MongoDB: 4 ways to view all users and their roles.

Approach 1: Use mongo Shell

The MongoDB shell is a powerful command-line interface that allows you to interact with your MongoDB instance. One can use it to show all users and their roles easily.

1. Connect to your MongoDB instance using the MongoDB shell.
2. Switch to the admin database, where user information is stored.
3. Use the show users command to list all users and their roles in that database.

Example:

use admin
show users

Notes: This solution is straightforward but requires shell access and sufficient privileges. The user must have the viewRole and viewUser permissions. It’s not suitable for automated scripts and does not provide filtering or formatting options.

Approach 2: db.getUsers() Method

For a more programmatic approach, MongoDB provides the db.getUsers() method to retrieve user information directly from the database.

1. Access the mongo shell and go to the admin database.
2. Call the db.getUsers() method to get a list of all user documents.

Example:

use admin
db.getUsers()

Notes: This method returns a list of user objects, including their roles. The performance is good, but like the shell, it requires interactive access. It can be embedded in JavaScript files and executed as part of scripts.

Approach 3: MongoDB Compass

MongoDB Compass is the official GUI for MongoDB. It presents users and roles in a more visual manner, which some may find easier to work with compared to command line interfaces or scripts.

1. Open MongoDB Compass and connect to your MongoDB instance.
2. Navigate to the admin database.
3. Under the Security tab, select Users to view all users and their roles.

Notes: This is a user-friendly method. It’s ideal for those who prefer graphical interfaces over command-line tools. Permissions to view users and roles are still required. This approach is not suitable for scripting or automation.

Approach 4: Aggregation Framework

The aggregation framework in MongoDB is a powerful set of tools for transforming and combining data. You can create a complex query to view users and their roles, potentially with more customization than other methods.

1. Connect to the MongoDB shell.
2. Switch to the admin database.
3. Use the aggregate function on the system.users collection to structure the output data as per the requirement.

Example:

use admin
db.system.users.aggregate([ // aggregation stages here ])

Notes: This solution is the most flexible and allows complex filtering, projection, and formatting. It is ideal for creating customized views of user and role data. However, it might be overkill for simple requirements and is more complex to set up.

Conclusion

Viewing all users and their roles in MongoDB can be accomplished through a variety of means, each catering to different needs and preferences. From the simplicity of the MongoDB shell to the graphical MongoDB Compass, and to the flexibility of the aggregation framework, DBAs and developers have multiple tools at their disposal to inspect user roles and privileges within their databases. Evaluate the context in which you need to view users and roles, such as for auditing or administration, to choose the most efficient and appropriate method for the task at hand. Security considerations and ease of use should guide the selection of the suitable solution.