I am using flask and flask-restx try to create a protocol to get a specific string from another service. I am trying to figure out a way to run the function in server in different threads. Here's my code sample:
from flask_restx import Api,fields,Resource
from flask import Flask
app = Flask(__name__)
api = Api(app)
parent = api.model('Parent', {
'name': fields.String(get_answer(a,b)),
'class': fields.String(discriminator=True)
})
#api.route('/language')
class Language(Resource):
# #api.marshal_with(data_stream_request)
#api.marshal_with(parent)
#api.response(403, "Unauthorized")
def get(self):
return {"happy": "good"}
What I expect:
In Client side, first the server should run, i.e., we should able to make curl -i localhost:8080 work. Then when a specific condition is true, the client side should receive a GET request with the parent JSON data I have in server. However, if that condition is true, the GET request should not be able to return the correct result.
What I did:
One of the method I used is wrap up the decorator and Class Language(Resource) part in a different function and wrong that function in a different thread, and put that thread under a condition check. Not sure if that's the right way to do.I was seeing anyone said celery might be a good choice but not sure if that can work in flask-restx.
I have the answer for you. to run a process in the background with flask, schedule it to run using another process using APScheduler. A very simple package that helps you schedule tasks to run functions at an interval, in your case one time at utcnow().
here is the link to Flask-APScheduler.
job = scheduler.add_job(myfunc, 'interval', minutes=2)
In your case use 'date' instead of 'interval' and specify run_date
job = scheduler.add_job(myfunc, 'date', run_date=datetime.utcnow())
You can send arguments to the function:
job = scheduler.add_job(myfunc, 'date', args = (your args), run_date=datetime.utcnow())
here is the documentation:
User Guide
Is there a way to set connections / variables programtically in airflow? I am aware this is defeating the very purpose of not exposing these details in the code, but to debug it would really help me big time if I could do something like the following pseudo code:
# pseudo code
from airflow import connections
connections.add({name:'...',
user:'...'})
Connection is DB entity and you can create it. See below
from airflow import settings
from airflow.models import Connection
conn = Connection(
conn_id=conn_id,
conn_type=conn_type,
host=host,
login=login,
password=password,
port=port
)
session = settings.Session()
session.add(conn)
session.commit()
As for variables - just use the API. See example below
from airflow.models import Variable
Variable.set("my_key", "my_value")
A good blog post on this topic can be found here.
I'm running a Bokeh app as shown in standalone_embed.py and want to use an authentication hook with it, as shown here. How do I set the auth_module in bokeh.settings.settings in standalone_embed.py?
I tried
from bokeh.settings import settings
settings.auth_module = "auth.py"
settings.xsrf_cookies = True
but that doesn't seem to do anything. Any help appreciated, thanks!
Found the answer:
Server can take the authentication module as param as follows:
auth_module_path = <path to auth.py>
if auth_module_path:
server_kwargs['auth_provider'] = AuthModule(auth_module_path)
server = Server(
bokeh_applications, # list of Bokeh applications
io_loop=loop, # Tornado IOLoop
**server_kwargs # port, num_procs, etc.
)
Trying to get authentication working with Django channels with a very simple websockets app that echoes back whatever the user sends over with a prefix "You said: ".
My processes:
web: gunicorn myproject.wsgi --log-file=- --pythonpath ./myproject
realtime: daphne myproject.asgi:channel_layer --port 9090 --bind 0.0.0.0 -v 2
reatime_worker: python manage.py runworker -v 2
I run all processes when testing locally with heroku local -e .env -p 8080, but you could also run them all separately.
Note I have WSGI on localhost:8080 and ASGI on localhost:9090.
Routing and consumers:
### routing.py ###
from . import consumers
channel_routing = {
'websocket.connect': consumers.ws_connect,
'websocket.receive': consumers.ws_receive,
'websocket.disconnect': consumers.ws_disconnect,
}
and
### consumers.py ###
import traceback
from django.http import HttpResponse
from channels.handler import AsgiHandler
from channels import Group
from channels.sessions import channel_session
from channels.auth import channel_session_user, channel_session_user_from_http
from myproject import CustomLogger
logger = CustomLogger(__name__)
#channel_session_user_from_http
def ws_connect(message):
logger.info("ws_connect: %s" % message.user.email)
message.reply_channel.send({"accept": True})
message.channel_session['prefix'] = "You said"
# message.channel_session['django_user'] = message.user # tried doing this but it doesn't work...
#channel_session_user_from_http
def ws_receive(message, http_user=True):
try:
logger.info("1) User: %s" % message.user)
logger.info("2) Channel session fields: %s" % message.channel_session.__dict__)
logger.info("3) Anything at 'django_user' key? => %s" % (
'django_user' in message.channel_session,))
user = User.objects.get(pk=message.channel_session['_auth_user_id'])
logger.info(None, "4) ws_receive: %s" % user.email)
prefix = message.channel_session['prefix']
message.reply_channel.send({
'text' : "%s: %s" % (prefix, message['text']),
})
except Exception:
logger.info("ERROR: %s" % traceback.format_exc())
#channel_session_user_from_http
def ws_disconnect(message):
logger.info("ws_disconnect: %s" % message.__dict__)
message.reply_channel.send({
'text' : "%s" % "Sad to see you go :(",
})
And then to test, I go into Javascript console on the same domain as my HTTP site, and type in:
> var socket = new WebSocket('ws://localhost:9090/')
> socket.onmessage = function(e) {console.log(e.data);}
> socket.send("Testing testing 123")
VM481:2 You said: Testing testing 123
And my local server log shows:
ws_connect: test#test.com
1) User: AnonymousUser
2) Channel session fields: {'_SessionBase__session_key': 'chnb79d91b43c6c9e1ca9a29856e00ab', 'modified': False, '_session_cache': {u'prefix': u'You said', u'_auth_user_hash': u'ca4cf77d8158689b2b6febf569244198b70d5531', u'_auth_user_backend': u'django.contrib.auth.backends.ModelBackend', u'_auth_user_id': u'1'}, 'accessed': True, 'model': <class 'django.contrib.sessions.models.Session'>, 'serializer': <class 'django.core.signing.JSONSerializer'>}
3) Anything at 'django_user' key? => False
4) ws_receive: test#test.com
Which, of course, makes no sense. Few questions:
Why would Django see message.user as an AnonymousUser but have the actual user id _auth_user_id=1 (this is my correct user ID) in the session?
I am running my local server (WSGI) on 8080 and daphne (ASGI) on 9090 (different ports). And I didn't include session_key=xxxx in my WebSocket connection - yet Django was able to read my browser's cookie for the correct user, test#test.com? According to Channels docs, this shouldn't be possible.
Under my setup, what is the best / simplest way to carry out authentication with Django channels?
Note: This answer is explicit to channels 1.x, channels 2.x uses a different auth mechanism.
I had a hard time with django channels too, i had to dig into the source code to better understand the docs ...
Question 1:
The docs mention this kind of long trail of decorators relying on each other (http_session, http_session_user ...) that you can use to wrap your message consumers, in the middle of that trail it states this:
Now, one thing to note is that you only get the detailed HTTP information during the connect message of a WebSocket connection (you can read more about that in the ASGI spec) - this means we’re not wasting bandwidth sending the same information over the wire needlessly.
This also means we’ll have to grab the user in the connection handler and then store it in the session;....
Its easy to get lost in all that, at least we both did ...
You just have to remember that this happens when you use channel_session_user_from_http:
It calls http_session_user
a. calls http_session which will parse the message and give us a message.http_session attribute.
b. Upon returning from the call, it initiates a message.user based on the information it got in message.http_session ( this will bite you later)
It calls channel_session which will initiate a dummy session in message.channel_session and ties it to the message reply channel.
Now it calls transfer_user which will move the http_session into the channel_session
This happens during the connection handling of a websocket, so on subsequent messages you won't have acces to detailed HTTP information, so what's happening after the connect is that you're calling channel_session_user_from_http again, which in this situation (post-connect messages) calls http_session_user which will attempt reading the Http information but fails resulting in setting message.http_session to None and overriding message.user to AnonymousUser.
That's why you need to use channel_session_user in this case.
Question 2:
Channels can use Django sessions either from cookies (if you’re running your websocket server on the same port as your main site, using something like Daphne), or from a session_key GET parameter, which works if you want to keep running your HTTP requests through a WSGI server and offload WebSockets to a second server process on another port.
Remember http_session, that decorator that gets us the message.http_session data? it appears that if it doesn't find a session_key GET parameter it fails to settings.SESSION_COOKIE_NAME, which is the regular sessionid cookie, so whether you provide session_key or not, you'll still get connected if you're logged in, of course that happens only when your ASGI and WSGI servers are on the same domain (127.0.0.1 in this case), the port difference doesn't matter.
I think the difference that the docs are trying to communicate but didn't expand on is that you need to setup session_key GET parameter when having your ASGI and WSGI servers on different domains since cookies are restricted by domain not port.
Due to that lack of explanation i had to test running ASGI and WSGI on same port and different port and the result was the same, i was still getting authenticated, changed one server domain to 127.0.0.2 instead of 127.0.0.1 and the authentication was gone, set the session_key get parameter and the authentication was back again.
Update: a rectification of the docs paragraph was just pushed to the channels repo, it was meant to mention domain instead of port like i mentioned.
Question 3:
my answer is the same as turbotux's but longer, you should use #channel_session_user_from_http on ws_connect and #channel_session_user on ws_receive and ws_disconnect, nothing from what you showed tells that it won't work if you do that change, maybe try removing http_user=True from your receive consumer? even thou i suspect it has no effect since its undocumented and intended only to be used by Generic Consumers...
Hope this helps!
To answer your first question you need to use the:
channel_session_user
decorator in the receive and disconnect calls.
channel_session_user_from_http
calls the transfer_user session during the connect method to transfer the http session to the channel session. This way all future calls may access the channel session to retrieve user information.
To your second question I believe what you are seeing is that default web socket library passes the browser cookies over the connection.
Third, I think your setup will be working quite well once have changed the decorators.
I ran into this problem and I found that it was due to a couple of issues that might be the cause. I'm not suggesting this will solve your issue, but might give you some insight. Keep in mind I am using rest framework. First I was overriding the User model. Second when I defined the application variable in my root routing.py I didn't use my own AuthMiddleware. I was using the docs suggested AuthMiddlewareStack. So, per the Channels docs, I defined my own custom authentication middleware, which takes my JWT value from the cookies, authenticates it and assigns it to the scope["user"] like so:
routing.py
from channels.routing import ProtocolTypeRouter, URLRouter
import app.routing
from .middleware import JsonTokenAuthMiddleware
application = ProtocolTypeRouter(
{
"websocket": JsonTokenAuthMiddleware(
(URLRouter(app.routing.websocket_urlpatterns))
)
}
middleware.py
from http import cookies
from django.contrib.auth.models import AnonymousUser
from django.db import close_old_connections
from rest_framework.authtoken.models import Token
from rest_framework_jwt.authentication import BaseJSONWebTokenAuthentication
class JsonWebTokenAuthenticationFromScope(BaseJSONWebTokenAuthentication):
def get_jwt_value(self, scope):
try:
cookie = next(x for x in scope["headers"] if x[0].decode("utf-8")
== "cookie")[1].decode("utf-8")
return cookies.SimpleCookie(cookie)["JWT"].value
except:
return None
class JsonTokenAuthMiddleware(BaseJSONWebTokenAuthentication):
def __init__(self, inner):
self.inner = inner
def __call__(self, scope):
try:
close_old_connections()
user, jwt_value =
JsonWebTokenAuthenticationFromScope().authenticate(scope)
scope["user"] = user
except:
scope["user"] = AnonymousUser()
return self.inner(scope)
Hope this helps this helps!
I would like to list Docker events using its API, so I created this class:
This is the simplest form of my code:
#!/usr/bin/env python
import requests_unixsocket
import json
session = requests_unixsocket.Session()
resp = session.get("http+unix://%2Fvar%2Frun%2Fdocker.sock/events")
print resp
When I run the script and create a Docker network in another terminal, I am supposed to see something like that:
{"Type":"network","Action":"create","Actor":{"ID":"20f9f862aa509bdd2b147252c3cb50f035b1e7b36542c9f7fad4ccbce0206507","Attributes":{"name":"network15","type":"bridge"}},"time":1481387403,"timeNano":1481387403635383908}
But I don't see anything happening, it seems like the program is listening in a infinite loop but not showing anything like I said.
Do you have an idea on how to stream these events and show them on my terminal ?
Found something. Adding stream = True resolved the problem:
session.get( self.base + self.url, stream= True)