feat: implement basic scheduled price fetching

apps/aggregator/.eslintrc.js

@@ -20,5 +20,6 @@ module.exports = {
         '@typescript-eslint/explicit-function-return-type': 'off',
         '@typescript-eslint/explicit-module-boundary-types': 'off',
         '@typescript-eslint/no-explicit-any': 'off',
+        '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
     },
 };

apps/ingestor/.env.example

@@ -1,6 +1,10 @@
 # Server Configuration
 PORT=3000
 
+# Scheduled Price Fetching
+FETCH_INTERVAL_MS=60000
+STOCK_SYMBOLS=AAPL,GOOGL,MSFT,TSLA
+
 # External API Keys
 # ALPHA_VANTAGE_API_KEY=your_alpha_vantage_api_key
 # YAHOO_FINANCE_API_KEY=your_yahoo_finance_api_key

apps/ingestor/package.json

@@ -17,8 +17,10 @@
   "dependencies": {
     "@oracle-stocks/shared": "*",
     "@nestjs/common": "^10.0.0",
+    "@nestjs/config": "^3.0.0",
     "@nestjs/core": "^10.0.0",
     "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/schedule": "^4.0.0",
     "reflect-metadata": "^0.1.13",
     "rxjs": "^7.8.1"
   },

apps/ingestor/src/app.module.ts

@@ -1,8 +1,17 @@
 import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { ScheduleModule } from '@nestjs/schedule';
 import { PricesModule } from './modules/prices.module';
 
 @Module({
-  imports: [PricesModule],
+  imports: [
+    ConfigModule.forRoot({
+      isGlobal: true,
+      envFilePath: '.env',
+    }),
+    ScheduleModule.forRoot(),
+    PricesModule,
+  ],
   controllers: [],
   providers: [],
 })

apps/ingestor/src/modules/prices.module.ts

@@ -1,10 +1,11 @@
 import { Module } from '@nestjs/common';
 import { PricesController } from '../controllers/prices.controller';
 import { PriceFetcherService } from '../services/price-fetcher.service';
+import { SchedulerService } from '../services/scheduler.service';
 
 @Module({
   controllers: [PricesController],
-  providers: [PriceFetcherService],
-  exports: [PriceFetcherService],
+  providers: [PriceFetcherService, SchedulerService],
+  exports: [PriceFetcherService, SchedulerService],
 })
 export class PricesModule {}

apps/ingestor/src/services/price-fetcher.service.spec.ts

@@ -0,0 +1,167 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { ConfigService } from '@nestjs/config';
+import { PriceFetcherService } from './price-fetcher.service';
+
+describe('PriceFetcherService', () => {
+  let service: PriceFetcherService;
+  let configService: jest.Mocked<ConfigService>;
+
+  beforeEach(async () => {
+    const mockConfigService = {
+      get: jest.fn((key: string, defaultValue?: unknown) => {
+        const config: Record<string, unknown> = {
+          STOCK_SYMBOLS: 'AAPL,GOOGL,MSFT',
+        };
+        return config[key] ?? defaultValue;
+      }),
+    };
+
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        PriceFetcherService,
+        { provide: ConfigService, useValue: mockConfigService },
+      ],
+    }).compile();
+
+    service = module.get<PriceFetcherService>(PriceFetcherService);
+    configService = module.get(ConfigService);
+  });
+
+  describe('constructor', () => {
+    it('should be defined', () => {
+      expect(service).toBeDefined();
+    });
+
+    it('should read symbols from config', () => {
+      expect(configService.get).toHaveBeenCalledWith('STOCK_SYMBOLS', 'AAPL,GOOGL,MSFT,TSLA');
+    });
+
+    it('should parse symbols correctly', () => {
+      expect(service.getSymbols()).toEqual(['AAPL', 'GOOGL', 'MSFT']);
+    });
+  });
+
+  describe('fetchRawPrices', () => {
+    it('should fetch prices for all configured symbols', async () => {
+      const prices = await service.fetchRawPrices();
+
+      expect(prices).toHaveLength(3); // One price per symbol from MockProvider
+      expect(prices.map(p => p.symbol)).toEqual(['AAPL', 'GOOGL', 'MSFT']);
+    });
+
+    it('should return prices with correct structure', async () => {
+      const prices = await service.fetchRawPrices();
+
+      prices.forEach(price => {
+        expect(price).toHaveProperty('symbol');
+        expect(price).toHaveProperty('price');
+        expect(price).toHaveProperty('timestamp');
+        expect(price).toHaveProperty('source');
+        expect(typeof price.symbol).toBe('string');
+        expect(typeof price.price).toBe('number');
+        expect(typeof price.timestamp).toBe('number');
+        expect(price.source).toBe('MockProvider');
+      });
+    });
+
+    it('should store fetched prices', async () => {
+      expect(service.getRawPrices()).toHaveLength(0);
+
+      await service.fetchRawPrices();
+
+      expect(service.getRawPrices().length).toBeGreaterThan(0);
+    });
+  });
+
+  describe('getRawPrices', () => {
+    it('should return empty array initially', () => {
+      expect(service.getRawPrices()).toEqual([]);
+    });
+
+    it('should return fetched prices', async () => {
+      await service.fetchRawPrices();
+      const prices = service.getRawPrices();
+
+      expect(prices.length).toBeGreaterThan(0);
+    });
+  });
+
+  describe('getSymbols', () => {
+    it('should return configured symbols', () => {
+      const symbols = service.getSymbols();
+
+      expect(Array.isArray(symbols)).toBe(true);
+      expect(symbols).toContain('AAPL');
+      expect(symbols).toContain('GOOGL');
+      expect(symbols).toContain('MSFT');
+    });
+
+    it('should return a copy of symbols array', () => {
+      const symbols1 = service.getSymbols();
+      const symbols2 = service.getSymbols();
+
+      expect(symbols1).not.toBe(symbols2);
+      expect(symbols1).toEqual(symbols2);
+    });
+  });
+
+  describe('symbol parsing', () => {
+    it('should handle symbols with extra whitespace', async () => {
+      const mockConfigWithSpaces = {
+        get: jest.fn((key: string, defaultValue?: unknown) => {
+          if (key === 'STOCK_SYMBOLS') {
+            return '  AAPL , GOOGL  , MSFT  ';
+          }
+          return defaultValue;
+        }),
+      };
+
+      const module: TestingModule = await Test.createTestingModule({
+        providers: [
+          PriceFetcherService,
+          { provide: ConfigService, useValue: mockConfigWithSpaces },
+        ],
+      }).compile();
+
+      const serviceWithSpaces = module.get<PriceFetcherService>(PriceFetcherService);
+      expect(serviceWithSpaces.getSymbols()).toEqual(['AAPL', 'GOOGL', 'MSFT']);
+    });
+
+    it('should filter out empty symbols', async () => {
+      const mockConfigWithEmpty = {
+        get: jest.fn((key: string, defaultValue?: unknown) => {
+          if (key === 'STOCK_SYMBOLS') {
+            return 'AAPL,,GOOGL,,,MSFT';
+          }
+          return defaultValue;
+        }),
+      };
+
+      const module: TestingModule = await Test.createTestingModule({
+        providers: [
+          PriceFetcherService,
+          { provide: ConfigService, useValue: mockConfigWithEmpty },
+        ],
+      }).compile();
+
+      const serviceWithEmpty = module.get<PriceFetcherService>(PriceFetcherService);
+      expect(serviceWithEmpty.getSymbols()).toEqual(['AAPL', 'GOOGL', 'MSFT']);
+    });
+
+    it('should use default symbols when env var is not set', async () => {
+      const mockConfigDefault = {
+        get: jest.fn((key: string, defaultValue?: unknown) => defaultValue),
+      };
+
+      const module: TestingModule = await Test.createTestingModule({
+        providers: [
+          PriceFetcherService,
+          { provide: ConfigService, useValue: mockConfigDefault },
+        ],
+      }).compile();
+
+      const serviceDefault = module.get<PriceFetcherService>(PriceFetcherService);
+      expect(serviceDefault.getSymbols()).toEqual(['AAPL', 'GOOGL', 'MSFT', 'TSLA']);
+    });
+  });
+});

apps/ingestor/src/services/price-fetcher.service.ts

@@ -1,4 +1,5 @@
 import { Injectable, Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
 import { RawPrice } from '@oracle-stocks/shared';
 import { PriceProvider, MockProvider } from '../providers';
 
@@ -7,22 +8,29 @@ export class PriceFetcherService {
   private readonly logger = new Logger(PriceFetcherService.name);
   private rawPrices: RawPrice[] = [];
   private readonly providers: PriceProvider[] = [];
+  private readonly symbols: string[];
 
-  constructor() {
+  constructor(private readonly configService: ConfigService) {
     this.providers.push(new MockProvider());
+
+    const symbolsEnv = this.configService.get<string>('STOCK_SYMBOLS', 'AAPL,GOOGL,MSFT,TSLA');
+    this.symbols = symbolsEnv
+      .split(',')
+      .map(s => s.trim())
+      .filter(s => s.length > 0);
+
+    this.logger.log(`Configured symbols: ${this.symbols.join(', ')}`);
   }
 
   async fetchRawPrices(): Promise<RawPrice[]> {
-    const symbols = ['AAPL', 'GOOGL', 'MSFT', 'TSLA'];
-
-    const pricePromises = this.providers.map(provider => provider.fetchPrices(symbols));
+    const pricePromises = this.providers.map(provider => provider.fetchPrices(this.symbols));
     const results = await Promise.all(pricePromises);
     this.rawPrices = results.flat();
 
     this.logger.log(`Fetched ${this.rawPrices.length} raw prices from ${this.providers.length} provider(s)`);
     this.rawPrices.forEach(price => {
       this.logger.debug(
-        `${price.source} - ${price.symbol}: $${price.price.toFixed(2)} at ${new Date(price.timestamp).toISOString()}`
+        `${price.source} - ${price.symbol}: $${price.price.toFixed(2)} at ${new Date(price.timestamp).toISOString()}`,
       );
     });
 
@@ -32,4 +40,8 @@ export class PriceFetcherService {
   getRawPrices(): RawPrice[] {
     return this.rawPrices;
   }
+
+  getSymbols(): string[] {
+    return [...this.symbols];
+  }
 }