variable collection of policies per component

* new feature variable collection of policies per component in DCAE
* massive refactoring
* dissolved the external PolicyEngine.py into policy_receiver.py
   - kept only the web-socket communication to PolicyEngine
* new /healthcheck - shows some stats of service running
* Unit Test coverage 75%

Change-Id: I816b7d5713ae0dd88fa73d3656f272b4f3e7946e
Issue-ID: DCAEGEN2-249
Signed-off-by: Alex Shatov <alexs@att.com>

1 files changed, 134 insertions, 0 deletions

diff --git a/policyhandler/policy_utils.py b/policyhandler/policy_utils.py
new file mode 100644
index 0000000..d664b21
--- /dev/null
+++ b/policyhandler/policy_utils.py
@@ -0,0 +1,134 @@
+"""policy-client communicates with policy-engine thru REST API"""
+
+# 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.
+
+import logging
+import json
+import re
+
+from .policy_consts import POLICY_ID, POLICY_VERSION, POLICY_NAME, POLICY_BODY, POLICY_CONFIG
+
+class PolicyUtils(object):
+    """policy-client utils"""
+    _logger = logging.getLogger("policy_handler.policy_utils")
+    _policy_name_ext = re.compile('[.][0-9]+[.][a-zA-Z]+$')
+
+    @staticmethod
+    def safe_json_parse(json_str):
+        """try parsing json without exception - returns the json_str back if fails"""
+        if not json_str:
+            return json_str
+        try:
+            return json.loads(json_str)
+        except (ValueError, TypeError) as err:
+            PolicyUtils._logger.warn("unexpected json %s: %s", str(json_str), str(err))
+        return json_str
+
+    @staticmethod
+    def extract_policy_id(policy_name):
+        """ policy_name  = policy_id + "." + <version> + "." + <extension>
+        For instance,
+        policy_name      = DCAE_alex.Config_alex_policy_number_1.3.xml
+               policy_id = DCAE_alex.Config_alex_policy_number_1
+            policy_scope = DCAE_alex
+            policy_class = Config
+          policy_version = 3
+        type = extension = xml
+               delimiter = "."
+        policy_class_delimiter = "_"
+        policy_name in PAP = DCAE_alex.alex_policy_number_1
+        """
+        if not policy_name:
+            return
+        return PolicyUtils._policy_name_ext.sub('', policy_name)
+
+    @staticmethod
+    def parse_policy_config(policy):
+        """try parsing the config in policy."""
+        if not policy:
+            return policy
+        config = policy.get(POLICY_BODY, {}).get(POLICY_CONFIG)
+        if config:
+            policy[POLICY_BODY][POLICY_CONFIG] = PolicyUtils.safe_json_parse(config)
+        return policy
+
+    @staticmethod
+    def convert_to_policy(policy_config):
+        """wrap policy_config received from policy-engine with policy_id."""
+        if not policy_config:
+            return
+        policy_name = policy_config.get(POLICY_NAME)
+        policy_version = policy_config.get(POLICY_VERSION)
+        if not policy_name or not policy_version:
+            return
+        policy_id = PolicyUtils.extract_policy_id(policy_name)
+        if not policy_id:
+            return
+        return {POLICY_ID:policy_id, POLICY_BODY:policy_config}
+
+    @staticmethod
+    def select_latest_policy(policy_configs, min_version_expected=None, ignore_policy_names=None):
+        """For some reason, the policy-engine returns all version of the policy_configs.
+        DCAE-Controller is only interested in the latest version
+        """
+        if not policy_configs:
+            return
+        latest_policy_config = {}
+        for policy_config in policy_configs:
+            policy_name = policy_config.get(POLICY_NAME)
+            policy_version = policy_config.get(POLICY_VERSION)
+            if not policy_name or not policy_version or not policy_version.isdigit():
+                continue
+            policy_version = int(policy_version)
+            if min_version_expected and policy_version < min_version_expected:
+                continue
+            if ignore_policy_names and policy_name in ignore_policy_names:
+                continue
+
+            if not latest_policy_config \
+            or int(latest_policy_config[POLICY_VERSION]) < policy_version:
+                latest_policy_config = policy_config
+
+        return PolicyUtils.parse_policy_config(PolicyUtils.convert_to_policy(latest_policy_config))
+
+    @staticmethod
+    def select_latest_policies(policy_configs):
+        """For some reason, the policy-engine returns all version of the policy_configs.
+        DCAE-Controller is only interested in the latest versions
+        """
+        if not policy_configs:
+            return {}
+        policies = {}
+        for policy_config in policy_configs:
+            policy = PolicyUtils.convert_to_policy(policy_config)
+            if not policy:
+                continue
+            policy_id = policy.get(POLICY_ID)
+            policy_version = policy.get(POLICY_BODY, {}).get(POLICY_VERSION)
+            if not policy_id or not policy_version or not policy_version.isdigit():
+                continue
+            if policy_id not in policies \
+            or int(policy_version) > int(policies[policy_id][POLICY_BODY][POLICY_VERSION]):
+                policies[policy_id] = policy
+
+        for policy_id in policies:
+            policies[policy_id] = PolicyUtils.parse_policy_config(policies[policy_id])
+
+        return policies