feat(boot): improve service booter to load classes decorated with @Bind

Author: raymondfeng

packages/boot/src/__tests__/fixtures/bindable-classes.artifact.ts

@@ -0,0 +1,35 @@
+// Copyright IBM Corp. 2019. All Rights Reserved.
+// Node module: @loopback/boot
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {bind, BindingScope, Provider} from '@loopback/core';
+
+@bind({
+  tags: {serviceType: 'local'},
+  scope: BindingScope.SINGLETON,
+})
+export class BindableGreetingService {
+  greet(whom: string = 'world') {
+    return Promise.resolve(`Hello ${whom}`);
+  }
+}
+
+@bind({tags: {serviceType: 'local', name: 'CurrentDate'}})
+export class DateProvider implements Provider<Date> {
+  value(): Promise<Date> {
+    return Promise.resolve(new Date());
+  }
+}
+
+export class NotBindableGreetingService {
+  greet(whom: string = 'world') {
+    return Promise.resolve(`Hello ${whom}`);
+  }
+}
+
+export class NotBindableDateProvider implements Provider<Date> {
+  value(): Promise<Date> {
+    return Promise.resolve(new Date());
+  }
+}

packages/boot/src/__tests__/integration/service.booter.integration.ts

@@ -21,8 +21,10 @@ describe('service booter integration tests', () => {
 
   it('boots services when app.boot() is called', async () => {
     const expectedBindings = [
-      `${SERVICES_PREFIX}.GeocoderService`,
-      // greeting service is skipped - service classes are not supported (yet)
+      'services.BindableGreetingService',
+      'services.CurrentDate',
+      'services.GeocoderService',
+      'services.NotBindableDate',
     ];
 
     await app.boot();
@@ -31,6 +33,18 @@ describe('service booter integration tests', () => {
     expect(bindings.sort()).to.eql(expectedBindings.sort());
   });
 
+  it('boots bindable classes when app.boot() is called', async () => {
+    const expectedBindings = [
+      `${SERVICES_PREFIX}.CurrentDate`,
+      `${SERVICES_PREFIX}.BindableGreetingService`,
+    ];
+
+    await app.boot();
+
+    const bindings = app.findByTag({serviceType: 'local'}).map(b => b.key);
+    expect(bindings.sort()).to.eql(expectedBindings.sort());
+  });
+
   async function getApp() {
     await sandbox.copyFile(resolve(__dirname, '../fixtures/application.js'));
     await sandbox.copyFile(
@@ -43,6 +57,11 @@ describe('service booter integration tests', () => {
       'services/greeting.service.js',
     );
 
+    await sandbox.copyFile(
+      resolve(__dirname, '../fixtures/bindable-classes.artifact.js'),
+      'services/bindable-classes.service.js',
+    );
+
     const MyApp = require(resolve(SANDBOX_PATH, 'application.js')).BooterApp;
     app = new MyApp();
   }

packages/boot/src/__tests__/unit/booters/service.booter.unit.ts

@@ -27,7 +27,7 @@ describe('service booter unit tests', () => {
   beforeEach(createStub);
   afterEach(restoreStub);
 
-  it('gives a warning if called on an app without RepositoryMixin', async () => {
+  it('does not require service mixin', async () => {
     const normalApp = new Application();
     await sandbox.copyFile(
       resolve(__dirname, '../../fixtures/service-provider.artifact.js'),
@@ -43,12 +43,7 @@ describe('service booter unit tests', () => {
     ];
     await booterInst.load();
 
-    sinon.assert.calledOnce(stub);
-    sinon.assert.calledWith(
-      stub,
-      'app.serviceProvider() function is needed for ServiceBooter. You can add ' +
-        'it to your Application using ServiceMixin from @loopback/service-proxy.',
-    );
+    sinon.assert.notCalled(stub);
   });
 
   it(`uses ServiceDefaults for 'options' if none are given`, () => {

packages/boot/src/booters/service.booter.ts

@@ -3,14 +3,20 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
+import {
+  BINDING_METADATA_KEY,
+  Constructor,
+  inject,
+  MetadataInspector,
+} from '@loopback/context';
 import {CoreBindings} from '@loopback/core';
 import {ApplicationWithServices} from '@loopback/service-proxy';
-import {inject, Provider, Constructor} from '@loopback/context';
+import * as debugFactory from 'debug';
 import {ArtifactOptions} from '../interfaces';
-import {BaseArtifactBooter} from './base-artifact.booter';
 import {BootBindings} from '../keys';
+import {BaseArtifactBooter} from './base-artifact.booter';
 
-type ServiceProviderClass = Constructor<Provider<object>>;
+const debug = debugFactory('loopback:boot:service-booter');
 
 /**
  * A class that extends BaseArtifactBooter to boot the 'Service' artifact type.
@@ -23,8 +29,6 @@ type ServiceProviderClass = Constructor<Provider<object>>;
  * @param bootConfig - Service Artifact Options Object
  */
 export class ServiceBooter extends BaseArtifactBooter {
-  serviceProviders: ServiceProviderClass[];
-
   constructor(
     @inject(CoreBindings.APPLICATION_INSTANCE)
     public app: ApplicationWithServices,
@@ -46,24 +50,12 @@ export class ServiceBooter extends BaseArtifactBooter {
   async load() {
     await super.load();
 
-    this.serviceProviders = this.classes.filter(isServiceProvider);
+    for (const cls of this.classes) {
+      if (!isBindableClass(cls)) continue;
 
-    /**
-     * If Service providers were discovered, we need to make sure ServiceMixin
-     * was used (so we have `app.serviceProvider()`) to perform the binding of a
-     * Service provider class.
-     */
-    if (this.serviceProviders.length > 0) {
-      if (!this.app.serviceProvider) {
-        console.warn(
-          'app.serviceProvider() function is needed for ServiceBooter. You can add ' +
-            'it to your Application using ServiceMixin from @loopback/service-proxy.',
-        );
-      } else {
-        this.serviceProviders.forEach(cls => {
-          this.app.serviceProvider(cls as Constructor<Provider<object>>);
-        });
-      }
+      debug('Bind class: %s', cls.name);
+      const binding = this.app.service(cls);
+      debug('Binding created for class: %j', binding);
     }
   }
 }
@@ -77,8 +69,20 @@ export const ServiceDefaults: ArtifactOptions = {
   nested: true,
 };
 
-function isServiceProvider(cls: Constructor<{}>): cls is ServiceProviderClass {
+function isServiceProvider(cls: Constructor<unknown>) {
   const hasSupportedName = cls.name.endsWith('Provider');
-  const hasValueMethod = 'value' in cls.prototype;
+  const hasValueMethod = typeof cls.prototype.value === 'function';
   return hasSupportedName && hasValueMethod;
 }
+
+function isBindableClass(cls: Constructor<unknown>) {
+  if (MetadataInspector.getClassMetadata(BINDING_METADATA_KEY, cls)) {
+    return true;
+  }
+  if (isServiceProvider(cls)) {
+    debug('Provider class found: %s', cls.name);
+    return true;
+  }
+  debug('Skip class not decorated with @bind: %s', cls.name);
+  return false;
+}

packages/core/src/__tests__/unit/application.unit.ts

@@ -270,11 +270,26 @@ describe('Application', () => {
       const binding = app.service(MyServiceProvider);
       expect(Array.from(binding.tagNames)).to.containEql(CoreTags.SERVICE);
       expect(binding.tagMap.date).to.eql('now');
-      expect(binding.key).to.equal('localServices.MyServiceProvider');
+      expect(binding.key).to.equal('localServices.MyService');
       expect(binding.scope).to.equal(BindingScope.TRANSIENT);
       expect(findKeysByTag(app, 'service')).to.containEql(binding.key);
     });
 
+    it('binds a service provider with name tag', () => {
+      @bind({tags: {date: 'now', name: 'my-service'}})
+      class MyServiceProvider implements Provider<Date> {
+        value() {
+          return new Date();
+        }
+      }
+
+      const binding = app.service(MyServiceProvider);
+      expect(Array.from(binding.tagNames)).to.containEql(CoreTags.SERVICE);
+      expect(binding.tagMap.date).to.eql('now');
+      expect(binding.key).to.equal('services.my-service');
+      expect(findKeysByTag(app, 'service')).to.containEql(binding.key);
+    });
+
     function givenApp() {
       app = new Application();
     }