Event processor first commit

.eslintrc.js

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+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  rules: {
+    "@typescript-eslint/no-inferrable-types": ["off"],
+    "max-len": ["off"],
+    "semi": ["error"],
+    "comma-dangle": ["error", "always-multiline"],
+    "@typescript-eslint/no-explicit-any": ["off"],
+    "@typescript-eslint/ban-types": ["off"]
+  },
+  ignorePatterns: ['.eslintrc.js'],
+};

.github/workflows/npm-publish.yml

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+name: Publish event processor
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  publish-npm:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 16
+          registry-url: https://registry.npmjs.org/
+
+      - name: Create release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          RELEASE_TAG=v$(node -p "require('./package.json').version")
+          gh release create $RELEASE_TAG --target=$GITHUB_SHA --title="$RELEASE_TAG" --generate-notes
+
+      - run: npm ci
+      - run: npm run build
+
+      - name: Publish to npmjs
+        env:
+          NODE_AUTH_TOKEN: ${{secrets.NPM_TOKEN}}
+        run: npm publish --access=public

.gitignore

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+node_modules/
+lib/
+
+.DS_Store

README.md

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+# Event Processor for JavaScript
+
+Event processor for JavaScript and TypeScript (written in TypeScript).
+
+## Distribution
+
+[npm](https://www.npmjs.com/package/@multiversx/sdk-event-processor)
+
+## Usage
+
+```js
+let eventProcessor = new EventProcessor();
+await eventProcessor.start({
+  onEventsReceived: (highestTimestamp, events) => {
+    console.log(`Received ${events.length} events with the latest timestamp ${highestTimestamp}`);
+  },
+});
+```
+
+[Here](example) is a full application ready to play with in.

example/crons/event.processor.module.ts

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+import { Module } from '@nestjs/common';
+import { ScheduleModule } from '@nestjs/schedule';
+import { EventProcessorService } from './event.processor.service';
+
+@Module({
+  imports: [
+    ScheduleModule.forRoot(),
+  ],
+  providers: [
+    EventProcessorService,
+  ],
+})
+
+export class EventProcessorModule {}

example/crons/event.processor.service.ts

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+import { Injectable, Logger } from '@nestjs/common';
+import { Cron } from '@nestjs/schedule';
+import { Locker } from '../utils/locker';
+import { EventProcessor } from "../../src/event.processor";
+
+@Injectable()
+export class EventProcessorService {
+  private readonly logger: Logger;
+  private lastTimestamp: number | undefined;
+
+  constructor() {
+    this.logger = new Logger(EventProcessorService.name);
+  }
+
+  @Cron('*/1 * * * * *')
+  async handleNewMultiversxEvents() {
+    Locker.lock('newMultiversxEvents', async () => {
+      const eventProcessor = new EventProcessor();
+      await eventProcessor.start({
+        elasticUrl: 'https://index.multiversx.com',
+        eventIdentifiers: ['ESDTTransfer'],
+        emitterAddresses: ['erd1r44w4rky0l29pynkp4hrmrjdhnmd5knrrmevarp6h2dg9cu74sas597hhl'],
+        pageSize: 1,
+        scrollTimeout: "1m",
+        getLastProcessedTimestamp: async () => {
+          await Promise.resolve();
+          return this.lastTimestamp ?? 0;
+        },
+        setLastProcessedTimestamp: async (timestamp: number) => {
+          this.lastTimestamp = timestamp;
+        },
+        onEventsReceived: async (highestTimestamp, events) => {
+          await Promise.resolve();
+          console.log(`onEventsReceived -> highestTimestamp: ${highestTimestamp}`);
+          console.log(`onEventsReceived -> events: ${JSON.stringify(events)}`);
+        },
+      });
+    });
+  }
+}

example/main.ts

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+import { NestFactory } from '@nestjs/core';
+import { EventProcessorModule } from "./crons/event.processor.module";
+
+async function start() {
+    const eventProcessorApp = await NestFactory.create(EventProcessorModule);
+    await eventProcessorApp.listen(4242);
+}
+
+start().then()

example/package.json

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+{
+  "name": "@multiversx/sdk-event-processor",
+  "version": "1.0.0",
+  "description": "Real-time event processor",
+  "main": "lib/event.processor.js",
+  "types": "lib/event.processor.d.ts",
+  "files": [
+    "lib"
+  ],
+  "scripts": {
+    "example": "npx ts-node ./main.ts",
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "build": "tsc"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/multiversx/mx-sdk-event-processor.git"
+  },
+  "keywords": [
+    "multiversx",
+    "event",
+    "processor"
+  ],
+  "author": "MultiversX",
+  "license": "GPL-3.0-or-later",
+  "devDependencies": {
+    "@types/axios": "^0.14.0",
+    "@types/node": "^16.11.10",
+    "typescript": "^4.3.5"
+  },
+  "dependencies": {
+    "@nestjs/common": "^10.4.1",
+    "@nestjs/platform-express": "^10.4.1",
+    "@nestjs/schedule": "^4.1.0",
+    "axios": "^1.7.4"
+  }
+}

example/tsconfig.json

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+{
+  "compilerOptions": {
+    "experimentalDecorators": true,
+    "target": "es2015",
+    "module": "commonjs",
+    "declaration": true,
+    "outDir": "./lib",
+    "baseUrl": "./",
+    "strict": true
+  },
+  "exclude": ["node_modules", "**/__tests__/*"]
+}

example/utils/locker.ts

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+import { Logger } from '@nestjs/common';
+import { PerformanceProfiler } from "./performance.profiler";
+
+export class Locker {
+  private static lockArray: string[] = [];
+
+  static async lock(key: string, func: () => Promise<void>, log: boolean = false) {
+    const logger = new Logger('Lock');
+
+    if (Locker.lockArray.includes(key) && log) {
+      logger.log(`${key} is already running`);
+      return;
+    }
+
+    Locker.lockArray.push(key);
+
+    const profiler = new PerformanceProfiler();
+
+    try {
+      await func();
+    } catch (error) {
+      logger.error(`Error running ${key}`);
+      logger.error(error);
+    } finally {
+      profiler.stop(`Running ${key}`, log);
+      const index = Locker.lockArray.indexOf(key);
+      if (index >= 0) {
+        Locker.lockArray.splice(index, 1);
+      }
+    }
+  }
+}

example/utils/performance.profiler.ts

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+import { Logger } from '@nestjs/common';
+
+export class PerformanceProfiler {
+  started: number;
+  description: string;
+
+  stopped: number = 0;
+  duration: number = 0;
+
+  constructor(description: string = '') {
+    this.started = Date.now();
+    this.description = description;
+  }
+
+  stop(description: string | null = null, log: boolean = false) {
+    this.stopped = Date.now();
+    this.duration = this.stopped - this.started;
+
+    if (log) {
+      const logger = new Logger(PerformanceProfiler.name);
+
+      logger.log(`${description ?? this.description}: ${this.duration}ms`);
+    }
+  }
+}