feat: implement MailGun webhook service for logging email events

Implemented a production-ready TypeScript/Express.js service to receive and log MailGun webhook events (delivered, failed, opened, clicked, etc.). Key features: - Webhook endpoint (POST /webhook) with comprehensive event logging - Full TypeScript type definitions for all MailGun event types - Prometheus metrics integration for monitoring - Health check endpoint (GET /ping) - Comprehensive Jest test suite with 87.76% coverage - Docker containerization with build scripts Removed template/example code: - All SQL/MSSQL dependencies and related code - Example auth router and middleware - PRTG metrics support (simplified to Prometheus only) - Unused middleware (CORS, IP whitelist, request parsing/validation) - Template documentation (kept only MailGun webhook API spec) The service is clean, minimal, and focused solely on receiving and logging MailGun webhook events to the console. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2026-01-02 20:56:22 +01:00
parent 4371a9a20a
commit 7aeea9353d
39 changed files with 12015 additions and 14 deletions
--- a/mailgun-webhook/tests/routers/errorRouter.spec.ts
+++ b/mailgun-webhook/tests/routers/errorRouter.spec.ts
@@ -0,0 +1,120 @@
+import { errorRouter } from '../../src/routes/errorRouter';
+import createError from "http-errors";
+import { mockHttpContext } from "../helpers/mockHttpContext";
+import { logWarn, resetAllLoggerMocks } from '../__mocks__/logger';
+
+// Mock the logger module
+jest.mock('../../src/lib/logger', () => require('../__mocks__/logger'));
+
+describe("errorRouter", () => {
+
+    beforeEach(() => {
+      resetAllLoggerMocks();
+    });
+
+    test("should return string message 'page not found' in case of 404 error", async () => {
+        const err = createError(404)
+        const {req,res,next} = mockHttpContext();
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).toHaveBeenCalledWith(404);
+        expect(res.setHeader).toHaveBeenCalledWith('Content-Type', "text/html");
+        expect(res.end).toHaveBeenCalledWith("page not found");
+      });
+
+      test("should log page not found warning in case of 404 error", async () => {
+        const err = createError(404)
+        const reqPath = "/some-path/";
+        const {req,res,next} = mockHttpContext({ reqPath });
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(logWarn).toHaveBeenCalledWith(`page not found GET ${reqPath}`);
+        expect(logWarn).toHaveBeenCalledWith(`${err.name}:page ${reqPath} not found`);
+      });
+
+      test("should not send headers again if they are already sent", async () => {
+        const err = createError(404)
+        const {req,res,next} = mockHttpContext({ headersSent:true, writableEnded:true });
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).not.toHaveBeenCalled();
+        expect(res.setHeader).not.toHaveBeenCalled();
+        expect(res.end).not.toHaveBeenCalled();
+      });
+
+      test("should call [end] method if it has NOT been called yet", async () => {
+        const err = createError(404)
+        const {req,res,next} = mockHttpContext({ headersSent:true, writableEnded:false });
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).not.toHaveBeenCalled();
+        expect(res.setHeader).not.toHaveBeenCalled();
+        expect(res.end).toHaveBeenCalled();
+      });
+  
+      test("should stop Prometheus Timer", async () => {
+        const err = createError(404)
+        const {req,res,next} = mockHttpContext({ headersSent:true, writableEnded:false });
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.locals.stopPrometheusTimer).toHaveBeenCalled();
+      });
+
+      test("should return string message 'internal server error' in case of 500 error", async () => {
+        const err = createError(500)
+        const {req,res,next} = mockHttpContext();
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).toHaveBeenCalledWith(500);
+        expect(res.setHeader).toHaveBeenCalledWith('Content-Type', "text/html");
+        expect(res.end).toHaveBeenCalledWith("internal server error");
+      });
+
+      test("should return string message 'bad request' and log error in case of 400 error", async () => {
+        const errorMessage = "mock error text 1";
+        const err = createError(400, errorMessage);
+        const {req,res,next} = mockHttpContext();
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).toHaveBeenCalledWith(400);
+        expect(res.setHeader).toHaveBeenCalledWith('Content-Type', "text/html");
+        expect(res.end).toHaveBeenCalledWith("bad request");
+
+        expect(logWarn).toHaveBeenCalledWith(`${err.name}:${errorMessage}`);
+      });
+
+      test("should return string message 'unauthorized' and log error in case of 401 error", async () => {
+        const errorMessage = "mock error text 2";
+        const err = createError(401, errorMessage)
+        const {req,res,next} = mockHttpContext();
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).toHaveBeenCalledWith(401);
+        expect(res.setHeader).toHaveBeenCalledWith('Content-Type', "text/html");
+        expect(res.end).toHaveBeenCalledWith("unauthorized");
+
+        expect(logWarn).toHaveBeenCalledWith(`${err.name}:${errorMessage}`);
+      });
+
+      test("should return string message 'forbidden' and log error in case of 403 error", async () => {
+        const errorMessage = "mock error text 3";
+        const err = createError(403, errorMessage);
+        const {req,res,next} = mockHttpContext();
+  
+        await errorRouter(err, req, res, next);
+  
+        expect(res.status).toHaveBeenCalledWith(403);
+        expect(res.setHeader).toHaveBeenCalledWith('Content-Type', "text/html");
+        expect(res.end).toHaveBeenCalledWith("forbidden");
+
+        expect(logWarn).toHaveBeenCalledWith(`${err.name}:${errorMessage}`);
+      });
+});
--- a/mailgun-webhook/tests/routers/webhookRouter.spec.ts
+++ b/mailgun-webhook/tests/routers/webhookRouter.spec.ts
@@ -0,0 +1,196 @@
+/**
+ * Tests for MailGun webhook router
+ */
+
+import request from 'supertest';
+import app from '../../src/app';
+import {
+  createMockDeliveredEvent,
+  createMockFailedEvent,
+  createMockOpenedEvent,
+  createMockClickedEvent,
+  createMockBouncedEvent,
+  createMockComplainedEvent,
+  createMockUnsubscribedEvent,
+  createInvalidEvent
+} from '../helpers/mockWebhookEvent';
+
+describe('MailGun Webhook Router', () => {
+  // Mock console.log to avoid cluttering test output
+  let consoleLogSpy: jest.SpyInstance;
+
+  beforeEach(() => {
+    consoleLogSpy = jest.spyOn(console, 'log').mockImplementation();
+  });
+
+  afterEach(() => {
+    consoleLogSpy.mockRestore();
+  });
+
+  describe('POST /webhook', () => {
+    it('should handle delivered event successfully', async () => {
+      const event = createMockDeliveredEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body).toEqual({
+        status: 'received',
+        message: 'Webhook event logged successfully'
+      });
+
+      // Verify console.log was called with event data
+      expect(consoleLogSpy).toHaveBeenCalled();
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('MailGun Webhook Event Received');
+      expect(logOutput).toContain('Event Type: delivered');
+      expect(logOutput).toContain('Recipient: user@example.com');
+    });
+
+    it('should handle failed event successfully', async () => {
+      const event = createMockFailedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body).toEqual({
+        status: 'received',
+        message: 'Webhook event logged successfully'
+      });
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: failed');
+      expect(logOutput).toContain('Severity: permanent');
+      expect(logOutput).toContain('Reason: bounce');
+    });
+
+    it('should handle opened event successfully', async () => {
+      const event = createMockOpenedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: opened');
+      expect(logOutput).toContain('City: San Francisco');
+      expect(logOutput).toContain('Device Type: desktop');
+    });
+
+    it('should handle clicked event successfully', async () => {
+      const event = createMockClickedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: clicked');
+      expect(logOutput).toContain('URL Clicked: https://example.com/link');
+    });
+
+    it('should handle bounced event successfully', async () => {
+      const event = createMockBouncedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: bounced');
+      expect(logOutput).toContain('SMTP Code: 550');
+    });
+
+    it('should handle complained event successfully', async () => {
+      const event = createMockComplainedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: complained');
+    });
+
+    it('should handle unsubscribed event successfully', async () => {
+      const event = createMockUnsubscribedEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Event Type: unsubscribed');
+    });
+
+    it('should return 400 for invalid event missing required fields', async () => {
+      const event = createInvalidEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(400);
+
+      // Error router returns plain text, not JSON
+      expect(response.text).toBe('bad request');
+    });
+
+    it('should handle URL-encoded form data (MailGun default format)', async () => {
+      const event = createMockDeliveredEvent();
+
+      const response = await request(app)
+        .post('/webhook')
+        .type('form')
+        .send(event)
+        .expect(200);
+
+      expect(response.body.status).toBe('received');
+    });
+
+    it('should log timestamp in human-readable format', async () => {
+      const event = createMockDeliveredEvent();
+
+      await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Timestamp: 1234567890');
+      // Check that ISO format date is logged
+      expect(logOutput).toMatch(/\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}/);
+    });
+
+    it('should log full event data as JSON', async () => {
+      const event = createMockDeliveredEvent();
+
+      await request(app)
+        .post('/webhook')
+        .send(event)
+        .expect(200);
+
+      const logOutput = consoleLogSpy.mock.calls.join('\n');
+      expect(logOutput).toContain('Full Event Data (JSON)');
+      expect(logOutput).toContain('"event": "delivered"');
+    });
+  });
+});