kytos.core.helpers.now() - Code Metrics - Inspection of "Unhandled exception on a listen_to decorated funct..." - kytos-ng/kytos - Measure and Improve Code Quality continuously with Scrutinizer

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Pull Request — master (#196)

by Vinicius

created 2022-03-25 18:21 UTC

kytos.core.helpers.now() A

↳ Parent: kytos.core.helpers

Complexity

Conditions

Size

Total Lines	11
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	2
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	2
nop	1
dl	0
loc	11
rs	10
c	0
b	0
f	0
ccs	2
cts	2
cp	1
crap	1

"""Utilities functions used in Kytos."""
import logging
from concurrent.futures import ThreadPoolExecutor
from datetime import datetime, timezone
from threading import Thread

from kytos.core.config import KytosConfig

__all__ = ['listen_to', 'now', 'run_on_thread', 'get_time']

LOG = logging.getLogger(__name__)

# APP_MSG = "[App %s] %s | ID: %02d | R: %02d | P: %02d | F: %s"


def get_thread_pool_max_workers():
    """Get the number of thread pool max workers."""
    return int(KytosConfig().options["daemon"].thread_pool_max_workers)


# pylint: disable=invalid-name
executor = None
if get_thread_pool_max_workers():
    executor = ThreadPoolExecutor(max_workers=get_thread_pool_max_workers())


def listen_to(event, *events):
    """Decorate Event Listener methods.

    This decorator was built to be used on NAPPs methods to define which
    type of event the method will handle. With this, we will be able to
    'schedule' the app/method to receive an event when a new event is
    registered on the controller buffers.
    By using the run_on_thread decorator, we also guarantee that the method
    (handler) will be called from inside a new thread, avoiding this method to
    block its caller.

    The decorator will add an attribute to the method called 'events', that
    will be a list of the events that the method will handle.

    The event that will be listened to is always a string, but it can represent
    a regular expression to match against multiple Event Types. All listened
    events are documented in :doc:`/developer/listened_events` section.

    Example of usage:

    .. code-block:: python3

        class MyAppClass(KytosApp):
            @listen_to('kytos/of_core.messages.in')
            def my_handler_of_message_in(self, event):
                # Do stuff here...

            @listen_to('kytos/of_core.messages.out')
            def my_handler_of_message_out(self, event):
                # Do stuff here...

            @listen_to('kytos/of_core.messages.in.ofpt_hello',
                       'kytos/of_core.messages.out.ofpt_hello')
            def my_handler_of_hello_messages(self, event):
                # Do stuff here...

            @listen_to('kytos/of_core.message.*.hello')
            def my_other_handler_of_hello_messages(self, event):
                # Do stuff here...

            @listen_to('kytos/of_core.message.*.hello')
            def my_handler_of_hello_messages(self, event):
                # Do stuff here...

            @listen_to('kytos/of_core.message.*')
            def my_stats_handler_of_any_message(self, event):
                # Do stuff here...
    """
    def thread_decorator(handler):
        """Decorate the handler method.

        Returns:
            A method with an `events` attribute (list of events to be listened)
            and also decorated to run on a new thread.

        """
        @run_on_thread
        def threaded_handler(*args):
            """Decorate the handler to run from a new thread."""
            handler(*args)

        threaded_handler.events = [event]
        threaded_handler.events.extend(events)
        return threaded_handler

    def thread_pool_decorator(handler):
        """Decorate the handler method.

        Returns:
            A method with an `events` attribute (list of events to be listened)
            and also decorated to run on in the thread pool

        """
        def done_callback(future):
            """Done callback."""
            if not future.exception():
                _ = future.result()
            else:
                exc_str = f"{type(future.exception())}: {future.exception()}"
                args = (
                    getattr(future, "__inner_args")
                    if hasattr(future, "__inner_args")
                    else tuple()
                )
                LOG.error(f"listen_to handler: {handler}, "
                          f"args: {args}, exception: {exc_str}")

        def inner(*args):
            """Decorate the handler to run in the thread pool."""
            future = executor.submit(handler, *args)
            setattr(future, "__inner_args", args)
            future.add_done_callback(done_callback)

        inner.events = [event]
        inner.events.extend(events)
        return inner

    if get_thread_pool_max_workers():
        return thread_pool_decorator
    return thread_decorator


def now(tzone=timezone.utc):
    """Return the current datetime (default to UTC).

    Args:
        tzone (datetime.timezone): Specific time zone used in datetime.

    Returns:
        datetime.datetime.now: Date time with specific time zone.

    """
    return datetime.now(tzone)


def run_on_thread(method):
    """Decorate to run the decorated method inside a new thread.

    Args:
        method (function): function used to run as a new thread.

    Returns:
        Decorated method that will run inside a new thread.
        When the decorated method is called, it will not return the created
        thread to the caller.

    """
    def threaded_method(*args):
        """Ensure the handler method runs inside a new thread."""
        thread = Thread(target=method, args=args)

        # Set daemon mode so that we don't have to wait for these threads
        # to finish when exiting Kytos
        thread.daemon = True
        thread.start()
    return threaded_method


def get_time(data=None):
    """Receive a dictionary or a string and return a datatime instance.

    data = {"year": 2006,
            "month": 11,
            "day": 21,
            "hour": 16,
            "minute": 30 ,
            "second": 00}

    or

    data = "21/11/06 16:30:00"

    2018-04-17T17:13:50Z

    Args:
        data (str, dict): python dict or string to be converted to datetime

    Returns:
        datetime: datetime instance.

    """
    if isinstance(data, str):
        date = datetime.strptime(data, "%Y-%m-%dT%H:%M:%S")
    elif isinstance(data, dict):
        date = datetime(**data)
    else:
        return None
    return date.replace(tzinfo=timezone.utc)


1		"""Utilities functions used in Kytos."""
2	2	import logging
3	2	from concurrent.futures import ThreadPoolExecutor
4	2	from datetime import datetime, timezone
5	2	from threading import Thread
6
7	2	from kytos.core.config import KytosConfig
8
9	2	__all__ = ['listen_to', 'now', 'run_on_thread', 'get_time']
10
11	2	LOG = logging.getLogger(__name__)
12
13		# APP_MSG = "[App %s] %s \| ID: %02d \| R: %02d \| P: %02d \| F: %s"
14
15
16	2	def get_thread_pool_max_workers():
17		"""Get the number of thread pool max workers."""
18	2	return int(KytosConfig().options["daemon"].thread_pool_max_workers)
19
20
21		# pylint: disable=invalid-name
22	2	executor = None
23	2	if get_thread_pool_max_workers():
24	2	executor = ThreadPoolExecutor(max_workers=get_thread_pool_max_workers())
25
26
27	2	def listen_to(event, *events):
28		"""Decorate Event Listener methods.
29
30		This decorator was built to be used on NAPPs methods to define which
31		type of event the method will handle. With this, we will be able to
32		'schedule' the app/method to receive an event when a new event is
33		registered on the controller buffers.
34		By using the run_on_thread decorator, we also guarantee that the method
35		(handler) will be called from inside a new thread, avoiding this method to
36		block its caller.
37
38		The decorator will add an attribute to the method called 'events', that
39		will be a list of the events that the method will handle.
40
41		The event that will be listened to is always a string, but it can represent
42		a regular expression to match against multiple Event Types. All listened
43		events are documented in :doc:`/developer/listened_events` section.
44
45		Example of usage:
46
47		.. code-block:: python3
48
49		class MyAppClass(KytosApp):
50		@listen_to('kytos/of_core.messages.in')
51		def my_handler_of_message_in(self, event):
52		# Do stuff here...
53
54		@listen_to('kytos/of_core.messages.out')
55		def my_handler_of_message_out(self, event):
56		# Do stuff here...
57
58		@listen_to('kytos/of_core.messages.in.ofpt_hello',
59		'kytos/of_core.messages.out.ofpt_hello')
60		def my_handler_of_hello_messages(self, event):
61		# Do stuff here...
62
63		@listen_to('kytos/of_core.message.*.hello')
64		def my_other_handler_of_hello_messages(self, event):
65		# Do stuff here...
66
67		@listen_to('kytos/of_core.message.*.hello')
68		def my_handler_of_hello_messages(self, event):
69		# Do stuff here...
70
71		@listen_to('kytos/of_core.message.*')
72		def my_stats_handler_of_any_message(self, event):
73		# Do stuff here...
74		"""
75	2	def thread_decorator(handler):
76		"""Decorate the handler method.
77
78		Returns:
79		A method with an `events` attribute (list of events to be listened)
80		and also decorated to run on a new thread.
81
82		"""
83		@run_on_thread
84		def threaded_handler(*args):
85		"""Decorate the handler to run from a new thread."""
86		handler(*args)
87
88		threaded_handler.events = [event]
89		threaded_handler.events.extend(events)
90		return threaded_handler
91
92	2	def thread_pool_decorator(handler):
93		"""Decorate the handler method.
94
95		Returns:
96		A method with an `events` attribute (list of events to be listened)
97		and also decorated to run on in the thread pool
98
99		"""
100	2	def done_callback(future):
101		"""Done callback."""
102		if not future.exception():
103		_ = future.result()
104		else:
105		exc_str = f"{type(future.exception())}: {future.exception()}"
106		args = (
107		getattr(future, "__inner_args")
108		if hasattr(future, "__inner_args")
109		else tuple()
110		)
111		LOG.error(f"listen_to handler: {handler}, "
112		f"args: {args}, exception: {exc_str}")
113
114	2	def inner(*args):
115		"""Decorate the handler to run in the thread pool."""
116	2	future = executor.submit(handler, *args)
117	2	setattr(future, "__inner_args", args)
118	2	future.add_done_callback(done_callback)
119
120	2	inner.events = [event]
121	2	inner.events.extend(events)
122	2	return inner
123
124	2	if get_thread_pool_max_workers():
125	2	return thread_pool_decorator
126		return thread_decorator
127
128
129	2	def now(tzone=timezone.utc):
130		"""Return the current datetime (default to UTC).
131
132		Args:
133		tzone (datetime.timezone): Specific time zone used in datetime.
134
135		Returns:
136		datetime.datetime.now: Date time with specific time zone.
137
138		"""
139	2	return datetime.now(tzone)
140
141
142	2	def run_on_thread(method):
143		"""Decorate to run the decorated method inside a new thread.
144
145		Args:
146		method (function): function used to run as a new thread.
147
148		Returns:
149		Decorated method that will run inside a new thread.
150		When the decorated method is called, it will not return the created
151		thread to the caller.
152
153		"""
154	2	def threaded_method(*args):
155		"""Ensure the handler method runs inside a new thread."""
156	2	thread = Thread(target=method, args=args)
157
158		# Set daemon mode so that we don't have to wait for these threads
159		# to finish when exiting Kytos
160	2	thread.daemon = True
161	2	thread.start()
162	2	return threaded_method
163
164
165	2	def get_time(data=None):
166		"""Receive a dictionary or a string and return a datatime instance.
167
168		data = {"year": 2006,
169		"month": 11,
170		"day": 21,
171		"hour": 16,
172		"minute": 30 ,
173		"second": 00}
174
175		or
176
177		data = "21/11/06 16:30:00"
178
179		2018-04-17T17:13:50Z
180
181		Args:
182		data (str, dict): python dict or string to be converted to datetime
183
184		Returns:
185		datetime: datetime instance.
186
187		"""
188	2	if isinstance(data, str):
189	2	date = datetime.strptime(data, "%Y-%m-%dT%H:%M:%S")
190	2	elif isinstance(data, dict):
191	2	date = datetime(**data)
192		else:
193	2	return None
194		return date.replace(tzinfo=timezone.utc)
195

kytos-ng / kytos

Pull Request — master (#196)

kytos.core.helpers.now() A

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