' mindset, I would expect `human_readable_size(1024)` to
return '1.00 KB' instead of '1024.00 KB'.

```
In [1]: from ceph_volume.util.disk import human_readable_size

In [2]: human_readable_size(1024)
Out[2]: '1024.00 B'

In [3]: human_readable_size(1024*1024)
Out[3]: '1024.00 KB'

```

Also, it doesn't support PB unit:

```
In [4]: human_readable_size(1024*1024*1024*1024*1024)
Out[4]: '1024.00 TB'

In [5]: human_readable_size(1024*1024*1024*1024*1024*1024)
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-31-0859861661dc> in <module>
----> 1 human_readable_size(1024*1024*1024*1024*1024*1024)

~/GIT/ceph/src/ceph-volume/ceph_volume/util/disk.py in human_readable_size(size)
    640     return "{size:.2f} {suffix}".format(
    641         size=size,
--> 642         suffix=suffixes[suffix_index])
    643
    644

IndexError: list index out of range
```

This commit fixes this.

Fixes: https://tracker.ceph.com/issues/48492

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/src/ceph-volume/ceph_volume/tests/util/test_disk.py b/src/ceph-volume/ceph_volume/tests/util/test_disk.py
index 5f4d57343e4..44f19e036fa 100644
--- a/src/ceph-volume/ceph_volume/tests/util/test_disk.py
+++ b/src/ceph-volume/ceph_volume/tests/util/test_disk.py
@@ -124,6 +124,9 @@ class TestHumanReadableSize(object):
         result = disk.human_readable_size(81.2*1024*1024*1024*1024)
         assert result == '81.20 TB'
 
+    def test_petabytes(self):
+        result = disk.human_readable_size(9.23*1024*1024*1024*1024*1024)
+        assert result == '9.23 PB'
 
 class TestSizeFromHumanReadable(object):
 
@@ -143,10 +146,14 @@ class TestSizeFromHumanReadable(object):
         result = disk.size_from_human_readable('2 G')
         assert result == disk.Size(gb=2)
 
-    def test_terrabytes(self):
+    def test_terabytes(self):
         result = disk.size_from_human_readable('2 T')
         assert result == disk.Size(tb=2)
 
+    def test_petabytes(self):
+        result = disk.size_from_human_readable('2 P')
+        assert result == disk.Size(pb=2)
+
     def test_case(self):
         result = disk.size_from_human_readable('2 t')
         assert result == disk.Size(tb=2)
@@ -182,10 +189,14 @@ class TestSizeParse(object):
         result = disk.Size.parse('2G')
         assert result == disk.Size(gb=2)
 
-    def test_terrabytes(self):
+    def test_terabytes(self):
         result = disk.Size.parse('2T')
         assert result == disk.Size(tb=2)
 
+    def test_petabytes(self):
+        result = disk.Size.parse('2P')
+        assert result == disk.Size(pb=2)
+
     def test_tb(self):
         result = disk.Size.parse('2Tb')
         assert result == disk.Size(tb=2)