Cascade config loader for typescript from different config providers
Partially inspired by go library confita
We want hierarchical config collected over different config providers such as environment variables, files, POTO (T for typescript), vault, etcd, consul etc.
Imagine you have some env file with content like this
DEV_MODE=true
LOG_LEVEL=debug
POSTGRES_DB_HOST=db
POSTGRES_DB=sample
POSTGRES_USER=sample
POSTGRES_PASSWORD=sample
POSTGRES_DB_PORT=5432
MAIL_HOST=mailcatcher
MAIL_PORT=1025
MAIL_USER=
MAIL_PASSWORD=And you want config class like this
class Config {
mail: {
host: string;
port: number;
user: string;
password: string;
};
database: {
name: string;
host: string;
port: number;
user: string;
password: string;
};
crypto: {
cryptoKey: string;
};
devMode: boolean;
logLevel: string;
}So you can use classes with property decorators to load config from envs and vault and put it to corresponding properties
import { EnvConfig, VaultConfig, NestedConfig } from 'confidog';
class MailConfig {
@EnvConfig({ key: 'MAIL_HOST', default: 'localhost' })
host: string;
@EnvConfig({ key: 'MAIL_PORT', default: 1025 })
port: number;
@EnvConfig({ key: 'MAIL_USER', default: '' })
user: string;
@EnvConfig({ key: 'MAIL_PASSWORD', default: '' })
password: string;
}
class DatabaseConfig {
@EnvConfig({ key: 'DATABASE_HOST', default: 'localhost' })
host: string;
@EnvConfig({ key: 'DATABASE_PORT', default: 5432 })
port: number;
@EnvConfig({ key: 'DATABASE_USER', default: 'postgres' })
user: string;
@EnvConfig({ key: 'DATABASE_PASSWORD', default: '' })
password: string;
}
class CryptoConfig {
@EnvConfig({ key: 'CRYPTO_KEY', default: 'some_not_really_secret_value_for_development' })
@VaultConfig({ key: 'crypto_key', default: 'unknown_crypto_key' })
cryptoKey: string;
}
export class Config {
@NestedConfig()
mail: MailConfig;
@NestedConfig()
database: DatabaseConfig;
@NestedConfig()
crypto: CryptoConfig;
@EnvConfig({ key: 'DEV_MODE', default: false })
devMode: boolean;
@EnvConfig({ key: 'LOG_LEVEL', default: 'debug' })
logLevel: string;
}Finally you just need to load it. You should define providers in such an order that the following provider get higher priority over the previous one. So in this example if there is a value in env and vault, the vault value (if exists) will override value from env.
import { ConfigLoader, EnvConfigProvider, VaultConfigProvider } from 'confidog';
const config = ConfigLoader.load(new Config(), {
providers: [
{ key: 'env', value: new EnvConfigProvider() },
{ key: 'value', value: new VaultConfigProvider({ path: 'localhost:8200/kv/my', secret: 'some_vault_secret' }) },
]
});You can use class-validator decorators to validate loaded config via them For example you have following config
import { IsString } from 'class-validator';
export class Config {
@EnvConfig({ key: 'DEV_MODE', default: false })
devMode: boolean;
@EnvConfig({ key: 'LOG_LEVEL', default: 'debug' })
@IsString()
logLevel: string;
}You can specify option validate set to true
import { ConfigLoader, EnvConfigProvider } from 'confidog';
const config = ConfigLoader.load(new Config(), {
providers: [{ key: 'env', value: new EnvConfigProvider() }],
options: {
validate: true
}
});If you want config to be immutable, set option freeze to true. It set to true by default
import { ConfigLoader, EnvConfigProvider } from 'confidog';
const config = ConfigLoader.load(new Config(), {
providers: [{ key: 'env', value: new EnvConfigProvider() }],
options: {
validate: true,
freeze: true,
}
});
### Samples
See `samples` directory. Also this samples are used in tests, so you can be sure that it is just working
### Usage with nestjs
See `samples/nestjs` directory.
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