Service configuration is fetched from $PROJECT_ROOT/config/$NODE_ENV/config.json5 by the service execution procedure.
JSON5 format is used which is basically less strict javascript-like JSON.

General description of service configuration options is defined by the ajv validation schema.
Extra configuration features whithin the config.json5 are described in the bi-config package.

    // $PROJECT_ROOT/index.js
    const Service = require('bi-service');
    const config  = require('bi-config');
    const service = new Service(config);

    service.config.get() //returns contents of $PROJECT_ROOT/config/$NODE_ENV/config.json5
    service.config.get('storage:postgres'); //returns nested value of the postgres property

Each App of AppManager has its own configuration scope which is populated with service.config.get('apps:<app_name>') once on the App initialization.

   service.appManager.get('myapp').config.get() //returns value of service.config.get('apps:myapp')

Basic config.json5 example

{
    exitOnInitError: true, //whether process should be terminated when an error occurs during service initialization
    apps: {
        <appname>: {
            baseUrl: 'http://127.0.0.1:3000',
            listen: 3000,
            stopOnError: false,
            doc: { //sub-app responsible for generating documentation for its parent app
                baseUrl: 'http://127.0.0.1:3001',
                listen: 3001,
                name: 'docs',
                title: '<appname>',
                stopOnError: true,
                tryItOut: true
            },
            response: {$ref: '#/response'},
            bodyParser: {$ref: '#/bodyParser'},
        }
    },
    response: {
        headers: [
            ["Access-Control-Allow-Methods", "GET, POST, OPTIONS, PUT, PATCH, DELETE, CONNECT"]
        ]
    },
    bodyParser: {
        json: {
            extended: true,
            type: 'application/json',
            limit: "2mb"
        },
        urlencoded: {
            type: 'application/x-www-form-urlencoded',
            limit: "2mb",
            extended: false
        }
    },
    storage: {
        postgres: {
            host: "127.0.0.1",
            ssl: false,
            databases: {
                main: {
                    db: "test",
                    username: "test",
                    password: "",
                }
            }
        }
    },
    logs: {
        exitOnError: false,  // determines whether a process will exit with status code 1 on 'uncaughtException' event
        transports: [
            {
                type: 'file',
                level: 'info', // maximum log level of this sepecific transport, [optional]
                json: false,
                priority: 1,
                dir: 'logs', // can be absolute or relative to the node's process
                autocreate: true // whether the `dir` should be created if it does not exist
            },
        ]
    }
}