Environment Configuration

Mapping Connection Strings

Inside the docker-compose.yml file, the `backend` service requires specific environment variables to discover databases within the isolated app-network bridge.

environment:
  - BASE_FRONTEND_URL=http://localhost
  - BASE_API_URL=http://localhost/api
  - DATABASE_DEFAULT=SQLITE
  - SQLITE_DATABASE=/app/storage/database.sqlite

Variables Explained

• BASE_FRONTEND_URL & BASE_API_URL (CRITICAL): Defines the public URLs where users access the nLink dashboard and API. These variables are mandatory for SAML SSO workflows and OAuth callbacks to function correctly.
• CREDENTIAL_SECRET_KEY (CRITICAL): A secure 32-character string used by the engine to perform AES-GCM encryption on all user credentials stored in the database. Do not lose or change this key after initialization, as existing credentials will become permanently inaccessible.
• DATABASE_DEFAULT: Specifies the primary database engine. Accepted values are SQLITE, MYSQL, or POSTGRES.
• MYSQL_HOST / POSTGRES_HOST: These variables define the internal DNS hostnames of your database containers. Thanks to Docker's internal networking, assigning =mysql_db automatically routes the connection to the container named `mysql_db`. You do not need to use `localhost` or an IP address.
• REDIS_ADDR: The complete address and port string for the Redis cache cluster (e.g., redis_server:6379 within the Docker network).
• NLINK_HEALING_OPENAI_KEY: Activates the AI Self-Healing Engine. Supply an OpenAI API key (e.g., sk-...) to allow the system to automatically repair data mapping errors and JSON structural changes from third-party APIs during execution.

Using a `.env` File

Hardcoding secret values inside `docker-compose.yml` is not recommended for production environments. Instead, map these variables dynamically using a .env file placed in the same directory:

# .env
BASE_FRONTEND_URL=https://app.yourdomain.com
BASE_API_URL=https://app.yourdomain.com/api
CREDENTIAL_SECRET_KEY=your_secure_32_char_random_string
DATABASE_DEFAULT=SQLITE
SQLITE_DATABASE=/app/storage/database.sqlite

Then, update your Docker Compose file to interpolate these variables:

environment:
  - BASE_FRONTEND_URL=${BASE_FRONTEND_URL}
  - BASE_API_URL=${BASE_API_URL}
  - CREDENTIAL_SECRET_KEY=${CREDENTIAL_SECRET_KEY}
  - DATABASE_DEFAULT=${DATABASE_DEFAULT}
  - SQLITE_DATABASE=${SQLITE_DATABASE}