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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var assert = require('assert');
var fork = require('child_process').fork;
var net = require('net');
var EventEmitter = require('events').EventEmitter;
var cluster = module.exports = new EventEmitter();
var debug;
if (process.env.NODE_DEBUG && /cluster/.test(process.env.NODE_DEBUG)) {
debug = function(x) {
var prefix = process.pid + ',' +
(process.env.NODE_WORKER_ID ? 'Worker' : 'Master');
console.error(prefix, x);
};
} else {
debug = function() { };
}
// Used in the master:
var masterStarted = false;
var ids = 0;
var workers = [];
var servers = {};
var workerFilename;
var workerArgs;
// Used in the worker:
var workerId = 0;
var queryIds = 0;
var queryCallbacks = {};
cluster.isWorker = 'NODE_WORKER_ID' in process.env;
cluster.isMaster = ! cluster.isWorker;
// Call this from the master process. It will start child workers.
//
// options.workerFilename
// Specifies the script to execute for the child processes. Default is
// process.argv[1]
//
// options.args
// Specifies program arguments for the workers. The Default is
// process.argv.slice(2)
//
// options.workers
// The number of workers to start. Defaults to os.cpus().length.
function startMaster() {
// This can only be called from the master.
assert(cluster.isMaster);
if (masterStarted) return;
masterStarted = true;
workerFilename = process.argv[1];
workerArgs = process.argv.slice(2);
process.on('uncaughtException', function(e) {
// Quickly try to kill all the workers.
// TODO: be session leader - will cause auto SIGHUP to the children.
eachWorker(function(worker) {
debug('kill worker ' + worker.pid);
worker.kill();
});
console.error('Exception in cluster master process: ' +
e.message + '\n' + e.stack);
process.exit(1);
});
}
function handleWorkerMessage(worker, message) {
// This can only be called from the master.
assert(cluster.isMaster);
debug('recv ' + JSON.stringify(message));
switch (message.cmd) {
case 'online':
debug('Worker ' + worker.pid + ' online');
worker.online = true;
break;
case 'queryServer':
var key = message.address + ':' +
message.port + ':' +
message.addressType;
var response = { _queryId: message._queryId };
if (!(key in servers)) {
// Create a new server.
debug('create new server ' + key);
servers[key] = net._createServerHandle(message.address,
message.port,
message.addressType);
}
worker.send(response, servers[key]);
break;
default:
// Ignore.
break;
}
}
function eachWorker(cb) {
// This can only be called from the master.
assert(cluster.isMaster);
for (var id in workers) {
if (workers[id]) {
cb(workers[id]);
}
}
}
cluster.fork = function() {
// This can only be called from the master.
assert(cluster.isMaster);
// Lazily start the master process stuff.
startMaster();
var id = ++ids;
var envCopy = {};
for (var x in process.env) {
envCopy[x] = process.env[x];
}
envCopy['NODE_WORKER_ID'] = id;
var worker = fork(workerFilename, workerArgs, { env: envCopy });
workers[id] = worker;
worker.on('message', function(message) {
handleWorkerMessage(worker, message);
});
worker.on('exit', function() {
debug('worker id=' + id + ' died');
delete workers[id];
cluster.emit('death', worker);
});
return worker;
};
// Internal function. Called from src/node.js when worker process starts.
cluster._startWorker = function() {
assert(cluster.isWorker);
workerId = parseInt(process.env.NODE_WORKER_ID, 10);
queryMaster({ cmd: 'online' });
// Make callbacks from queryMaster()
process.on('message', function(msg, handle) {
debug('recv ' + JSON.stringify(msg));
if (msg._queryId && msg._queryId in queryCallbacks) {
var cb = queryCallbacks[msg._queryId];
if (typeof cb == 'function') {
cb(msg, handle);
}
delete queryCallbacks[msg._queryId];
}
});
};
function queryMaster(msg, cb) {
assert(cluster.isWorker);
debug('send ' + JSON.stringify(msg));
// Grab some random queryId
msg._queryId = (++queryIds);
msg._workerId = workerId;
// Store callback for later. Callback called in _startWorker.
if (cb) {
queryCallbacks[msg._queryId] = cb;
}
// Send message to master.
process.send(msg);
}
// Internal function. Called by lib/net.js when attempting to bind a
// server.
cluster._getServer = function(address, port, addressType, cb) {
assert(cluster.isWorker);
queryMaster({
cmd: 'queryServer',
address: address,
port: port,
addressType: addressType
}, function(msg, handle) {
cb(handle);
});
};