Configuration management for Lotus.

Handles loading and validating configuration from the application environment using NimbleOptions.

Required Configuration

Lotus requires a storage repository where it will store query definitions:

config :lotus,
  ecto_repo: MyApp.Repo  # Where Lotus stores its query definitions

Data Repositories Configuration

Configure named data repositories that Lotus can execute queries against:

config :lotus,
  data_repos: %{
    "primary" => MyApp.Repo,
    "analytics" => MyApp.AnalyticsRepo,
    "warehouse" => MyApp.WarehouseRepo
  }

Visibility Configuration

Control which schemas and tables are accessible through Lotus with visibility rules:

config :lotus,
  # Schema-level rules (higher precedence)
  schema_visibility: %{
    postgres: [
      allow: ["public", ~r/^tenant_/],  # Only public + tenant schemas
      deny: ["legacy"]                  # Block legacy schema
    ],
    mysql: [
      # In MySQL, schemas = databases
      allow: ["app_db", "analytics_db"],
      deny: ["staging_db"]
    ]
  },

  # Table-level rules (lower precedence)
  table_visibility: %{
    default: [
      deny: ["user_passwords", "api_keys", ~r/^audit_/]
    ],
    postgres: [
      allow: [
        {"public", ~r/^dim_/},      # Dimension tables only
        {"analytics", ~r/.*/}       # All analytics tables
      ]
    ]
  }

Key Principle: Schema visibility gates table visibility. If a schema is denied, all tables within it are blocked regardless of table-level rules.

Database-Specific Schema Behavior:

• PostgreSQL: True namespaced schemas within a database (public, reporting, etc.)
• MySQL: Schemas = Databases (when you connect to MySQL, you can access multiple databases)
• SQLite: Schema-less (visibility rules don't apply)

See the Visibility Guide for detailed configuration examples.

Optional Configuration

config :lotus,
  default_repo: "primary",       # Default data repo for queries
  unique_names: false,           # Defaults to true
  read_only: false               # Defaults to true; set to false to allow writes