bolawen

2024年04月09日

柏拉文

越努力，越幸运

一、认识

---

请求重试, 实现了对任务的重试逻辑（默认重试 3 次）, 并加入指数退避, 每次重试等待更长时间, 以降低连续重试带来的压力

二、实现

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function request() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      reject("ok");
    }, 3000);
  });
}

function wait(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

function requestWithRetry(data, retries = 3) {
  return new Promise((resolve, reject) => {
    function attempt(remaining) {
      request(data)
        .then(resolve)
        .catch(async (err) => {
          if (remaining > 0) {
            await wait(1000 * (retries - remaining + 1));
            console.log(
              `⚠️ 任务 ${data} 失败，正在重试 (${
                retries - remaining + 1
              }/${retries})...`
            );

            attempt(remaining - 1);
          } else {
            reject(err);
          }
        });
    }
    attempt(retries);
  });
}

三、测试

---

requestWithRetry(3, 500)
  .then(res => {
    console.log('res', res);
  })
  .catch(error => {
    console.log('error', error);
  });