William Valentin
c2cc052694
- Add deepMerge utility for recursive object merging (arrays replace, not concat) - Extend loadConfig with optional overlayPath parameter - Merge happens before env var expansion and Zod validation - Add 6 deepMerge unit tests and 4 overlay integration tests - Re-export deepMerge from config/index.ts - All 1087 existing tests still pass
86 lines
2.5 KiB
TypeScript
86 lines
2.5 KiB
TypeScript
import { readFileSync } from 'fs';
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import { parse } from 'yaml';
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import { configSchema, type Config } from './schema.js';
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function expandEnvVars(value: string): string {
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return value.replace(/\$\{([^}]+)\}/g, (_, envVar) => {
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const envValue = process.env[envVar];
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if (envValue === undefined) {
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throw new Error(`Environment variable ${envVar} is not set`);
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}
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return envValue;
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});
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}
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function expandEnvVarsInObject(obj: unknown): unknown {
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if (typeof obj === 'string') {
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return expandEnvVars(obj);
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}
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if (Array.isArray(obj)) {
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return obj.map(expandEnvVarsInObject);
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}
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if (obj !== null && typeof obj === 'object') {
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const result: Record<string, unknown> = {};
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for (const [key, value] of Object.entries(obj)) {
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result[key] = expandEnvVarsInObject(value);
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}
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return result;
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}
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return obj;
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}
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/**
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* Deep merge two plain objects. Overlay values override base values.
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* Arrays in overlay replace base arrays (not concatenated).
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* null in overlay explicitly sets key to null.
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* Only plain objects recurse; arrays, primitives, and null are overwritten.
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*/
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export function deepMerge(
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base: Record<string, unknown>,
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overlay: Record<string, unknown>,
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): Record<string, unknown> {
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const result = { ...base };
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for (const [key, value] of Object.entries(overlay)) {
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if (
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value !== null &&
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typeof value === 'object' &&
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!Array.isArray(value) &&
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typeof result[key] === 'object' &&
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result[key] !== null &&
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!Array.isArray(result[key])
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) {
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result[key] = deepMerge(
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result[key] as Record<string, unknown>,
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value as Record<string, unknown>,
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);
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} else {
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result[key] = value;
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}
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}
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return result;
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}
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/**
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* Load and validate a Flynn config from YAML file(s).
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* If overlayPath is provided, the overlay YAML is deep-merged on top of
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* the base config BEFORE env var expansion and Zod validation.
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*/
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export function loadConfig(configPath: string, overlayPath?: string): Config {
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const rawContent = readFileSync(configPath, 'utf-8');
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let rawConfig = parse(rawContent);
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if (overlayPath) {
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const overlayContent = readFileSync(overlayPath, 'utf-8');
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const overlayConfig = parse(overlayContent);
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if (overlayConfig && typeof overlayConfig === 'object') {
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rawConfig = deepMerge(
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rawConfig as Record<string, unknown>,
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overlayConfig as Record<string, unknown>,
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);
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}
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}
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const expandedConfig = expandEnvVarsInObject(rawConfig);
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return configSchema.parse(expandedConfig);
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}
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