check whether service exists (before stopping)

[chipitsine]

No description provided.

[mattock]

I assume the idea is to prevent nasty-looking errors showing up OpenVPNService and/or OpenVPNServiceLegacy are not registered as Windows services. I did some really quick testing with try-catch blocks, but those did not seem to suppress the errors. However, these seem to do the trick:

Stop-Service -Erroraction Ignore OpenVPNService
Stop-Service -Erroraction Ignore OpenVPNServiceLegacy

If this solves your problem, I can push this change to the repository. Thoughts?

[chipitsine]

one part is to avoid stopping non registered service. there're several ways to achive that

1. try/catch (powershell is strange with that, you need to specify proper -ErrorAction, otherwise, it is not caught)
2. trap { ....}
3. -EA Ignore
4. check for existance

another part is that service stop is asynchronous. you send a command to service and it might not stop immediately. so, I wait for service to stop.

[mattock]

Here are a couple of tricks that should force Stop-Service finish before starting anything:

Stop-Service -Erroraction Ignore OpenVPNService|Out-Null

The above would be a minimal change, and the piping trick works for external commands at least - I've used that in the past.

Another approach that should work alternatively start the service as a job and wait for the job to finish:

$job = Start-Job { Stop-Service OpenVPNService }
Wait-Job $job|Out-Null
Stop-Job $job

This would be quite readable, and could be made into a loop easily.

Then there's the rather dummy approach of just sleeping (say, 1 sec) after Stop-Service.

[chipitsine]

no, when you issue Stop-Service, you actually tell a service to stop gracefully.
it does not mean it will stop right after Stop-Service is done

it might not be noticeable on simple services, but it is clearly seen, for example on sql server.

[mattock]

Ok, I was probably a bit confusing. I attempted to say that the above tricks should ensure that Stop-Service finishes before any other command does anything else. Basically the tricks should emulate a synchronous Stop-Service.

[chipitsine]

Stop-Service is not synchoronous.
it is not possible to emulate that

[mattock]

Let's suppose, for the sake of argument, that "Stop-Service OpenVPNService" takes 10 seconds to finish. Then we run this code:

$job = Start-Job { Stop-Service OpenVPNService }
Wait-Job $job|Out-Null
Write-Host "I should run after OpenVPNService has stopped"
Stop-Job $job

Would Write-Host actually run before OpenVPNService has stopped?

[chipitsine]

yes, it could happen

[mattock]

Do you know of a slow-running "installed by default" asynchronous CmdLet I could do some testing with?

Also, wouldn't a "Sleep -Seconds 2" be good enough a workaround? The changes you propose are rather large in comparison.

[chipitsine]

http://www.powershellmagazine.com/2013/04/10/pstip-wait-for-a-service-to-reach-a-specified-status/

it seems we can either switch to "while" (it saves extra "sleep"), or use .WaitForStatus('Stopped')

[mattock]

Ah yes, sounds good. I did run through "Get-Service|Get-Member", but somehow managed to overlook the WaitForStatus method. It would definitely be more readable than the original PR.

[mattock]

@chipitsine : I forked this repo to https://github.com/OpenVPN/openvpn-windows-test, and I suggest we start using it as the upstream repository. I opened a PR already, if you want to have a look:

[mattock]

I created OpenVPN/openvpn-windows-test PR#2 that based on my testing solves both of the problems you identified and fixed here, just in a more readable fashion. Does that PR look good to you?