VOL-1395: Common shared libraries needed for Python based device adapters.

This is an initial check-in of code from the master branch.  Additional work
is expected on a few items to work with the new go-core and will be covered
by separate JIRAs and commits.

Change-Id: I0856ec6b79b8d3e49082c609eb9c7eedd75b1708
diff --git a/python/adapters/extensions/omci/tasks/reboot_task.py b/python/adapters/extensions/omci/tasks/reboot_task.py
new file mode 100644
index 0000000..316e23b
--- /dev/null
+++ b/python/adapters/extensions/omci/tasks/reboot_task.py
@@ -0,0 +1,125 @@
+#
+# Copyright 2018 the original author or authors.
+#
+# 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.
+#
+from task import Task
+from enum import IntEnum
+from twisted.internet import reactor
+from twisted.internet.defer import inlineCallbacks, failure, TimeoutError
+from voltha.extensions.omci.omci_defs import ReasonCodes, EntityOperations
+from voltha.extensions.omci.omci_me import OntGFrame
+from voltha.extensions.omci.omci_cc import DEFAULT_OMCI_TIMEOUT
+
+RC = ReasonCodes
+OP = EntityOperations
+
+
+class RebootException(Exception):
+    pass
+
+
+class DeviceBusy(Exception):
+    pass
+
+
+class RebootFlags(IntEnum):
+    Reboot_Unconditionally = 0,
+    Reboot_If_No_POTS_VoIP_In_Progress = 1,
+    Reboot_If_No_Emergency_Call_In_Progress = 2
+
+
+class OmciRebootRequest(Task):
+    """
+    OpenOMCI routine to request reboot of an ONU
+    """
+    task_priority = Task.MAX_PRIORITY
+    name = "ONU OMCI Reboot Task"
+    # adopt the global default
+    DEFAULT_REBOOT_TIMEOUT = DEFAULT_OMCI_TIMEOUT
+
+    def __init__(self, omci_agent, device_id,
+                 flags=RebootFlags.Reboot_Unconditionally,
+                 timeout=DEFAULT_REBOOT_TIMEOUT):
+        """
+        Class initialization
+
+        :param omci_agent: (OmciAdapterAgent) OMCI Adapter agent
+        :param flags: (RebootFlags) Reboot condition
+        """
+        super(OmciRebootRequest, self).__init__(OmciRebootRequest.name,
+                                                omci_agent,
+                                                device_id,
+                                                priority=OmciRebootRequest.task_priority,
+                                                exclusive=True)
+        self._device = omci_agent.get_device(device_id)
+        self._flags = flags
+        self._timeout = timeout
+        self._local_deferred = None
+
+    def cancel_deferred(self):
+        super(OmciRebootRequest, self).cancel_deferred()
+
+        d, self._local_deferred = self._local_deferred, None
+        try:
+            if d is not None and not d.called:
+                d.cancel()
+        except:
+            pass
+
+    def start(self):
+        """ Start task """
+        super(OmciRebootRequest, self).start()
+        self._local_deferred = reactor.callLater(0, self.perform_reboot)
+
+    @inlineCallbacks
+    def perform_reboot(self):
+        """
+        Perform the reboot requests
+
+        Depending on the ONU implementation, a response may not be returned. For this
+        reason, a timeout is considered successful.
+        """
+        self.log.info('perform-reboot')
+
+        try:
+            frame = OntGFrame().reboot(reboot_code=self._flags)
+            self.strobe_watchdog()
+            results = yield self._device.omci_cc.send(frame, timeout=self._timeout)
+
+            status = results.fields['omci_message'].fields['success_code']
+            self.log.debug('reboot-status', status=status)
+
+            # Did it fail
+            if status != RC.Success.value:
+                if self._flags != RebootFlags.Reboot_Unconditionally and\
+                        status == RC.DeviceBusy.value:
+                    raise DeviceBusy('ONU is busy, try again later')
+                else:
+                    msg = 'Reboot request failed with status {}'.format(status)
+                    raise RebootException(msg)
+
+            self.log.info('reboot-success')
+            self.deferred.callback(self)
+
+        except TimeoutError:
+            self.log.info('timeout', msg='Request timeout is not considered an error')
+            self.deferred.callback(None)
+
+        except DeviceBusy as e:
+            self.log.warn('perform-reboot', msg=e)
+            self.deferred.errback(failure.Failure(e))
+
+        except Exception as e:
+            self.log.exception('perform-reboot', e=e)
+            self.deferred.errback(failure.Failure(e))