Error handling for EADDRINUSE about lw.comm-server

[cprezzi]

@jorgerobles Thanks. I will insert the makeSingleInstance into the electron code. That's the most common reason for this error. I probably also need to implement a netstat check if the port is already used by another server.

https://www.nallex.com/questions/example-of-how-to-handle-eaddrinuse-errors-in-nodejs

@cprezzi Hi Claudio, do you have any resolutions to capturing this error?
It is being reported by many LW4 users.

[jorgerobles]

Maybe we can specify a range of ports and if catch error open other port (809x).
Downside could be the fill up of all the alternative ports. Have to say 8000/8080 are pretty common ports, maybe we can move to 90xx

https://www.npmjs.com/package/node-netstat could be useful, scanning first if that port is used...

[jorgerobles]

@DarklyLabs have you experienced that error? If so, could use a network diagnose tool to know what is on 8000? Maybe LW is not cleaning up correctly on binary or there's a common software that uses that port.

Is it possible to only allow one instance of LW to run on a computer at any time?
We have found situations where the computer has gone to sleep and upon awakening chrome crashed but there is still an instance of LW running when we check the processes.

@jorgerobles We can replicate the error by starting 2 instances of LW.

[jorgerobles]

Yes, as it's using a specific port to launch, means that if is used conflicts each other.
The problem here is the new instance cannot kill the former. Will investigate.

Thanks for the feedback!

[jorgerobles]

@cprezzi https://github.com/electron/electron/blob/master/docs/api/app.md#appmakesingleinstancecallback

[cprezzi]

I have implemented the makeSingleInstance function to prohibit starting multiple instances. Instead, the main window is activated.
See commit 52bd4c1