Deploying CherryPy application using gunicorn - python

I have a basic application written in CherryPy. It looks somewhat like this:
import cherrypy
class API():
#cherrypy.expose
def index(self):
return "<h3>Its working!<h3>"
if __name__ == '__main__':
cherrypy.config.update({
'server.socket_host': '127.0.0.1',
'server.socket_port': 8082,
})
cherrypy.quickstart(API())
I would like to deploy this application with gunicorn, possibly with multiple workers. gunicorn starts when I run this in terminal
gunicorn -b localhost:8082 -w 4 test_app:API
But everytime I try to access the default method, it gives an internal server error. However, running this standalone using CherryPy works.
Here is the error:
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/gunicorn/workers/sync.py", line 130, in handle
self.handle_request(listener, req, client, addr)
File "/usr/local/lib/python2.7/dist-packages/gunicorn/workers/sync.py", line 171, in handle_request
respiter = self.wsgi(environ, resp.start_response)
TypeError: this constructor takes no arguments
I have a fairly large CherryPy application that I would like to deploy using gunicorn. Is there any to mix CherryPy and gunicorn?

Related

Server Flask app with cheroot server results to error in HTTPServer.tick after each request

I'm trying to serve a Flask (v1.1.2) wsgi application using cheroot server of CherryPy (v18.6.0) and after each request executed via Postman or browser I'm getting the following exception in my console. I'm running python v3.8.5
Error in HTTPServer.tick
Traceback (most recent call last):
File "C:\myproject\venv\lib\site-packages\cheroot\server.py", line 1795, in serve
self.tick()
File "C:\myproject\venv\lib\site-packages\cheroot\server.py", line 2030, in tick
self.connections.expire()
File "C:\myproject\venv\lib\site-packages\cheroot\connections.py", line 107, in expire
for sock_fd, conn in timed_out_connections:
File "C:\myproject\venv\lib\site-packages\cheroot\connections.py", line 103, in <genexpr>
(sock_fd, conn)
File "C:\python\lib\_collections_abc.py", line 743, in __iter__
for key in self._mapping:
RuntimeError: dictionary changed size during iteration
Code as follows:
from cheroot.wsgi import Server
from flask import Flask
app = Flask(__name__)
#app.route("/", methods=["GET"])
def index():
return "Hello"
if __name__ == "__main__":
server = Server(bind_addr=("0.0.0.0", 3000), wsgi_app=app)
try:
server.start()
finally:
server.stop()
Any idea causing that exception and how we can resolve it?
This is a recent and acknowledged issue with cheroot, take a look to the cheroot GitHub Issue 312.

Apache Web server using flask, deploying my web app

I have a small flask application, and I am trying to host in on my website. It works whenever I run it on my computer, and connect via localhost:5000/ but when I upload to my server, and run the python code, i get multiple errors. When it runs, it only runs on localhost, and can be connected to via the servers console, but when I try to specify that it is to be hosted on all public facing ip's, it says operation not permitted.
here is the terminal output
`/home/public]$ python app.py
Traceback (most recent call last):
File "app.py", line 14, in <module>
app.run(host='0.0.0.0', port=port, debug=True)
File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 841, in
run
run_simple(host, port, self, **options)
File "/usr/local/lib/python2.7/site-packages/werkzeug/serving.py", line
717, in run_simple
s.bind((hostname, port))
File "/usr/local/lib/python2.7/socket.py", line 228, in meth
return getattr(self._sock,name)(*args)
socket.error: [Errno 1] Operation not permitted
`
my app.py
from flask import Flask, render_template, request
import time
app = Flask(__name__)
port=33
#app.route("/")
def index():
x = int(round(time.time() * 1000))
return render_template("index.html", stylevar=x)
if __name__ == "__main__":
app.run(host='0.0.0.0', port=port, debug=True)
if I connect via the domain name, and navigate to /templates, my index.html file will show, but it wont be running the python code.
Would really appreciate any direction on how to get it to be connected to from the browser. I understand that flask is not meant for production environments, but this is just a small personal project. If there are any other environments other than flask this could be accomplished in, I am willing to try something else.
The script does not have the rights for running with a port below of 1024. If you really need to use port 33 you have to run the script as root.

Deploying aiohttp.web Application using gunicorn and nginx

I am trying to deploy an aiohttp web app, but can't figure out how to get the app to serve over a unix socket, which I think I need in order to get nginx and gunicorn to talk to each other.
Simple example app from aiohttp documentation saved as app.py:
import asyncio
from aiohttp import web
#asyncio.coroutine
def hello(request):
return web.Response(body=b'Hello')
app = web.Application()
app.router.add_route('GET', '/', hello)
if __name__ == "__main__":
loop = asyncio.get_event_loop()
handler = app.make_handler()
f = loop.create_server(handler, '0.0.0.0', 8080)
srv = loop.run_until_complete(f)
try:
loop.run_forever()
except KeyboardInterrupt:
pass
finally:
loop.run_until_complete(handler.finish_connections(1.0))
srv.close()
loop.run_until_complete(srv.wait_closed())
loop.run_until_complete(app.finish())
loop.close()
Running this with gunicorn directly works:
gunicorn -k aiohttp.worker.GunicornWebWorker -b 0.0.0.0:8000 app:app
But when I try to bind it instead to a unix socket, I get the following errors.
gunicorn -k aiohttp.worker.GunicornWebWorker -b unix:my_sock.sock app:app
Traceback:
[2015-08-09 12:26:05 -0700] [26898] [INFO] Booting worker with pid: 26898
[2015-08-09 12:26:06 -0700] [26898] [ERROR] Exception in worker process:
Traceback (most recent call last):
File "/home/claire/absapp/venv/lib/python3.4/site- packages/gunicorn/arbiter.py", line 507, in spawn_worker
worker.init_process()
File "/home/claire/absapp/venv/lib/python3.4/site-packages/aiohttp/worker.py", line 28, in init_process
super().init_process()
File "/home/claire/absapp/venv/lib/python3.4/site-packages/gunicorn/workers/base.py", line 124, in init_process
self.run()
File "/home/claire/absapp/venv/lib/python3.4/site-packages/aiohttp/worker.py", line 34, in run
self.loop.run_until_complete(self._runner)
File "/usr/lib/python3.4/asyncio/base_events.py", line 268, in run_until_complete
return future.result()
File "/usr/lib/python3.4/asyncio/futures.py", line 277, in result
raise self._exception
File "/usr/lib/python3.4/asyncio/tasks.py", line 236, in _step
result = next(coro)
File "/home/claire/absapp/venv/lib/python3.4/site-packages/aiohttp/worker.py", line 81, in _run
handler = self.make_handler(self.wsgi, *sock.cfg_addr)
TypeError: make_handler() takes 4 positional arguments but 11 were given
[2015-08-09 12:26:06 -0700] [26898] [INFO] Worker exiting (pid: 26898)
I came across something in an aiohttp issue (https://github.com/KeepSafe/aiohttp/issues/136)
that uses socket to create a socket to put as a parameter in the loop.create_server() function, but I just couldn't get anything to work. (I also don't know if the app in his code is the same web.Application object)
Does anybody know how I can make this work? Thanks!
The problem is that GunicornWebWorker doesn't support unix domain sockets. It comes from GunicornWebWorker.make_handler(self, app, host, port), which wants parameters: host and port. Obviously you don't have them if you're using unix socket, but have path to socket instead.
Let's take a look at the beginning of GunicornWebWorker._run():
def _run(self):
for sock in self.sockets:
handler = self.make_handler(self.wsgi, *sock.cfg_addr)
...
In case of -b localhost:8000 sock.cfg_addr is ['localhost', 8000], but for -b unix:my_sock.sock it's just 'my_sock.sock'. This is where error TypeError: make_handler() takes 4 positional arguments but 11 were given comes from. It unpacks string, instead of list.
The quick way to fix it is to subclass GunicornWebWorker and redefine GunicornWebWorker.make_handler() to ignore host and port. They are not used anyway. You can do it like this:
class FixedGunicornWebWorker(worker.GunicornWebWorker):
def make_handler(self, app, *args):
if hasattr(self.cfg, 'debug'):
is_debug = self.cfg.debug
else:
is_debug = self.log.loglevel == logging.DEBUG
return app.make_handler(
logger=self.log,
debug=is_debug,
timeout=self.cfg.timeout,
keep_alive=self.cfg.keepalive,
access_log=self.log.access_log,
access_log_format=self.cfg.access_log_format)
NOTE You'll need to have package with fixed worker in your PYTHONPATH. Otherwise Gunicorn won't be able to locate it. For example if you put fixed worker inside fixed_worker.py file inside the same directory you run gunicorn from, you can use it like:
$ PYTHONPATH="`pwd`:$PYTHONPATH" gunicorn -k fixed_worker.FixedGunicornWebWorker -b unix:my_sock.sock app:app
UPD Also opened issue in aiohttp repository.

unable to serve pyramid app

I'm pretty inexperienced with gunicorn. I have it installed within a virtual env and am trying to serve a pyramid app with the following:
env/bin/gunicorn --pid /home/staging/gunicorn.pid --bind 0.0.0.0:8000 pyzendoc:main
However everytime a request is sent I get the following trace from gunicorn
2013-10-30 14:16:20 [1284] [ERROR] Error handling request
Traceback (most recent call last):
File "/home/staging/api/env/local/lib/python2.7/site-packages/gunicorn/workers/sync.py", line 126, in handle_request
respiter = self.wsgi(environ, resp.start_response)
TypeError: main() takes exactly 1 argument (2 given)
I'm guessing that main in the gunicorn refers to the main method in pyramids init but that method takes (global_config, **settings) as args so I think that maybe gunicorn is somehow looking at the wrong method. Has anyone seen anything similar before?
Thanks
C
The invocation pyzendoc:main is expecting to find a callable that accepts an (environ, start_response) signature, as a WSGI app, which you don't have until main(global_conf, **settings) returns one. A better option is to use gunicorn_paster, as shown here.

Troubleshoot TemplateNotFound error from Flask under Gunicorn

I've got a Flask app that I'm trying to deploy using Gunicorn and nginx. However, although it works fine locally, it throws a TemplateNotFound error when I run in with Gunicorn on my remote server.
I'm not sure how to even start debugging this, let alone why it's failing...would love help on the former, if not the latter. I thought maybe it was a permissions issue, so chmod'd the templates folder to 777...no luck. Here's all the relavant details:
install script
Starting with a bare Ubuntu 10.04 install, I run this to set up the server and pull in my code: https://github.com/total-impact/total-impact-deploy/blob/master/deploy.sh. Then I put this nginx config file at /etc/nginx/sites-available/total-impact:
server {
location / {
proxy_pass http://127.0.0.1:8000;
}
}
Finally, I navigate the app directory and run gunicorn web:app, and hit the server's IP address. This generates a 500 in the browser, and this output on the command line:
stack trace:
root#jc:/home/ti/total-impact-webapp/totalimpactwebapp# gunicorn web:app2012-05-28 23:15:06 [15313] [INFO] Starting gunicorn 0.14.3
2012-05-28 23:15:06 [15313] [INFO] Listening at: http://127.0.0.1:8000 (15313)
2012-05-28 23:15:06 [15313] [INFO] Using worker: sync
2012-05-28 23:15:06 [15316] [INFO] Booting worker with pid: 15316
2012-05-28 23:15:12,274 - totalimpactwebapp.core - ERROR - Exception on / [GET]
Traceback (most recent call last):
File "/usr/local/lib/python2.6/dist-packages/flask/app.py", line 1292, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python2.6/dist-packages/flask/app.py", line 1062, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python2.6/dist-packages/flask/app.py", line 1060, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python2.6/dist-packages/flask/app.py", line 1047, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/home/ti/total-impact-webapp/totalimpactwebapp/web.py", line 60, in home
return render_template('index.html', commits=False)
File "/usr/local/lib/python2.6/dist-packages/flask/templating.py", line 120, in render_template
return _render(ctx.app.jinja_env.get_template(template_name),
File "/usr/local/lib/python2.6/dist-packages/jinja2/environment.py", line 719, in get_template
return self._load_template(name, self.make_globals(globals))
File "/usr/local/lib/python2.6/dist-packages/jinja2/environment.py", line 693, in _load_template
template = self.loader.load(self, name, globals)
File "/usr/local/lib/python2.6/dist-packages/jinja2/loaders.py", line 115, in load source, filename, uptodate = self.get_source(environment, name)
File "/usr/local/lib/python2.6/dist-packages/flask/templating.py", line 61, in get_source
raise TemplateNotFound(template)
TemplateNotFound: index.html
Are your templates in [app root]/templates/?
If so, check to be sure your path is correct. Put this as the first line in the view that handles your homepage:
return app.root_path
If that's what you expect to see - or if you're using Blueprints or another method that changes the default Jinja Environment somehow - it's a little more complicated.
Oddly, Jinja doesn't seem to have a jinja2.Environment.FileSystemLoader.get_search_path() method. I assumed it would have one :(
Today, I experienced identical problems after a long period of my Flask app behaving quite normally (ie not throwing TemplateNotFound exceptions). None of the approaches mentioned by others here hit the mark or seemed appropriate (eg app.debug, path manipulation).
Instead, I tracked it down to the standard Flask app initialisation line:
app = Flask(__name__)
I had changed __name__ to another value (to get access to a named logger), not expecting for all this carnage to unfold :-) Don't change this value unless you are very familiar with Flask internals.
I have just spent 2 hours in a very similar situation and thought I'd post what ended up being the solution.
I was suddenly getting TemplateNotFound errors in the Apache logs from my Flask application, in production, which had been running fine until then. This resulted in 500 errors across the site.
First issue was that the TemplateNotFound errors did not show unless I had Flask's "debug" flag on -- there was no sign of any problems at all in the Apache log despite LogLevel set to info.
Running the app "locally" (Flask listens on localhost:5000) was fine (one can test the pages via wget 127.0.0.0:5000). It turned out that a copy of the main web app python code had somehow landed in the directory above where it should have been. This was imported by wsgi first and, as a result, the relative path to templates was incorrect.

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