Скачать или смотреть Resolving the Connection refused Error in Symfony Docker for MySQL Database

Discover the solution to the `SQLSTATE[HY000] [2002] Connection refused` error in Symfony Docker by adjusting your database connection settings.
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Troubleshooting the Connection refused Error in Symfony with Docker

If you are developing a Symfony application using Docker and you encounter the frustrating error message:
An exception occurred in driver: SQLSTATE[HY000] [2002] Connection refused, you're not alone. This issue typically arises when Symfony is unable to establish a connection to your MySQL database, and it can stem from various misconfigurations in your setup.

In this guide, we will explore the common causes of this error and provide a comprehensive solution to ensure that your Symfony application can successfully connect to the MySQL database running in Docker.

Identifying the Problem

The error occurs when trying to create new Articles using a controller method, while the connection seems fine when running database migrations with:

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

This inconsistency might indicate a problem with how the database is configured in your Docker environment. Let's dive deeper into the necessary configurations to resolve this issue.

Understanding Your Configuration

To effectively address the problem, it's essential to review your environment settings and Docker configuration files.

1. Symfony Environment Configuration

In your Symfony project, you have likely defined your database URL in the .env file. Here’s the relevant snippet:

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

Important Note: The 127.0.0.1 IP address references the localhost of the Symfony application, not the Docker container.

2. Docker Compose Configuration

Here’s an excerpt from your docker-compose.yml file:

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

This defines a service named database that will run your MySQL setup.

3. Docker Environment Variables

Your .env file for Docker explicitly sets the database configuration:

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

Solution: Adjusting Your Database Connection

To resolve the connection refused error, you need to update the DATABASE_URL in the Symfony .env file. Change the host from 127.0.0.1 to the service name defined in your docker-compose.yml, which is database. Your updated configuration should look like this:

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

Why This Change Works

By specifying database instead of 127.0.0.1:

You instruct Symfony to connect to the MySQL container directly via Docker's internal networking.

Docker resolves the service name database to the correct container running MySQL, avoiding connection issues.

Final Steps

After making this adjustment, ensure to:

Rebuild your Docker containers for the changes to take effect:

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

Once the containers are up and running, try creating an article again. The connection should now be established successfully.

Conclusion

Fixing the connection issue between Symfony and your MySQL database in Docker is a matter of adjusting your host settings in the .env file. By replacing 127.0.0.1 with database, you leverage Docker's networking capabilities to resolve this connection error.

If you continue to experience difficulties, re-check all configurations and ensure the necessary ports are exposed correctly. Happy coding!