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Added getExistingProcesses()#454

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millerm wants to merge 1 commit into from
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Added getExistingProcesses() #454

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43 changes: 35 additions & 8 deletions scripts/start.js
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Original file line numberDiff line numberDiff line change
Expand Up@@ -16,6 +16,7 @@ var WebpackDevServer = require('webpack-dev-server');
var historyApiFallback = require('connect-history-api-fallback');
var httpProxyMiddleware = require('http-proxy-middleware');
var execSync = require('child_process').execSync;
var exec = require('child_process').exec;
var opn = require('opn');
var detect = require('detect-port');
var prompt = require('./utils/prompt');
Expand DownExpand Up@@ -72,6 +73,20 @@ function clearConsole() {
process.stdout.write('\x1bc');
}

function getExistingProcesses(port) {
//determine if another process running on the desired port
return new Promise(function (resolve, reject) {
var command = 'lsof -P | grep TCP | grep :' + port + ' | cut -d \' \' -f 1';

@TryingToImproveTryingToImproveAug 17, 2016•
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lsof, grep or cut is not valid windows commands..

netstat might be helpful, by requires administrative privileges..

C:\WINDOWS\system32>netstat -aon | findstr 3000
TCP 127.0.0.1:3000 0.0.0.0:0 LISTENING 15564
C:\WINDOWS\system32>tasklist /fi "pid eq 15564"
Image Name PID Session Name Session# Mem Usage
========================= ======== ================ =========== ============
node.exe 15564 Console 5 125.580 K

@vjeuxvjeuxAug 17, 2016

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Can you also run the second line I mentioned this way you get the entire command that started it instead of just "node". This way we get the entire path of the app running which should be more helpful :)

@vjeuxvjeuxAug 17, 2016

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For windows support, let's make it work on one platform and have the infra in place so that someone using windows can chime in and make it work over there with a good user experience!

exec(command, function (error, stdout, stderr) {

@vjeuxvjeuxAug 17, 2016

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Please use execSync, it's going to make the code way easier to understand

if (error) {
reject(error);
}

resolve(stdout);
});
});
}

function setupCompiler(port) {
// "Compiler" is a low-level interface to Webpack.
// It lets us listen to some events and provide our own custom messages.
Expand DownExpand Up@@ -259,6 +274,7 @@ function run(port) {
runDevServer(port);
}


// We attempt to use the default port but if it is busy, we offer the user to
// run on a different port. `detect()` Promise resolves to the next free port.
detect(DEFAULT_PORT).then(port => {
Expand All@@ -268,13 +284,24 @@ detect(DEFAULT_PORT).then(port => {
}

clearConsole();
var question =
chalk.yellow('Something is already running on port ' + DEFAULT_PORT + '.') +
'\n\nWould you like to run the app on another port instead?';

prompt(question, true).then(shouldChangePort => {
if (shouldChangePort) {
run(port);
}
});

getExistingProcesses(DEFAULT_PORT)
.then(res => chalk.yellow(
`Something is already running on port ${DEFAULT_PORT}:

The existing process is: ${res}

Would you like to run the app on another port instead?
`
))
.then(question => prompt(question, true))
.then((shouldChangePort) => {
if (shouldChangePort) {
run(port);
}
})
.catch((err) => {
throw new Error(err);

@vjeuxvjeuxAug 17, 2016

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We don't want to abort the entire thing if we couldn't determine what's running on the port. Not printing the hint around what is running on that port would be better.

@gaearongaearonAug 17, 2016

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I’d prefer to print something along these lines:

// could not determine
Something is already running on port ${DEFAULT_PORT}:

// could determine
Something (probably, node) is already running on port ${DEFAULT_PORT}:

});
});