k6 で REST API に負荷テストを実行してみた（段階的負荷テスト・スパイクテスト・耐久テスト）

Base URL: https://XXXXXXXX.execute-api.ap-northeast-1.amazonaws.com/v1

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

// 環境変数から BASE_URL を取得（未設定時はローカル環境をデフォルトに）
const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';

// カスタムメトリクス
const errorRate = new Rate('errors');
const itemCreationTrend = new Trend('item_creation_duration');

// 共通ヘッダー
const headers = {
  'Content-Type': 'application/json',
};

// 全アイテム取得
export function getAllItems() {
  const res = http.get(`${BASE_URL}/items`);
  check(res, {
    'GET /items - status is 200': (r) => r.status === 200,
  });
  errorRate.add(res.status !== 200);
  return res;
}

// アイテム作成
export function createItem(name: string, description: string) {
  const payload = JSON.stringify({ name, description });
  const res = http.post(`${BASE_URL}/items`, payload, { headers });

  check(res, {
    'POST /items - status is 200 or 201': (r) => r.status === 200 || r.status === 201,
  });

  errorRate.add(res.status !== 200 && res.status !== 201);
  itemCreationTrend.add(res.timings.duration);

  return res;
}

// 個別アイテム取得
export function getItem(id: string) {
  const res = http.get(`${BASE_URL}/items/${id}`);
  check(res, {
    'GET /items/{id} - status is 200': (r) => r.status === 200,
  });
  errorRate.add(res.status !== 200);
  return res;
}

// アイテム更新
export function updateItem(id: string, name: string, description: string) {
  const payload = JSON.stringify({ name, description });
  const res = http.put(`${BASE_URL}/items/${id}`, payload, { headers });

  check(res, {
    'PUT /items/{id} - status is 200': (r) => r.status === 200,
  });
  errorRate.add(res.status !== 200);
  return res;
}

// アイテム削除
export function deleteItem(id: string) {
  const res = http.del(`${BASE_URL}/items/${id}`);
  check(res, {
    'DELETE /items/{id} - status is 200 or 204': (r) => r.status === 200 || r.status === 204,
  });
  errorRate.add(res.status !== 200 && res.status !== 204);
  return res;
}

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate } from 'k6/metrics';

// 環境変数から BASE_URL を取得
const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';
const errorRate = new Rate('errors');

export const options = {
  stages: [
    { duration: '1m', target: 20 },   // 1分かけて20VUまで増加
    { duration: '1m', target: 50 },   // 1分かけて50VUまで増加
    { duration: '1m', target: 100 },  // 1分かけて100VUまで増加
    { duration: '1m', target: 100 },  // 1分間100VUを維持
    { duration: '1m', target: 0 },    // 1分かけて0VUまで減少
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],
    errors: ['rate<0.1'],
  },
};

export default function () {
  const res = http.get(`${BASE_URL}/items`);

  check(res, {
    'status is 200': (r) => r.status === 200,
  });

  errorRate.add(res.status !== 200);
  sleep(1);
}

VUs
100 |              ┌────────┐
    |             /          \
 50 |        ┌───┘            \
    |       /                  \
 20 |  ┌───┘                    \
  0 |──┘                         \───
    0    1    2    3    4    5 (分)

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate } from 'k6/metrics';

// 環境変数から BASE_URL を取得
const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';
const errorRate = new Rate('errors');

export const options = {
  stages: [
    { duration: '30s', target: 10 },   // ウォームアップ
    { duration: '30s', target: 200 },  // 30秒で一気に200VUまで急増
    { duration: '1m', target: 200 },   // 1分間200VUを維持
    { duration: '30s', target: 10 },   // 30秒で10VUまで急減
    { duration: '1m30s', target: 10 }, // 1分30秒間安定確認
    { duration: '1m', target: 0 },     // クールダウン
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],
    errors: ['rate<0.2'],
  },
};

export default function () {
  const res = http.get(`${BASE_URL}/items`);

  check(res, {
    'status is 200': (r) => r.status === 200,
  });

  errorRate.add(res.status !== 200);
  sleep(1);
}

VUs
200 |      ┌──────────┐
    |     /            \
    |    /              \
    |   /                \
 10 |──┘                  └──────────────
  0 |_____________________________________
    0  0.5  1    2   2.5   4    5 (分)

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate } from 'k6/metrics';

// 環境変数から BASE_URL を取得
const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';
const errorRate = new Rate('errors');

const headers = {
  'Content-Type': 'application/json',
};

export const options = {
  stages: [
    { duration: '1m', target: 30 },   // 1分かけて30VUまで増加
    { duration: '13m', target: 30 },  // 13分間30VUを維持
    { duration: '1m', target: 0 },    // 1分かけて終了
  ],
  thresholds: {
    http_req_duration: ['p(95)<500', 'p(99)<1000'],
    errors: ['rate<0.05'],
  },
};

export default function () {
  // 全アイテム取得
  const listRes = http.get(`${BASE_URL}/items`);
  check(listRes, { 'GET /items - status is 200': (r) => r.status === 200 });
  errorRate.add(listRes.status !== 200);
  sleep(1);

  // アイテム作成
  const payload = JSON.stringify({
    name: `SoakTest-${Date.now()}`,
    description: 'Created during soak test',
  });
  const createRes = http.post(`${BASE_URL}/items`, payload, { headers });
  check(createRes, { 'POST /items - status is 200': (r) => r.status === 200 });
  errorRate.add(createRes.status !== 200);

  // 作成したアイテムを削除
  if (createRes.status === 200) {
    const body = JSON.parse(createRes.body as string);
    if (body.id) {
      sleep(1);
      const deleteRes = http.del(`${BASE_URL}/items/${body.id}`);
      check(deleteRes, { 'DELETE /items/{id} - status is 200': (r) => r.status === 200 });
      errorRate.add(deleteRes.status !== 200);
    }
  }
  sleep(1);
}

VUs
30 |  ┌─────────────────────────────────────────────┐
   | /                                               \
   |/                                                 \
 0 |___________________________________________________
   0    1                      14   15 (分)

$ npm run build

> k6-project@1.0.0 build
> esbuild *.ts --bundle --target=es2015 --platform=node --outdir=dist --external:k6 --external:k6/*

  dist/api-test.js      3.7kb
  dist/soak-test.js     3.2kb
  dist/spike-test.js    2.6kb
  dist/ramping-test.js  2.6kb

⚡ Done in 4ms

# 環境変数を設定してからテストを実行
$ export BASE_URL=https://XXXXXXXXXX.execute-api.ap-northeast-1.amazonaws.com/v1

# 段階的負荷テスト（約5分）
$ k6 run dist/ramping-test.js

# スパイクテスト（約5分）
$ k6 run dist/spike-test.js

# 持続テスト（15分）
$ k6 run dist/soak-test.js

$ k6 run --out json=results.json dist/ramping-test.js

[ec2-user@ip-10-0-2-242 k6-project]$ k6 run dist/spike-test.js

         /\      Grafana   /‾‾/
    /\  /  \     |\  __   /  /
   /  \/    \    | |/ /  /   ‾‾\
  /          \   |   (  |  (‾)  |
 / __________ \  |_|\_\  \_____/

     execution: local
        script: dist/spike-test.js
        output: -

     scenarios: (100.00%) 1 scenario, 200 max VUs, 5m30s max duration (incl. graceful stop):
              * default: Up to 200 looping VUs for 5m0s over 6 stages (gracefulRampDown: 30s, gracefulStop: 30s)

  █ THRESHOLDS

    errors
    ✓ 'rate<0.2' rate=0.00%

    http_req_duration
    ✓ 'p(95)<2000' p(95)=120.36ms

  █ TOTAL RESULTS

    checks_total.......: 33727   112.319703/s
    checks_succeeded...: 100.00% 33727 out of 33727
    checks_failed......: 0.00%   0 out of 33727

    ✓ status is 200

    CUSTOM
    errors.........................: 0.00%  0 out of 33727

    HTTP
    http_req_duration..............: avg=84.44ms  min=27.54ms  med=77.88ms max=2.08s p(90)=105.72ms p(95)=120.36ms
      { expected_response:true }...: avg=84.44ms  min=27.54ms  med=77.88ms max=2.08s p(90)=105.72ms p(95)=120.36ms
    http_req_failed................: 0.00%  0 out of 33727
    http_reqs......................: 33727  112.319703/s

    EXECUTION
    iteration_duration.............: avg=585.16ms min=528.56ms med=578.6ms max=2.59s p(90)=606.61ms p(95)=621.16ms
    iterations.....................: 33727  112.319703/s
    vus............................: 1      min=1          max=200
    vus_max........................: 200    min=200        max=200

    NETWORK
    data_received..................: 26 MB  86 kB/s
    data_sent......................: 1.6 MB 5.5 kB/s

running (5m00.3s), 000/200 VUs, 33727 complete and 0 interrupted iterations
default ✓ [======================================] 000/200 VUs  5m0s

// GET /items - Get all items
app.get("/items", async (_req: Request, res: Response) => {
  const command = new ScanCommand({
    TableName: TABLE_NAME,
  });
  const result = await docClient.send(command);
  res.json({ items: result.Items || [] });
});