Resolving the Issue of Spring Boot Only Initializing One Data Source

Discover how to troubleshoot and resolve the common problem of Spring Boot only initializing one data source when you are trying to set up multiple databases in your application.
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Resolving the Issue of Spring Boot Only Initializing One Data Source

When working with Spring Boot applications, you might encounter issues with setting up multiple data sources. A common problem is when Spring Boot initializes only one data source and ignores the other, leading to frustrating errors during development. In this post, we will explore this problem and provide a thorough solution to help you set up multiple data sources effectively.

Understanding the Problem

The problem originates when you define multiple data source beans in your Spring Boot application but find that only one data source bean is being initialized. For instance, you might have a configuration like the following:

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

The Symptoms

Only one data source is initialized: When starting the application, you may notice that only the dataSource bean is created, while the storeFrontDataSource bean is not.

Error messages: You may encounter exceptions similar to:

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

These symptoms indicate that the second data source is not being registered correctly.

Analyzing the Root Cause

After some debugging, one common root cause of this issue can be attributed to how Spring Boot manages bean definitions and dependencies. If any component or service within your Spring Boot application expects an instance of HikariDataSource but is not correctly configured or separated from your application context, it may cause Spring to disregard one of the defined beans.

Solution: How to Fix the Issue

Here are the steps to troubleshoot and resolve the issue effectively:

1. Check Bean Annotations

Ensure all your data sources are correctly annotated and that their names and prefixes in the configuration properties are distinct.

2. Verify Dependencies

3. Update the Configuration Classes

If you find that classes from dependent libraries are injecting HikariDataSource instead of DataSource, update them to ensure proper dependency injection.

4. Test in Isolation

Remove any components that may be indirectly affecting your data source initialization to test in isolation. This can help in pinpointing the issue.

5. Log Outputs

Utilize logging within your configuration to confirm which beans are being created:

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

This will help you trace the initialization process and confirm if both beans are being registered.

6. Spring Profiles (Optional)

If applicable, consider using Spring profiles to manage different environments (e.g., development, production). This allows you more granular control over which configurations are active.

Conclusion

By following these steps, you should be able to resolve the issue of Spring Boot only initializing one data source. If the problem persists, further investigation into the application context and dependencies used within different parts of your application may be necessary. Hopefully, with this guide, you'll be back on track in no time, effectively leveraging multiple data sources in your Spring Boot applications.