dcrouter/test/suite/smtpclient_performance/test.cperf-06.caching-strategies.ts

import { tap, expect } from '@git.zone/tstest/tapbundle';
import { startTestServer, stopTestServer, type ITestServer } from '../../helpers/server.loader.js';
import { createSmtpClient, createPooledSmtpClient } from '../../../ts/mail/delivery/smtpclient/index.js';
import { Email } from '../../../ts/mail/core/classes.email.js';

tap.test('setup - start SMTP server for caching tests', async () => {
  // Just a placeholder to ensure server starts properly
});

tap.test('CPERF-06: caching strategies - connection caching', async () => {
  const testServer = await startTestServer({
    secure: false,
    authOptional: true,
  });

  console.log('Testing connection caching strategies...');
  
  // Create a pooled client with connection caching
  const poolClient = createPooledSmtpClient({
    host: 'localhost',
    port: 2525,
    secure: false,
    authOptional: true,
    maxConnections: 2,
  });

  // First batch - establish connections
  console.log('Sending first batch to establish cached connections...');
  const firstBatchStart = Date.now();
  
  const firstBatch = Array(4).fill(null).map((_, i) => 
    new Email({
      from: 'sender@example.com',
      to: [`cached${i}@example.com`],
      subject: `Cache test ${i}`,
      text: `Testing connection caching - message ${i}`,
    })
  );

  const firstResults = await Promise.all(
    firstBatch.map(email => poolClient.sendMail(email))
  );
  
  firstResults.forEach(result => expect(result.success).toBeTrue());
  const firstBatchTime = Date.now() - firstBatchStart;
  
  // Small delay to ensure connections are properly cached
  await new Promise(resolve => setTimeout(resolve, 100));
  
  // Second batch - should use cached connections
  console.log('Sending second batch using cached connections...');
  const secondBatchStart = Date.now();
  
  const secondBatch = Array(4).fill(null).map((_, i) => 
    new Email({
      from: 'sender@example.com',
      to: [`cached2-${i}@example.com`],
      subject: `Cache test 2-${i}`,
      text: `Testing cached connections - message ${i}`,
    })
  );

  const secondResults = await Promise.all(
    secondBatch.map(email => poolClient.sendMail(email))
  );
  
  secondResults.forEach(result => expect(result.success).toBeTrue());
  const secondBatchTime = Date.now() - secondBatchStart;
  
  console.log(`First batch (cold): ${firstBatchTime}ms`);
  console.log(`Second batch (cached): ${secondBatchTime}ms`);
  console.log(`Performance improvement: ${((firstBatchTime - secondBatchTime) / firstBatchTime * 100).toFixed(1)}%`);
  
  // Cached connections should be faster (allowing some variance)
  expect(secondBatchTime).toBeLessThanOrEqual(firstBatchTime + 100);
  
  await poolClient.close();
  await stopTestServer(testServer);
});

tap.test('CPERF-06: caching strategies - server capability caching', async () => {
  const testServer = await startTestServer({
    secure: false,
    authOptional: true,
  });

  console.log('Testing server capability caching...');
  
  const client = createSmtpClient({
    host: 'localhost',
    port: 2525,
    secure: false,
    authOptional: true,
  });

  // First email - discovers capabilities
  console.log('First email - discovering server capabilities...');
  const firstStart = Date.now();
  
  const email1 = new Email({
    from: 'sender@example.com',
    to: ['recipient1@example.com'],
    subject: 'Capability test 1',
    text: 'Testing capability discovery',
  });

  const result1 = await client.sendMail(email1);
  expect(result1.success).toBeTrue();
  const firstTime = Date.now() - firstStart;
  
  // Second email - uses cached capabilities
  console.log('Second email - using cached capabilities...');
  const secondStart = Date.now();
  
  const email2 = new Email({
    from: 'sender@example.com',
    to: ['recipient2@example.com'],
    subject: 'Capability test 2',
    text: 'Testing cached capabilities',
  });

  const result2 = await client.sendMail(email2);
  expect(result2.success).toBeTrue();
  const secondTime = Date.now() - secondStart;
  
  console.log(`First email (capability discovery): ${firstTime}ms`);
  console.log(`Second email (cached capabilities): ${secondTime}ms`);
  
  // Both should complete quickly
  expect(firstTime).toBeLessThan(1000);
  expect(secondTime).toBeLessThan(1000);
  
  await client.close();
  await stopTestServer(testServer);
});

tap.test('CPERF-06: caching strategies - message batching', async () => {
  const testServer = await startTestServer({
    secure: false,
    authOptional: true,
  });

  console.log('Testing message batching for cache efficiency...');
  
  const poolClient = createPooledSmtpClient({
    host: 'localhost',
    port: 2525,
    secure: false,
    authOptional: true,
    maxConnections: 3,
  });

  // Test sending messages in batches
  const batchSizes = [2, 4, 6];
  
  for (const batchSize of batchSizes) {
    console.log(`\nTesting batch size: ${batchSize}`);
    const batchStart = Date.now();
    
    const emails = Array(batchSize).fill(null).map((_, i) => 
      new Email({
        from: 'sender@example.com',
        to: [`batch${batchSize}-${i}@example.com`],
        subject: `Batch ${batchSize} message ${i}`,
        text: `Testing batching strategies - batch size ${batchSize}`,
      })
    );

    const results = await Promise.all(
      emails.map(email => poolClient.sendMail(email))
    );
    
    results.forEach(result => expect(result.success).toBeTrue());
    
    const batchTime = Date.now() - batchStart;
    const avgTime = batchTime / batchSize;
    
    console.log(`  Batch completed in ${batchTime}ms`);
    console.log(`  Average time per message: ${avgTime.toFixed(1)}ms`);
    
    // Larger batches should have better average time per message
    expect(avgTime).toBeLessThan(500);
  }
  
  await poolClient.close();
  await stopTestServer(testServer);
});

tap.test('cleanup - stop SMTP server', async () => {
  // Cleanup is handled in individual tests
});

tap.start();