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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"intermittent unexpected socket closure on Mac OS X","articleBody":"Ref: https://github.com/nodejs/node/issues/1100\nRef: https://github.com/joyent/node/issues/16805\n\nThe following code will throw on OS X. It might take a while but it will happen. I usually see the error before runcount hits 2000.\n\n``` javascript\n'use strict';\nconst fork = require('child_process').fork;\nconst net = require('net');\nconst count = 12;\nconst port = 12346;\n\nif (process.argv[2] === 'child') {\n  let sockets = [];\n\n  process.on('message', function(m, socket) {\n    function sendClosed(id) {\n      process.send({ id: id, status: 'closed'});\n    };\n\n    if (m.cmd === 'new') {\n      sockets.push(socket);\n    }\n\n    if (m.cmd === 'close') {\n      if (sockets[m.id].destroyed) {\n        throw new Error('socket already destroyed');\n      }\n      sockets[m.id].once('close', sendClosed.bind(null, m.id));\n      sockets[m.id].destroy();\n    }\n\n    if (m.cmd === 'clear') {\n      sockets = [];\n    }\n  });\n\n} else {\n  const child = fork(process.argv[1], ['child']);\n\n  const server = net.createServer();\n  let sockets = [];\n\n  server.on('connection', function(socket) {\n    child.send({ cmd: 'new' }, socket);\n    sockets.push(socket);\n\n    if (sockets.length === count) {\n      closeSockets(0);\n    }\n  });\n\n  function createSockets() {\n    let j = count, client;\n    while (j--) {\n      client = net.connect(port, '127.0.0.1');\n    }\n  }\n\n  server.on('listening', function() {\n    createSockets();\n  });\n\n  let runCount = 0;\n  function closeSockets(i) {\n    if (i === count) {\n      console.log('run count: ' + ++runCount);\n      child.send({ cmd: 'clear' });\n      sockets = [];\n      return createSockets();\n    }\n\n    child.once('message', function(m) {\n      server.getConnections(function(err, num) {\n        closeSockets(i + 1);\n      });\n    });\n    child.send({ id: i, cmd: 'close' });\n  };\n\n  server.listen(port, '127.0.0.1');\n}\n```\n","author":{"url":"https://github.com/Trott","@type":"Person","name":"Trott"},"datePublished":"2015-08-29T04:12:06.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":11},"url":"https://github.com/2610/node/issues/2610"}