add feature flag service with CRUD endpoints in db-service and api-gateway

Author: aishanibal

packages/api-gateway/src/app.module.ts

@@ -12,6 +12,7 @@ import { FileConfigModule } from './modules/file_config/file_config.module';
 import { AnalyticsModule } from './modules/analytics/analytics.module';
 import { AnalyticsConfigModule } from './modules/analytics_config/analytics_config.module';
 import { FileDeleteModule } from './modules/file_delete/file_delete.module';
+import { FeatureFlagModule } from './modules/feature_flag/feature_flag.module';
 
 @Module({
   imports: [
@@ -28,6 +29,7 @@ import { FileDeleteModule } from './modules/file_delete/file_delete.module';
     FileDeleteModule,
     AnalyticsModule,
     AnalyticsConfigModule,
+    FeatureFlagModule,
   ],
 })
 export class AppModule {}

packages/api-gateway/src/models/feature_flag.dto.ts

@@ -0,0 +1,63 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsString, IsOptional, IsBoolean } from 'class-validator';
+import { FeatureFlagProto } from 'juno-proto';
+
+export class CreateFeatureFlagModel {
+  @ApiProperty({
+    type: 'string',
+    description: 'Unique identifier for the feature flag',
+  })
+  @IsString()
+  id: string;
+
+  @ApiPropertyOptional({
+    type: 'boolean',
+    description: 'Whether the flag is enabled. Defaults to false.',
+  })
+  @IsOptional()
+  @IsBoolean()
+  enabled?: boolean;
+
+  @ApiPropertyOptional({
+    type: 'string',
+    description: 'Human-readable description of the flag',
+  })
+  @IsOptional()
+  @IsString()
+  description?: string;
+}
+
+export class UpdateFeatureFlagModel {
+  @ApiPropertyOptional({
+    type: 'boolean',
+    description: 'Whether the flag is enabled',
+  })
+  @IsOptional()
+  @IsBoolean()
+  enabled?: boolean;
+
+  @ApiPropertyOptional({
+    type: 'string',
+    description: 'Human-readable description of the flag',
+  })
+  @IsOptional()
+  @IsString()
+  description?: string;
+}
+
+export class FeatureFlagResponse {
+  @ApiProperty({ type: 'string', description: 'Feature flag ID' })
+  id: string;
+
+  @ApiProperty({ type: 'boolean', description: 'Whether the flag is enabled' })
+  enabled: boolean;
+
+  @ApiPropertyOptional({ type: 'string', description: 'Flag description' })
+  description?: string;
+
+  constructor(flag: FeatureFlagProto.FeatureFlag) {
+    this.id = flag.id;
+    this.enabled = flag.enabled;
+    this.description = flag.description;
+  }
+}

packages/api-gateway/src/modules/feature_flag/feature_flag.controller.ts

@@ -0,0 +1,120 @@
+import {
+  Controller,
+  Get,
+  Post,
+  Put,
+  Delete,
+  Inject,
+  OnModuleInit,
+  Param,
+  Body,
+} from '@nestjs/common';
+import { ClientGrpc } from '@nestjs/microservices';
+import {
+  ApiBearerAuth,
+  ApiBadRequestResponse,
+  ApiCreatedResponse,
+  ApiNotFoundResponse,
+  ApiOkResponse,
+  ApiOperation,
+  ApiTags,
+  ApiUnauthorizedResponse,
+} from '@nestjs/swagger';
+import { FeatureFlagProto } from 'juno-proto';
+import { lastValueFrom } from 'rxjs';
+import {
+  CreateFeatureFlagModel,
+  UpdateFeatureFlagModel,
+  FeatureFlagResponse,
+} from 'src/models/feature_flag.dto';
+
+const { FEATURE_FLAG_SERVICE_NAME } = FeatureFlagProto;
+
+@ApiBearerAuth('API_Key')
+@ApiTags('feature-flag')
+@Controller('feature-flags')
+export class FeatureFlagController implements OnModuleInit {
+  private featureFlagService: FeatureFlagProto.FeatureFlagServiceClient;
+
+  constructor(
+    @Inject(FEATURE_FLAG_SERVICE_NAME) private featureFlagClient: ClientGrpc,
+  ) {}
+
+  onModuleInit() {
+    this.featureFlagService =
+      this.featureFlagClient.getService<FeatureFlagProto.FeatureFlagServiceClient>(
+        FEATURE_FLAG_SERVICE_NAME,
+      );
+  }
+
+  @Post()
+  @ApiOperation({ summary: 'Create a feature flag' })
+  @ApiCreatedResponse({
+    description: 'Feature flag created successfully',
+    type: FeatureFlagResponse,
+  })
+  @ApiUnauthorizedResponse({ description: 'Unauthorized' })
+  @ApiBadRequestResponse({ description: 'Bad Request' })
+  async createFlag(
+    @Body() request: CreateFeatureFlagModel,
+  ): Promise<FeatureFlagResponse> {
+    const response = await lastValueFrom(
+      this.featureFlagService.createFlag({
+        id: request.id,
+        enabled: request.enabled,
+        description: request.description,
+      }),
+    );
+    return new FeatureFlagResponse(response.flag);
+  }
+
+  @Get(':id')
+  @ApiOperation({ summary: 'Get a feature flag by ID' })
+  @ApiOkResponse({
+    description: 'Feature flag retrieved successfully',
+    type: FeatureFlagResponse,
+  })
+  @ApiNotFoundResponse({ description: 'Feature flag not found' })
+  @ApiUnauthorizedResponse({ description: 'Unauthorized' })
+  async getFlag(@Param('id') id: string): Promise<FeatureFlagResponse> {
+    const response = await lastValueFrom(
+      this.featureFlagService.getFlag({ id }),
+    );
+    return new FeatureFlagResponse(response.flag);
+  }
+
+  @Put(':id')
+  @ApiOperation({ summary: 'Update a feature flag' })
+  @ApiOkResponse({
+    description: 'Feature flag updated successfully',
+    type: FeatureFlagResponse,
+  })
+  @ApiNotFoundResponse({ description: 'Feature flag not found' })
+  @ApiUnauthorizedResponse({ description: 'Unauthorized' })
+  @ApiBadRequestResponse({ description: 'Bad Request' })
+  async setFlag(
+    @Param('id') id: string,
+    @Body() request: UpdateFeatureFlagModel,
+  ): Promise<FeatureFlagResponse> {
+    const response = await lastValueFrom(
+      this.featureFlagService.setFlag({
+        id,
+        enabled: request.enabled,
+        description: request.description,
+      }),
+    );
+    return new FeatureFlagResponse(response.flag);
+  }
+
+  @Delete(':id')
+  @ApiOperation({ summary: 'Delete a feature flag' })
+  @ApiOkResponse({ description: 'Feature flag deleted successfully' })
+  @ApiNotFoundResponse({ description: 'Feature flag not found' })
+  @ApiUnauthorizedResponse({ description: 'Unauthorized' })
+  async deleteFlag(@Param('id') id: string): Promise<{ success: boolean }> {
+    const response = await lastValueFrom(
+      this.featureFlagService.deleteFlag({ id }),
+    );
+    return { success: response.success };
+  }
+}

packages/api-gateway/src/modules/feature_flag/feature_flag.module.ts

@@ -0,0 +1,62 @@
+import { MiddlewareConsumer, Module, NestModule } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { ClientsModule, Transport } from '@nestjs/microservices';
+import { join } from 'path';
+import { FeatureFlagController } from './feature_flag.controller';
+import {
+  ApiKeyProto,
+  ApiKeyProtoFile,
+  FeatureFlagProto,
+  FeatureFlagProtoFile,
+  JwtProto,
+  JwtProtoFile,
+} from 'juno-proto';
+import { ApiKeyMiddleware } from 'src/middleware/api_key.middleware';
+
+const { JWT_SERVICE_NAME, JUNO_JWT_PACKAGE_NAME } = JwtProto;
+const { API_KEY_SERVICE_NAME, JUNO_API_KEY_PACKAGE_NAME } = ApiKeyProto;
+const { FEATURE_FLAG_SERVICE_NAME, JUNO_FEATURE_FLAG_PACKAGE_NAME } =
+  FeatureFlagProto;
+
+@Module({
+  imports: [
+    ConfigModule.forRoot({
+      envFilePath: join(__dirname, '../../../../../.env.local'),
+    }),
+    ClientsModule.register([
+      {
+        name: JWT_SERVICE_NAME,
+        transport: Transport.GRPC,
+        options: {
+          url: process.env.AUTH_SERVICE_ADDR,
+          package: JUNO_JWT_PACKAGE_NAME,
+          protoPath: JwtProtoFile,
+        },
+      },
+      {
+        name: API_KEY_SERVICE_NAME,
+        transport: Transport.GRPC,
+        options: {
+          url: process.env.AUTH_SERVICE_ADDR,
+          package: JUNO_API_KEY_PACKAGE_NAME,
+          protoPath: ApiKeyProtoFile,
+        },
+      },
+      {
+        name: FEATURE_FLAG_SERVICE_NAME,
+        transport: Transport.GRPC,
+        options: {
+          url: process.env.DB_SERVICE_ADDR,
+          package: JUNO_FEATURE_FLAG_PACKAGE_NAME,
+          protoPath: FeatureFlagProtoFile,
+        },
+      },
+    ]),
+  ],
+  controllers: [FeatureFlagController],
+})
+export class FeatureFlagModule implements NestModule {
+  configure(consumer: MiddlewareConsumer) {
+    consumer.apply(ApiKeyMiddleware).forRoutes('feature-flags*');
+  }
+}