Connect meteor/nginx app to mongoDB with authentication - mongodb

Question

I have a meteor app with nginx and on the same server I have a mongoDB database which have an authentication.
When I want to connect on the database in ssh, it works fine with the authentication.
But on the meteor app, I always have a 502 bad gateway error.
I think it's because the application can't connect to the database but I don't know how to connect it.
On the file /etc/init/myapp.conf , I change the mongo url :
export MONGO_URL=mongodb://user:password#127.0.0.1:27017/myapp
but I have always the same problem.
And in the file /var/log/mongodb/mongodb.log, I have these errors :
[initandlisten] connection accepted from 127.0.0.1:45266 #2680 (3 connections now open)
[conn2680] assertion 16550 not authorized for query on myapp.system.indexes ns:myapp.system.indexes query:{ ns: "myapp.users"$
[conn2680] ntoskip:0 ntoreturn:1000
[conn2680] end connection 127.0.0.1:45266 (2 connections now open)
[initandlisten] connection accepted from 127.0.0.1:45268 #2681 (3 connections now open)
[conn2681] assertion 16550 not authorized for query on myapp.system.indexes ns:myapp.system.indexes query:{ ns: "myapp.users"$
[conn2681] ntoskip:0 ntoreturn:1000
[conn2681] end connection 127.0.0.1:45268 (2 connections now open)
When I remove the authentication in the database, it works fine, but I need this authentication.
Do you know how to connect the application to the database with authentication ?
Update :
In the file /home/myapp/myapp.log, I have :
Exception in setInterval callback: MongoError: not authorized for update on myapp.users
at Object.Future.wait (/home/myapp/bundle/programs/server/node_modules/fibers/future.js:449:15)
at [object Object].<anonymous> (packages/meteor.js:213:24)
at [object Object].MongoConnection.(anonymous function) [as update] (packages/mongo/mongo_driver.js:774:49)
at [object Object].update (packages/mongo/collection.js:581:29)
at AccountsServer.Ap._expireTokens (packages/accounts-base/accounts_server.js:1115:14)
at packages/accounts-base/accounts_server.js:1204:14
at [object Object]._.extend.withValue (packages/meteor.js:1122:17)
at packages/meteor.js:445:45
at runWithEnvironment (packages/meteor.js:1176:24)
- - - - -
at Function.MongoError.create (/home/myapp/bundle/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/error.js:31:$
at toError (/home/myapp/bundle/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb/lib/utils.js:114:22)
at /home/myapp/bundle/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb/lib/collection.js:1047:60
at getLastErrorCallback (/home/myapp/bundle/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/wireprotocol/2_4_s$
at /home/theroofwebapp/bundle/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/pool.js:455:18
at process._tickCallback (node.js:355:11)

Answer 1

Connect to mongo shell and authenticate as admin and then try below
use admin
db.system.users.update({"user" : "your_user"}, {$addToSet: {'otherDBRoles.myapp': 'readWrite'}}, false, false)
Replace your_user with your db username and myapp with the targeted database name

Answer 2

Here are some things for you to double check.
Make sure that you are exporting MONGO_URL wherever you are starting your Meteor app. You mentioned that you are doing your export MONGO_URL in /etc/init/myapp.conf. That doesn't sound like the correct place.
Make sure you are actually including your real username and password in the mongodb connection string and the connection string is using the correct port where mongodb is actually running. What you included in your question is a generic example but also included your app's name so its unclear if this is actually what you are using.
Double check the role you setup for the mongodb user used by your Meteor app. Make sure you at least gave the role of readWrite. Here is an example.
db.createUser(
{
user: "meteor",
pwd: "meteor",
roles: [ { role: "readWrite", db: "meteor_app" } ]
}
);