Docker Environment for DatAscend

Application development with Docker Compose

The Docker Compose file is designed to provide a complete development environment for a the application. It includes a PostgreSQL database, a database seeding service, and the main application container.

Services

The compose file defines three primary services:

• Database service

  • Image: postgres:latest - Uses the latest PostgreSQL image from Docker Hub.
  • Container Name: da-database - A descriptive name for the database container.
  • Healthcheck: Implements a health check to ensure the database is fully operational before dependent services start.
  • Environment:
    • CONTAINER=TEST: Sets a test environment flag, potentially used by scripts within the container.
    • POSTGRES_PASSWORD=postgres: Sets the PostgreSQL password to postgres. Important: This is for development/testing purposes only and should not be used in production.
  • Ports: Maps port 54320 on the host to port 5432 inside the container. This allows accessing the database using localhost:54320 from the host machine.

• Database seeding service

  • Image: postgres:latest - Uses the latest PostgreSQL image to run the database seed script.
  • Container Name: da-seed-database - Clearly names the container responsible for database seeding.
  • Command: ["/data/scripts/seed_db.sh", "/data/database"] - Executes the seed_db.sh script located in the mounted project directory. The second argument /data/database is a parameter passed to the script, potentially containing data or configuration needed for seeding.
  • Depends On: database - Ensures that the database service is healthy before the database_script starts, guaranteeing the availability of the database.
  • Volumes: Mounts the current project directory (..) on the host into the /data directory inside the container, making project scripts and data accessible.
  • Environment: Sets environment variables required for database access, including connection details that target the database service using its service name. These ensure the seeding script can connect to the database correctly.

• Application service

  • Image: node:16.16.0 - Uses Node.js 16.16.0 for running the application.
  • Container Name: da-application - Clearly names the container that runs the main application.
  • Working Dir: /data - Sets the working directory for the container to /data which is where the code is mounted.
  • Command: /bin/bash -c "chmod +x /data/scripts/entrypoint.sh && /data/scripts/entrypoint.sh" - Executes the entrypoint.sh script after setting execution permissions. This script will likely start the application’s main process.
  • Depends On:
    • database: Ensures the database is healthy before starting the application.
    • database_script: Ensures the database seeding process has completed successfully before starting the application, preventing application startup issues related to missing initial data.
  • Volumes:
    • backend_modules:/data/backend/node_modules : Defines a named volume for backend node modules.
    • project:/data: Binds the host directory to /data inside the container. This ensures code changes on the host are directly reflected within the container.
  • Ports: Maps port 4000 on the host to port 4000 inside the container. This allows accessing the application through localhost:4000 from the host machine.
  • Environment: Sets up environment variables for the application, including database connection details and application configuration. This environment makes the container aware of its test mode and database connection parameters.

Volumes

The following named volumes are defined for data cache and code synchronization:

• backend_modules: A named volume used to persist the /backend/node_modules directory between container restarts.
• project: A bind mount that directly links the current project directory on the host to the /data directory inside the containers. This ensures that code changes are immediately available inside the containers without rebuilding the image.

Usage

To start the application, navigate to the directory containing this docker-compose.yml file and run:

docker-compose -f ./Dockerfiles/docker-compose.yml up -d

Note: Any environment variables required by the application could be set by adding them to this command, this allows for easy testing of different database configurations, environments, etc.