Using "single-instance": false to avoid problems

[weggesser]

First - thanks for your effort! While integrationg your module I had an issue which appeared sometimes - the downloaded and extracted app was not launched. I guess it's because by default node-webkit apps are single-instance only and the downloaded app was launched at a time the old app was not completely shut down. Perhaps you could mention that somewhere in the readme? This issue can be avoided with

"single-instance" : false

setting in the app's packeage json.

[edjafarov]

wow, nice hint! didn't know - definitely should go in readme.
@adam-lynch you might like it - it should make running apps more stable.

[adam-lynch]

Yeah, this makes sense and I didn't think of it but this then allows users to open your app multiple times, any time :/

[adam-lynch]

This then means though that there's more of a chance that the original app is still open when the temporary app is open which deletes the files where the original app exists, which will fail if the original app is still open. But we do have code in there that retries that deletion, right @edjafarov?

[majodev]

Tried that just now, works way more consistent now.

Just an idea: To keep apps restricted to run in a single instance only, one might want to add this flag to the package.json of a newly downloaded + unpacked release and remove it after the first startup of the upgraded app.

[adam-lynch]

remove it after the first startup of the upgraded app.

How?

On Tue, 2 Dec 2014 12:31 Mario Ranftl [email protected] wrote:

Tried that just now, works way more consistent now.

Just an idea: To keep apps restricted to run in a single instance only,
one might want to add this flag to the package.json of a newly downloaded

• unpacked release and remove it after the first startup of the upgraded
  app.

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#62 (comment)
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[majodev]

@adam-lynch example procedure after update first start:

var pkg = require('./package.json');
var fs = require('fs');

if (pkg["single-instance"] === false) {
  pkg["single-instance"] = true;

  fs.writeFile('./package.json', JSON.stringify(pkg), function(err) {
    if (err) return console.log(err);
  });
}

Works on bundled (via node-webkit-builder) 32bit mac app, all other platforms untested

[adam-lynch]

@majodev ah cool, but the original app won't have single-instance set to true so then.

[edjafarov]

But we do have code in there that retries that deletion, right @edjafarov?

it is for windows only, we might need to add retries for other OSes
https://github.com/edjafarov/node-webkit-updater/blob/master/app/updater.js#L359

[majodev]

@adam-lynch Well it's really just an hack-y idea, I'm really not sure if this "trick" will work consistently across all platforms, so don't use it in production.

It would be perfect if node-webkit provides a way to toggle the single-instance behavior during runtime (I filed an issue...)

[rodolfoag]

How about using a different package.name for each version, for instance "name": "app-v1.0.0" for old version and "app-v1.0.1" for the new one. This way nw won't interfere since it's use package.name to handle single-instance. Would you consider it a bad practice? Thx.

[adam-lynch]

Interesting @rodolfoag. I wouldn't have a new version for the each new version (that might have some side-effects depending on OS) but maybe the middle step of the updating process the name could have "-updating" on the end, but I don't know how that could even be done for just the middle step without having to download two versions of the new app. Also if we did this and apps could run alongside each other, would it help us that much? Because on Windows the first app will have to be dead by the time the next step tries to delete it / overwrite it. We might run into more problems with this, maybe this constraint makes it safer for us.