Fix DriverFilter/GoodnessWeigher string evaluations

When trying to compare two values that are non-numeric using the driver
filter, the filter function will give an error. This is not desirable as
it might be interesting to support comparatives with non-numeric values
provided by the filter objects (share, host, etc). For example, the
following formula failed before the fix:

filter_function = '(share.project_id == "bb212f09317a4f4a8952ef3f729c2551")'

Copied from cinder 87a7e80a2c

Closes-Bug: #1975715
Change-Id: Icbfabb3bc0f608ebdd0784337db0921cc7763c53

manila/scheduler/evaluator/evaluator.py

@@ -56,9 +56,9 @@ class EvalConstant(object):
         except ValueError:
             try:
                 result = float(result)
-            except ValueError as e:
-                msg = _("ValueError: %s") % e
-                raise exception.EvaluatorParseException(reason=msg)
+            except ValueError:
+                if isinstance(result, str):
+                    result = result.replace('"', '').replace('\'', '')
 
         return result
 
@@ -233,6 +233,7 @@ def _def_parser():
     Combine = pyparsing.Combine
     Forward = pyparsing.Forward
     nums = pyparsing.nums
+    quoted_string = pyparsing.quotedString
     oneOf = pyparsing.oneOf
     opAssoc = pyparsing.opAssoc
     infixNotation = pyparsing.infixNotation
@@ -244,7 +245,7 @@ def _def_parser():
     number = real | integer
     expr = Forward()
     fn = Word(alphas + '_' + '.')
-    operand = number | variable | fn
+    operand = number | variable | fn | quoted_string
 
     signop = oneOf('+ -')
     addop = oneOf('+ -')

manila/tests/scheduler/evaluator/test_evaluator.py

@@ -128,11 +128,12 @@ class EvaluatorTestCase(test.TestCase):
     def test_nonnumber_comparison(self):
         nonnumber = {'test': 'foo'}
         request = {'test': 'bar'}
-        self.assertRaises(
-            exception.EvaluatorParseException,
-            evaluator.evaluate,
-            "nonnumber.test != request.test",
-            nonnumber=nonnumber, request=request)
+        self.assertTrue(
+            evaluator.evaluate("nonnumber.test != request.test",
+                               nonnumber=nonnumber, request=request))
+        self.assertFalse(
+            evaluator.evaluate("nonnumber.test == request.test",
+                               nonnumber=nonnumber, request=request))
 
     def test_div_zero(self):
         self.assertRaises(exception.EvaluatorParseException,

releasenotes/notes/bug-1975715-fix-driverfilter-string-evaluations-3886a68d4d7fa3a1.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Goodness_function expects integer or float else raise parseException. This
+    causes example such as "(share.share_proto == 'CIFS') ? 100 : 50" to fail
+    during evaluation. Fix it by adding support of string evalution.