kytos.core.helpers.now() - Code Metrics - Inspection of "Merge pull request #232 from kytos-ng/fix/listen_t..." - kytos-ng/kytos - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Push — master ( 63a652...50cc5d )

by Vinicius

created 2022-06-23 21:30 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
import traceback
from concurrent.futures import ThreadPoolExecutor
from datetime import datetime, timezone
from threading import Thread

from kytos.core.apm import ElasticAPM
from kytos.core.config import KytosConfig

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

LOG = logging.getLogger(__name__)


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


def get_apm_name():
    """Get apm backend name."""
    return KytosConfig().options["daemon"].apm


# pylint: disable=invalid-name
executors = {name: ThreadPoolExecutor(max_workers=max_workers,
                                      thread_name_prefix=f"thread_pool_{name}")
             for name, max_workers in get_thread_pool_max_workers().items()}


def listen_to(event, *events, pool=None):
    """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.

    The pool option gives you control on which ThreadPoolExecutor that will
    execute the decorated handler. This knob is meant for prioritization,
    allowing executions on different pools depending on the handler primary
    responsibility and importance to avoid potential scheduling starvation.

    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...

            @listen_to("some_db_oriented_event", pool="db")
            def db_update(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

    # pylint: disable=broad-except
    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()
                return

        # pylint: disable=unused-argument
        def handler_context(*args, **kwargs):
            """Handler's context for ThreadPool."""
            cls, kytos_event = args[0], args[1]
            try:
                result = handler(*args)
            except Exception:
                result = None
                traceback_str = traceback.format_exc().replace("\n", ", ")
                LOG.error(f"listen_to handler: {handler}, "
                          f"args: {args} traceback: {traceback_str}")
                if hasattr(cls, "controller"):
                    cls.controller.dead_letter.add_event(kytos_event)
            return result

        def handler_context_apm(*args, apm_client=None):
            """Handler's context for ThreadPool APM instrumentation."""
            cls, kytos_event = args[0], args[1]
            trace_parent = kytos_event.trace_parent
            tx_type = "kytos_event"
            tx = apm_client.begin_transaction(transaction_type=tx_type,
                                              trace_parent=trace_parent)
            kytos_event.trace_parent = tx.trace_parent
            tx.name = f"{kytos_event.name}@{cls.napp_id}"
            try:
                result = handler(*args)
                tx.result = result
            except Exception as exc:
                result = None
                traceback_str = traceback.format_exc().replace("\n", ", ")
                LOG.error(f"listen_to handler: {handler}, "
                          f"args: {args} traceback: {traceback_str}")
                if hasattr(cls, "controller"):
                    cls.controller.dead_letter.add_event(kytos_event)
                apm_client.capture_exception(
                    exc_info=(type(exc), exc, exc.__traceback__),
                    context={"args": args},
                    handled=False,
                )
            tx.end()
            apm_client.tracer.queue_func("transaction", tx.to_dict())
            return result

        handler_func, kwargs = handler_context, {}
        if get_apm_name() == "es":
            handler_func = handler_context_apm
            kwargs = dict(apm_client=ElasticAPM.get_client())

        def get_executor(pool, event, default_pool="app"):
            """Get executor."""
            if pool:
                return executors[pool]
            if not event:
                return executors[default_pool]

            if event.name.startswith("kytos/of_core") and "sb" in executors:
                return executors["sb"]
            core_of = "kytos/core.openflow"
            if event.name.startswith(core_of) and "sb" in executors:
                return executors["sb"]
            if event.name.startswith("kytos.storehouse") and "db" in executors:
                return executors["db"]
            return executors[default_pool]

        def inner(*args):
            """Decorate the handler to run in the thread pool."""
            event = args[1] if len(args) > 1 else None
            executor = get_executor(pool, event)
            future = executor.submit(handler_func, *args, **kwargs)
            future.add_done_callback(done_callback)

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

    if executors:
        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	1	import logging
3	1	import traceback
4	1	from concurrent.futures import ThreadPoolExecutor
5	1	from datetime import datetime, timezone
6	1	from threading import Thread
7
8	1	from kytos.core.apm import ElasticAPM
9	1	from kytos.core.config import KytosConfig
10
11	1	__all__ = ['listen_to', 'now', 'run_on_thread', 'get_time']
12
13	1	LOG = logging.getLogger(__name__)
14
15
16	1	def get_thread_pool_max_workers():
17		"""Get the number of thread pool max workers."""
18	1	return KytosConfig().options["daemon"].thread_pool_max_workers
19
20
21	1	def get_apm_name():
22		"""Get apm backend name."""
23	1	return KytosConfig().options["daemon"].apm
24
25
26		# pylint: disable=invalid-name
27	1	executors = {name: ThreadPoolExecutor(max_workers=max_workers,
28		thread_name_prefix=f"thread_pool_{name}")
29		for name, max_workers in get_thread_pool_max_workers().items()}
30
31
32	1	def listen_to(event, *events, pool=None):
33		"""Decorate Event Listener methods.
34
35		This decorator was built to be used on NAPPs methods to define which
36		type of event the method will handle. With this, we will be able to
37		'schedule' the app/method to receive an event when a new event is
38		registered on the controller buffers.
39		By using the run_on_thread decorator, we also guarantee that the method
40		(handler) will be called from inside a new thread, avoiding this method to
41		block its caller.
42
43		The decorator will add an attribute to the method called 'events', that
44		will be a list of the events that the method will handle.
45
46		The event that will be listened to is always a string, but it can represent
47		a regular expression to match against multiple Event Types. All listened
48		events are documented in :doc:`/developer/listened_events` section.
49
50		The pool option gives you control on which ThreadPoolExecutor that will
51		execute the decorated handler. This knob is meant for prioritization,
52		allowing executions on different pools depending on the handler primary
53		responsibility and importance to avoid potential scheduling starvation.
54
55		Example of usage:
56
57		.. code-block:: python3
58
59		class MyAppClass(KytosApp):
60		@listen_to('kytos/of_core.messages.in')
61		def my_handler_of_message_in(self, event):
62		# Do stuff here...
63
64		@listen_to('kytos/of_core.messages.out')
65		def my_handler_of_message_out(self, event):
66		# Do stuff here...
67
68		@listen_to('kytos/of_core.messages.in.ofpt_hello',
69		'kytos/of_core.messages.out.ofpt_hello')
70		def my_handler_of_hello_messages(self, event):
71		# Do stuff here...
72
73		@listen_to('kytos/of_core.message.*.hello')
74		def my_other_handler_of_hello_messages(self, event):
75		# Do stuff here...
76
77		@listen_to('kytos/of_core.message.*.hello')
78		def my_handler_of_hello_messages(self, event):
79		# Do stuff here...
80
81		@listen_to('kytos/of_core.message.*')
82		def my_stats_handler_of_any_message(self, event):
83		# Do stuff here...
84
85		@listen_to("some_db_oriented_event", pool="db")
86		def db_update(self, event):
87		# Do stuff here...
88		"""
89	1	def thread_decorator(handler):
90		"""Decorate the handler method.
91
92		Returns:
93		A method with an `events` attribute (list of events to be listened)
94		and also decorated to run on a new thread.
95
96		"""
97		@run_on_thread
98		def threaded_handler(*args):
99		"""Decorate the handler to run from a new thread."""
100		handler(*args)
101
102		threaded_handler.events = [event]
103		threaded_handler.events.extend(events)
104		return threaded_handler
105
106		# pylint: disable=broad-except
107	1	def thread_pool_decorator(handler):
108		"""Decorate the handler method.
109
110		Returns:
111		A method with an `events` attribute (list of events to be listened)
112		and also decorated to run on in the thread pool
113
114		"""
115	1	def done_callback(future):
116		"""Done callback."""
117		if not future.exception():
118		_ = future.result()
119		return
120
121		# pylint: disable=unused-argument
122	1	def handler_context(args, *kwargs):
123		"""Handler's context for ThreadPool."""
124		cls, kytos_event = args[0], args[1]
125		try:
126		result = handler(*args)
127		except Exception:
128		result = None
129		traceback_str = traceback.format_exc().replace("\n", ", ")
130		LOG.error(f"listen_to handler: {handler}, "
131		f"args: {args} traceback: {traceback_str}")
132		if hasattr(cls, "controller"):
133		cls.controller.dead_letter.add_event(kytos_event)
134		return result
135
136	1	def handler_context_apm(*args, apm_client=None):
137		"""Handler's context for ThreadPool APM instrumentation."""
138		cls, kytos_event = args[0], args[1]
139		trace_parent = kytos_event.trace_parent
140		tx_type = "kytos_event"
141		tx = apm_client.begin_transaction(transaction_type=tx_type,
142		trace_parent=trace_parent)
143		kytos_event.trace_parent = tx.trace_parent
144		tx.name = f"{kytos_event.name}@{cls.napp_id}"
145		try:
146		result = handler(*args)
147		tx.result = result
148		except Exception as exc:
149		result = None
150		traceback_str = traceback.format_exc().replace("\n", ", ")
151		LOG.error(f"listen_to handler: {handler}, "
152		f"args: {args} traceback: {traceback_str}")
153		if hasattr(cls, "controller"):
154		cls.controller.dead_letter.add_event(kytos_event)
155		apm_client.capture_exception(
156		exc_info=(type(exc), exc, exc.__traceback__),
157		context={"args": args},
158		handled=False,
159		)
160		tx.end()
161		apm_client.tracer.queue_func("transaction", tx.to_dict())
162		return result
163
164	1	handler_func, kwargs = handler_context, {}
165	1	if get_apm_name() == "es":
166		handler_func = handler_context_apm
167		kwargs = dict(apm_client=ElasticAPM.get_client())
168
169	1	def get_executor(pool, event, default_pool="app"):
170		"""Get executor."""
171	1	if pool:
172		return executors[pool]
173	1	if not event:
174	1	return executors[default_pool]
175
176		if event.name.startswith("kytos/of_core") and "sb" in executors:
177		return executors["sb"]
178		core_of = "kytos/core.openflow"
179		if event.name.startswith(core_of) and "sb" in executors:
180		return executors["sb"]
181		if event.name.startswith("kytos.storehouse") and "db" in executors:
182		return executors["db"]
183		return executors[default_pool]
184
185	1	def inner(*args):
186		"""Decorate the handler to run in the thread pool."""
187	1	event = args[1] if len(args) > 1 else None
188	1	executor = get_executor(pool, event)
189	1	future = executor.submit(handler_func, args, *kwargs)
190	1	future.add_done_callback(done_callback)
191
192	1	inner.events = [event]
193	1	inner.events.extend(events)
194	1	return inner
195
196	1	if executors:
197	1	return thread_pool_decorator
198		return thread_decorator
199
200
201	1	def now(tzone=timezone.utc):
202		"""Return the current datetime (default to UTC).
203
204		Args:
205		tzone (datetime.timezone): Specific time zone used in datetime.
206
207		Returns:
208		datetime.datetime.now: Date time with specific time zone.
209
210		"""
211	1	return datetime.now(tzone)
212
213
214	1	def run_on_thread(method):
215		"""Decorate to run the decorated method inside a new thread.
216
217		Args:
218		method (function): function used to run as a new thread.
219
220		Returns:
221		Decorated method that will run inside a new thread.
222		When the decorated method is called, it will not return the created
223		thread to the caller.
224
225		"""
226	1	def threaded_method(*args):
227		"""Ensure the handler method runs inside a new thread."""
228	1	thread = Thread(target=method, args=args)
229
230		# Set daemon mode so that we don't have to wait for these threads
231		# to finish when exiting Kytos
232	1	thread.daemon = True
233	1	thread.start()
234	1	return threaded_method
235
236
237	1	def get_time(data=None):
238		"""Receive a dictionary or a string and return a datatime instance.
239
240		data = {"year": 2006,
241		"month": 11,
242		"day": 21,
243		"hour": 16,
244		"minute": 30 ,
245		"second": 00}
246
247		or
248
249		data = "21/11/06 16:30:00"
250
251		2018-04-17T17:13:50Z
252
253		Args:
254		data (str, dict): python dict or string to be converted to datetime
255
256		Returns:
257		datetime: datetime instance.
258
259		"""
260	1	if isinstance(data, str):
261	1	date = datetime.strptime(data, "%Y-%m-%dT%H:%M:%S")
262	1	elif isinstance(data, dict):
263	1	date = datetime(**data)
264		else:
265	1	return None
266		return date.replace(tzinfo=timezone.utc)
267

kytos-ng / kytos

Push — master ( 63a652...50cc5d )

kytos.core.helpers.now() A

Complexity

Size

Duplication

Code Coverage

Importance

Duplication Side-by-Side

Filter issues like