Fix output of small floats in results

For now we have output of small floats in scientific notation:
3.79085540771e-05
Fix that to 0.000037. Also floats in fixed place will output as:
  0.0000001 -> 0.0
  0.000000 -> 0.0
  37 -> 37.0
  1.0000001 -> 1.0
  1.0000011 -> 1.000001
  1.0000019 -> 1.000002

This can be made in different ways like:
  "%f" % float(decimal.Decimal(num).normalize())
or in more weird way but I choose that one (see in the patch) like
the most flat, simple and explicit.

Change-Id: I4b9cdbb01f3f8e2eeaedc9d33e1203247ea79f89

rally/cli/commands/task.py

@@ -438,9 +438,9 @@ class TaskCommands(object):
                         print()
 
             print(_("Load duration: %s") %
-                  result["info"]["load_duration"])
+                  rutils.format_float_to_str(result["info"]["load_duration"]))
             print(_("Full duration: %s") %
-                  result["info"]["full_duration"])
+                  rutils.format_float_to_str(result["info"]["full_duration"]))
 
             print("\nHINTS:")
             print(_("* To plot HTML graphics with this data, run:"))

rally/common/utils.py

@@ -631,3 +631,25 @@ class LockedDict(dict):
     def clear(self, *args, **kwargs):
         self._check_is_unlocked()
         return super(LockedDict, self).clear(*args, **kwargs)
+
+
+def format_float_to_str(num):
+    """Format number into human-readable float format.
+
+     More precise it convert float into the string and remove redundant
+     zeros from the floating part.
+     It will format the number by the following examples:
+     0.0000001 -> 0.0
+     0.000000 -> 0.0
+     37 -> 37.0
+     1.0000001 -> 1.0
+     1.0000011 -> 1.000001
+     1.0000019 -> 1.000002
+
+    :param num: Number to be formatted
+    :return: string representation of the number
+    """
+
+    num_str = "%f" % num
+    float_part = num_str.split(".")[1].rstrip("0") or "0"
+    return num_str.split(".")[0] + "." + float_part

rally/task/engine.py

@@ -25,6 +25,7 @@ import six
 from rally.common.i18n import _
 from rally.common import logging
 from rally.common import objects
+from rally.common import utils
 from rally import consts
 from rally import exceptions
 from rally import osclients
@@ -112,9 +113,12 @@ class ResultConsumer(object):
 
         load_duration = max(self.load_finished_at - self.load_started_at, 0)
 
-        LOG.info("Load duration is: %s" % load_duration)
-        LOG.info("Full runner duration is: %s" % self.runner.run_duration)
-        LOG.info("Full duration is %s" % (self.finish - self.start))
+        LOG.info("Load duration is: %s" % utils.format_float_to_str(
+            load_duration))
+        LOG.info("Full runner duration is: %s" %
+                 utils.format_float_to_str(self.runner.run_duration))
+        LOG.info("Full duration is %s" % utils.format_float_to_str(
+            self.finish - self.start))
 
         self.task.append_results(self.key, {
             "raw": self.results,

tests/unit/common/test_utils.py

@@ -548,3 +548,42 @@ class LockedDictTestCase(test.TestCase):
         self.assertEqual(({"foo": "bar", "spam": {"a": ("b", {"c": "d"})}},),
                          args)
         self.assertEqual({"memo": "foo_memo"}, kw)
+
+
+@ddt.ddt
+class FloatFormatterTestCase(test.TestCase):
+
+    @ddt.data(
+        {
+            "num_float": 0,
+            "num_str": "0.0"
+        },
+        {
+            "num_float": 37,
+            "num_str": "37.0"
+        },
+        {
+            "num_float": 0.0000001,
+            "num_str": "0.0"
+        },
+        {
+            "num_float": 0.000000,
+            "num_str": "0.0"
+        },
+        {
+            "num_float": 1.0000001,
+            "num_str": "1.0"
+        },
+        {
+            "num_float": 1.0000011,
+            "num_str": "1.000001"
+        },
+        {
+            "num_float": 1.0000019,
+            "num_str": "1.000002"
+        }
+
+    )
+    @ddt.unpack
+    def test_format_float_to_str(self, num_float, num_str):
+        self.assertEquals(num_str, utils.format_float_to_str(num_float))