I have a flask-script command that spawns a long sequence of greenlets. The problem is, these greenlets are unable to access my app context. I get a
"> failed with RuntimeError" at all times (accessing app.logger, per example). Suggestions?
On of my attempts:
spawn(method, app, arg1, arg2)
def spawn(app, arg1, arg2):
with app.app_context():
app.logger.debug('bla bla') # doesn't work
... do stuff
Edit: below gives you access to the request object, but not the current_app, probably not what you are searching for.
You are probably looking for flask.copy_current_request_context(f) which is documented here: http://flask.pocoo.org/docs/0.10/api/#flask.copy_current_request_context
Example:
import gevent
from flask import copy_current_request_context
#app.route('/')
def index():
#copy_current_request_context
def do_some_work():
# do some work here, it can access flask.request like you
# would otherwise in the view function.
...
gevent.spawn(do_some_work)
return 'Regular response'
you can pass a copy of the relevant info from the request, e.g.
import gevent
#app.route('/')
def index():
def do_some_work(data):
# do some work here with data
...
data = request.get_json()
gevent.spawn(do_some_work, data)
return 'Regular response'
Related
Based on the following example:
app = Flask(__name__)
#app.route('/users')
def get_users():
return UsersAPI().get_users()
And the following tests (using pytest and pytest-mock):
#pytest.fixture
def users():
return UsersAPI(how_many=1)
def test_simple(users, mocker):
mocker.patch("???", return_value=users)
I simply want to call UsersAPI(how_many=1) instead of UsersAPI(). Is this possible to do?
(if you know how to get done with unittest.mock that is also fine since pytest-mock is simply some pytest wrapper)
Turns out it is as easy as:
#pytest.fixture
def users():
return UsersAPI(how_many=1)
def test_simple(users, mocker):
mocker.patch("path.to.module.UsersAPI", return_value=users)
And this also works:
mocker.patch.object(path.to.module, 'UsersAPI', return_value=users)
I want to build monitoring system using RabbitMQ and Tornado. I can run the producer and my consumer can consume the data on queue but the data cant be show on website.
This just my experiment before I using the sensor
import pika
import tornado.ioloop
import tornado.web
import tornado.websocket
import logging
from threading import Thread
logging.basicConfig(lvl=logging.INFO)
clients=[]
credentials = pika.credentials.PlainCredentials('ayub','ayub')
connection = pika.BlockingConnection(pika.ConnectionParameters('192.168.43.101',
5672,
'/',
credentials))
channel = connection.channel()
def threaded_rmq():
channel.basic_consume('Queue',
on_message_callback= consumer_callback,
auto_ack=True,
exclusive=False,
consumer_tag=None,
arguments=None)
channel.start_consuming()
def disconect_rmq():
channel.stop_consuming()
Connection.close()
logging.info('Disconnected from broker')
def consumer_callback(ch,method,properties,body):
for itm in clients:
itm.write_message(body)
class SocketHandler(tornado.websocket.WebSocketHandler):
def open(self):
logging.info('websocket open')
clients.remove(self)
def close(self):
logging.info('websocket closed')
clients.remove(self)
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.render("websocket.html")
application = tornado.web.Application([
(r'/ws',SocketHandler),
(r"/", MainHandler),
])
def startTornado():
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
def stopTornado():
tornado.ioloop.IOLoop.instance().stop()
if __name__ == "__main__":
logging.info('starting thread RMQ')
threadRMQ = Thread(target=threaded_rmq)
threadRMQ.start()
logging.info('starting thread tornado')
threadTornado = Thread(target=startTornado)
threadTornado.start()
try:
raw_input("server ready")
except SyntaxError:
pass
try:
logging.info('disconnected')
disconnect_rmq()
except Exception, e:
pass
stopTornado()
but I got this error
WARNING:tornado.access:404 GET /favicon.ico (192.168.43.10) 0.98ms
please help me
In your SocketHandler.open function you need to add the client not remove it.
Also consider using a set for clients instead of a list because the remove operation will be faster:
clients = set()
...
class SocketHandler(tornado.websocket.WebSocketHandler):
def open(self):
logging.info('websocket open')
clients.add(self)
def close(self):
logging.info('websocket closed')
clients.remove(self)
The message you get regarding favicon.ico is actually a warning and it's harmless (the browser is requesting an icon to show for web application but won't complain if none is available).
You might also run into threading issues because Tornado and Pika are running in different threads so you will have to synchronize them; you can use Tornado's IOLoop.add_callback method for that.
My web application makes API calls to Spotify. In one of my Flask views I use the same method with different endpoints. Specifically:
sh = SpotifyHelper()
...
#bp.route('/profile', methods=['GET', 'POST'])
#login_required
def profile():
...
profile = sh.get_data(header, 'profile_endpoint')
...
playlist = sh.get_data(header, 'playlist_endpoint')
...
# There are 3 more like this to different endpoints -- history, top_artists, top_tracks
...
return render_template(
'profile.html',
playlists=playlists['items'],
history=history['items'],
...
)
I do not want to make an API call during testing so I wrote a mock.json that replaces the JSON response from the API. I have done this successfully when the method is only used once per view:
class MockResponse:
#staticmethod
def profile_response():
with open(path + '/music_app/static/JSON/mock.json') as f:
response = json.load(f)
return response
#pytest.fixture
def mock_profile(monkeypatch):
def mock_json(*args, **kwargs):
return MockResponse.profile_response()
monkeypatch.setattr(sh, "get_data", mock_json)
My problem is that I need to call get_data to different endpoints with different responses. My mock.json is written:
{'playlists': {'items': [# List of playlist data]},
'history': {'items': [# List of playlist data]},
...
So for each API endpoint I need something like
playlists = mock_json['playlists']
history = mock_json['history']
I can write mock_playlists(), mock_history(), etc., but how do I write a monkeypatch for each? Is there some way to pass the endpoint argument to monkeypatch.setattr(sh, "get_data", mock_???)?
from unittest.mock import MagicMock
#other code...
mocked_response = MagicMock(side_effect=[
# write it in the order of calls you need
profile_responce_1, profile_response_2 ... profile_response_n
])
monkeypatch.setattr(sh, "get_data", mocked_response)
I have made something like that
#app.task
def some_task()
logger.info(app.current_task.request.id)
some_func()
def some_func()
logger.info(app.current_task.request.id)
So I receive normal id inside some_task, but it equals to None inside some_func. How can I get real task id?
You could bind the task and pass the request around rather than relying on a global.
#app.task(bind=True)
def some_task(self)
logger.info(self.request.id)
some_func(self.request)
def some_func(celery_request=None)
# celery_request is optional assuming you're using it elsewhere.
if celery_request:
logger.info(celery_request.id)
I am currently developing a Django application based on django-tenants-schema. You don't need to look into the actual code of the module, but the idea is that it has a global setting for the current database connection defining which schema to use for the application tenant, e.g.
tenant = tenants_schema.get_tenant()
And for setting
tenants_schema.set_tenant(xxx)
For some of the tasks I would like them to remember the current global tenant selected during the instantiation, e.g. in theory:
class AbstractTask(Task):
'''
Run this method before returning the task future
'''
def before_submit(self):
self.run_args['tenant'] = tenants_schema.get_tenant()
'''
This method is run before related .run() task method
'''
def before_run(self):
tenants_schema.set_tenant(self.run_args['tenant'])
Is there an elegant way of doing it in celery?
Celery (as of 3.1) has signals you can hook into to do this. You can alter the kwargs that were passed in, and on the other side, undo your alterations before they're given to the actual task:
from celery import shared_task
from celery.signals import before_task_publish, task_prerun, task_postrun
from threading import local
current_tenant = local()
#before_task_publish.connect
def add_tenant_to_task(body=None, **unused):
body['kwargs']['tenant_middleware.tenant'] = getattr(current_tenant, 'id', None)
print 'sending tenant: {t}'.format(t=current_tenant.id)
#task_prerun.connect
def extract_tenant_from_task(kwargs=None, **unused):
tenant_id = kwargs.pop('tenant_middleware.tenant', None)
current_tenant.id = tenant_id
print 'current_tenant.id set to {t}'.format(t=tenant_id)
#task_postrun.connect
def cleanup_tenant(**kwargs):
current_tenant.id = None
print 'cleaned current_tenant.id'
#shared_task
def get_current_tenant():
# Here is where you would do work that relied on current_tenant.id being set.
import time
time.sleep(1)
return current_tenant.id
And if you run the task (not showing logging from the worker):
In [1]: current_tenant.id = 1234; ct = get_current_tenant.delay(); current_tenant.id = 5678; ct.get()
sending tenant: 1234
Out[1]: 1234
In [2]: current_tenant.id
Out[2]: 5678
The signals are not called if no message is sent (when you call the task function directly, without delay() or apply_async()). If you want to filter on the task name, it is available as body['task'] in the before_task_publish signal handler, and the task object itself is available in the task_prerun and task_postrun handlers.
I am a Celery newbie, so I can't really tell if this is the "blessed" way of doing "middleware"-type stuff in Celery, but I think it will work for me.
I'm not sure what you mean here, is before_submit executed before the task is called by a client?
In that case I would rather use a with statement here:
from contextlib import contextmanager
#contextmanager
def set_tenant_db(tenant):
prev_tenant = tenants_schema.get_tenant()
try:
tenants_scheme.set_tenant(tenant)
yield
finally:
tenants_schema.set_tenant(prev_tenant)
#app.task
def tenant_task(tenant=None):
with set_tenant_db(tenant):
do_actions_here()
tenant_task.delay(tenant=tenants_scheme.get_tenant())
You can of course create a base task that does this automatically,
you can apply the context in Task.__call__ for example, but I'm not sure
if that saves you much if you can just use the with statement explicitly.