Server pausing or hibernation

[MercifulCamel]

Hi not sure if this has already been asked for or is already implemented.

But I was wondering if it's possible to make the server paus when there are no users online.
Basically make it check for users and if there are none the server pauses or "freezes" until someone connects.

Loving the work so far

[mbround18]

I don't think there is any technical way this could be implemented 0.o Valheim does not support pausing and I think if I set up a udp listener the server would take too long to start back up for the user to connect securely. Maybe this could be solved with a Valheim mod?

[joryirving]

I'd be interested to know how you do it, but I can't stop the PC, since it's running other containers, doing other things.

[Android3000]

Sorry I missed your follow up @LilDrunkenSmurf ! So basically this uses the Valve A2S_INFO server query: https://developer.valvesoftware.com/wiki/Server_queries

I found a snippet on Reddit someone had written in Python to do the basic query. I was just testing at that point and stupidly never copied the link to give proper credit, so thank you unknown Redditor out there. The rest of the automation is in PowerShell. It is by no means resilient code, but it's worked for me so far for my own internal private use. Use at your own peril 😬

(The $playerCount = python -c line is probably the most interesting for you)

Add-Type -AssemblyName System.Windows.Forms;

function Log-Formatted($message) {
    "[$(Get-Date -Format "MM/dd/yyyy hh:mm:ss tt")] $message" | Out-File -Append -FilePath C:\path\to\log.txt -Encoding utf8
}

function Check-Players-Active { 
    $playerCount = python -c "import socket; addr = ('127.0.0.1', 2457); message = '\xff\xff\x54\x53\x6f\x75\x72\x63\x65\x20\x45\x6e\x67\x69\x6e\x65\x20\x51\x75\x65\x72\x79\x00'; client_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM); client_socket.settimeout(1.0); client_socket.sendto(message.encode(), addr); data = client_socket.recvfrom(2048)[0].decode('utf-8', errors='ignore')[2:].split(chr(0x0)); print(ord(data[6][0]) if data[6] else 0);"
    if ($LASTEXITCODE -ne 0) {
        Log-Formatted "Received a non-zero exit code. Exiting idle check."        
        exit
    } else {
        Log-Formatted "Got players: $playerCount"
        if ($playerCount -ne 0) {
            Log-Formatted "Server active, exiting check."
            exit
        }    
    }
}

Check-Players-Active
Start-Sleep -Seconds 300
Check-Players-Active
Start-Sleep -Seconds 300
Check-Players-Active
Log-Formatted "Server appears to be idle; backing up and sleeping."
$fileName = "$(Get-Date -Format "yyyyMMdd-HHmmss")-sleep-backup.tar.gz"
docker exec -it valheim-server odin backup /home/steam/.config/unity3d/IronGate/Valheim /home/steam/backups/$($fileName)
Start-Sleep -Seconds 15
Log-Formatted "Backup complete, going to sleep after final player check."
Check-Players-Active
Log-Formatted "Sleeping."
[System.Windows.Forms.Application]::SetSuspendState([System.Windows.Forms.PowerState]::Suspend, $false, $false)

[mbround18]

Sorry I missed your follow up @LilDrunkenSmurf ! So basically this uses the Valve A2S_INFO server query: https://developer.valvesoftware.com/wiki/Server_queries

I found a snippet on Reddit someone had written in Python to do the basic query. I was just testing at that point and stupidly never copied the link to give proper credit, so thank you unknown Redditor out there. The rest of the automation is in PowerShell. It is by no means resilient code, but it's worked for me so far for my own internal private use. Use at your own peril 😬

This would sleep the server but how would you reinitialize it once a player tries to connect?

[Android3000]

In my case, as this is a private family server, I have a link that issues a remote Wake-On-LAN broadcast that wakes the PC up (takes just a few seconds to start back up). Unfortunately nothing built in to automatically issue that upon attempting to connect (as the server wouldn't even be showing up in the server browser anyways at that point). It also has some scheduled tasks that wake it for daily update checks and stuff as well.

The idea above is that folks may be able to use the AS2_INFO server query to build in their own automation that fits their use case (e.g. spinning up/down EC2 instances or whatnot).

[dghodgson]

Just wanted to chime in on this.

From what I understand, the server already pauses game state if no players are online, so if you're concerned about the world continuing to progress without you, that shouldn't be an issue.

I confirmed this myself when my buddy logged off while a troll was attacking one of our forward bases. When I logged in 10 minutes later, the Troll was mid-swing and I was right in front of it.

If that's not enough for you (e.g. you want to put your physical server to sleep) then you might need to look in to the A2S_INFO query as above.