Config-dug NPM

Config Dug

Config Management library for Node.js

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Major features

Strongly typed config object
Specify config schema with Zod
- Support for many data types including: string, number, boolean, array, object, enum, date and more
Plugin support with included plugins for AWS Secrets Manager and AWS AppConfig
- Live reloading of config values from plugins
Compatible with dependency injection frameworks like tsyringe and InversifyJS
Support for CJS and ESM projects

Usage

Installing

npm install config-dug

Basic Usage

import { ConfigDug, z } from 'config-dug';

const schema = {
  logLevel: z.string().default('info'),
};

const config = await ConfigDug.getConfig(schema);

Advanced Usage

import { ConfigDug, z } from 'config-dug';
import { AWSSecretsManagerPlugin } from '@config-dug/plugin-aws-secrets-manager';

const schema = {
  logLevel: z.string().default('info'),
  apiToken: {
    schema: z.string(),
    sensitive: true,
  },
};

const awsSecretsManagerPlugin = new AWSSecretsManagerPlugin({
  secrets: [
    {
      name: 'config-dug-test/config',
      region: 'ca-central-1',
      reloadInterval: '1m',
    },
  ],
});

const configDug = new ConfigDug(schema, { plugins: [awsSecretsManagerPlugin] });

configDug.on('config-loaded', (config) => {
  console.log('config-loaded event received', config);
});

configDug.on('config-reloaded', (config) => {
  console.log('config-reloaded event received', config);
});

await configDug.load();

const getConfig = () => {
  return configDug.getConfig();
};

export { getConfig };

Options

Name	Type	Default	Description
`basePath`	`string`	`process.cwd()`	The directory to load config files from
`envKey`	`string`	`APP_ENV`	The environment variable specifying the application environment
`loadConfigFiles`	`boolean`	`true`	Load config values from `config.*.{js\|cjs\|mjs}` files
`loadEnvironment`	`boolean`	`true`	Load config values from the environment
`plugins`		`[]`	An array of plugins to load. Plugins are evaluated in order so config values that come from a plugin that is specified later will override config values from plugins specified earlier
`printConfig`	`boolean`	`false`	Print the resolved config when loaded
`strict`	`boolean`	`false`	When `false` config values are preprocessed first to coerce them to the specified type
`warnOnLocalConfigFile`	`boolean`	`true`	Print a warning when a local config file `config.*.local.{js\|cjs\|mjs}` is loaded

Plugins

TODO: Add instructions on using plugins
TODO: Add a guide on writing plugins

Plugin Interface

interface ConfigDugPlugin {
  public load(): Promise<UntypedConfig>;
  public reload(): Promise<UntypedConfig>;
}

Plugin Return Value

{
  values: UntypedConfig, // Record<string, unknown>
  valueOrigins: ValueOrigins, // Record<string, string[]>
  nextReloadIn: number | undefined
}

Plugin Lifecycle

flowchart TB
    A[Initialize] --> B
    B[onBeforeLoadConfigFiles] --> C
    C[loadConfigFiles] --> D
    D[onAfterLoadConfigFiles] --> E
    E[onBeforeLoadPlugins] --> F
    F[loadPlugins] --> G
    G[onAfterLoadPlugins] --> H
    H[onBeforeLoadLocalConfigFiles] --> I
    I[loadLocalConfigFiles] --> J
    J[onAfterLoadLocalConfigFiles] --> K
    K[onBeforeLoadEnvironment] --> L
    L[loadEnvironment] --> M
    M[onAfterLoadEnvironment]