Setup gevent with Lighttpd, weird stuff - python

I have wary odd problem. I configured Lighttpd to pass /test to fastcgi backend.
just added this in config
fastcgi.server = ("/test" =>
("127.0.0.1" =>
(
"host" => "127.0.0.1",
"port" => 7101,
"docroot" => "/",
"check-local" => "disable"
)
)
)
Now, when i start flup example, and hit 127.0.0.1:80/test everything work fine. Tested uWSGI to, still fine.
flup example:
#!/usr/bin/env python
from flup.server.fcgi import WSGIServer
def myapp(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/plain')])
return ['Hello World']
WSGIServer(myapp, bindAddress = ('127.0.0.1',7101)).run()
Now, only problem is when I start gevent it won't work. Lighttpd mod_fastcgi says that backend just blocked.
Funny part is when I alter handler to return just string, cause WSGI require iterable, and hit 127.0.0.1:7101 from my browser it work as expected. This should be WSGIServer, how can it work this way?
Here is gevent code:
#!/usr/bin/python
"""WSGI server example"""
from gevent.wsgi import WSGIServer
def app(env, start_response):
start_response('200 OK', [('Content-Type','text/html')])
#return ["Hello World", StopIteration] # this is WSGI test, not working
return "Hello World"
# when set like this, frontend :80 still wont work (500 Internal error),
# but 127.0.0.1:7101 work like standard http
if __name__ == '__main__':
WSGIServer(('', 7101), app).serve_forever()
Bottom line is , why only gevent wont work in this setup, and both flup and uWSGI are working? Is there some secret setting not mention in official example here.

Because gevent.wsgi.WSGIServer is not a fcgi server, it's only http server. Your can proxy your requests from lighttpd to gevent as http, or use wsgi.

U can see that flup here states it SPEAK FastCGI (not HTTP), and uWSGI here says "Born as a WSGI-only server".
Now Gevent says here "Fast WSGI server based on libevent-http", that confused me, but then I try gunicorn, and it steel failed.
Then i found here "Gunicorn 'Green Unicorn' is a Python WSGI HTTP Server for UNIX". That means that gevent and gunicorn WSGI handlers are HTTP request not FastCGI, but ,as Fedor Gogolev said, for your handlers they are WSGI servers.
So for Flup and uWSGI u configure lighttpd (or any other web server) to use fastcgi module, but for gunicorn and gevent u use proxy module, and for them u don't have to use frontend at all!If don't have static stuff to serve or other reason u can omit frontend cause gunicorn state it is wary fast and stable.

Related

Flask, FlaskSocketIO - RuntimeError: Cannot obtain socket from WSGI environment

When I try to use the functionality that uses websockets in my application, I get this error in the console:
File "/Users/user/venv/lib/python3.7/site-packages/simple_websocket/ws.py", line 138, in __init__
raise RuntimeError('Cannot obtain socket from WSGI environment.')
RuntimeError: Cannot obtain socket from WSGI environment.
I also get this error in the browser console:
WebSocket connection to 'ws://localhost:5000/socket.io/?EIO=4&transport=websocket&sid=40NYzDgGYStMR0CEAAAJ' failed:
I tried using gevent, gevent-websocket, and eventlet, but this created other issues, and I'm not sure that I need to use gevent or eventlet for this use case.
Here's the rest of the relevant code:
__ init __.py
from flask_socketio import SocketIO
...
socketio = SocketIO()
def create_app(config_class=Config):
app = Flask(__name__)
app.config.from_object(Config)
socketio.init_app(app, cors_allowed_origins='*')
...
return app
app.py
from app import create_app, socketio
app = create_app()
if __name__ == '__main__':
socketio.run(app)
routes.py
This only accepts POST requests because I send data to this route from a Celery task
from app import socketio
...
#main_bp.route('/send_message', methods=['POST'])
def send_message():
...
socketio.emit('test_message', {'msg':'Test'}, namespace='/test')
return 'Results Sent'
index.html
var socket = io.connect('http://localhost:5000/test');
socket.on('connect', function(){
console.log('Connected to socket')
});
socket.on('test_message', function(message){
console.log('Received test message');
}
)
Note that in the browser console I'll see "Connected to socket", but not "Received test message"
You are using the simple-websocket package. This package has a list of supported web servers. The error indicates that you are using a web server that is not in the supported list.
Supported web servers are:
The Flask dev server (for development purposes only, of course)
Gunicorn
Eventlet
Gevent
From this list, it seems your only choice for a production web server is Gunicorn, since you say that eventlet/gevent won't work for your needs.
The use of Gunicorn is covered in the documentation. In that section, simple-websocket is the third option mentioned. Here is the example start up command:
gunicorn -w 1 --threads 100 module:app
Maybe you can turn on the logger and the engine.io logger. that qould give you an idea what is the issue.
don't use eventlet and gevent together. use anyone and uninstall the other.

How to launch a Bottle application over a CherryPy standalone web server?

I have a python web app developed using the bottle framework. My bottle app is web API that provide methods that return JSon data, so no static content is needed. I am trying to deploy it to production using a CherryPy server which is supposed to be robust for production applications.
My web_api.py file (my bottle app) looks something like this:
from bottle import Bottle, request
app = Bottle()
#app.get('/stuff')
def do_stuff():
'''
Method that does stuff.
'''
stuff = {'data': 'some data'}
# Return the environment info as Json data
return stuff
I have a server.py file to launch the Bottle app over the CherryPy server that looks like this:
from my_package.web_api import app
from cherrypy.wsgiserver import CherryPyWSGIServer
server = CherryPyWSGIServer(
('0.0.0.0', 80),
app,
server_name='My_App',
numthreads=30)
server.start()
so when I run my server using this command:
python server.py
My server is successfully started and start listening in port 80 as expected. However once I start my web server I cannot stop it any more. I have tried Ctrl + C which works with the development server but has no effect here. Am I starting the server the right way? How do I stop it once it is running? Is this the correct way to launch a Bottle app over CherryPy?
BTW, I am running python 2.7 in Windows 8.
Your code is correct, you just need to add a try/catch statement:
from my_package.web_api import app
from cherrypy.wsgiserver import CherryPyWSGIServer
server = CherryPyWSGIServer(
('0.0.0.0', 80),
app,
server_name='My_App',
numthreads=30)
try:
server.start()
except KeyboardInterrupt:
server.stop()
You might wanna also consider to do some logging with wsgi-request-logger or something similar.
This are three alternative ways on hosting a WSGI application within cherrypy:
import cherrypy as cp
from cherrypy.wsgiserver import CherryPyWSGIServer
from cherrypy.process.servers import ServerAdapter
from bottle import Bottle
app = Bottle()
#app.get('/stuff')
def do_stuff():
'''
Method that does stuff.
'''
stuff = {'data': 'some dataX'}
return stuff
def run_decoupled(app, host='0.0.0.0', port=8080, **config):
server = CherryPyWSGIServer((host, port), app, **config)
try:
server.start()
except KeyboardInterrupt:
server.stop()
def run_in_cp_tree(app, host='0.0.0.0', port=8080, **config):
cp.tree.graft(app, '/')
cp.config.update(config)
cp.config.update({
'server.socket_port': port,
'server.socket_host': host
})
cp.engine.signals.subscribe() # optional
cp.engine.start()
cp.engine.block()
def run_with_adapter(app, host='0.0.0.0', port=8080, config=None, **kwargs):
cp.server.unsubscribe()
bind_addr = (host, port)
cp.server = ServerAdapter(cp.engine,
CherryPyWSGIServer(bind_addr, app, **kwargs),
bind_addr).subscribe()
if config:
cp.config.update(config)
cp.engine.signals.subscribe() # optional
cp.engine.start()
cp.engine.block()
The run_in_cp_tree and run_with_adapter functions are using the cherrypy engine, which enables the use of plugins to have off-the-shelf auto-reload, pidfile, daemonization, signal management and some more goodies, along with the possibility to create one of your own.
Notice that you can also use the WSGIPathInfoDispatcher to attach multiple wsgi applications on the CherryPyWSGIServer.
Trying to connect any WSGI server to my BottlePy app here in 2019 turned out to be rather tricky(to a noobie like me).
I tried connecting several ones, spent most off my time with CherryPy, which has changed his syntax.
The simpliest to me turned out to be waitress https://waitress.readthedocs.io/en/latest/usage.html
After i figured out how to use it on waitress i got it in cherrypy also. So:
CherryPy http://docs.cherrypy.org/en/latest/advanced.html?highlight=WSGi#host-a-foreign-wsgi-application-in-cherrypy
1)add after imports
import cherrypy as cp
app = bottle.Bottle()
2) change in routes "#bottle" to "#app"
3)add this as main function
cp.tree.graft(app, '/')
cp.server.start()
Waitress
1)add after imports
import waitress
app = bottle.Bottle()
2)add this as main function
waitress.serve(app, listen='*:44100')
3) change in routes "#bottle" to "#app"

Running Tornado in apache

My end goal is to implement a WebSocket server using python.
I'm accomplishing this by importing tornado in my python scripts. I've also installed mod_wsgi in apache, and their script outputs Hello World!, so WSGI seems to be working fine. Tornado is also working fine as far as I can tell.
The issue comes when I use tornado's wsgi "Hello, world" script:
import tornado.web
import tornado.wsgi
import wsgiref.simple_server
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world")
if __name__ == "__main__":
application = tornado.wsgi.WSGIApplication([
(r"/", MainHandler),
])
server = wsgiref.simple_server.make_server('', 8888, application)
server.serve_forever()
First, I get a 500 error and the log tells me WSGI can't find 'application'.
So I remove if __name__ == "__main__", and the page loads infinitely.
I assume this is because of server.serve_forever() so I removed it in an attempt to see Hello, world
But now I just get 404: Not Found. It's not my apache 404 page, and I know that the server can find my main .wsgi file...
You can't use websockets with Tornado's WSGIApplication. To use Tornado's websocket support you have to use Tornado's HTTPServer, not apache.
The WSGIApplication handlers are relative to the webserver root. If your application url is /myapp, your 'application' must look like this:
application = tornado.wsgi.WSGIApplication([
(r"/myapp", MainHandler),
(r"/myapp/login/etc", LoginEtcHandler),
])
Oh, and it seems like the documentation is shit (as usual) and __name__ will look something like this when running under apache: _mod_wsgi_8a447ce1677c71c08069303864e1283e.
So! a correct "Hello World" python script will look like this:
/var/www/wsgi-scripts/myapp.wsgi:
import tornado.web
import tornado.wsgi
import wsgiref.simple_server
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write('Hello World')
application = tornado.wsgi.WSGIApplication([
(r"/myapp", MainHandler),
])
And in the apache config (not .htaccess):
WSGIScriptAlias /myapp /var/www/wsgi-scripts/myapp.wsgi
To use tornado in apache,add a mod-wsgi plugin to apache.
apt-get install libapache2-mod-wsgi
Write a tornado wsgi server with
.wsgi
NOTE:Dont use__name__
Configure the apache.conf to run your server.To configure use this mod-wsgi guide
If you still want to combine them both, you can use Apache as a proxy that will just be the 1st point in front of the user - but actually reroute the traffic to your local Tornado server ( In / Out )
In my case for example, my Apache listen in port 443 ( some default config )
Then I run my tornado in port 8080, and given a path - will redirect
#File: conf.d/myapp.conf
<VirtualHost *:80>
ErrorLog "logs/myapp_error_log"
ProxyPreserveHost On
ProxyRequests off
ProxyPreserveHost On
<Proxy *>
Require all granted
</Proxy>
RewriteEngine on
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
ProxyPassMatch "/myapp/(.*)" "http://localhost:8080/myapp/$1"
ProxyPassReverse "/myapp/" "http://localhost:8080/myapp/"
</VirtualHost>
If you're using RedHat "family" OS also turn on the ability to forward network connections:
setsebool -P httpd_can_network_connect 1

Serve static files in wsgi testing environment

I am building a wsgi application. The production environment is Apache mod_wsgi and configured appropriately. For development, I use wsgiref.simple_server to serve the wsgi app locally. However, I would like my dev server to serve static content also with minimal overhead. For purposes of answering the question, assume I want to serve static file "/favicon.ico".
I have come across the package "static": http://lukearno.com/projects/static/ but found the documentation a bit lacking, and haven't been able to configure it to serve both static content and my application.
Here is a sample wsgi application.
from cgi import parse_qs
def application(environ, start_response):
qs = parse_qs(environ['QUERY_STRING'])
response_body, content_type = ('Hello World', ('Content-type', 'text/plain'))
content_length = 0
for s in response_body:
content_length += len(s)
status = '200 OK'
response_headers = [content_type,
('Content-Length', str(content_length))]
start_response(status, response_headers)
return response_body
if __name__ == '__main__':
from wsgiref.simple_server import make_server
# Instantiate the WSGI web server.
httpd = make_server('192.168.1.1', # The host name.
8080, # A port number where to wait for the request.
application # Our application object name, in this case a function.
)
httpd.serve_forever()
Note: This may be a duplicate of unanswered question Serving static content with python wsgiref? from December. I wanted to add more than just a comment and did not want to dig up a dead thread.
Let me propose the werkzeug package. It comes with a SharedDataMiddleware that solves precisely this task.

Twisted web server behind apache - no resource found

I am running twisted.web.server on localhost at port 8001 and apache2 with mod_proxy.
Apache is set to proxy according to the following config
http://localhost/jarvis ----> http://localhost:8001/
The httpd config for this rule is
ProxyPass /jarvis http://localhost:8001/
ProxyPassReverse /jarvis http://localhost:8001/
The twisted app's code fragment for server config is as follows:
if __name__ == '__main__':
root = Resource()
root.putChild("clientauth", boshProtocol())
logging.basicConfig()
factory = Site(root)
reactor.listenTCP(8001, factory)
reactor.run()
When I go to
http://localhost:8001/clientauth
it runs as expected.
However when I use
http://localhost/jarvis/clientauth
It give the error - "No such child resource."
As i understand - the request is correctly proxied to the twisted web server. But why is the child resource not identified?
You are missing a RewriteRule. I haven't tested it, but the fix for your problem is more or less like this:
RewriteRule ^/jarvis/(.*) /$1
Be sure to have mod_rewrite enabled.
Here is a link I usually use for reference: http://httpd.apache.org/docs/2.0/misc/rewriteguide.html
Good luck!

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