2.3.0 policy-handler - periodically catch_up

- periodically catchup - interval is configurable
     = max_skips defines the number of times the catch_up
        message that is identical to previous one can be skipped
- do not catchup more often than the interval
    even between the manual catchup and auto catchup
- do not send the same catchup message twice in a row
   to the deployment-handler but not exceed a hard limit
   on catchup max_skips
- catchup if the deployment-handler instance is changed

Change-Id: I9a3fcc941e8a9e553abb3952dd882c37e0f5fdfe
Signed-off-by: Alex Shatov <alexs@att.com>
Issue-ID: DCAEGEN2-389

1 files changed, 63 insertions, 0 deletions

diff --git a/policyhandler/step_timer.py b/policyhandler/step_timer.py
new file mode 100644
index 0000000..6e2b3f6
--- /dev/null
+++ b/policyhandler/step_timer.py
@@ -0,0 +1,63 @@
+# ================================================================================
+# Copyright (c) 2018 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.
+
+"""periodically callback"""
+
+from threading import Event, Thread
+
+
+class StepTimer(Thread):
+    """call on_time after interval number of seconds, then wait to continue"""
+    def __init__(self, name, interval, on_time, *args, **kwargs):
+        Thread.__init__(self, name=name)
+        self._interval = interval
+        self._on_time = on_time
+        self._args = args
+        self._kwargs = kwargs
+
+        self._timeout = Event()
+        self._paused = Event()
+        self._continue = Event()
+        self._finished = Event()
+
+    def next(self):
+        """continue with the next timeout"""
+        self._paused.clear()
+        self._continue.set()
+
+    def pause(self):
+        """pause the timer"""
+        self._paused.set()
+
+    def stop(self):
+        """stop the timer if it hasn't finished yet"""
+        self._finished.set()
+        self._timeout.set()
+        self._continue.set()
+
+    def run(self):
+        """loop until stopped=finished"""
+        while True:
+            self._timeout.wait(self._interval)
+            if self._finished.is_set():
+                break
+            self._timeout.clear()
+            self._continue.clear()
+            if not self._paused.is_set():
+                self._on_time(*self._args, **self._kwargs)
+            self._continue.wait()