variable collection of policies per component

* new feature variable collection of policies per component in DCAE
* massive refactoring
* Unit Test coverage 100%
* moved module docstring below the license text

Change-Id: I5ba392cb5c42ec136306772163c370d64974ae3c
Issue-ID: DCAEGEN2-249
Signed-off-by: Alex Shatov <alexs@att.com>

1 files changed, 121 insertions, 0 deletions

diff --git a/onap-dcae-dcaepolicy-lib/onap_dcae_dcaepolicy_lib/utils.py b/onap-dcae-dcaepolicy-lib/onap_dcae_dcaepolicy_lib/utils.py
new file mode 100644
index 0000000..c631c7d
--- /dev/null
+++ b/onap-dcae-dcaepolicy-lib/onap_dcae_dcaepolicy_lib/utils.py
@@ -0,0 +1,121 @@
+# org.onap.dcae
+# ================================================================================
+# Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
+# ================================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============LICENSE_END=========================================================
+#
+# ECOMP is a trademark and service mark of AT&T Intellectual Property.
+
+"""generic utils to be used by dcae_policy decorators for the policy lifecycle in cloudify"""
+
+from copy import deepcopy
+from decimal import Decimal, DecimalException
+
+FIELD_NAME_DELIMITER = ":"
+FIELD_TYPE_DELIMITER = "::"
+FIELD_TYPE_NUMBER = "number"
+KEYWORD_DESC = "desc"
+KEYWORD_NULLS_LAST = "nulls-last"
+
+class Utils(object):
+    """generic static class used for policy operations"""
+
+    @staticmethod
+    def remove_empties(any_list):
+        """returns the any_list without empty elements"""
+        return [element for element in any_list or [] if element]
+
+    @staticmethod
+    def get_field_value(parent, field_path, field_type=None):
+        """
+        Find and return the field :field_path: under :parent:
+
+        Optionally, converts the field value to field_type.
+
+        Parser of the :field_path: is using the delimiter ":" (semicolon)
+
+        Example:
+            parent = ctx.node.properties
+            field_path = "docker_config:policy:apply_order"
+
+            will return the value of the apply_order field under the ctx.node.properties in
+
+                properties:
+                    docker_config:
+                        policy:
+                            apply_order
+        """
+        if not parent or not field_path or not isinstance(parent, dict):
+            return
+
+        field_path = Utils.remove_empties([
+            path.strip() for path in field_path.split(FIELD_NAME_DELIMITER)
+        ])
+
+        if not field_path:
+            return
+
+        field_value = None
+        field_idx = len(field_path) - 1
+        for (idx, field_name) in enumerate(field_path):
+            parent = parent.get(field_name)
+            if idx == field_idx:
+                field_value = deepcopy(parent)
+                if field_type in [FIELD_TYPE_NUMBER] and isinstance(field_value, (str, unicode)):
+                    try:
+                        field_value = Decimal(field_value)
+                    except DecimalException:
+                        pass
+            elif not parent or not isinstance(parent, dict):
+                return
+        return field_value
+
+    @staticmethod
+    def parse_clause_item(clause_item):
+        """
+        Parses: the :clause_item: in policy_apply_order_clause
+        and returns (field_path, field_type, reverse, nulls_last)
+
+        delimiters: are whitespaces, "::"
+
+        nulls-first is the default sorting order
+
+        :clause_item: format is <field_path> [:: <field_type>] [desc] [nulls-last]
+
+        Examples: "config:db_client" versus "config:foo desc" versus
+            "matchingConditions:priority::number desc nulls-last"
+        """
+        field_path = field_type = desc = nulls_last = None
+
+        if not clause_item or not isinstance(clause_item, (str, unicode)):
+            return field_path, field_type, bool(desc), bool(nulls_last)
+
+        for idx, token in enumerate(clause_item.split()):
+            if idx == 0:
+                split_for_type = token.split(FIELD_TYPE_DELIMITER)
+                field_path = split_for_type[0]
+                field_type = split_for_type[1] if len(split_for_type) > 1 else None
+            elif token == KEYWORD_DESC:
+                desc = True
+            elif token == KEYWORD_NULLS_LAST:
+                nulls_last = True
+        return field_path, field_type, bool(desc), bool(nulls_last)
+
+    @staticmethod
+    def key_with_none_in_sort(reverse, nulls_last, value):
+        """
+        constructs tuple for proper placement of None values (last versus first)
+        in the sorted list of values regardless of the :reverse:
+        """
+        return reverse == nulls_last or value is None, value