Resolving Node.js MySQL Connection Issues in Docker Containers

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This type of issue can lead to frustrating error messages, such as Error: connect ETIMEDOUT, especially when local setups work seamlessly with the same database configuration.

Understanding the Scenario

Key Components in the Docker Configuration

Docker-Compose File: This file defines the services, networks, and environments for the Docker setup.

Here’s a brief overview:

MySQL Service: Runs a MySQL container with environment configurations (like database name, user, and passwords).

The Problem

Why Does This Happen?

Upon analyzing the Docker-Compose file, the problem stems from network configurations. Here’s what's likely happening:

The app service and database service are on different Docker networks.

Without proper network setup, the two containers cannot communicate with each other.

Solution: Simplifying the Network Setup

Modify the Docker-Compose File

Here’s the modified part of the Docker-Compose file:

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

Explanation of Changes

Remove the Named Network: By omitting the specific networks, we allow both services to reside within the same network. This setup is simpler and usually sufficient for most applications where no additional network isolation is required.

Maintain Environment Variables: The necessary environment variables for MySQL connectivity remain intact, ensuring the application has the correct parameters when trying to establish a connection.

Testing the Configuration

After making the changes, you should follow these steps:

Rebuild and Restart the Containers: Run the command:

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

Debug if Necessary: If the connection still fails, check the console logs for errors and adjust configurations accordingly.

Conclusion