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

Test Failed

Pull Request — master (#196)

by Vinicius

created 2022-03-25 17:45 UTC

kytos.core.helpers.run_on_thread() A

↳ Parent: kytos.core.helpers

Complexity

Conditions

Size

Total Lines	21
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	6
nop	1
dl	0
loc	21
rs	10
c	0
b	0
f	0
ccs	6
cts	6
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)
            inner_args = args[1:] if len(args) > 1 else args
            setattr(future, "__inner_args", inner_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
4	2	from concurrent.futures import ThreadPoolExecutor
5	2	from datetime import datetime, timezone
6	2	from threading import Thread
7
8	2	from kytos.core.config import KytosConfig
9
10	2	__all__ = ['listen_to', 'now', 'run_on_thread', 'get_time']
11
12	2	LOG = logging.getLogger(__name__)
13
14		# APP_MSG = "[App %s] %s \| ID: %02d \| R: %02d \| P: %02d \| F: %s"
15
16
17	2	def get_thread_pool_max_workers():
18		"""Get the number of thread pool max workers."""
19	2	return int(KytosConfig().options["daemon"].thread_pool_max_workers)
20
21
22		# pylint: disable=invalid-name
23	2	executor = None
24	2	if get_thread_pool_max_workers():
25	2	executor = ThreadPoolExecutor(max_workers=get_thread_pool_max_workers())
26
27
28	2	def listen_to(event, *events):
29		"""Decorate Event Listener methods.
30
31		This decorator was built to be used on NAPPs methods to define which
32		type of event the method will handle. With this, we will be able to
33		'schedule' the app/method to receive an event when a new event is
34		registered on the controller buffers.
35		By using the run_on_thread decorator, we also guarantee that the method
36		(handler) will be called from inside a new thread, avoiding this method to
37		block its caller.
38
39		The decorator will add an attribute to the method called 'events', that
40		will be a list of the events that the method will handle.
41
42		The event that will be listened to is always a string, but it can represent
43		a regular expression to match against multiple Event Types. All listened
44		events are documented in :doc:`/developer/listened_events` section.
45
46		Example of usage:
47
48		.. code-block:: python3
49
50		class MyAppClass(KytosApp):
51		@listen_to('kytos/of_core.messages.in')
52		def my_handler_of_message_in(self, event):
53		# Do stuff here...
54
55		@listen_to('kytos/of_core.messages.out')
56		def my_handler_of_message_out(self, event):
57		# Do stuff here...
58
59		@listen_to('kytos/of_core.messages.in.ofpt_hello',
60		'kytos/of_core.messages.out.ofpt_hello')
61		def my_handler_of_hello_messages(self, event):
62		# Do stuff here...
63
64		@listen_to('kytos/of_core.message.*.hello')
65		def my_other_handler_of_hello_messages(self, event):
66		# Do stuff here...
67
68		@listen_to('kytos/of_core.message.*.hello')
69		def my_handler_of_hello_messages(self, event):
70		# Do stuff here...
71
72		@listen_to('kytos/of_core.message.*')
73		def my_stats_handler_of_any_message(self, event):
74		# Do stuff here...
75		"""
76	2	def thread_decorator(handler):
77		"""Decorate the handler method.
78
79		Returns:
80		A method with an `events` attribute (list of events to be listened)
81		and also decorated to run on a new thread.
82
83		"""
84		@run_on_thread
85		def threaded_handler(*args):
86		"""Decorate the handler to run from a new thread."""
87		handler(*args)
88
89		threaded_handler.events = [event]
90		threaded_handler.events.extend(events)
91		return threaded_handler
92
93	2	def thread_pool_decorator(handler):
94		"""Decorate the handler method.
95
96		Returns:
97		A method with an `events` attribute (list of events to be listened)
98		and also decorated to run on in the thread pool
99
100		"""
101	2	def done_callback(future):
102		"""Done callback."""
103		if not future.exception():
104		_ = future.result()
105		else:
106		exc_str = f"{type(future.exception())}: {future.exception()}"
107		args = (
108		getattr(future, "__inner_args")
109		if hasattr(future, "__inner_args")
110		else tuple()
111		)
112		LOG.error(f"listen_to handler: {handler}, "
113		f"args: {args}, exception: {exc_str}")
114
115	2	def inner(*args):
116		"""Decorate the handler to run in the thread pool."""
117	2	future = executor.submit(handler, *args)
118	2	inner_args = args[1:] if len(args) > 1 else args
119	2	setattr(future, "__inner_args", inner_args)
120	2	future.add_done_callback(done_callback)
121
122	2	inner.events = [event]
123	2	inner.events.extend(events)
124	2	return inner
125
126	2	if get_thread_pool_max_workers():
127	2	return thread_pool_decorator
128		return thread_decorator
129
130
131	2	def now(tzone=timezone.utc):
132		"""Return the current datetime (default to UTC).
133
134		Args:
135		tzone (datetime.timezone): Specific time zone used in datetime.
136
137		Returns:
138		datetime.datetime.now: Date time with specific time zone.
139
140		"""
141	2	return datetime.now(tzone)
142
143
144	2	def run_on_thread(method):
145		"""Decorate to run the decorated method inside a new thread.
146
147		Args:
148		method (function): function used to run as a new thread.
149
150		Returns:
151		Decorated method that will run inside a new thread.
152		When the decorated method is called, it will not return the created
153		thread to the caller.
154
155		"""
156	2	def threaded_method(*args):
157		"""Ensure the handler method runs inside a new thread."""
158	2	thread = Thread(target=method, args=args)
159
160		# Set daemon mode so that we don't have to wait for these threads
161		# to finish when exiting Kytos
162	2	thread.daemon = True
163	2	thread.start()
164	2	return threaded_method
165
166
167	2	def get_time(data=None):
168		"""Receive a dictionary or a string and return a datatime instance.
169
170		data = {"year": 2006,
171		"month": 11,
172		"day": 21,
173		"hour": 16,
174		"minute": 30 ,
175		"second": 00}
176
177		or
178
179		data = "21/11/06 16:30:00"
180
181		2018-04-17T17:13:50Z
182
183		Args:
184		data (str, dict): python dict or string to be converted to datetime
185
186		Returns:
187		datetime: datetime instance.
188
189		"""
190	2	if isinstance(data, str):
191	2	date = datetime.strptime(data, "%Y-%m-%dT%H:%M:%S")
192	2	elif isinstance(data, dict):
193	2	date = datetime(**data)
194		else:
195	2	return None
196		return date.replace(tzinfo=timezone.utc)
197

kytos-ng / kytos

Pull Request — master (#196)

kytos.core.helpers.run_on_thread() A

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