Open more than on instance of Zerotier UI

[asparatu]

You can run more than one instance of the Desktop UI in Windows 10 Pro.

Example:

[0mWh]

This has been a source of confusion for many users in my experience.
There should be some single instance per user functionality.

Here is a crate for that: single-instance

[navhaxs]

I had a quick look at the codebase. Found that there is already code for a single instance lock, but it was commented out in commit 0c6df22 back in 2021 - @adamierymenko do you think this can be added back now? :)

Agreed, the current behaviour is confusing

DesktopUI/src/main.rs

Lines 364 to 370 in b2a7a30

	/*
	let single = single_instance::SingleInstance::new(std::env::temp_dir().join("ZeroTierUI_InstanceLock").to_str().unwrap());
	if single.is_err() || !single.unwrap().is_single() {
	println!("FATAL: another instance of the ZeroTier UI is already running.");
	std::process::exit(1);
	}
	*/

[navhaxs]

Figured out how to compile the codebase. Testing on Windows.

Once I uncomment the above block, execution always enters inside the if condition block and exits. I suspect there is something wrong with how that temp_dir string logic is being used - because once I remove that, the "single instance functionality" does work as expected 👍🏼

i.e. This seems to work correctly for me:

    let instance = SingleInstance::new("ZeroTierUI_InstanceLock").unwrap();
    if !instance.is_single() {
        println!("FATAL: another instance of the ZeroTier UI is already running.");
        std::process::exit(1);
    }

Do excuse my ignorance as this is my first time poking around with a Rust codebase! 😄