Resolving Authentication failed Issues When Connecting MongoDB with Spring Boot in Docker Compose

Learn how to fix `Authentication failed` errors when connecting your MongoDB database with a Spring Boot application in Docker Compose. Follow our clear step-by-step guide to troubleshoot and solve the problem!
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Understanding Authentication Errors in MongoDB

If you are working with a Spring Boot application that connects to a MongoDB database using Docker Compose, you might encounter an error similar to the following:

[[See Video to Reveal this Text or Code Snippet]]

This error indicates a problem with authentication, specifically that the MongoDB cannot find the user you specified for the database. Let's take a closer look at this issue and how you can fix it.

The Problem Explained

The primary reasons for encountering this issue include:

Incorrect username or password: Make sure that the credentials you are using are correct.

User not present in the specified authentication database: The user you are trying to authenticate needs to exist in the correct database.

Missing or incorrect authentication source: MongoDB requires specific connection parameters, including the authentication source.

In this case, the error clearly states that the user "user" cannot be found for the database "user_db".

Solution: Update Your Spring Boot Configuration

Step 2: Modify the MongoDB URI

You will need to add the authSource=admin parameter to your MongoDB connection URI. This specifies the database against which the user credentials will be validated. The updated configuration should look like this:

[[See Video to Reveal this Text or Code Snippet]]

user: Replace this with your actual username.

pass: Replace this with your corresponding password.

user_db: This needs to be the name of the database you intend to access.

Step 3: Restart Your Application

After updating the configuration, make sure to restart your Spring Boot application. This allows the application to read the new settings and authenticate correctly with the MongoDB database.

Conclusion

By specifying the correct authSource, you can resolve the authentication error that may arise when connecting your Spring Boot application with MongoDB in Docker Compose. Ensuring the integrity of your credentials and the user’s existence in the correct database is paramount to a seamless connection.

If you continue to experience issues, verify the credentials, check the MongoDB logs for more details, and ensure that the MongoDB instance is correctly configured.

Now you're on your way to resolving any authentication problems and setting up a smooth connection between your Spring Boot application and MongoDB!