@travetto/config/src/source/override.ts

Configuration support

import { SchemaRegistry } from '@travetto/schema';

import { ConfigData } from '../parser/types.ts';
import { ConfigSource, ConfigSpec } from './types.ts';

export const OverrideConfigSymbol = Symbol.for('@travetto/config:overrides');

/**
 * Configuration Override
 */
export type OverrideConfig = {
  ns: string;
  fields: Record<string, () => (unknown | undefined)>;
};

/**
 * Overridable config source, provides ability to override field level values, currently used by
 * - @EnvVar as a means to allow environment specific overrides
 */
export class OverrideConfigSource implements ConfigSource {
  #build(): ConfigData {
    const out: ConfigData = {};
    for (const cls of SchemaRegistry.getClasses()) {
      const { ns, fields = {} } = SchemaRegistry.getMetadata<OverrideConfig>(cls, OverrideConfigSymbol) ?? {};
      for (const [key, value] of Object.entries(fields)) {
        const val = value();
        if (val !== undefined && val !== '') {
          out[`${ns}.${key}`] = val;
        }
      }
    }
    return out;
  }

  get(): ConfigSpec {
    return { data: this.#build(), priority: 999, source: 'memory://override' };
  }
}