Flask mongoengine connect through uri - mongodb

Question

I have a small flask application which I am deploying to Heroku.
My local configuration looks like this:
from flask import Flask
from flask.ext.mongoengine import MongoEngine
app = Flask(__name__)
app.debug = True
app.config["MONGODB_SETTINGS"] = {'DB': "my_app"}
app.config["SECRET_KEY"] = "secretpassword"
db = MongoEngine(app)
So, I know that I need to configure the app to use the Mongo URI method of connection, and I have my connection info:
mongodb://<user>:<password>#alex.mongohq.com:10043/app12345678
I am just a little stuck as to the syntax for modifying my app to connect through the URI.

Answer 1

So I got it working (finally):
from flask import Flask
from mongoengine import connect
app = Flask(__name__)
app.config["MONGODB_DB"] = 'app12345678'
connect(
'app12345678',
username='heroku',
password='a614e68b445d0d9d1c375740781073b4',
host='mongodb://<user>:<password>#alex.mongohq.com:10043/app12345678',
port=10043
)
Though I anticipate that various other configurations will work.

Answer 2

When you look at the flask-mongoengine code, you can see what configuration variables are available
So this should work:
app.config["MONGODB_HOST"] = 'alex.mongohq.com/app12345678'
app.config["MONGODB_PORT"] = 10043
app.config["MONGODB_DATABASE"] = 'dbname'
app.config["MONGODB_USERNAME"] = 'user'
app.config["MONGODB_PASSWORD"] = 'password'
db = MongoEngine(app)
I'm not sure, if app123 is the app or the database name. You might have to fiddle arround a little to get the connection. I had the same problem with Mongokit + MongoLab on Heroku :)
Also you could use the URI like this.
app.config["MONGODB_SETTINGS"] = {'DB': "my_app", "host":'mongodb://<user>:<password>#alex.mongohq.com:10043/app12345678'}
I have actually no idea, at what point "MONGODB_SETTINGS" is read, but it seemed to work, when I tried it in the shell.

Answer 3

I figured out how to use the flask.ext.mongoengine.MongoEngine wrapper class to do this rather than mongoengine.connect():
from flask import Flask
from flask.ext.mongoengine import MongoEngine
app = Flask(__name__)
HOST = '<hostname>' # ex: 'oceanic.mongohq.com'
db_settings = {
'MONGODB_DB': '<database>',
'MONGODB_USERNAME': '<username>',
'MONGODB_PASSWORD': '<password>',
'MONGODB_PORT': <port>,
}
app.config = dict(list(app.config.items()) + list(db_settings.items()))
app.config["MONGODB_HOST"] = ('mongodb://%(MONGODB_USERNAME)s:%(MONGODB_PASSWORD)s#'+
HOST +':%(MONGODB_PORT)s/%(MONGODB_DB)s') % db_settings
db = MongoEngine(app)
if __name__ == '__main__':
app.run()
If you're using mongohq, app.config["MONGODB_HOST"] should match the Mongo URI under Databases->Admin->Overview.
You can then follow MongoDB's tumblelog tutorial using this setup to write your first app called tumblelog.
Using python's nifty object introspection (python oh how I love you so), you can see how the MongoEngine wrapper class accomplishes this:
from flask.ext.mongoengine import MongoEngine
import inspect
print(inspect.getsource(MongoEngine))
...
conn_settings = {
'db': app.config.get('MONGODB_DB', None),
'username': app.config.get('MONGODB_USERNAME', None),
'password': app.config.get('MONGODB_PASSWORD', None),
'host': app.config.get('MONGODB_HOST', None),
'port': int(app.config.get('MONGODB_PORT', 0)) or None
}
...
self.connection = mongoengine.connect(**conn_settings)
...
self.app = app