How to Use the depends_on Setting in Docker Compose
When setting up a development environment using Docker Compose, you might encounter service dependency issues. Take a simple example: the database container usually needs to start up first before the API server container can follow. This is because the API server might need to establish a connection pool with the database before it can offer API services; otherwise, errors could occur and cause the container to fail to start.
In this situation, the API server container relies on the database container to function properly, which is what we refer to as service dependency. Without understanding service dependencies, you could frequently experience inconsistent results with docker-compose, sometimes successful and sometimes not, as services might or might not start up in time or be ready.
To address this, Docker Compose provides a solution with the depends_on setting.
This article will guide you on how to use the depends_on setting.