Let’s break down what this script does in detail. The script is named new_docker_container.sh, authored by GJS (homelab-alpha), and its purpose is to create a new Docker container directory structure and configuration files based on user input. The script ensures that the necessary tools are available, checks for proper execution permissions, and creates a comprehensive directory structure and configuration files for Docker containers.

Here’s a detailed explanation:

Script Metadata

  • Filename: new_docker_container.sh
  • Author: GJS (homelab-alpha)
  • Date: May 18, 2024
  • Version: 1.0.1
  • Description: This script creates a new Docker container directory structure and configuration files based on user input.
  • RAW Script: new_docker_container.sh

Check for sudo Permissions 

if [ "$EUID" -ne 0 ]; then
  echo "Please run this script with sudo."
  exit 1
fi

This section ensures that the script is run with sudo to have the necessary permissions for creating directories and files.


Validate Existence of Required Commands 

for cmd in mkdir touch chown; do
  if ! command -v "$cmd" &>/dev/null; then
    echo "ERROR: $cmd command not found. Please install it and try again."
    exit 1
  fi
done

This part checks if the required commands (mkdir, touch, chown) are available on the system. If any of these commands are missing, the script will exit with an error message.


Display Message Function 

display_message() {
  echo -e "\n$1\n"
}

This function is used to display messages to the user in a formatted manner.


Prompt for Docker Container Name 

display_message "What is the name of the new Docker container:"
read -r container_name

The script prompts the user to enter the name of the new Docker container and reads the input into the variable container_name.


Validate Container Name 

if [[ ! "$container_name" =~ ^[a-zA-Z0-9_-]+$ ]]; then
  display_message "Invalid container name. Use only letters, numbers, underscore (_), and hyphen (-)."
  exit 1
fi

This validation ensures that the container name only contains letters, numbers, underscores, and hyphens.


Set Base Directory for Docker Containers 

base_dir="${docker_base_dir:-/docker}"
dir_path="$base_dir/$container_name"

This section sets the base directory for Docker containers. If docker_base_dir is not set, it defaults to /docker. The full directory path for the new container is constructed.


Check if Directory Already Exists 

if [ -d "$dir_path" ]; then
  display_message "The directory already exists. Choose a different name for the container."
  exit 1
fi

This checks if a directory with the specified container name already exists. If it does, the script exits with a message.


Create Required Directories 

declare -a directories=(
  "notes"
  "production/.cert" "production/app" "production/config" "production/db" "production/log" "production/redis"
  "testing/.cert" "testing/app" "testing/config" "testing/db" "testing/log" "testing/redis"
)
for dir in "${directories[@]}"; do
  if ! mkdir -p "$dir_path/$dir"; then
    display_message "Failed to create directory: $dir_path/$dir"
    exit 1
  fi
done

This part creates the required directory structure for the Docker container, including directories for notes, production, and testing environments.


Create Docker Startup Files 

if ! touch "$dir_path/.dockerignore" "$dir_path/.env" "$dir_path/docker-compose.yml" "$dir_path/Dockerfile" "$dir_path/README.md"; then
  display_message "Failed to create Docker startup files in $dir_path."
  exit 1
fi

The script creates essential Docker startup files in the new container directory.


Add Content to .dockerignore 

cat <<EOL >"$dir_path/.dockerignore"
*/temp*
*/*/temp*
temp?
EOL

This section writes predefined content to the .dockerignore file to exclude certain files from Docker builds.


Add Content to .env 

cat <<EOL >"$dir_path/.env"
# API keys and secrets
API_KEY=
SECRET_KEY=

# App configuration
MYSQL_HOST_APP=${container_name}
MYSQL_PORT_APP=3306
MYSQL_NAME_APP=${container_name}
MYSQL_USER_APP=${container_name}
MYSQL_PASSWORD_APP=

# Database configuration
MYSQL_ROOT_PASSWORD_DB=
MYSQL_DATABASE_DB=${container_name}_db
MYSQL_USER_DB=${container_name}
MYSQL_PASSWORD_DB=
EOL

This writes configuration settings, including API keys, secrets, and database details, to the .env file.


Add Content to docker-compose.yml 

cat <<EOL >"$dir_path/docker-compose.yml"
version: "3.9"
networks:
  ${container_name}_net:
    name: ${container_name}
    driver: bridge
    ipam:
      config:
        - subnet: 172.20.0.0/24
          gateway: 172.20.0.1
services:
  ${container_name}_db:
    restart: unless-stopped
    container_name: ${container_name}_db
    image: change_me:latest
    volumes:
      - /docker/${container_name}/production/db:/change_me
    environment:
      MYSQL_DATABASE: "${container_name}_db"
      MYSQL_USER: "${container_name}"
    networks:
      ${container_name}_net:
        ipv4_address: 172.20.0.2
  ${container_name}_app:
    restart: unless-stopped
    container_name: ${container_name}
    image: change_me:latest
    volumes:
      - /docker/${container_name}/production/app:/change_me
    environment:
      MYSQL_HOST: "${container_name}_db"
      MYSQL_DATABASE: "${container_name}_db"
    networks:
      ${container_name}_net:
        ipv4_address: 172.20.0.3
volumes:
  ${container_name}_db:
    external: true
  ${container_name}_app:
    external: true
EOL

This section adds content to the docker-compose.yml file, specifying the configuration for Docker services and networks.


Add Content to Dockerfile 

cat <<EOL >"$dir_path/Dockerfile"
EOL

This creates an empty Dockerfile, which should be populated with build instructions.


Add Content to README.md 

cat <<EOL >"$dir_path/README.md"
.. ${container_name}::
.
├── notes                - Note files and information about the configuration.
├── production           - Configuration files and data for the production environment.
│   ├── .cert            - SSL certificates for secure connections.
│   ├── app              - Application files.
│   ├── config           - Configuration files for the application.
│   ├── db               - Database files.
│   ├── log              - Log files.
│   └── redis            - Redis database files.
├── testing              - Configuration files and data for the testing environment.
│   ├── .cert            - SSL certificates for secure connections.
│   ├── app              - Application files.
│   ├── config           - Configuration files for the application.
│   ├── db               - Database files.
│   └── log              - Log files.
├── .dockerignore        - Excludes files from Docker builds.
├── .env                 - Environment variables for the Docker containers.
├── docker-compose.yml   - Docker Compose configuration.
├── Dockerfile           - Docker container build instructions.
└── README.md            - Instructions and information about the project.
\`\`\`

## Customization

- Update placeholder values (change_me, USER, ROLE, etc.) in the Docker Compose files with your specific configurations.
- Modify the .env file with API keys, secrets, and MySQL configurations.

## Author

GJS (homelab-alpha)

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE.md) file for details.

[LICENSE]: https://github.com/homelab-alpha/shell-script/blob/main/LICENSE.md
EOL

This section populates the README.md file with a directory structure overview and customization instructions.


Completion Message 

display_message "Docker container directory structure created in $dir_path."

Finally, the script displays a message indicating that the Docker container directory structure has

been successfully created.


Conclusion

The script is a well-structured tool to automate the creation of a standardized Docker container setup. It ensures that the necessary commands and permissions are in place, validates user input, and creates a comprehensive directory structure with essential configuration files for Docker containers. This can significantly streamline the setup process for Docker-based projects, ensuring consistency and reducing the risk of errors.

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Last updated 01 Sep 2024, 10:22 CEST . history