How to use Flask-Script and Gunicorn
I'm working on on a Flask app using Flask's built in dev server. I start it using Flask-Script. I want to switch to using Gunicorn as the web server. To do so, do I need to write some sort of integration code between Flask-Script and Gunicorn? Or is Flask-Script irrelevant to running the app using Gunicorn?
Thanks in advance!
Props to @sean-lynch. The following is working, tested code based on his answer. The changes I made were:
Options that aren't recognized by Gunicorn are removed from
sys.argvinremove_non_gunicorn_command_line_args()before trying to start the server. Otherwise Gunicorn throws an error with a message like this:error: unrecognized arguments: --port 5010. I remove-pbecause, even though it doesn't cause the error, that's only because Gunicorn thinks its the short form of itspidfileoption, which is obviously not what's intended.GunicornServer.handle() signature modified to match the method it overrides i.e. Command.handle()
-
from flask_script import Command
from gunicorn.app.base import Application
class GunicornServer(Command):
description = 'Run the app within Gunicorn'
def __init__(self, host='127.0.0.1', port=8000, workers=6):
self.port = port
self.host = host
self.workers = workers
def get_options(self):
return (
Option('-t', '--host',
dest='host',
default=self.host),
Option('-p', '--port',
dest='port',
type=int,
default=self.port),
Option('-w', '--workers',
dest='workers',
type=int,
default=self.workers),
)
def handle(self, app, *args, **kwargs):
host = kwargs['host']
port = kwargs['port']
workers = kwargs['workers']
def remove_non_gunicorn_command_line_args():
import sys
args_to_remove = ['--port','-p']
def args_filter(name_or_value):
keep = not args_to_remove.count(name_or_value)
if keep:
previous = sys.argv[sys.argv.index(name_or_value) - 1]
keep = not args_to_remove.count(previous)
return keep
sys.argv = filter(args_filter, sys.argv)
remove_non_gunicorn_command_line_args()
from gunicorn import version_info
if version_info < (0, 9, 0):
from gunicorn.arbiter import Arbiter
from gunicorn.config import Config
arbiter = Arbiter(Config({'bind': "%s:%d" % (host, int(port)),'workers': workers}), app)
arbiter.run()
else:
class FlaskApplication(Application):
def init(self, parser, opts, args):
return {
'bind': '{0}:{1}'.format(host, port),
'workers': workers
}
def load(self):
return app
FlaskApplication().run()
manager.add_command('gunicorn', GunicornServer())
As Dhaivat said, you can just use your Flask app directly with Gunicorn.
If you still want to use Flask-Script, you will need to create a custom Command. I don't have any experience with Gunicorn, but I found a similar solution for Flask-Actions and ported it to Flask-Script, although be warned, it's untested.
from flask_script import Command, Option
class GunicornServer(Command):
description = 'Run the app within Gunicorn'
def __init__(self, host='127.0.0.1', port=8000, workers=4):
self.port = port
self.host = host
self.workers = workers
def get_options(self):
return (
Option('-H', '--host',
dest='host',
default=self.host),
Option('-p', '--port',
dest='port',
type=int,
default=self.port),
Option('-w', '--workers',
dest='workers',
type=int,
default=self.workers),
)
def handle(self, app, host, port, workers):
from gunicorn import version_info
if version_info < (0, 9, 0):
from gunicorn.arbiter import Arbiter
from gunicorn.config import Config
arbiter = Arbiter(Config({'bind': "%s:%d" % (host, int(port)),'workers': workers}), app)
arbiter.run()
else:
from gunicorn.app.base import Application
class FlaskApplication(Application):
def init(self, parser, opts, args):
return {
'bind': '{0}:{1}'.format(host, port),
'workers': workers
}
def load(self):
return app
FlaskApplication().run()
You can then either register it to replace Flask's local development server at python manage.py runserver
manager.add_command("runserver", GunicornServer())
or register as a new command such as python manage.py gunicorn
manager.add_command("gunicorn", GunicornServer())
Edit June 2016: With the latest version of Flask-Script, change the method handle with __call__. old flask-script vs new flask-script
I wrote a better version of GunicornServer based on Sean Lynch's, the command now accept all gunicorn's arguments
from yourapp import app
from flask.ext.script import Manager, Command, Option
class GunicornServer(Command):
"""Run the app within Gunicorn"""
def get_options(self):
from gunicorn.config import make_settings
settings = make_settings()
options = (
Option(*klass.cli, action=klass.action)
for setting, klass in settings.iteritems() if klass.cli
)
return options
def run(self, *args, **kwargs):
from gunicorn.app.wsgiapp import WSGIApplication
app = WSGIApplication()
app.app_uri = 'manage:app'
return app.run()
manager = Manager(app)
manager.add_command("gunicorn", GunicornServer())
Based the answer of the Sean, I also wrote a version more preferred to me.
@manager.option('-h', '--host', dest='host', default='127.0.0.1')
@manager.option('-p', '--port', dest='port', type=int, default=6969)
@manager.option('-w', '--workers', dest='workers', type=int, default=3)
def gunicorn(host, port, workers):
"""Start the Server with Gunicorn"""
from gunicorn.app.base import Application
class FlaskApplication(Application):
def init(self, parser, opts, args):
return {
'bind': '{0}:{1}'.format(host, port),
'workers': workers
}
def load(self):
return app
application = FlaskApplication()
return application.run()
you can run the gunicorn using command like thispython manager.py gunicorn
Flask actually has docs to run Gunicorn here.
You have to remember that Gunicorn is a WSGI server with some niceties.