Flatten hypervisor-show dictionary for printing

Flatten the nested dicts so that hypervisor information can be more
easily used at the command line.

Change-Id: I5dfcf9d10f917a63bde09f0b5a691784a5e8f02b
Closes-bug: #1243512

novaclient/tests/test_utils.py

@@ -163,3 +163,24 @@ class PrintResultTestCase(test_utils.TestCase):
                          '| k3   | 3     |\n'
                          '| k2   | 2     |\n'
                          '+------+-------+\n')
+
+
+class FlattenTestCase(test_utils.TestCase):
+    def test_flattening(self):
+        squashed = utils.flatten_dict(
+            {'a1': {'b1': 1234,
+                    'b2': 'string',
+                    'b3': set((1, 2, 3)),
+                    'b4': {'c1': ['l', 'l', ['l']],
+                           'c2': 'string'}},
+             'a2': ['l'],
+             'a3': ('t',)})
+
+        self.assertEqual({'a1_b1': 1234,
+                          'a1_b2': 'string',
+                          'a1_b3': set([1, 2, 3]),
+                          'a1_b4_c1': ['l', 'l', ['l']],
+                          'a1_b4_c2': 'string',
+                          'a2': ['l'],
+                          'a3': ('t',)},
+                         squashed)

novaclient/utils.py

@@ -1,3 +1,4 @@
+import json
 import os
 import pkg_resources
 import re
@@ -177,6 +178,47 @@ def print_list(objs, fields, formatters={}, sortby_index=None):
     print(result)
 
 
+def _flatten(data, prefix=None):
+    """Flatten a dict, using name as a prefix for the keys of dict.
+
+    >>> _flatten('cpu_info', {'arch':'x86_64'})
+    [('cpu_info_arch': 'x86_64')]
+
+    """
+    if isinstance(data, dict):
+        for key, value in six.iteritems(data):
+            new_key = '%s_%s' % (prefix, key) if prefix else key
+            if isinstance(value, (dict, list)):
+                for item in _flatten(value, new_key):
+                    yield item
+            else:
+                yield new_key, value
+    else:
+        yield prefix, data
+
+
+def flatten_dict(data):
+    """Return a new dict whose sub-dicts have been merged into the
+    original.  Each of the parents keys are prepended to the child's
+    to prevent collisions.  Any string elements will be JSON parsed
+    before flattening.
+
+    >>> flatten_dict({'service': {'host':'cloud9@compute-068', 'id': 143}})
+    {'service_host': colud9@compute-068', 'service_id': 143}
+
+    """
+    data = data.copy()
+    # Try and decode any nested JSON structures.
+    for key, value in six.iteritems(data):
+        if isinstance(value, six.string_types):
+            try:
+                data[key] = json.loads(value)
+            except ValueError:
+                pass
+
+    return dict(_flatten(data))
+
+
 def print_dict(d, dict_property="Property", dict_value="Value", wrap=0):
     pt = prettytable.PrettyTable([dict_property, dict_value], caching=False)
     pt.align = 'l'

novaclient/v1_1/shell.py

@@ -2935,14 +2935,7 @@ def do_hypervisor_servers(cs, args):
 def do_hypervisor_show(cs, args):
     """Display the details of the specified hypervisor."""
     hyper = _find_hypervisor(cs, args.hypervisor)
-
-    # Build up the dict
-    info = hyper._info.copy()
-    info['service_id'] = info['service']['id']
-    info['service_host'] = info['service']['host']
-    del info['service']
-
-    utils.print_dict(info)
+    utils.print_dict(utils.flatten_dict(hyper._info))
 
 
 @utils.arg('hypervisor',