feat: add getEggObjects API to fetch all instances (#189)

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##### Checklist
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[x]. -->

- [x] `npm test` passes
- [x] tests and/or benchmarks are included
- [x] documentation is changed or added
- [ ] commit message follows commit guidelines

##### Affected core subsystem(s)
<!-- Provide affected core subsystem(s). -->


##### Description of change
<!-- Provide a description of the change below this comment. -->

新增 `eggObjectFactory.getEggObjects` 接口，用于获取抽象类对应的所有实现。

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- any feature?
- close https://github.com/eggjs/egg/ISSUE_URL
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---------

Co-authored-by: SangLv <sanglv.wl@antgroup.com>

Author: sang4lv

README.md

@@ -934,14 +934,35 @@ import { EggObjectFactory } from '@eggjs/tegg';
 export class HelloService {
   @Inject()
   private readonly eggObjectFactory: EggObjectFactory;
-  
+
   async hello(): Promise<string> {
     const helloImpl = await this.eggObjectFactory.getEggObject(AbstractHello, HelloType.BAR);
     return helloImpl.hello();
   }
 }
 ```
 
+动态获取多个实现，通过 for/await 循环获得实例。
+
+```ts
+import { EggObjectFactory } from '@eggjs/tegg';
+
+@ContextProto()
+export class HelloService {
+  @Inject()
+  private readonly eggObjectFactory: EggObjectFactory;
+
+  async hello(): Promise<string[]> {
+    const helloImpls = await this.eggObjectFactory.getEggObjects(AbstractHello);
+    const messages = [];
+    for await (const helloImpl of helloImpls) {
+      messages.push(helloImpl.hello());
+    }
+    return messages;
+  }
+}
+```
+
 ### 配置项目 module
 
 一般情况下，无需在项目中手动声明包含了哪些 module，tegg 会自动在项目目录下进行扫描。但是会存在一些特殊的情况，tegg 无法扫描到，比如说 module 是通过 npm 包的方式来发布。因此 tegg 支持通过 `config/module.json` 的方式来声明包含了哪些 module。

core/dynamic-inject-runtime/src/EggObjectFactory.ts

@@ -1,6 +1,11 @@
 import type { EggContainerFactory } from '@eggjs/tegg-runtime';
-import { EggAbstractClazz, EggObjectFactory as IEggObjectFactory, QualifierImplUtil } from '@eggjs/tegg-dynamic-inject';
 import { AccessLevel, PrototypeUtil, QualifierValue, SingletonProto } from '@eggjs/core-decorator';
+import {
+  EggAbstractClazz,
+  EggObjectFactory as IEggObjectFactory,
+  QualifierImplUtil,
+} from '@eggjs/tegg-dynamic-inject';
+
 import { EGG_OBJECT_FACTORY_PROTO_IMPLE_TYPE } from './EggObjectFactoryPrototype';
 
 @SingletonProto({
@@ -23,4 +28,26 @@ export class EggObjectFactory implements IEggObjectFactory {
     const eggObject = await this.eggContainerFactory.getOrCreateEggObject(protoObj, protoObj.name);
     return eggObject.obj as T;
   }
+
+  async getEggObjects<T extends object>(abstractClazz: EggAbstractClazz<T>) {
+    const implClazzMap = QualifierImplUtil.getQualifierImpMap(abstractClazz);
+    const getEggObject = this.getEggObject.bind(this);
+    const qualifierValues = Array.from(implClazzMap.keys());
+
+    return {
+      [Symbol.asyncIterator]() {
+        return {
+          key: 0,
+          async next() {
+            if (this.key === qualifierValues.length) {
+              return { done: true } as IteratorResult<T>;
+            }
+
+            const value = await getEggObject(abstractClazz, qualifierValues[this.key++]);
+            return { value, done: false } as IteratorResult<T>;
+          },
+        };
+      },
+    };
+  }
 }

core/dynamic-inject-runtime/test/fixtures/modules/dynamic-inject-module/HelloService.ts

@@ -1,8 +1,9 @@
 import { ContextProto, Inject } from '@eggjs/core-decorator';
-import { ContextHelloType, SingletonHelloType } from './FooType';
+import { EggObjectFactory } from '@eggjs/tegg-dynamic-inject';
+
 import { AbstractContextHello } from './AbstractContextHello';
 import { AbstractSingletonHello } from './AbstractSingletonHello';
-import { EggObjectFactory } from '@eggjs/tegg-dynamic-inject';
+import { ContextHelloType, SingletonHelloType } from './FooType';
 
 @ContextProto()
 export class HelloService {
@@ -19,4 +20,19 @@ export class HelloService {
     const msgs = helloImpls.map(helloImpl => helloImpl.hello());
     return msgs;
   }
+
+  async sayHelloToAll(): Promise<string[]> {
+    const singletonHellos = await this.eggObjectFactory.getEggObjects(AbstractSingletonHello);
+    const contextHellos = await this.eggObjectFactory.getEggObjects(AbstractContextHello);
+
+    const msgs: string[] = [];
+    for await (const helloImpl of singletonHellos) {
+      msgs.push(helloImpl.hello());
+    }
+    for await (const helloImpl of contextHellos) {
+      msgs.push(helloImpl.hello());
+    }
+
+    return msgs;
+  }
 }

core/dynamic-inject-runtime/test/index.test.ts

@@ -1,10 +1,12 @@
+import assert from 'assert';
 import path from 'path';
-import { LoadUnitInstance, LoadUnitInstanceFactory } from '@eggjs/tegg-runtime';
+
 import { LoadUnitFactory } from '@eggjs/tegg-metadata';
+import { LoadUnitInstance, LoadUnitInstanceFactory } from '@eggjs/tegg-runtime';
+
 import { EggTestContext } from '../../test-util';
-import { HelloService } from './fixtures/modules/dynamic-inject-module/HelloService';
 import { CoreTestHelper } from '../../test-util/CoreTestHelper';
-import assert from 'assert';
+import { HelloService } from './fixtures/modules/dynamic-inject-module/HelloService';
 
 describe('test/dynamic-inject-runtime.test.ts', () => {
   let modules: Array<LoadUnitInstance>;
@@ -47,4 +49,18 @@ describe('test/dynamic-inject-runtime.test.ts', () => {
       ]);
     });
   });
+
+  it('should work with getAllEggObjects', async () => {
+    await EggTestContext.mockContext(async () => {
+      const helloService = await CoreTestHelper.getObject(HelloService);
+      const msgs = await helloService.sayHelloToAll();
+      assert.deepStrictEqual(msgs, [
+        'hello, bar(singleton:0)',
+        'hello, foo(singleton:0)',
+        'hello, bar(context:0)',
+        'hello, foo(context:0)',
+      ]);
+    });
+
+  });
 });

core/dynamic-inject/src/EggObjectFactory.ts

@@ -1,6 +1,8 @@
-import { EggAbstractClazz } from './typing';
 import { QualifierValue } from '@eggjs/core-decorator';
 
+import { EggAbstractClazz } from './typing';
+
 export interface EggObjectFactory {
   getEggObject<T extends object>(abstractClazz: EggAbstractClazz<T>, qualifierValue: QualifierValue): Promise<T>;
+  getEggObjects<T extends object>(abstractClazz: EggAbstractClazz<T>): Promise<AsyncIterable<T>>;
 }

core/dynamic-inject/src/QualifierImplUtil.ts

@@ -1,6 +1,7 @@
-import { EggAbstractClazz } from './typing';
 import { EggProtoImplClass, MetadataUtil, QualifierValue } from '@eggjs/core-decorator';
 
+import { EggAbstractClazz } from './typing';
+
 export const QUALIFIER_IMPL_MAP = Symbol.for('EggPrototype#qualifierImplMap');
 
 export class QualifierImplUtil {
@@ -9,8 +10,13 @@ export class QualifierImplUtil {
     implMap.set(qualifierValue, implClazz);
   }
 
-  static getQualifierImp(abstractClazz: EggAbstractClazz, qualifierValue: QualifierValue):EggProtoImplClass | undefined {
+  static getQualifierImp(abstractClazz: EggAbstractClazz, qualifierValue: QualifierValue): EggProtoImplClass | undefined {
     const implMap: Map<QualifierValue, EggProtoImplClass> | undefined = MetadataUtil.getMetaData(QUALIFIER_IMPL_MAP, abstractClazz as unknown as EggProtoImplClass);
     return implMap?.get(qualifierValue);
   }
+
+  static getQualifierImpMap(abstractClazz: EggAbstractClazz): Map<QualifierValue, EggProtoImplClass> {
+    const implMap: Map<QualifierValue, EggProtoImplClass> | undefined = MetadataUtil.getMetaData(QUALIFIER_IMPL_MAP, abstractClazz as unknown as EggProtoImplClass);
+    return implMap || new Map();
+  }
 }