@alliage/service-loader v0.1.0-beta.3

Alliage Service Loader

Automatic import and registration of services.

Dependencies

• @alliage/di
• @alliage/lifecycle
• @alliage/module-installer
• @alliage/config-loader

Installation

yarn add @alliage/service-loader

With npm

npm install @alliage/service-loader

Registration

If you have already installed @alliage/module-installer you just have to run the following command:

$(npm bin)/alliage-scripts install @alliage/service-loader

Otherwise, update your alliage-modules.json file to add this at the bottom:

{
  // ... other modules
  "@alliage/service-loader": {
    "module": "@alliage/service-loader",
    "deps": [
      "@alliage/lifecycle",
      "@alliage/di",
      "@alliage/module-installer",
      "@alliage/config-loader"
    ],
    "envs": [],
  }
}

Usage

The goal of this module is to allow us to import and register services without having to create an alliage module.

Configuration

Once installed, a new file located in config/services.yaml should be available that should look like this.

basePath: 'src'
paths: ['services/**/*']
exclude: ['services/**/NotAService.*']

• The basePath parameters just tells the module where is located the source code of our application.
• The paths parameters will define which files must be considered as services and thus must be automatically imported and registered.
• The exclude parameter will allow to exclude files that could match one of the paths.

Define a service

To define a service, the module must follow the following rules:

• Its path must match with what's configured in the config/services.yaml file
• It must export the service as default
• It must declare the service using the Service decorator

Like in the following example:

import { Service } from '@alliage/service-loader';
import { service, parameter } from '@alliage/di';

class MyService {
  constructor(otherService, dummyParameter) {
    super();
    this.otherService = otherService;
    this.dummyParameter = dummyParameter;
  }

  // ...
}

export default Service('my_service', [
  service('other_service'),
  parameter('parameters.dummy_parameter'),
])(MyService);

The Service decorator takes following parameters:

• The service's name (which must be unique)
• The list of dependencies

Once done, the service will be automatically loaded !

Events

Service loader events

import { SERVICE_LOADER_EVENTS } from '@alliage/service-loader';

ServiceLoaderBeforeAllEvent

This is the instance of the event object received in any SERVICE_LOADER_EVENTS.BEFORE_ALL listener.

• getBasePath(): string: Returns the base path as configured in the configuration file
• getPaths(): string[]: Returns the paths as configured in the configuration file
• getExclude(): string[]: Returns the exclusions as configured in the configuration file
• setPaths(paths: string[]): ServiceLoaderBeforeAllEvent: Allows to re-define the paths
• setExclude(exclude: string[]): ServiceLoaderBeforeAllEvent: Allows to re-define the exclusions

ServiceLoaderBeforeOneEvent

This is the instance of the event object received in any SERVICE_LOADER_EVENTS.BEFORE_ONE listener.

• getModulePath(): string: Returns the path of the service about to be loaded
• getName(): string: Returns the unique name of the service about to be loaded
• getConstructor(): string: Returns the constructor of the service about to be loaded
• getDependencies(): Dependency[]: Returns the list of dependencies of the service about to be loaded
• setConstructor(constructor: any): ServiceLoaderBeforeOneEvent: Allows to re-define the constructor of the service about to be loaded
• setDependencies(dependencies: Dependency[]): ServiceLoaderBeforeOneEvent: Allows to re-define the dependencies of the service about to be loaded

ServiceLoaderAfterOneEvent

This is the instance of the event object received in any SERVICE_LOADER_EVENTS.AFTER_ONE listener.

• getModulePath(): string: Returns the path of the loaded service
• getName(): string: Returns the unique name of the loaded service
• getConstructor(): string: Returns the constructor of the loaded service
• getDependencies(): Dependency[]: Returns the list of dependencies of the loaded service

ServiceLoaderAfterAllEvent

This is the instance of the event object received in any SERVICE_LOADER_EVENTS.AFTER_ALL listener.

• getBasePath(): string: Returns the base path as configured in the configuration file
• getPaths(): string[]: Returns the paths as configured in the configuration file
• getExclude(): string[]: Returns the exclusions as configured in the configuration file