Core

Universal Core is a generic framework to run any kind of node application in a conventional way, it can be anything, a web server, a background jobs worker, a web sockets server, a game runner, whatever you want. You just build the entry point as a CoreApp class and the universal core cli runner will take care of the rest.

Install

To initialize a core project you can use the cli by running

npx @universal-packages/core new my-app

To initialize a typescript project use the flag -ts

npx @universal-packages/core new my-app --ts

You will end up with the following structure

- my-new-app
  |- src
    |- config  // All the configuration goes here
    |- modules // All custom modules go here
    |- tasks // All custom tasks go here
    |- example.app.js|ts // Example app so you know what's up
  |- core.yaml

Alternatively you can start from scratch installing this package

npm install @universal-packages/core

CLI

The universal core cli is very simple and your entry point to run universal core projects.

new

ucore new <project-name> <--ts|--typescript>?

Initialize a new project in its own directory, install packages and inits git for you.

Example:

ucore new web-app

run

ucore run <app-name> <options>

Loads core config, loads project configuration, loads all available modules and runs an universal core application, <options> are arbitrary args that may be used by the app.

Example:

ucore run server -p 3002 -h localhost

exec

ucore exec <task-name> <task-directive> <task-options> <options>

Loads core config, loads project configuration, loads all available modules and runs an universal core task, <options> are arbitrary args that may be used by the task.

Example:

ucore exec database-task generate-migration create-users-table --fast

initialize

ucore initialize <initializer-name> <--ts|--typescript>?

If a universal core library offers some kind of initializer you can use this command to initialize it in your project, <initializer-name> is the name of the library you want to initialize, it will may provide a typescript template that will be populated.

Example:

ucore initialize some-core-library --typescript

console

ucore console

Loads core config, loads project configuration, loads all available modules and runs an interactive console.

Core Configuration

In order for the universal core to find and load everything smoothly you need to provide a core configuration file at the root of your project.

Example:

default:
  apps:
    location: ./src/apps

development:
  apps:
    watcher:
      enabled: true
      ignore:
        - tests
  logger:
    level: TRACE
    terminal:
      clear: true

As you can see you can provide configuration depending on the environment you are running or in other words depending what NODE_ENV value is set.

Config

• apps map

  • location string default: ./src Where core should look for app modules to load.
  • watcher map
    • enabled boolean default: false Should the runner watch your project for changes and reload the app on the fly?.
    • ignore string[] Which files and folders should the watcher ignore.

• config map

  • location string default: ./src/config Where all the project config is.

• environments map

  • location string default: ./src Where all your environments are.

• modules map

  • asGlobals boolean default: true All modules will be available in the global scope like myCustomModule.
  • location string default: ./src Where all your custom modules are.

• tasks map

  • location string default: ./src Where all your custom tasks are.

• logger map See Logger Options

• terminalPresenter map See Terminal Presenter Options

Core Module

Core modules need to be built as a conventional class with some required and optional methods. Modules are meant to be a modularized piece of logic that provides encapsulated capabilities to be used all across the project. If possible and in case the user want modules to be shared globally, a subject property needs to be set for core to set it as a global, in the example below a redisSubject global variable equal to the subject property will be set.

import { CoreModule } from '@universal-packages/core'
import ActualRedis from 'some-good-redis-lib'

export default class RedisModule extends CoreModule {
  static moduleName = 'redis-module'
  static description = 'Redis encapsulation'
  static defaultConfig = { port: 3789 }
  static environment = 'production'
  static onlyFor = 'apps'
  static tideTo = 'web-server-app'

  subject = null

  async prepare() {
    this.subject = new ActualRedis(this.config)
    await this.subject.connect()
  }

  async release() {
    await this.subject.disconnect()
  }
}

Configuration for this module should be in ./src/config/redis-module.json|yaml|js

Example:

default:
  db: 0
development:
  port: 6379

Static properties

moduleName String

Name to be used when loading an collecting modules, internally this is preferred before using the class name, module names will be used to name the subject when globals are enabled, try to follow a convention to use module at the end of your module name, for example redis-module, this way your global subject will be called redisSubject, you can still name it what ever you want and subject will be appended at the end of the module name.

description String

Quick explanation of what your modules provides.

defaultConfig String

Before core passed the configuration loaded to this module it can optionally grab this default configuration and merge it with the loaded one, normally used to avoid errors while configuring the subject.

environment String | String[]

If specified the module will only be loaded if NODE_ENV matches one of the values, for instance the example above will only be loaded when NODE_ENV is equal to production, another example will be to set it like static environment = ['production', 'staging'] to only be ran in those.

It is also supported negated environments, for instance static environment = '!development' will be loaded in any environment except development.

onlyFor 'apps' | 'tasks' | 'console'

If specified the environment will only be loaded if the process type matches, for instance the example above will only be loaded if we are running an app, another example will be to set it like static onlyFor = ['apps', 'console'] to only be ran in those.

tideTo String | String[]

If specified the environment will only be loaded if the process name matches, for instance the example above will only be loaded if we are running an app called web-server-app, another example will be to set it like static tideTo = ['web-server-app', 'worker-app'] to only be ran in those.

Instance properties

config Object

Use the config passed to this instance via this Module's configuration file via this.config the configuration file should be named the same as your module's name ./src/config/custom-module.yaml | json | js | ts

logger Logger

A logger will be passed to the environment to be used accessed as this.logger

subject Any

Set this if you want core to set it as a global to use, normally modules abstract a subject and normalize it to shared across the app through a subject.

Instance methods (Module life cycle)

prepare() required

Modules are loaded before the app or task are loaded, so they can access all modules to prepare themselves. Every time a module is loaded its prepare method will be called for instantiation, so all sorts of preparations can be made to leave the module ready to be used across the project.

release() required

Modules normally will release any connections to local services such as databases.

Core Apps

Core apps need to be built as a conventional class with some required and optional methods. Apps are meant to keep alive once running.

import { CoreApp } from '@universal-packages/core'
import { createServer, destroyServer } from 'some-useful-http-server'

export default class WebServer extends CoreApp {
  static appName = 'web-server'
  static description = 'Http server'
  static defaultConfig = { host: 'localhost' }

  webServer = null

  async prepare() {
    // possible core module loaded
    const migrated = await databaseModule.checkMigrations()
    if (!migrated) throw new Error('Migrate db before running')

    this.webServer = await createServer(this.config.serverConfig)
  }

  async run() {
    await this.webServer.start({ port: this.config.port })
    this.logger.log({ level: 'INFO', title: 'Web app has started' })
  }

  async stop() {
    await this.webServer.stop()
    this.logger.log({ level: 'INFO', title: 'Web app has stopped' })
  }

  async release() {
    await destroyServer(this.webServer)
  }
}

Configuration for this app should be in ./src/config/web-server.json|yaml|js

Example:

default:
  serverConfig:
    routes:
      - /users/:id
      - /posts/:id
development:
  port: 3000

Static properties

appName String

Name to be used when finding an app to run, internally this is preferred before using the class name.

description String

Quick explanation of what your app provides.

defaultConfig String

Before core passed the configuration loaded to this app it can optionally grab this default configuration and merge it with the loaded one, normally used to avoid errors.

allowAppWatch boolean default: true

If your apps provides its own way to reload itself when a file changes you can set this to false to avoid conflicts with the core watcher. This overrides the watcher configuration in the core configuration file.

allowLoadModules boolean default: true

Some apps may not need any module because they are self sufficient, if this is the case you can set this to false to avoid loading any module.

allowLoadEnvironments boolean default: true

Some apps may not need any environment because they are self sufficient, if this is the case you can set this to false to avoid loading any environment.

Instance properties

config Object

Use the config passed to this instance via this App's configuration file via this.config the configuration file should be named the same as your app's name ./src/config/example-app.yaml | json | js | ts

logger Logger

A logger will be passed to the environment to be used accessed as this.logger

args oBJECT

Any params passed via command line will be passed to the app instance and can be accessed via this.args

ucore run example-app -p 80000
                      |       |
                        args

Instance methods (App life cycle)

prepare() optional

When core loads your app, it will call this method so you can prepare any custom stuff you need to prepare in order for your app to run smoothly. Core modules are already loaded at this point so feel free to use them. Sometimes you just want custom stuff to happen before starting the app.

run() required

Once all modules have been loaded as well as your app prepared, this method is called, here you can start listening for connections, or start a worker, or any kind of whatever, after all, a core app is meant to be use in a universal way.

stop() required

After pressing CTRL+C universal core will call this method so you can start shutting down your app gracefully, starting draining sockets or whatever.

release() optional

This is the counterpart of prepare, use this after your app has stopped to release any resources or custom routines to ensure your app has released everything to finish the process.

Core Tasks

Core tasks need to be built as a conventional class with some required and optional methods. Tasks are meant to execute once and finish in one go. Tasks does not hold any configuration.

import { CoreTask } from '@universal-packages/core'

export default class SendEmailsTask extends CoreTask {
  static taskName = 'send-emails-task'
  static description = 'Send an email to all our users'

  allUsers = []
  stopping = false

  async exec() {
    for (let i = 0; i < this.allUsers, length; i++) {
      if (this.stopping) return
      await emailModule.send(this.directive, { to: allUsers[i].email })
    }
  }

  async abort() {
    this.stopping = true
  }
}

Static properties

taskName String

Name to be used when finding an task to exec, internally this is preferred before using the class name.

description String

Quick explanation of what your task does.

allowLoadModules boolean default: true

Some apps may not need any module because they are self sufficient, if this is the case you can set this to false to avoid loading any module.

allowLoadEnvironments boolean default: true

Some apps may not need any environment because they are self sufficient, if this is the case you can set this to false to avoid loading any environment.

Instance properties

this.directive, this.directiveOptions String, String[]

For tasks instead of loading a configuration in the this.config instance property the task executioner will pass a directive and directiveOptions and these can be accessed via this.directive this.directiveOptions.

ucore exec send-emails-task hola admins
                            |   | |   |
                            ----- -----
                            |       |
                        directive  directiveOptions ['admins']

this.args Object

Any params passed via command line will be passed to the app instance and can be accessed via this.args

ucore exec send-emails-task hola admins --fast
                                        |       |
                                          args

this.logger Logger

You can use the core project logger passed to the instance via this.logger.

Instance methods (Task life cycle)

exec() required

Once all is loaded and prepared exec any kind of whatever. Some data migration or a bulk email sending or whatever.

abort() optional

After pressing CTRL+C universal core will optionally call this method, if you have a way to stop your task do it here so the execution can be stopped gracefully.

If your exec method is just a loop you can set here a this.stopping = true property.

Core Initializers

When building a universal core library you can provide an initializer to help users to start using your library, initializers are meant to be ran once and they can be used to setup a project with some boilerplate code.

If your library provides some boilerplate code you can place your templates in a templates folder in the same directory as your initializer file.

- universal-core-easy-mailing
  |- src
    |- easy-mailing.universal-core-initializer.js
    |- templates
      |- default
        |- source
          |- mailing
            |- Example.mailer.js
          |- config
            |- easy-mailing-module.yaml
      |- typescript
        |- source
          |- mailing
            |- Example.mailer.ts
          |- config
            |- easy-mailing-module.yaml
        |- root
          |- tsconfig.json

Thats the only thing you need to do, all core initializers will populate the templates.

If you need to do some custom stuff you can do it in the initialize protected method.

import { CoreInitializer } from '@universal-packages/core'

export default class EasyMailingInitializer extends CoreInitializer {
  static initializerName = 'easy-mailing'
  static description = 'Easy mailing initialization, sets up some stuff for you'

  // This is always required so that knows where to find the templates
  readonly templatesLocation: string = `${__dirname}/templates`

  async beforeTemplatePopulate() {
    // Do some custom stuff before the templates are populated
  }

  async afterTemplatePopulate() {
    // Do some custom stuff after the templates are populated
  }

  async abort() {
    // If the user aborts the initialization process, you can gracefully stop it here
  }
}

Static properties

initializerName String

Name to be used when finding an initializer to run, internally this is preferred before using the class name.

description String

Quick explanation of what your initializer does.

this.args Object

Any params passed via command line will be passed to the app instance and can be accessed via this.args

ucore initialize easy-mailing --gmail
                             |       |
                                args

this.typescript boolean

If the user passed the --typescript flag this property will be set to true.

ucore initialize easy-mailing --typescript
                             |             |
                                typescript

this.sourceLocation string

If the user passed the --source to a different source location this property will be set to the value.

ucore initialize easy-mailing --source ./code
                             |                |
                               sourceLocation

this.templatesLocation string

This always needs to be set to the location of the templates folder. So that the automatic population knows where to find the templates.

this.logger Logger

You can use the core project logger passed to the instance via this.logger.

Instance methods (Initializer life cycle)

initialize() optional

This will be called after the templates have been populated, you can do some custom stuff here.

rollback() optional

After pressing CTRL+C universal core will optionally call this method, if you have a way to stop your initialization process do it here so the execution can be stopped gracefully.

If your initialize method is just a loop you can set here a this.stopping = true property.

CoreEnvironment

Core environment are callback driven pieces of logic, its event callbacks (methods) are going to be called once depending on the sate of the core running or execution process.

import { CoreEnvironment } from '@universal-packages/core'

export default class MyEnvironment extends CoreEnvironment {
  static environment = 'production'
  static onlyFor = 'apps'
  static tideTo = 'web-server-app'

  beforeModulesLoad() {}
  afterModulesLoad() {}

  beforeAppPrepare() {}
  afterAppPrepare() {}

  beforeAppRuns() {}
  afterAppRuns() {}

  beforeTaskExec() {}
  afterTaskExec() {}

  beforeConsoleRuns() {}
  afterConsoleRuns() {}

  beforeAppStops() {}
  afterAppStops() {}

  beforeTaskAborts() {}
  afterTaskAborts() {}

  afterConsoleStops() {}

  beforeAppRelease() {}
  afterAppRelease() {}

  beforeModulesRelease() {}
  afterModulesRelease() {}
}

Static properties

environment String | String[]

If specified the environment will only be loaded if NODE_ENV matches one of the values, for instance the example above will only be loaded when NODE_ENV is equal to production, another example will be to set it like static environment = ['production', 'staging'] to only be ran in those.

It is also supported negated environments, for instance static environment = '!development' will be loaded in any environment except development.

onlyFor 'apps' | 'tasks' | 'console'

If specified the environment will only be loaded if the process type matches, for instance the example above will only be loaded if we are running an app, another example will be to set it like static onlyFor = ['apps', 'console'] to only be ran in those.

tideTo String | String[]

If specified the environment will only be loaded if the process name matches, for instance the example above will only be loaded if we are running an app called web-server-app, another example will be to set it like static tideTo = ['web-server-app', 'worker-app'] to only be ran in those.

Instance properties

logger Logger

A logger will be passed to the environment to be used accessed as this.logger

Instance methods (event callbacks)

beforeModulesLoad()

Use it when you want to stuff to happen right before modules are loaded.

afterModulesLoad()

Use it when you want to stuff to happen right after modules were loaded.

beforeAppPrepare()

Use it when you want to stuff to happen right before app prepare method is called.

afterAppPrepare()

Use it when you want to stuff to happen right after app has been prepared.

beforeAppRuns()

Use it when you want to stuff to happen right before app run method is called.

afterAppRuns()

Use it when you want to stuff to happen right after app has been ran and is up.

beforeTaskExec()

Use it when you want to stuff to happen right before task exec method is called.

afterTaskExec()

Use it when you want to stuff to happen right after task exec method finishes.

beforeConsoleRuns()

Use it when you want to stuff to happen right before console starts running.

afterConsoleRuns()

Use it when you want to stuff to happen right after console has been ran and is active.

beforeAppStops()

Use it when you want to stuff to happen right before app stop method is called.

afterAppStops()

Use it when you want to stuff to happen right after app has been stopped.

beforeTaskAborts()

Use it when you want to stuff to happen right before task abort method is called.

afterTaskAborts()

Use it when you want to stuff to happen right after task abort method was called (Is stopping probably?).

afterConsoleStops()

Use it when you want to stuff to happen right after console is being exited.

beforeAppRelease()

Use it when you want to stuff to happen right before app release method is called.

afterAppRelease()

Use it when you want to stuff to happen right after app has been released.

beforeModulesRelease()

Use it when you want to stuff to happen right before modules are released.

afterModulesRelease()

Use it when you want to stuff to happen right after modules have been released.

Typescript

This library is developed in TypeScript and shipped fully typed.

Contributing

The development of this library happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving this library.

• Code of Conduct
• Contributing Guide

License

MIT licensed.