github.com/muhammedhassanm/blockchain@v0.0.0-20200120143007-697261defd4d/sawtooth-core-master/sdk/python/sawtooth_sdk/consensus/engine.py (about)

     1  # Copyright 2018 Intel Corporation
     2  #
     3  # Licensed under the Apache License, Version 2.0 (the "License");
     4  # you may not use this file except in compliance with the License.
     5  # You may obtain a copy of the License at
     6  #
     7  #     http://www.apache.org/licenses/LICENSE-2.0
     8  #
     9  # Unless required by applicable law or agreed to in writing, software
    10  # distributed under the License is distributed on an "AS IS" BASIS,
    11  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  # See the License for the specific language governing permissions and
    13  # limitations under the License.
    14  # -----------------------------------------------------------------------------
    15  
    16  import abc
    17  from collections import namedtuple
    18  
    19  
    20  StartupState = namedtuple(
    21      'StartupInfo',
    22      ['chain_head', 'peers', 'local_peer_info'])
    23  
    24  
    25  class Engine(metaclass=abc.ABCMeta):
    26      @abc.abstractmethod
    27      def start(self, updates, service, startup_state):
    28          '''Called after the engine is initialized, when a connection to the
    29          validator has been established. Notifications from the
    30          validator are sent along UPDATES. SERVICE is used to send
    31          requests to the validator.
    32  
    33          Args:
    34              updates (Queue)
    35              service (Service)
    36              startup (StartupInfo)
    37          '''
    38  
    39      @abc.abstractmethod
    40      def stop(self):
    41          '''Called before the engine is dropped in order to give the engine a
    42          chance to notify peers and clean up.'''
    43  
    44      @abc.abstractproperty
    45      def version(self):
    46          '''Get the version of this engine.
    47  
    48          Return:
    49              str
    50          '''
    51  
    52      @abc.abstractproperty
    53      def name(self):
    54          '''Get the name of the engine, typically the algorithm being
    55          implemented.
    56  
    57          Return:
    58              str
    59          '''