common/python/rift/mano/dts/rpc/core.py

   1 """
   2 #
   3 #   Copyright 2016 RIFT.IO Inc
   4 #
   5 #   Licensed under the Apache License, Version 2.0 (the "License");
   6 #   you may not use this file except in compliance with the License.
   7 #   You may obtain a copy of the License at
   8 #
   9 #       http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 #   Unless required by applicable law or agreed to in writing, software
  12 #   distributed under the License is distributed on an "AS IS" BASIS,
  13 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 #   See the License for the specific language governing permissions and
  15 #   limitations under the License.
  16 #
  17
  18 @file core.py
  19 @author Varun Prasad (varun.prasad@riftio.com)
  20 @date 28-Sep-2016
  21
  22 """
  23
  24 import abc
  25 import asyncio
  26
  27 import gi
  28 gi.require_version("RwDts", "1.0")
  29
  30 from gi.repository import RwDts as rwdts
  31 import rift.tasklets
  32
  33 from ..core import DtsHandler
  34
  35
  36 class AbstractRpcHandler(DtsHandler):
  37     """Base class to simplify RPC implementation
  38     """
  39     def __init__(self, log, dts, loop):
  40         super().__init__(log, dts, loop)
  41
  42         if not asyncio.iscoroutinefunction(self.callback):
  43             raise ValueError('%s has to be a coroutine' % (self.callback))
  44
  45     @abc.abstractproperty
  46     def xpath(self):
  47         pass
  48
  49     @property
  50     def input_xpath(self):
  51         return "I,{}".format(self.xpath)
  52
  53     @property
  54     def output_xpath(self):
  55         return "O,{}".format(self.xpath)
  56
  57     def flags(self):
  58         return rwdts.Flag.PUBLISHER
  59
  60     @asyncio.coroutine
  61     def on_prepare(self, xact_info, action, ks_path, msg):
  62         assert action == rwdts.QueryAction.RPC
  63
  64         try:
  65             rpc_op = yield from self.callback(ks_path, msg)
  66             xact_info.respond_xpath(
  67                 rwdts.XactRspCode.ACK,
  68                 self.output_xpath,
  69                 rpc_op)
  70
  71         except Exception as e:
  72             self.log.exception(e)
  73             xact_info.respond_xpath(
  74                 rwdts.XactRspCode.NACK,
  75                 self.output_xpath)
  76
  77     @asyncio.coroutine
  78     def register(self):
  79         reg_event = asyncio.Event(loop=self.loop)
  80
  81         @asyncio.coroutine
  82         def on_ready(regh, status):
  83             reg_event.set()
  84
  85         handler = rift.tasklets.DTS.RegistrationHandler(
  86                 on_prepare=self.on_prepare,
  87                 on_ready=on_ready)
  88
  89         with self.dts.group_create() as group:
  90             self.reg = group.register(
  91                   xpath=self.input_xpath,
  92                   handler=handler,
  93                   flags=self.flags())
  94
  95         yield from reg_event.wait()
  96
  97     @abc.abstractmethod
  98     @asyncio.coroutine
  99     def callback(self, ks_path, msg):
 100         """Subclass needs to override this method
 101
 102         Args:
 103             ks_path : Key spec path
 104             msg : RPC input
 105         """
 106         pass
 107