How do I set the default connection URL for mongo CLI? - mongodb

Question

I cannot find anywhere to set the default connection URL for the mongo CLI. I want to be able to specify a particular username/password/hostname/database, which can all be specified as a URL. However, I want to just be able to type mongo instead of mongo "mongodb://…" in the shell.
I also don’t want the password to show up in /proc/«PID»/cmdline, but having it in a dotfile in my home directory is perfectly fine with me.
It doesn’t appear that ~/.mongorc.js allows specifying the default connection string. But I would expect such an option to be available because the mysql CLI supports ~/.my.cnf which allows you to specify username/password/hostname/database. So, where is this for mongodb?
EDIT: The solution has to work even if the mongodb at localhost is fully secured (no insecure local test database should be required—I thought this went without saying).

Answer 1

You can run mongo shell commands in ~/.mongorc.js. So you can just run the connect method in your ~/.mongorc.js:
db = connect("mongodb://username:password#host:27017/myDatabase")
When you run mongo it will first connect to localhost, then connect to the database passed to the connect method.
A MongoDB server must be running on localhost, otherwise the mongo shell will error and exit before trying to connect to the other DB.
Run mongo --nodb to get around needing to connect on localhost before connecting to whatever is defined in ~/.mongorc.js.

Answer 2

To directly launch mongo against a particular hostname/database/username/password without prompting for a password, without passing the password on the CLI, and without requiring an insecure database at mongodb://localhost/test, you can use this technique. Write a script file which does the connection for you and then launch mongo with the appropriate arguments. For example:
~/.mongo-do-auth.js
// https://docs.mongodb.com/manual/reference/program/mongo/#cmdoption-nodb
// https://docs.mongodb.com/manual/tutorial/write-scripts-for-the-mongo-shell/#mongo-shell-new-connections
//
// Run this with:
//
// mongo --nodb --shell ~/.mongo-do-auth.js
db = connect('localhost/admin', 'root', 'asdf123');
And then, simply launch it from the CLI to get an interactive session:
sam ~ # mongo --nodb --shell ~/.mongo-do-auth.js
MongoDB shell version: 2.6.12
type "help" for help
connecting to: localhost/admin
> quit()
Or, to run a script noninteractively, simply remove --shell and append your script. Consider a script:
s2.js:
print('connected to database ' + db);
To run:
sam ~ # mongo --nodb ~/.mongo-do-auth.js ~/s2.js
MongoDB shell version: 2.6.12
loading file: /root/.mongo-do-auth.js
connecting to: localhost/admin
loading file: /root/s2.js
connected to database admin
However, this requires a lot of work and invoking mongo with arguments. It appears that this is a limitation of mongo because no one has suggested any alternative which works as smoothly as the mysql CLI client’s ~/.my.cnf. This means that all shell scripts which directly invoke mongo will need to allow the the user to pass through --nodb and a path to a connection script instead of being able to rely on implicit per-user configuration.