Finalize project

3_Codeabgabe/components/shared/.gitignore

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+build
+dist
+dse_shared_libs.egg-info

3_Codeabgabe/components/shared/RADME.md

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+### Contains shared libraries like rabbitMQ wrapper
+* To have life changes (develop package only links to this folder): `pip install -e .`
+* To install as independent package: `pip install .`
+* Create installable package via `python setup.py sdist`
+
+### Access shared libs via
+* `from dse_shared_libs.* import *`
+* e.g. `from dse_shared_libs.message_broker_wrapper import MBWrapper`

3_Codeabgabe/components/shared/dse_shared_libs/daf.py

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+from dataclasses import dataclass
+from datetime import datetime
+import geopy.distance
+
+
+@dataclass
+class DAF:
+    """
+    "Datenaufzeichnung für automatisiertes Fahren" (DAF), see 2021_DSE_Exercise_V1.0_Final.pdf page 7
+    """
+
+    vehicle_identification_number: str
+    gps_location: geopy.Point
+    velocity: float
+    near_crash_event: bool
+    timestamp: datetime
+
+    def to_dict(self):
+        return {'vehicle_identification_number': self.vehicle_identification_number,
+                'gps_location': {'latitude': self.gps_location.latitude,
+                                 'longitude': self.gps_location.longitude
+                                 },
+                'velocity': self.velocity,
+                'near_crash_event': self.near_crash_event,
+                'timestamp': self.timestamp.timestamp()
+                }

3_Codeabgabe/components/shared/dse_shared_libs/message_broker_wrapper.py

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+import time
+from threading import Thread
+from typing import Union
+
+import pika
+from pika.exceptions import AMQPConnectionError
+
+
+class MBWrapper:
+    host: str
+    exchange_type: str
+    exchange_name: str
+    callback: callable
+
+    _logger: Union['MBWrapper', None]
+
+    _type: str = None
+    _connection: pika.BlockingConnection
+    _channel: pika.BlockingConnection.channel
+
+    def __init__(self,
+                 host: str = 'rabbitmq',
+                 exchange_type: str = 'fanout',
+                 exchange_name: str = None,
+                 callback: callable = None,
+                 verbose: bool = False):
+        """
+        Initializes a new Message Broker Wrapper (MBWrapper). Initialize this object afterwards with
+        self.setup_sender() or self.setup_receiver() if messages will be published to or received from the queue.
+
+        If the exchange_name is not "logger", the MBWrapper will also initialize an sending queue which forwards
+        EVERY request to this exchange, too. Therefore, every request routed via a MBWrapper is logged. Except if it is
+        the logger MBWrapper. This one is initialized in the EventStore Service and receives all messages.
+
+        :param host: of running rabbitMQ instance
+        :param exchange_type: rabbitMQ exchange type to use
+        :param exchange_name: name of exchange
+        :param callback: callable callback to execute if message receiver will be set up, can also be set later on.
+        :param verbose: print handled messages to console
+        """
+        assert exchange_name, 'Please define an exchange name'
+
+        # append a connection to the logging broker, if it isn't the logging broker itself
+        if exchange_name != 'logger':
+            self._logger = MBWrapper(exchange_name='logger')
+            self._logger.setup_sender()
+        else:
+            self._logger = None
+
+        self.host = host
+        self.exchange_type = exchange_type
+        self.exchange_name = exchange_name
+        self.callback = callback
+        self.verbose = verbose
+
+    def print(self, *msg):
+        """
+        Modified print which prints only to stout with self.verbose.
+        :param msg: to print
+        """
+        if self.verbose:
+            print(*msg)
+
+    def setup_sender(self):
+        """
+        Setup the MBWrapper as sender.
+        """
+        assert self._type != 'receiver', 'MBWrapper is already a receiver. Use another MBWrapper.'
+        self._type = 'sender'
+        self._setup_channel()
+
+    def setup_receiver(self, callback: callable = None):
+        """
+        Setup the MBWrapper as a receiver.
+        A callback method which can handle the response bytes as input is mandatory.
+        Set it here if not already done on init.
+        """
+        if callback:
+            self.callback = callback
+
+        assert self._type != 'sender', 'MBWrapper is already a sender. Use another MBWrapper.'
+        assert self.callback, \
+            'Please setup MBWrapper with "on response" self.callback which can handle a byte string as input.'
+
+        def consumer():
+            """
+            If initialized as receiver: Consumer thread which waits for incoming messages, invokes self._receive
+            """
+            self._setup_channel()
+            result = self._channel.queue_declare(queue='', exclusive=True)
+            queue_name = result.method.queue
+
+            self._channel.queue_bind(exchange=self.exchange_name, queue=queue_name)
+
+            self.print('[{}] Waiting for messages.'.format(self.exchange_name))
+
+            self._channel.basic_consume(
+                queue=queue_name, on_message_callback=self._receive, auto_ack=True)
+
+            self._channel.start_consuming()
+
+        Thread(target=consumer).start()
+
+    def send(self, message: bytes):
+        """
+        Send the message to the queue. Forward also to logger.
+
+        :param message: msg to send
+        """
+        if type(message) is not bytes:
+            message = str(message).encode()
+        self._channel.basic_publish(exchange=self.exchange_name, routing_key='', body=message)
+        self.print("[{}] Sent {}".format(self.exchange_name, message))
+
+        # has a logger IFF not 'logger' as exchange name -> forwards everything to logger exchange, too
+        if self.__getattribute__('_logger'):
+            # print('logging')
+            self._logger.send(message)
+
+    def close(self):
+        """
+        Closes the connection.
+        """
+        self._connection.close()
+
+    def _setup_channel(self):
+        """
+        Setup the rabbitMQ channel. Retry if not succeeded (Allow the dependencies to
+        boot). Wait one second between retries.
+        """
+        connect_succeeded = False
+        while not connect_succeeded:
+            try:
+                self._connection = pika.BlockingConnection(
+                    pika.ConnectionParameters(host=self.host))
+                connect_succeeded = True
+            except pika.exceptions.AMQPConnectionError:
+                print('Could not connect, retry')
+                time.sleep(1)
+
+        self._channel = self._connection.channel()
+        self._channel.exchange_declare(exchange=self.exchange_name, exchange_type=self.exchange_type)
+
+    def _receive(self, ch, method, properties, body):
+        """
+        Reduce complexity, only forward the message body to the callback method. The others are not necessary for our
+        application example.
+        """
+        self.callback(body)

3_Codeabgabe/components/shared/dse_shared_libs/mock/datetime.py

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+class MyDate:
+    timestamp = None
+
+    @classmethod
+    def set_timestamp(cls, timestamp):
+        cls.timestamp = timestamp
+
+    @classmethod
+    def utcnow(cls):
+        return cls.timestamp

3_Codeabgabe/components/shared/dse_shared_libs/mock/rabbit_mq_mocks.py

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+class MyQueue:
+    @property
+    def queue(self):
+        return None
+
+
+class MyMethod:
+    method = MyQueue()
+
+
+class MyChannel:
+    @staticmethod
+    def exchange_declare(*args, **kwargs):
+        return None
+
+    @staticmethod
+    def queue_declare(*args, **kwargs):
+        return MyMethod
+
+    @staticmethod
+    def queue_bind(*args, **kwargs):
+        return None
+
+    @staticmethod
+    def basic_consume(*args, **kwargs):
+        return None
+
+    @staticmethod
+    def basic_publish(*args, **kwargs):
+        return None
+
+    @staticmethod
+    def start_consuming(*args, **kwargs):
+        return None
+
+
+class MyBlockingConnection:
+    def __init__(self, *args, **kwargs):
+        ...
+
+    @staticmethod
+    def channel():
+        return MyChannel()

3_Codeabgabe/components/shared/dse_shared_libs/mock/response.py

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+class MyResponse:
+    def __init__(self, *args, **kwargs):
+        ...
+
+    @staticmethod
+    def json(*args, **kwargs):
+        return {'cursor': []}

3_Codeabgabe/components/shared/dse_shared_libs/target_velocity.py

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+from dataclasses import dataclass
+from datetime import datetime
+
+
+@dataclass
+class TargetVelocity:
+    vin: str
+    target_velocity: float
+    timestamp: datetime
+
+    def to_dict(self):
+        return {'vin': self.vin,
+                'target_velocity': self.target_velocity,
+                'timestamp': self.timestamp.timestamp()
+                }

3_Codeabgabe/components/shared/dse_shared_libs/traffic_light_color.py

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+from enum import Enum
+
+
+class TrafficLightColor(Enum):
+    GREEN = 0
+    RED = 1

3_Codeabgabe/components/shared/dse_shared_libs/traffic_light_state.py

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+from dataclasses import dataclass
+from datetime import datetime
+
+from dse_shared_libs.traffic_light_color import TrafficLightColor
+
+
+@dataclass
+class TrafficLightState:
+    tlid: str
+    color: TrafficLightColor
+    last_switch: datetime
+
+    def to_dict(self):
+        return {'tlid': self.tlid,
+                'color': self.color.name,
+                'last_switch': self.last_switch.timestamp()}

3_Codeabgabe/components/shared/setup.py

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+from setuptools import find_packages, setup
+
+setup(name='dse-shared-libs',
+      version=1,
+      packages=find_packages(),
+      include_package_data=True,
+      license='BSD License',  # example licensez
+      install_requires=['pika', 'geopy']
+      )