[GH-15] capacity report enhancement

This enhancement includes:
1. Update readme document to include capacity report function
2. Refine round_it util

README.rst

@@ -57,6 +57,7 @@ Feature List
         - list/create/delete NFS share
         - show system domain information
         - list hosts
+        - show system capacity
     - supported feature/operations
         - list/start/cancel migration sessions
         - enable/disable LUN deduplication

storops/lib/common.py

@@ -435,3 +435,5 @@ def _inner(*args, **kwargs):
             return round(value, ndigits)
         return _inner
     return inner
+
+round_3 = round_it(3)

storops/vnx/resource/capacity.py

@@ -18,7 +18,7 @@
 from storops.vnx.resource.disk import VNXDisk
 from storops.vnx.resource.block_pool import VNXPool
 from storops.vnx.resource.rg import VNXRaidGroup
-from storops.lib.common import JsonPrinter, round_it
+from storops.lib.common import JsonPrinter, round_3
 from storops.lib.converter import mb_to_gb
 
 __author__ = 'Tina Tang'
@@ -41,15 +41,15 @@ def get(cls, cli):
         return VNXCapacity(cli)
 
     @property
-    @round_it()
+    @round_3
     def total(self):
         """Total disk capacity in GB"""
         if self._total is None:
             self._update_disk_capacity()
         return self._total
 
     @property
-    @round_it()
+    @round_3
     def free_raw_disk(self):
         """Free raw disk capacity in GB
 
@@ -61,7 +61,7 @@ def free_raw_disk(self):
         return self._free_raw_disk
 
     @property
-    @round_it()
+    @round_3
     def free_storage_pool(self):
         """Free storage pool capacity in GB
 
@@ -73,7 +73,7 @@ def free_storage_pool(self):
         return self._free_storage_pool
 
     @property
-    @round_it()
+    @round_3
     def used(self):
         """Total used capacity in GB
 

storops/vnx/resource/rg.py

@@ -17,7 +17,7 @@
 
 from storops.vnx.resource import VNXCliResource, VNXCliResourceList
 from storops import exception as ex
-from storops.lib.common import round_it
+from storops.lib.common import round_3
 from storops.lib.converter import block_to_gb
 
 __author__ = 'Cedric Zhuang'
@@ -58,7 +58,7 @@ def get(cls, cli, raid_group_id=None):
         return ret
 
     @property
-    @round_it()
+    @round_3
     def available_capacity_gbs(self):
         return block_to_gb(self.free_capacity_blocks_non_contiguous)