Node.js中出现未捕获异常的处理方法

const http = require('http');
const PORT = 3000;
const server = http.createServer((req, res) => {
 if (req.url === '/error') {
  a.b;
  res.end('error');
 } else {
  setTimeout(() => res.end('ok!'), 1000 * 10);
 }
});

 
server.listen(PORT, () => console.log(`port is listening on ${PORT}.`));

// https://github.com/cnpm/cnpmjs.org/blob/master/worker.js#L18
graceful({
 server: [registry, web],
 error: function (err, throwErrorCount) {
  if (err.message) {
   err.message += ' (uncaughtException throw ' + throwErrorCount + ' times on pid:' + process.pid + ')';
  }
  console.error(err);
  console.error(err.stack);
  logger.error(err);
 }
});

const http = require('http');

/**
 * graceful
 * @param { Number } options.killTimeout 超时时间
 * @param { Function } options.onError 产生错误信息会执行该回调函数
 * @param { Array } options.servers Http Server
 * @returns
 */
function graceful(options = {}) {
 options.killTimeout = options.killTimeout || 1000 * 30;
 options.onError = options.onError || function () {};
 options.servers= options.servers || [];
 process.on('uncaughtException', error => handleUncaughtException(error, options));
 process.on('unhandledRejection', error => handleUnhandledRejection(error, options));
}

const throwCount = {
 uncaughtException: 0,
 unhandledRejection: 0
};
function handleUncaughtException(error, options) {
 throwCount.uncaughtException += 1;
 options.onError(error, 'uncaughtException', throwCount.uncaughtException);

 if (throwCount.uncaughtException > 1) return;
 handleError(options);
};

function handleUnhandledRejection(error, options) {
 throwCount.unhandledRejection += 1;
 options.onError(error, 'unhandledRejection', throwCount.unhandledRejection);

 if (throwCount.unhandledRejection > 1) return;
 handleError(options);
}

function handleError(options) {
 const { servers, killTimeout } = options;
 // 关闭当前请求的链接
 for (const server of servers) {
  console.log('server instanceof http.Server: ', server instanceof http.Server);
  if (server instanceof http.Server) {
   server.on('request', (req, res) => {
    req.shouldKeepAlive = false;
    res.shouldKeepAlive = false;
    if (!res._header) {
     res.setHeader('Connection', 'close');
    }
   });
  }
 }

 // 延迟退出
 const timer = setTimeout(() => {
  process.exit(1);
 }, killTimeout);
 
 if (timer && timer.unref) {
  timer.unref();
 }
}
module.exports = graceful;

const graceful = require('./graceful.js');
...
server.listen(PORT, () => console.log(`port is listening on ${PORT}.`));

graceful({
 servers: [server],
 onError: (error, type, throwErrorCount) => {
  console.log('[%s] [pid: %s] [throwErrorCount: %s] %s: %s', new Date(), process.pid, throwErrorCount, type, error.stack || error);
 }
});

$ npm install graceful -S

const graceful = require('graceful');
...

graceful({
 servers: [server1, server2, restapi],
 killTimeout: '15s',
});