# -*- coding: utf-8 -*- {{{
# vim: set fenc=utf-8 ft=python sw=4 ts=4 sts=4 et:
#
# Copyright 2019, Battelle Memorial Institute.
#
# 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.
#
# This material was prepared as an account of work sponsored by an agency of
# the United States Government. Neither the United States Government nor the
# United States Department of Energy, nor Battelle, nor any of their
# employees, nor any jurisdiction or organization that has cooperated in the
# development of these materials, makes any warranty, express or
# implied, or assumes any legal liability or responsibility for the accuracy,
# completeness, or usefulness or any information, apparatus, product,
# software, or process disclosed, or represents that its use would not infringe
# privately owned rights. Reference herein to any specific commercial product,
# process, or service by trade name, trademark, manufacturer, or otherwise
# does not necessarily constitute or imply its endorsement, recommendation, or
# favoring by the United States Government or any agency thereof, or
# Battelle Memorial Institute. The views and opinions of authors expressed
# herein do not necessarily state or reflect those of the
# United States Government or any agency thereof.
#
# PACIFIC NORTHWEST NATIONAL LABORATORY operated by
# BATTELLE for the UNITED STATES DEPARTMENT OF ENERGY
# under Contract DE-AC05-76RL01830
# }}}
import logging
from volttron.platform import jsonapi
from volttron.platform.agent.utils import (get_aware_utc_now,
format_timestamp,
parse_timestamp_string)
CURRENT_STATUS = "current_status"
LAST_UPDATED = "utc_last_updated"
CONTEXT = "context"
STATUS_GOOD = "GOOD"
STATUS_BAD = "BAD"
STATUS_UNKNOWN = "UNKNOWN"
STATUS_STARTING = "STARTING"
STARTING_STATUS = STATUS_STARTING
GOOD_STATUS = STATUS_GOOD
BAD_STATUS = STATUS_BAD
UNKNOWN_STATUS = STATUS_UNKNOWN
ACCEPTABLE_STATUS = (GOOD_STATUS, BAD_STATUS, UNKNOWN_STATUS, STARTING_STATUS)
ALERT_KEY = "alert_key"
_log = logging.getLogger(__name__)
[docs]class Status(object):
"""
The `Status` objects wraps the context status and last reported into a
small object that can be serialized and sent across the zmq message bus.
There are two static methods for constructing `Status` objects:
- from_json() Expects a json string as input.
- build() Expects at least a status in the `ACCEPTABLE_STATUS` tuple.
The build() method also takes a context and a callback function that will
be called when the status changes.
"""
def __init__(self):
self._status = GOOD_STATUS
self._context = None
self._last_updated = format_timestamp(get_aware_utc_now())
self._status_changed_callback = None
@property
def status(self):
return self._status
@property
def context(self):
if self._context:
if isinstance(self._context, str):
return self._context
return self._context.copy()
return None
@property
def last_updated(self):
return self._last_updated
[docs] def update_status(self, status, context=None):
"""
Updates the internal state of the `Status` object.
This method will throw errors if the context is not serializable or
if the status parameter is not within the ACCEPTABLE_STATUS tuple.
:param status:
:param context:
:return:
"""
if status not in ACCEPTABLE_STATUS:
raise ValueError('Invalid status value {}'.format(status))
try:
jsonapi.dumps(context)
except TypeError:
raise ValueError('Context must be JSON serializable.')
status_changed = status != self._status
self._status = status
self._context = context
self._last_updated = format_timestamp(get_aware_utc_now())
if status_changed and self._status_changed_callback:
self._status_changed_callback()
[docs] def as_dict(self):
"""
Returns a copy of the status object properties as a dictionary.
@return:
"""
cp = dict(status=self.status, context=self.context,
last_updated=self.last_updated)
return cp
[docs] def as_json(self):
"""
Serializes the object to a json string.
Note:
Does not serialize the change callback function.
:return:
"""
return jsonapi.dumps(self.as_dict())
[docs] @staticmethod
def from_json(data, status_changed_callback=None):
"""
Deserializes a `Status` object and returns it to the caller.
:param data:
:param status_changed_callback:
:return:
"""
_log.debug("from_json {}".format(data))
statusobj = Status()
cp = jsonapi.loads(data)
cp['_status'] = cp['status']
cp['_last_updated'] = cp['last_updated']
cp['_context'] = cp['context']
del cp['status']
del cp['last_updated']
del cp['context']
statusobj.__dict__ = cp
statusobj._status_changed_callback = status_changed_callback
return statusobj
[docs] @staticmethod
def build(status, context=None, status_changed_callback=None):
"""
Constructs a `Status` object and initializes its state using the
passed parameters.
:param status:
:param context:
:param status_changed_callback:
:return:
"""
statusobj = Status()
statusobj.update_status(status, context)
statusobj._status_changed_callback = status_changed_callback
return statusobj