I am spinning up a Waitress web server in a background thread to run functional tests. How it is possible to clean up and quit waitress at the end of test run in clean(ish) manner? The public waitress API gives only one way entry point which expects KeyboardInterrupt as the quit signal.
Currently I just run the server in a daemon thread and all new web servers are pending clean up until the test runner quits.
My test web server code:
"""py.test fixtures for spinning up a WSGI server for functional test run."""
import threading
import time
from pyramid.router import Router
from waitress import serve
from urllib.parse import urlparse
import pytest
from backports import typing
#: The URL where WSGI server is run from where Selenium browser loads the pages
HOST_BASE = "http://localhost:8521"
class ServerThread(threading.Thread):
"""Run WSGI server on a background thread.
This thread starts a web server for a given WSGI application. Then the Selenium WebDriver can connect to this web server, like to any web server, for running functional tests.
"""
def __init__(self, app:Router, hostbase:str=HOST_BASE):
threading.Thread.__init__(self)
self.app = app
self.srv = None
self.daemon = True
self.hostbase = hostbase
def run(self):
"""Start WSGI server on a background to listen to incoming."""
parts = urlparse(self.hostbase)
domain, port = parts.netloc.split(":")
try:
# TODO: replace this with create_server call, so we can quit this later
serve(self.app, host='127.0.0.1', port=int(port))
except Exception as e:
# We are a background thread so we have problems to interrupt tests in the case of error. Try spit out something to the console.
import traceback
traceback.print_exc()
def quit(self):
"""Stop test webserver."""
# waitress has no quit
# if self.srv:
# self.srv.shutdown()
Webtest provides a WSGI server named StopableWSGIServer that gets started in a separate thread, and then can be shutdown() when you are done running your tests.
Check out: https://docs.pylonsproject.org/projects/webtest/en/latest/api.html#module-webtest.http
According to the documentation it was specifically built for use with casperjs or selenium.
Related
I am trying to run an XMLRPC server and an XMLRPC client on Mininet hosts, using the script below.
from mininet.topo import Topo
from mininet.net import Mininet
from mininet.node import OVSController
class MyTopo(Topo):
def __init__(self):
# Initialize topology
Topo.__init__(self)
# Add hosts
server1 = self.addHost('server1')
server2 = self.addHost('server2')
# Add switch
s1 = self.addSwitch('s1')
# Add links
self.addLink(server1, s1)
self.addLink(server2, s1)
if __name__ == '__main__':
net = Mininet(topo=MyTopo(), controller=OVSController)
net.start()
print(net.hosts[0].cmd('python3 xmlrpc_server.py'))
print(net.hosts[1].cmd('python3 xmlrpc_client.py'))
The file xmlrpc_server.py is:
from xmlrpc.server import SimpleXMLRPCServer
import threading
def is_even(n):
return n%2 == 0
server = SimpleXMLRPCServer(("0.0.0.0", 8000), logRequests=True, allow_none = True)
server.register_function(is_even, "is_even")
print("Listening on port 8000...")
server_thread = threading.Thread(target=server.serve_forever)
server_thread.start()
The file xmlrpc_client.py is:
import xmlrpc.client
proxy = xmlrpc.client.ServerProxy("http://10.0.0.1:8000/")
print("3 is even: %s" % str(proxy.is_even(3)))
print("100 is even: %s" % str(proxy.is_even(100)))
The problem is that although I have used a thread, when I run the xmlrpc_server.py script on server1, the execution pauses at line server_thread.start() waiting for the script execution to be completed before moving on and thus never goes on to the next line, which means that the XMLRPC client script never runs. How do I overcome this problem?
P.S.: xmlrpc_server.py and xmlrpc_client.py can be executed through the server terminals (by using the commands xterm server1 and xterm server2 on Mininet CLI and then using the commands python3 xmlrpc_server.py and python3 xmlrpc_client.py on the xterm terminals that open), but I need to start the server and client through a python script so as to perform some further calculations after the communication between the two servers.
Replace print(net.hosts[0].cmd('python3 xmlrpc_server.py')) with print(net.hosts[0].sendCmd('python3 xmlrpc_server.py')). Connection is sometimes refused, but that issue can be resolved with exception handling on the client script.
I have the following problem.
I'd like to run tests on the local flask server before deploying to production. I use pytest for that. My conftest.py looks like that for the moment:
import pytest
from toolbox import Toolbox
import subprocess
def pytest_addoption(parser):
"""Add option to pass --testenv=local to pytest cli command"""
parser.addoption(
"--testenv", action="store", default="exodemo", help="my option: type1 or type2"
)
#pytest.fixture(scope="module")
def testenv(request):
return request.config.getoption("--testenv")
#pytest.fixture(scope="module")
def testurl(testenv):
if testenv == 'local':
return 'http://localhost:5000/'
else:
return 'https://api.domain.com/'
This allows me to test the production api by typing the command pytest and to test a local flask server by typing pytest --testenv=local
This code WORKS flawlessly.
My problem is that I have to manually instantiate the local flask server from the terminal each time I want to test locally like this:
source ../pypyenv/bin/activate
python ../app.py
Now I wanted to add a fixture that initiates a terminal in the background at the beginning of the tests and closes the server down after having finished testing. After a lot of research and testing, I still cannot get it to work. This is the line I added to the conftest.py:
#pytest.fixture(scope="module", autouse=True)
def spinup(testenv):
if testenv == 'local':
cmd = ['../pypyenv/bin/python', '../app.py']
p = subprocess.Popen(cmd, shell=True)
yield
p.terminate()
else:
pass
The errors I get are from the requests package that says that there is no connection/ refused.
E requests.exceptions.ConnectionError:
HTTPConnectionPool(host='localhost', port=5000): Max retries exceeded
with url: /login (Caused by
NewConnectionError(': Failed to establish a new connection:
[Errno 111] Connection refused',))
/usr/lib/python3/dist-packages/requests/adapters.py:437:
ConnectionError
This means for me that the flask server under app.py is not online. Any suggestions? I am open to more elegant alternatives
For local testing the Flask test_client is a more elegant solution. See the docs on Testing. You can create a fixture for the test_client and create test requests with that:
#pytest.fixture
def app():
app = create_app()
yield app
# teardown here
#pytest.fixture
def client(app):
return app.test_client()
And use it like this:
def test_can_login(client):
response = client.post('/login', data={username='username', password='password'})
assert response.status_code == 200
If the only problem are the manual steps, maybe consider a bash script that does your manual setup for you and after that executes pytest.
I am using the following for this purpose so that testing configuration is also preserved in the test server
#pytest.fixture(scope="session")
def app():
db_fd, db_path = tempfile.mkstemp()
app = create_app({
'TESTING': True,
'DATABASE': db_path
})
yield app
os.close(db_fd)
os.unlink(db_path)
from flask import request
def shutdown_server():
func = request.environ.get('werkzeug.server.shutdown')
if func is None:
raise RuntimeError('Not running with the Werkzeug Server')
func()
#pytest.fixture
def server(app):
#app.route('/shutdown',methods=('POST',))
def shutdown():
shutdown_server()
return 'Shutting down server ...'
import threading
t = threading.Thread(target=app.run)
yield t.start()
import requests
requests.post('http://localhost:5000/shutdown')
References
https://flask.palletsprojects.com/en/1.1.x/tutorial/tests/
How do I terminate a flask app that's running as a service?
How to stop flask application without using ctrl-c
With a bash script (thanks #ekuusela) I now finally succeeded in what I wanted.
I added a fixture that calls the bashscript spinserver.sh in a new terminal window. This works in ubuntu, the command is different in different environments (see Execute terminal command from python in new terminal window? for other environments).
#pytest.fixture(scope="session", autouse=True)
def client(testenv):
if testenv != 'local':
pass
else:
p = subprocess.Popen(['gnome-terminal', '-x', './spinserver.sh'])
time.sleep(3)
yield
Here the very simple bashscript
#!/bin/bash
cd ..
source pypyenv/bin/activate
python app.py
The sleep command is necessary because the server takes some time to
initialize.
Don't forget to make your bash script executable (chmod
u+x spinserver.sh)
I tried to do a teardown after yield, but p.kill does not really
close the window. This is acceptable for me as it does not matter
if I have to manually close a terminal window & I can even see
flask debugging if necessary
This is my code:
import _thread
import http.server
import socketserver
def func():
PORT = 8002
Handler = http.server.SimpleHTTPRequestHandler
httpd = socketserver.TCPServer(("", PORT),Handler)
_thread.start_new_thread(httpd.serve_forever())
func()
I want to run this on the background, Is it possible.The above code is not working as expected it is working on the foreground.How can I make it on the Background?
I want this to test my downloader written in python.
.....
r=requests.get('http://localhost:8002/file.dat',stream=True)
with open('file.dat','wb')as f:
for chunk in r.iter_content(chunk_size=(1*1024*1024):
f.write(chunk)
......
And I can't use more than one processor because I am writing this code in pythonista in iOS which does not support the use of more than one process but supports the use of multithreading
My small aiohttp1 app was working fine until I have started preparing for deploying to Heroku servers. Heroku forces me to use gunicorn. It wasn't working with aiohttp1 (some strange errors), and after a small migration aiohttp2 I have started app with
gunicorn app:application --worker-class aiohttp.GunicornUVLoopWebWorker
command and I works, until I have requested view that calls class' async method with
with async_timeout.timeout(self.timeout):
res = await self.method()
code inside and it raises RuntimeError: Timeout context manager should be used inside a task error.
The only thing that changed until last successful version: the fact that I'm using gunicorn. I'm using Python 3.5.2 and uvloop 0.8.0 and gunicorn 19.7.1.
What is wrong and how can I fix this?
UPD
The problem is that I have LOOP variable that store newly created event loop. This variable definition is in setting.py file, so before aiohttp.web.Application creating, code below gets evaluated:
LOOP = uvloop.new_event_loop()
asyncio.set_evet_loop(LOOP)
and this causes error when using async_timeout.timeout context manager.
Code to reproduce the error:
# test.py
from aiohttp import web
import uvloop
import asyncio
import async_timeout
asyncio.set_event_loop(uvloop.new_event_loop())
class A:
async def am(self):
with async_timeout.timeout(timeout=1):
await asyncio.sleep(0.5)
class B:
a = A()
async def bm(self):
await self.a.am()
b = B()
async def hello(request):
await b.bm()
return web.Response(text="Hello, world")
app = web.Application()
app.router.add_get('/', hello)
if __name__ == '__main__':
web.run_app(app, port=5000, host='localhost')
and just run gunicorn test:app --worker-class aiohttp.GunicornUVLoopWebWorker (same error when using GunicornWebWorker with uvloop event loop, or any other combination).
solution
I have fixed this by calling asyncio.get_event_loop when I need to use event loop.
I want to set variables when starting my Tornado webserver, so I tried to override initialize on my RequestHandler class. But apparently, initialize is launched each time a request is made, according to the following code and its output:
#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
import tornado.web
class MainHandler(tornado.web.RequestHandler):
def initialize(self):
print("Launching initialization...")
def get(self):
print("Get: {}{}".format(self.request.host, self.request.uri))
app = tornado.web.Application([=
(r"/.*", MainHandler)
])
def runserver():
import tornado.ioloop
app.listen(8080)
tornado.ioloop.IOLoop.instance().start()
if __name__ == "__main__":
runserver()
stdout:
~ ➤ ./redirector.py
Launching initialization...
Get: 127.0.0.1:8080/
Launching initialization...
Get: 127.0.0.1:8080/favicon.ico
Launching initialization...
Get: 127.0.0.1:8080/favicon.ico
Launching initialization...
Get: 127.0.0.1:8080/
This behavior is the complete contrary to what is written in the doc:
Hook for subclass initialization.
(Meaning it is called at the end of __init__)
So, does anybody know how to do what I want to ?
Thanks in advance.
It's not contrary to the doc; have a look at the Structure of a Tornado app section. A RequestHandler object is created for each request.
If you want code to be executed when the app is started only, subclass the Application class and override __init__, or just put it in your runserver function.