@qte/nest-config

A module for advanced configurations in Nest, supporting YAML, Env values, and Google Secret Manager secrets. The module aims to provide flexibility, while also providing a great deal of safety. One of the guiding principles is to fail fast. The module will throw early errors crashing the application if anything goes wrong.

Installation

$ yarn add @qte/nest-config

Note that zod is a peer-dependency and must be installed separately.

Quick start

Import and configure the module in the following way

import { ConfigModule, ConfigService, DEVELOPMENT } from '@qte/nest-config'
import { z } from 'zod'

const mySchema = z.object({
  port: z.number()
}).strict()
type Config = z.infer<typeof mySchema>

// The module is global
ConfigModule.forRoot({
  env: DEVELOPMENT,
  schema: mySchema,
  configPath: './config' // Optional argument, defaults to the ./config directory relative to the running node process
})

// Later on in any other Nest provider or controller
const myConfig = ConfigService.getConfig<Config>()

You must create the following files

touch ./config/index.yaml # This is your base configuration
touch ./config/env.development.yaml # This file is loaded if env is DEVELOPMENT
touch ./config/env.staging.yaml # This file is loaded if env is STAGING
touch ./config/env.production.yaml # This file is loaded if env is PRODUCTION

The final configuration is built from first parsing index.yaml, then merging it with the environment specific configuration.

Duplicate keys

Duplicate object keys are merged recursively, while all other duplicates are overriden, and the environment configuration is prioritised.

# index.yaml
database:
  user: postgres
  password: development

# env.production.yaml
database:
  password: super-secret-prod-password # Ideally read from a secret

Merges to

const config = {
  database: {
    user: 'postgres',
    password: 'super-secret-prod-password',
  }
}

Env and Secrets

Configuration files can contain ENV values and Google Secrets Manager secrets. See examples below

database:
  host:
    $from:
      env: DATABASE_ENV # Will read PROCESS.ENV.DATABASE_ENV
  password:
    $from:
      secret: projects/some-gcp-project/secrets/some-secret/versions/latest # Will read the secret from GCP

the parsed configuration will match the following schema

z.object({
  database: z.object({
    host: z.string(),
    password: z.string(),
  }),
})

Cache

The package caches secrets in development mode. Clear the cache by running

rm -rf $TMPDIR/nest-config

You can also disable caching by setting cache: false in the module options

License

@qte/nest-config is MIT licensed.