PsHelper.psm1

Import-Module $PSScriptRoot\Logger.psm1
function Remove-StaleSession {

    param (
        [psobject] $staleSession
    )

    try {
        $staleSessions | Remove-PSSession -ErrorAction SilentlyContinue
    }
    catch {}
}
function Get-ReliablePsSession {
    param (
        [string] $computerName = @(hostname)
    )

    $s = Get-PSSession -ComputerName $computerName -ErrorAction SilentlyContinue | Where-Object { $_.State -eq "Opened" } | Select -Last 1     

    if ($s -eq $null) {
        return $null
    }

    try {
        Invoke-Command -Session $s -ScriptBlock { Get-Date | Out-Null } -ErrorAction Stop | Out-Null
        return $s
    }
    catch {
        Remove-StaleSession -staleSession $s
    }

    return $null
}
function New-ReliablePsSession {
    param (
        [string] $computerName = @(hostname),
        [pscredential] $credential = [pscredential]::Empty
    )

    $retry = 0
    
    while ($true) {
        try {
            Write-TraceLog "New-ReliablePsSession: Creating new session to computer $computerName, retryCount $retry"
            $s = New-PSSession -ComputerName $computerName -Credential $credential -ErrorAction Stop
            Invoke-Command -Session $s -ScriptBlock { } -ErrorAction Stop | Out-Null
            Write-TraceLog "New-ReliablePsSession: session created to $computerName"
            return $s
        }
        catch {
            $retry++

            if ($retry -eq 3) {
                Write-TraceLog "New-ReliablePsSession: Failed to create pssession to $computerName, error $_"
                throw
            }

            Start-Sleep 5
        }
    }
}
function Invoke-ReliableCommand {
    param (
        [string] $computerName = @(hostname),
        [pscredential] $credential = [pscredential]::Empty,
        [scriptblock] $scriptblock,
        [array] $argumentList
    )

    if ($computerName.StartsWith($(hostname))) {
        return Invoke-Command $scriptblock -ArgumentList $argumentList
    }

    $staleSessions = Get-PSSession -ComputerName $computerName -ErrorAction SilentlyContinue | Where-Object { $_.State -ne "Opened" }
    if ($staleSessions -ne $null) {
        Remove-StaleSession -staleSession $staleSessions
    }

    $s = Get-ReliablePsSession -ComputerName $computerName

    if ($s -eq $null) {
        $s = New-ReliablePsSession -ComputerName $computerName -Credential $credential
    }

    return Invoke-Command -Session $s -ScriptBlock $scriptblock -ArgumentList $argumentList
}

function Invoke-PowershellCommand {
    param(
        [string][Parameter(Mandatory = $true)]$cmd
    )

    $bytes = [Text.Encoding]::Unicode.GetBytes($cmd)
    $encodedCommand = [Convert]::ToBase64String($bytes)
    $result = powershell.exe -noprofile -encodedCommand $encodedCommand
    return $result
}

function Invoke-PowershellCommandOnVmInternal {

    param(
        [string] $vmName,
        [string] $hostName,
        [string] $cmd,
        [pscredential] $hostCredentials = [pscredential]::Empty,
        [pscredential] $vmCredentials = [pscredential]::Empty
    )

    # Write-FunctionEntryWithParams -FunctionName $MyInvocation.MyCommand.Name -boundparameters $psboundparameters -UnboundArguments $MyINvocation.UnboundArguments -ParamSet $psCmdlet
    Write-TraceLog "psOnVm: vm:$vmName host:$hostName command:{$cmd}"

    Invoke-Command -ComputerName $hostName -Credential $hostCredentials -ScriptBlock {
        $sb = [scriptblock]::Create($using:cmd)

        Invoke-Command -ScriptBlock $sb -VMName $using:vmName -Credential $using:vmCredentials
    }
}