The code below works on localhost. I get the message '50' which is the number of rows I have. But it doesn't work when I push it to heroku. I get the "Application error message" and the heroku logs just say app crashed.
And yes, the heroku app has the mongolab add-on connected.
What am I doing incorrectly?
import os
from flask import Flask
from flask.ext.pymongo import PyMongo
app = Flask(__name__)
app.debug = True
app.config['MONGO_URI'] = os.environ['MONGOLAB_URI']
mongo = PyMongo(app, config_prefix='MONGO')
#app.route("/")
def hello():
num = mongo.db.test.count()
return '%s' % num
if __name__ == "__main__":
app.run()
On heroku (unless you've changed it) mongolab stores its URI at MONGOLAB_URI (per these docs).
The crash is probably PyMongo saying it can't connect to NULL, but you can check that with heroku logs on the cli.
Check that you PyMongo version is compatible with Mongo 3.0. MongoLab has switched to it recently: http://blog.mongolab.com/2015/07/mongodb-version-3-0-now-ga-on-mongolab/
Related
I am using apscheduler in a flask application where i pull data from a site every 5 miniutes and insert data every 5 miniutes.The apsscheduler works fine till this point.But the problem occurs whenever i hit this server address http://127.0.0.1:5000 . anyhow through any api i get an assertion error:
AssertionError: A setup function was called after the first request was handled. This usually indicates a bug in the application where a module was not imported and decorators or other functionality was called too late.
To fix this make sure to import all your view modules, database models, and everything related at a central place before the application starts serving requests.
After this the save api stop working.The database doesnot work anymore.From what i get it happens due to sqlalchemy error.
this is app.py file:
from apscheduler.schedulers.background import BackgroundScheduler
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from Config.config import Config
from Service.anyService import job
app = Flask(__name__)
app.config.from_object(Config)
db = SQLAlchemy(app)
db.init_app(app)
scheduler = BackgroundScheduler()
scheduler.add_job(func=job, trigger="interval", seconds=300, args=[app])
scheduler.start()
if __name__ == "__main__":
from waitress import serve
serve(app, host="0.0.0.0", port=5000)
this is the file for saving data:
from flask_sqlalchemy import SQLAlchemy
def job(app):
db = SQLAlchemy(app)
connection = db.engine.connect(close_with_result=True)
# pull some data from a site and sql query to inset data
db.session.add()
db.session.commit()
I am using waitress server.the application seems to be working fine if i run python -m flask run. But if i run python3 app.py and i hit the server it stops working on saving data.what am i doing wrong here
I have been using the following python 3 script in a CDSW session which run just fine as long as the session is not killed.
I am able to click on the top-right grid and select my app
hello.py
from flask import Flask
import os
app = Flask(__name__)
#app.route('/')
def index():
return 'Web App with Python Flask!'
app.run(host=os.getenv("CDSW_IP_ADDRESS"), port=int(os.getenv('CDSW_PUBLIC_PORT')))
I would like this app to run 24/7, so instead of using a Session or scheduling a job that never ends, I would like to create a CDSW Application so that it doesn't stop.
This is the settings on my application:
Logs:
from flask import Flask
import os
app = Flask(__name__)
#app.route('/')
def index():
return 'Web App with Python Flask!'
app.run(host=os.getenv("CDSW_IP_ADDRESS"), port=int(os.getenv('CDSW_PUBLIC_PORT')))
* Serving Flask app "__main__" (lazy loading)
* Environment: production
WARNING: Do not use the development server in a production environment.
Use a production WSGI server instead.
* Debug mode: off
OSError: [Errno 98] Address already in use
I tried to change the port from CDSW_PUBLIC_PORT to CDSW_APP_PORT but it ends up the same.
As it mentions here maybe you need to change this line of code
app.run(host=os.getenv("CDSW_IP_ADDRESS"), port=int(os.getenv('CDSW_PUBLIC_PORT')))
to this
app.run(host="127.0.0.1", port=int(os.environ['CDSW_APP_PORT']))
Hope it works!
after a working production app was connected to local mongo, we've decided to move to Mongo Atlas.
This caused production errors.
Our stack is docker -> alping 3.6 -> python 2.7.13 -> Flask -> uwsgi (2.0.17) -> nginx running on aws
flask-mongoengine-0.9.3 mongoengine-0.14.3 pymongo-3.5.1
when starting the app in staging/production, The uwsgi is sending No replica set members found yet.
We don't know why.
We've tried different connection settings connect: False which is lazy connecting, meaning not on initializing, but on first query.
It caused the nginx to fail for resource temporarily unavailable error on some of our apps. We had to restart multiple times for the app to finally start serving requests.
I think the issue is with pymongo and the fact that it's not fork-safe
http://api.mongodb.com/python/current/faq.html?highlight=thread#id3
and uwsgi is using forks
I suspect it might be related to the way my app is being initalized.
might by aginst Using PyMongo with Multiprocessing
here is the app init code:
from app import FlaskApp
from flask import current_app
app = None
from flask_mongoengine import MongoEngine
import logging
application, app = init_flask_app(app_instance, module_name='my_module')
def init_flask_app(app_instance, **kwargs):
app_instance.init_instance(environment_config)
application = app_instance.get_instance()
app = application.app
return application, app
# app_instance.py
import FlaskApp
def init_instance(env):
global app
app = FlaskApp(env)
return app
def get_instance():
if globals().get('app') is None:
app = current_app.flask_app_object
else:
app = globals().get('app')
assert app is not None
return app
class FlaskApp(object):
def __init__(self, env):
.....
# Initialize the DB
self.db = Database(self.app)
....
# used in app_instance.py to get the flask app object in case it's None
self.app.flask_app_object = self
def run_server(self):
self.app.run(host=self.app.config['HOST'], port=self.app.config['PORT'], debug=self.app.config['DEBUG'])
class Database(object):
def __init__(self, app):
self.db = MongoEngine(app)
def drop_all(self, database_name):
logging.warn("Dropping database %s" % database_name)
self.db.connection.drop_database(database_name)
if __name__ == '__main__':
application.run_server()
help in debugging this will be appreciated!
I've set up an Application on OpenShift like this:
I am using Flask with python on the server-side.
Note: I just need to connect Python to MySQL, Flask is irrelevant.
My Hello World program works fine:
flaskapp.py
from flask import Flask
app = Flask(__name__)
#app.route('/')
def hello_world():
return "Hello World!"
if __name__ == '__main__':
app.run()
In the requirements.txt the following dependency was added: Flask==0.10.1
I'm wondering is it necessary to add the MySQL dependency, like this: MySQLdb==5.5?
I've tried importing and using MySQL in flaskapp.py like this:
from flask import Flask
import mysql # I tried MySQLdb as well
app = Flask(__name__)
#app.route('/')
def hello_world():
output = ''
db = mysql.connect(host="mysql://$OPENSHIFT_MYSQL_DB_HOST:$OPENSHIFT_MYSQL_DB_PORT/", # your host, usually localhost
user="adminIChJ87N",
passwd="mypassword",
db="python")
cur = db.cursor()
cur.execute("SELECT * FROM MyTable")
for row in cur.fetchall():
output+=row[0]
db.close()
return output
if __name__ == '__main__':
app.run()
How exactly do I use this MySQL database with Python? There seems to be no code on Openshift's website
The name of the package for MySQLdb is mysqlclient (if you want it to work with Python3, otherwise it is a fork of MySQL-python). So this is what you need to put in the dependencies. Run pip install mysqlclient to try it.
I have a python app developed on Flask. Everything works fine offline, I tried deploying on CherryPy successfully too. Now, I'm trying to deploy the same on www.pythonanywhere.com.
Here's the deploy.py I use for deploying the Flask app on CherryPy
from cherrypy import wsgiserver
from appname import app
def initiate():
app_list = wsgiserver.WSGIPathInfoDispatcher({'/appname': app})
server = wsgiserver.CherryPyWSGIServer( ('http://username.pythonanywhere.com/'), app_list)
try:
server.start()
except KeyboardInterrupt:
server.stop()
print "Server initiated..."
initiate()
print "Ended"
I created a "manual configuration" app on pythonanywhere.com.
Here's the configuration file (username_pythonanywhere_com_wsgi.py):
import sys
path = '/home/username/appname'
if path not in sys.path:
sys.path.append(path)
import deploy
deploy.initiate()
Now I'm pretty sure that it "almost worked", because in the server logs I could see my "Server initiated..." message.
2013-09-27 09:57:16 +0000 username.pythonanywhere.com - *** Operational MODE: single process ***
Server initiated...
Now the problem, when I try to view my app username.pyhtonanywhere.com/about, it times out.
This I believe is caused due to incorrect port given while starting the CherryPy server (in deploy.py).
Could anyone please tell how I can properly initiate the CherryPy server?
Joe Doherty is right. You want something more like this in you wsgi file:
import sys
sys.path = [ <path to your web app> ] + sys.path
from cherrypy._cpwsgi import CPWSGIApp
from cherrypy._cptree import Application
from <your_web_app> import <your web app class>
config_path = '<path to your cherrypy config>'
application = CPWSGIApp(
Application(<your web app class>(), '', config = config_path)
I stuck everything that should be based on your particular app in <>s.