AppHost
Simple, functional configuration manager. Load and merge config from JSON files, environment variables and cli args.
Install
npm install apphost -P
Usage
// config/index.js
const {
configure,
setConfigPath,
addFile,
addEnv,
addArgv
} = require("apphost");
module.exports = configure(
// Optional. configPath defaults to CWD/config/
setConfigPath('./config'),
addFile("appsettings.json"),
addFile(`appsettings.${process.env.NODE_ENV || "development"}.json`, {
required: false,
}),
addEnv({
// Optional: merge all env vars starting with prefix
prefix: 'APP_HOST_',
// OR explicitly map env var to config object paths
envToConfigMapping: {
// process.env.DB_PASSWORD will map to
// { database: { password: '' }}
DB_PASSWORD: 'database.password'
}
}),
addArgv({
// Optional: Specify aliases
argvAliases: [{ argv: 'app', aliases: ['a'] }],
// Map argv options to config object paths
argvToConfigMapping: {
// -a is an alias for --app.
// Both will map to { app: { name: '' }}
app: 'app.name'
},
})
);Config files
addFile supports loading and merging JSON files into the config object.
config/appsettings.json
{
"app": {
"name": "MyApp",
"version": "1.0.0",
"description": "cool app"
},
"database": {
"url": "",
"user": "",
"password": ""
},
"logging": {
"level": "errors"
}
}config/appsettings.development.json
{
"logging": {
"level": "debug"
}
}Environment variables
Enviroment variables map to the config object in two ways.
Variables specified in the envToConfigMapping option map as outlined in the mapping.
Variables that match the prefix option, if provided, are lowercased and then _ are treated as spaces and the joined as a camelCase string.
NODE_ENV=development
# Maps to database.user
APP_HOST_DATABASE.USER=admin
# Maps to database.password
DB.PASSWORD=password123
CLI args
Like environment variables, cli args map to config object in two ways. Those in the argvToConfigMapping are mapped according to the mapping. Alternatively, object paths can be passed directly to the script.
Running the application with
# -a is an alias for --app which maps to app.name
node app.js -a "My Awesome App" --database.url "dbUrl"Results in
// config
{
"app": {
"name": "My Awesome App",
"version": "1.0.0",
"description": "cool app"
},
"database": {
"url": "dbUrl",
"user": "admin",
"password": "password123"
},
"logging": {
"level": "debug"
}
};