policy-handler seed code

Change-Id: I35cd80b6e082f4b84740bab752774e8abc40ca35
Issue-Id: DCAEGEN2-46
Signed-off-by: Alex Shatov <alexs@att.com>

1 files changed, 124 insertions, 0 deletions

diff --git a/policyhandler/policy_updater.py b/policyhandler/policy_updater.py
new file mode 100644
index 0000000..1f1539f
--- /dev/null
+++ b/policyhandler/policy_updater.py
@@ -0,0 +1,124 @@
+"""policy-updater thread"""
+
+# 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
+from Queue import Queue
+from threading import Thread, Lock
+
+from .policy_rest import PolicyRest
+from .deploy_handler import DeployHandler
+
+class PolicyUpdater(Thread):
+    """queue and handle the policy-updates in a separate thread"""
+    _logger = logging.getLogger("policy_handler.policy_updater")
+
+    def __init__(self):
+        """init static config of PolicyUpdater."""
+        Thread.__init__(self)
+        self.name = "policy_updater"
+        self.daemon = True
+
+        self._req_shutdown = None
+        self._req_catch_up = None
+
+        self._lock = Lock()
+        self._queue = Queue()
+
+    def enqueue(self, audit=None, policy_names=None):
+        """enqueue the policy-names"""
+        policy_names = policy_names or []
+        PolicyUpdater._logger.info("policy_names %s", json.dumps(policy_names))
+        self._queue.put((audit, policy_names))
+
+    def run(self):
+        """wait and run the policy-update in thread"""
+        while True:
+            PolicyUpdater._logger.info("waiting for policy-updates...")
+            audit, policy_names = self._queue.get()
+            PolicyUpdater._logger.info("got policy-updates %s", json.dumps(policy_names))
+            if not self._keep_running():
+                self._queue.task_done()
+                break
+            if self._on_catch_up():
+                continue
+
+            if not policy_names:
+                self._queue.task_done()
+                continue
+
+            updated_policies = PolicyRest.get_latest_policies_by_names((audit, policy_names))
+            PolicyUpdater.policy_update(audit, updated_policies)
+            audit.audit_done()
+            self._queue.task_done()
+
+        PolicyUpdater._logger.info("exit policy-updater")
+
+    def _keep_running(self):
+        """thread-safe check whether to continue running"""
+        self._lock.acquire()
+        keep_running = not self._req_shutdown
+        self._lock.release()
+        if self._req_shutdown:
+            self._req_shutdown.audit_done()
+        return keep_running
+
+    def catch_up(self, audit):
+        """need to bring the latest policies to DCAE-Controller"""
+        self._lock.acquire()
+        self._req_catch_up = audit
+        self._lock.release()
+        self.enqueue()
+
+    def _on_catch_up(self):
+        """Bring the latest policies to DCAE-Controller"""
+        self._lock.acquire()
+        req_catch_up = self._req_catch_up
+        if self._req_catch_up:
+            self._req_catch_up = None
+            self._queue.task_done()
+            self._queue = Queue()
+        self._lock.release()
+        if not req_catch_up:
+            return False
+
+        PolicyUpdater._logger.info("catch_up")
+        latest_policies = PolicyRest.get_latest_policies(req_catch_up)
+        PolicyUpdater.policy_update(req_catch_up, latest_policies)
+        req_catch_up.audit_done()
+        return True
+
+    @staticmethod
+    def policy_update(audit, updated_policies):
+        """Invoke deploy-handler"""
+        if updated_policies:
+            PolicyUpdater._logger.info("updated_policies %s", json.dumps(updated_policies))
+            DeployHandler.policy_update(audit, updated_policies)
+
+    def shutdown(self, audit):
+        """Shutdown the policy-updater"""
+        PolicyUpdater._logger.info("shutdown policy-updater")
+        self._lock.acquire()
+        self._req_shutdown = audit
+        self._lock.release()
+        self.enqueue()
+        if self.is_alive():
+            self.join()