[BUGFIX] Fixes IPC disconnected error

[DB-Alex]

Fixes the Error: IPC channel is already disconnected which is happening when we are trying to disconnect an already disconnected process

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

• What is the current behavior? (You can also link to an open issue here)

• What is the new behavior (if this is a feature change)?

• Other information:

[DB-Alex]

After more tests, this is not a full fix.

More information about error:

This only happens when the redisBeacon is on! For now I disabled redis and then its working fine.

[askmike]

ping @eusorov

This only happens when the redisBeacon is on! For now I disabled redis and then its working fine.

Gekko with or without this fix?

[DB-Alex]

It happens without the fix and redis on very fast. With the fix and redis on it still happens but it takes longer for the error to appear.

[askmike]

Looking at the stack trace you shared this error gets thrown async after the disconnect call. Else we could simply wrap the disconnect in a try/catch. Seems we are not the only ones with this problem, I could find this less than ideal solution: https://stackoverflow.com/a/18753988/843033

With the fix and redis on it still happens but it takes longer for the error to appear.

Sounds like a race condition, it might be that during the if check the client is connected but by the time it actually tries to disconnect it isn't anymore.

[DB-Alex]

Nice work! I think if its a race condition it should fail silently and not make it crash the whole UI.

[askmike]

agreed, but is pretty much nodejs acting a bit strange. I suggest we merge this since it already improved the behaviour. And after that: we could do some testing to see if the child process fires more messages (in which case gekko would try to disconnect them multiple times). However I can't reproduce this as is..