/**
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* Clusters of Node.js processes can be used to run multiple instances of Node.js
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* that can distribute workloads among their application threads. When process
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* isolation is not needed, use the `worker_threads` module instead, which
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* allows running multiple application threads within a single Node.js instance.
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*
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* The cluster module allows easy creation of child processes that all share
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* server ports.
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*
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* ```js
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* import cluster from 'cluster';
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* import http from 'http';
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* import { cpus } from 'os';
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* import process from 'process';
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*
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* const numCPUs = cpus().length;
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*
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* if (cluster.isPrimary) {
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* console.log(`Primary ${process.pid} is running`);
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*
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* // Fork workers.
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* for (let i = 0; i < numCPUs; i++) {
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* cluster.fork();
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* }
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*
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* cluster.on('exit', (worker, code, signal) => {
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* console.log(`worker ${worker.process.pid} died`);
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* });
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* } else {
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* // Workers can share any TCP connection
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* // In this case it is an HTTP server
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* http.createServer((req, res) => {
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* res.writeHead(200);
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* res.end('hello world\n');
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* }).listen(8000);
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*
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* console.log(`Worker ${process.pid} started`);
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* }
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* ```
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*
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* Running Node.js will now share port 8000 between the workers:
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*
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* ```console
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* $ node server.js
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* Primary 3596 is running
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* Worker 4324 started
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* Worker 4520 started
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* Worker 6056 started
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* Worker 5644 started
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* ```
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*
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* On Windows, it is not yet possible to set up a named pipe server in a worker.
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* @see [source](https://github.com/nodejs/node/blob/v18.0.0/lib/cluster.js)
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*/
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declare module 'cluster' {
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import * as child from 'node:child_process';
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import EventEmitter = require('node:events');
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import * as net from 'node:net';
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export interface ClusterSettings {
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execArgv?: string[] | undefined; // default: process.execArgv
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exec?: string | undefined;
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args?: string[] | undefined;
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silent?: boolean | undefined;
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stdio?: any[] | undefined;
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uid?: number | undefined;
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gid?: number | undefined;
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inspectPort?: number | (() => number) | undefined;
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}
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export interface Address {
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address: string;
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port: number;
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addressType: number | 'udp4' | 'udp6'; // 4, 6, -1, "udp4", "udp6"
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}
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/**
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* A `Worker` object contains all public information and method about a worker.
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* In the primary it can be obtained using `cluster.workers`. In a worker
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* it can be obtained using `cluster.worker`.
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* @since v0.7.0
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*/
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export class Worker extends EventEmitter {
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/**
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* Each new worker is given its own unique id, this id is stored in the`id`.
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*
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* While a worker is alive, this is the key that indexes it in`cluster.workers`.
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* @since v0.8.0
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*/
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id: number;
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/**
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* All workers are created using `child_process.fork()`, the returned object
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* from this function is stored as `.process`. In a worker, the global `process`is stored.
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*
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* See: `Child Process module`.
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*
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* Workers will call `process.exit(0)` if the `'disconnect'` event occurs
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* on `process` and `.exitedAfterDisconnect` is not `true`. This protects against
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* accidental disconnection.
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* @since v0.7.0
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*/
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process: child.ChildProcess;
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/**
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* Send a message to a worker or primary, optionally with a handle.
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*
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* In the primary, this sends a message to a specific worker. It is identical to `ChildProcess.send()`.
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*
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* In a worker, this sends a message to the primary. It is identical to`process.send()`.
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*
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* This example will echo back all messages from the primary:
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*
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* ```js
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* if (cluster.isPrimary) {
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* const worker = cluster.fork();
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* worker.send('hi there');
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*
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* } else if (cluster.isWorker) {
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* process.on('message', (msg) => {
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* process.send(msg);
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* });
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* }
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* ```
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* @since v0.7.0
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* @param options The `options` argument, if present, is an object used to parameterize the sending of certain types of handles. `options` supports the following properties:
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*/
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send(message: child.Serializable, callback?: (error: Error | null) => void): boolean;
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send(message: child.Serializable, sendHandle: child.SendHandle, callback?: (error: Error | null) => void): boolean;
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send(message: child.Serializable, sendHandle: child.SendHandle, options?: child.MessageOptions, callback?: (error: Error | null) => void): boolean;
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/**
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* This function will kill the worker. In the primary worker, it does this by
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* disconnecting the `worker.process`, and once disconnected, killing with`signal`. In the worker, it does it by killing the process with `signal`.
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*
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* The `kill()` function kills the worker process without waiting for a graceful
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* disconnect, it has the same behavior as `worker.process.kill()`.
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*
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* This method is aliased as `worker.destroy()` for backwards compatibility.
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*
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* In a worker, `process.kill()` exists, but it is not this function;
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* it is `kill()`.
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* @since v0.9.12
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* @param [signal='SIGTERM'] Name of the kill signal to send to the worker process.
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*/
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kill(signal?: string): void;
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destroy(signal?: string): void;
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/**
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* In a worker, this function will close all servers, wait for the `'close'` event
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* on those servers, and then disconnect the IPC channel.
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*
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* In the primary, an internal message is sent to the worker causing it to call`.disconnect()` on itself.
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*
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* Causes `.exitedAfterDisconnect` to be set.
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*
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* After a server is closed, it will no longer accept new connections,
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* but connections may be accepted by any other listening worker. Existing
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* connections will be allowed to close as usual. When no more connections exist,
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* see `server.close()`, the IPC channel to the worker will close allowing it
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* to die gracefully.
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*
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* The above applies _only_ to server connections, client connections are not
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* automatically closed by workers, and disconnect does not wait for them to close
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* before exiting.
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*
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* In a worker, `process.disconnect` exists, but it is not this function;
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* it is `disconnect()`.
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*
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* Because long living server connections may block workers from disconnecting, it
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* may be useful to send a message, so application specific actions may be taken to
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* close them. It also may be useful to implement a timeout, killing a worker if
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* the `'disconnect'` event has not been emitted after some time.
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*
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* ```js
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* if (cluster.isPrimary) {
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* const worker = cluster.fork();
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* let timeout;
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*
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* worker.on('listening', (address) => {
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* worker.send('shutdown');
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* worker.disconnect();
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* timeout = setTimeout(() => {
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* worker.kill();
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* }, 2000);
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* });
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*
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* worker.on('disconnect', () => {
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* clearTimeout(timeout);
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* });
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*
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* } else if (cluster.isWorker) {
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* const net = require('net');
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* const server = net.createServer((socket) => {
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* // Connections never end
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* });
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*
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* server.listen(8000);
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*
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* process.on('message', (msg) => {
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* if (msg === 'shutdown') {
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* // Initiate graceful close of any connections to server
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* }
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* });
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* }
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* ```
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* @since v0.7.7
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* @return A reference to `worker`.
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*/
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disconnect(): void;
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/**
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* This function returns `true` if the worker is connected to its primary via its
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* IPC channel, `false` otherwise. A worker is connected to its primary after it
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* has been created. It is disconnected after the `'disconnect'` event is emitted.
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* @since v0.11.14
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*/
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isConnected(): boolean;
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/**
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* This function returns `true` if the worker's process has terminated (either
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* because of exiting or being signaled). Otherwise, it returns `false`.
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*
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* ```js
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* import cluster from 'cluster';
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* import http from 'http';
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* import { cpus } from 'os';
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* import process from 'process';
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*
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* const numCPUs = cpus().length;
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*
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* if (cluster.isPrimary) {
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* console.log(`Primary ${process.pid} is running`);
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*
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* // Fork workers.
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* for (let i = 0; i < numCPUs; i++) {
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* cluster.fork();
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* }
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*
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* cluster.on('fork', (worker) => {
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* console.log('worker is dead:', worker.isDead());
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* });
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*
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* cluster.on('exit', (worker, code, signal) => {
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* console.log('worker is dead:', worker.isDead());
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* });
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* } else {
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* // Workers can share any TCP connection. In this case, it is an HTTP server.
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* http.createServer((req, res) => {
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* res.writeHead(200);
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* res.end(`Current process\n ${process.pid}`);
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* process.kill(process.pid);
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* }).listen(8000);
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* }
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* ```
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* @since v0.11.14
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*/
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isDead(): boolean;
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/**
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* This property is `true` if the worker exited due to `.disconnect()`.
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* If the worker exited any other way, it is `false`. If the
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* worker has not exited, it is `undefined`.
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*
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* The boolean `worker.exitedAfterDisconnect` allows distinguishing between
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* voluntary and accidental exit, the primary may choose not to respawn a worker
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* based on this value.
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*
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* ```js
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* cluster.on('exit', (worker, code, signal) => {
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* if (worker.exitedAfterDisconnect === true) {
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* console.log('Oh, it was just voluntary – no need to worry');
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* }
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* });
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*
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* // kill worker
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* worker.kill();
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* ```
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* @since v6.0.0
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*/
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exitedAfterDisconnect: boolean;
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/**
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* events.EventEmitter
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* 1. disconnect
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* 2. error
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* 3. exit
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* 4. listening
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* 5. message
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* 6. online
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*/
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addListener(event: string, listener: (...args: any[]) => void): this;
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addListener(event: 'disconnect', listener: () => void): this;
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addListener(event: 'error', listener: (error: Error) => void): this;
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addListener(event: 'exit', listener: (code: number, signal: string) => void): this;
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addListener(event: 'listening', listener: (address: Address) => void): this;
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addListener(event: 'message', listener: (message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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addListener(event: 'online', listener: () => void): this;
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emit(event: string | symbol, ...args: any[]): boolean;
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emit(event: 'disconnect'): boolean;
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emit(event: 'error', error: Error): boolean;
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emit(event: 'exit', code: number, signal: string): boolean;
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emit(event: 'listening', address: Address): boolean;
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emit(event: 'message', message: any, handle: net.Socket | net.Server): boolean;
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emit(event: 'online'): boolean;
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on(event: string, listener: (...args: any[]) => void): this;
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on(event: 'disconnect', listener: () => void): this;
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on(event: 'error', listener: (error: Error) => void): this;
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on(event: 'exit', listener: (code: number, signal: string) => void): this;
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on(event: 'listening', listener: (address: Address) => void): this;
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on(event: 'message', listener: (message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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on(event: 'online', listener: () => void): this;
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once(event: string, listener: (...args: any[]) => void): this;
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once(event: 'disconnect', listener: () => void): this;
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once(event: 'error', listener: (error: Error) => void): this;
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once(event: 'exit', listener: (code: number, signal: string) => void): this;
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once(event: 'listening', listener: (address: Address) => void): this;
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once(event: 'message', listener: (message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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once(event: 'online', listener: () => void): this;
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prependListener(event: string, listener: (...args: any[]) => void): this;
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prependListener(event: 'disconnect', listener: () => void): this;
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prependListener(event: 'error', listener: (error: Error) => void): this;
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prependListener(event: 'exit', listener: (code: number, signal: string) => void): this;
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prependListener(event: 'listening', listener: (address: Address) => void): this;
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prependListener(event: 'message', listener: (message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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prependListener(event: 'online', listener: () => void): this;
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prependOnceListener(event: string, listener: (...args: any[]) => void): this;
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prependOnceListener(event: 'disconnect', listener: () => void): this;
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prependOnceListener(event: 'error', listener: (error: Error) => void): this;
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prependOnceListener(event: 'exit', listener: (code: number, signal: string) => void): this;
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prependOnceListener(event: 'listening', listener: (address: Address) => void): this;
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prependOnceListener(event: 'message', listener: (message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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prependOnceListener(event: 'online', listener: () => void): this;
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}
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export interface Cluster extends EventEmitter {
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disconnect(callback?: () => void): void;
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fork(env?: any): Worker;
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/** @deprecated since v16.0.0 - use isPrimary. */
|
readonly isMaster: boolean;
|
readonly isPrimary: boolean;
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readonly isWorker: boolean;
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schedulingPolicy: number;
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readonly settings: ClusterSettings;
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/** @deprecated since v16.0.0 - use setupPrimary. */
|
setupMaster(settings?: ClusterSettings): void;
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/**
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* `setupPrimary` is used to change the default 'fork' behavior. Once called, the settings will be present in cluster.settings.
|
*/
|
setupPrimary(settings?: ClusterSettings): void;
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readonly worker?: Worker | undefined;
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readonly workers?: NodeJS.Dict<Worker> | undefined;
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readonly SCHED_NONE: number;
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readonly SCHED_RR: number;
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/**
|
* events.EventEmitter
|
* 1. disconnect
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* 2. exit
|
* 3. fork
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* 4. listening
|
* 5. message
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* 6. online
|
* 7. setup
|
*/
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addListener(event: string, listener: (...args: any[]) => void): this;
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addListener(event: 'disconnect', listener: (worker: Worker) => void): this;
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addListener(event: 'exit', listener: (worker: Worker, code: number, signal: string) => void): this;
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addListener(event: 'fork', listener: (worker: Worker) => void): this;
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addListener(event: 'listening', listener: (worker: Worker, address: Address) => void): this;
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addListener(event: 'message', listener: (worker: Worker, message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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addListener(event: 'online', listener: (worker: Worker) => void): this;
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addListener(event: 'setup', listener: (settings: ClusterSettings) => void): this;
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emit(event: string | symbol, ...args: any[]): boolean;
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emit(event: 'disconnect', worker: Worker): boolean;
|
emit(event: 'exit', worker: Worker, code: number, signal: string): boolean;
|
emit(event: 'fork', worker: Worker): boolean;
|
emit(event: 'listening', worker: Worker, address: Address): boolean;
|
emit(event: 'message', worker: Worker, message: any, handle: net.Socket | net.Server): boolean;
|
emit(event: 'online', worker: Worker): boolean;
|
emit(event: 'setup', settings: ClusterSettings): boolean;
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on(event: string, listener: (...args: any[]) => void): this;
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on(event: 'disconnect', listener: (worker: Worker) => void): this;
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on(event: 'exit', listener: (worker: Worker, code: number, signal: string) => void): this;
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on(event: 'fork', listener: (worker: Worker) => void): this;
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on(event: 'listening', listener: (worker: Worker, address: Address) => void): this;
|
on(event: 'message', listener: (worker: Worker, message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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on(event: 'online', listener: (worker: Worker) => void): this;
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on(event: 'setup', listener: (settings: ClusterSettings) => void): this;
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once(event: string, listener: (...args: any[]) => void): this;
|
once(event: 'disconnect', listener: (worker: Worker) => void): this;
|
once(event: 'exit', listener: (worker: Worker, code: number, signal: string) => void): this;
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once(event: 'fork', listener: (worker: Worker) => void): this;
|
once(event: 'listening', listener: (worker: Worker, address: Address) => void): this;
|
once(event: 'message', listener: (worker: Worker, message: any, handle: net.Socket | net.Server) => void): this; // the handle is a net.Socket or net.Server object, or undefined.
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once(event: 'online', listener: (worker: Worker) => void): this;
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once(event: 'setup', listener: (settings: ClusterSettings) => void): this;
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prependListener(event: string, listener: (...args: any[]) => void): this;
|
prependListener(event: 'disconnect', listener: (worker: Worker) => void): this;
|
prependListener(event: 'exit', listener: (worker: Worker, code: number, signal: string) => void): this;
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prependListener(event: 'fork', listener: (worker: Worker) => void): this;
|
prependListener(event: 'listening', listener: (worker: Worker, address: Address) => void): this;
|
// the handle is a net.Socket or net.Server object, or undefined.
|
prependListener(event: 'message', listener: (worker: Worker, message: any, handle?: net.Socket | net.Server) => void): this;
|
prependListener(event: 'online', listener: (worker: Worker) => void): this;
|
prependListener(event: 'setup', listener: (settings: ClusterSettings) => void): this;
|
prependOnceListener(event: string, listener: (...args: any[]) => void): this;
|
prependOnceListener(event: 'disconnect', listener: (worker: Worker) => void): this;
|
prependOnceListener(event: 'exit', listener: (worker: Worker, code: number, signal: string) => void): this;
|
prependOnceListener(event: 'fork', listener: (worker: Worker) => void): this;
|
prependOnceListener(event: 'listening', listener: (worker: Worker, address: Address) => void): this;
|
// the handle is a net.Socket or net.Server object, or undefined.
|
prependOnceListener(event: 'message', listener: (worker: Worker, message: any, handle: net.Socket | net.Server) => void): this;
|
prependOnceListener(event: 'online', listener: (worker: Worker) => void): this;
|
prependOnceListener(event: 'setup', listener: (settings: ClusterSettings) => void): this;
|
}
|
const cluster: Cluster;
|
export default cluster;
|
}
|
declare module 'node:cluster' {
|
export * from 'cluster';
|
export { default as default } from 'cluster';
|
}
|
