feat(campaign-sender): exponential backoff retry on transient dispatch failures (EVO-1219)

src/runners/campaign-sender/batch-dispatcher.retry.integration.spec.ts

@@ -0,0 +1,142 @@
+import * as http from 'http';
+import type { AddressInfo } from 'net';
+import { ConfigService } from '@nestjs/config';
+import { CrmInboxDispatcher } from '../../shared/messaging-channels/dispatchers/crm-inbox.dispatcher';
+import { BatchDispatcherService } from './services/batch-dispatcher.service';
+import { MessageTemplate } from '../../shared/entities/message-template.entity';
+import type { HydratedContact } from '../../shared/crm-client/types/contact';
+
+/**
+ * Story 4.5's E2E smoke as a repeatable spec: a REAL HTTP server answers
+ * 503, 503, 200 and the REAL CrmInboxDispatcher + BatchDispatcherService
+ * stack (only db/rate-limiter/logger stubbed) must deliver after 2 backoff
+ * retries with measurable exponential timing.
+ */
+describe('BatchDispatcherService retry integration (EVO-1219)', () => {
+  let server: http.Server;
+  let baseUrl: string;
+  let statuses: number[];
+  let hits: number;
+
+  const template = {
+    id: 'tpl-1',
+    name: 'welcome',
+    content: 'Hi {contact.name}',
+    language: 'pt_BR',
+    category: 'marketing',
+    variables: [],
+  } as unknown as MessageTemplate;
+
+  const contact: HydratedContact = {
+    id: 'contact-1',
+    name: 'Ana',
+    blocked: false,
+    customAttributes: {},
+    additionalAttributes: {},
+  };
+
+  beforeAll((done) => {
+    server = http.createServer((req, res) => {
+      hits++;
+      const status = statuses.shift() ?? 200;
+      res.statusCode = status;
+      res.setHeader('content-type', 'application/json');
+      res.end(
+        status === 200
+          ? JSON.stringify({ id: 'conv-1', messages: [{ id: 'msg-1' }] })
+          : JSON.stringify({ error: 'upstream unavailable' }),
+      );
+    });
+    server.listen(0, '127.0.0.1', done);
+  });
+
+  afterAll((done) => {
+    server.close(done);
+  });
+
+  const RETRY_ENVS = [
+    'DISPATCH_RETRY_COUNT',
+    'DISPATCH_BACKOFF_BASE_MS',
+    'DISPATCH_BACKOFF_CAP_MS',
+  ] as const;
+  const envBackup: Record<string, string | undefined> = {};
+
+  beforeEach(() => {
+    hits = 0;
+    statuses = [];
+    const { port } = server.address() as AddressInfo;
+    baseUrl = `http://127.0.0.1:${port}`;
+    for (const name of RETRY_ENVS) {
+      envBackup[name] = process.env[name];
+      delete process.env[name];
+    }
+    process.env.DISPATCH_BACKOFF_BASE_MS = '200';
+    process.env.DISPATCH_BACKOFF_CAP_MS = '30000';
+  });
+
+  afterEach(() => {
+    for (const [name, value] of Object.entries(envBackup)) {
+      if (value === undefined) delete process.env[name];
+      else process.env[name] = value;
+    }
+  });
+
+  const buildService = (): BatchDispatcherService => {
+    const config = {
+      get: (key: string) =>
+        key === 'EVOAI_CRM_BASE_URL'
+          ? baseUrl
+          : key === 'EVOAI_CRM_API_TOKEN'
+            ? 'test-token'
+            : undefined,
+    } as unknown as ConfigService;
+
+    return new BatchDispatcherService(
+      { getRepository: () => ({ findOne: jest.fn() }) } as never,
+      new CrmInboxDispatcher(config),
+      { acquire: jest.fn().mockResolvedValue(true) } as never,
+      { log: jest.fn(), warn: jest.fn(), error: jest.fn() } as never,
+    );
+  };
+
+  it('delivers after two 503s with exponential backoff timing (503,503,200)', async () => {
+    statuses = [503, 503];
+
+    const started = Date.now();
+    const outcome = await buildService().dispatch({
+      campaignId: 'camp-1',
+      inboxId: 'inbox-1',
+      template,
+      contact,
+    });
+    const elapsed = Date.now() - started;
+
+    expect(outcome.kind).toBe('sent');
+    if (outcome.kind === 'sent') {
+      expect(outcome.result.conversationId).toBe('conv-1');
+      expect(outcome.result.messageId).toBe('msg-1');
+    }
+    expect(hits).toBe(3);
+    // Two backoffs: 200ms + 400ms = 600ms minimum (real sleeps, real HTTP).
+    expect(elapsed).toBeGreaterThanOrEqual(550);
+    expect(elapsed).toBeLessThan(2500);
+  });
+
+  it('fails fast on a real 4xx without retrying', async () => {
+    statuses = [422];
+
+    const outcome = await buildService().dispatch({
+      campaignId: 'camp-1',
+      inboxId: 'inbox-1',
+      template,
+      contact,
+    });
+
+    expect(hits).toBe(1);
+    expect(outcome).toMatchObject({
+      kind: 'failed',
+      reason: 'http_4xx: 422',
+      statusCode: 422,
+    });
+  });
+});