modules/InboundNatPoolsMigration/InboundNatPoolsMigration.psm1

# Load Modules
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/Log/Log.psd1") 
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/UpdateVmssInstances/UpdateVmssInstances.psd1")
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/UpdateVmss/UpdateVmss.psd1")
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/GetVmssFromBasicLoadBalancer/GetVmssFromBasicLoadBalancer.psd1")
function _HardCopyObject {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory = $True)][System.Collections.Generic.List[Microsoft.Azure.Management.Compute.Models.SubResource]] $listSubResource
    )
    $options = [System.Text.Json.JsonSerializerOptions]::new()
    $options.WriteIndented = $true
    $options.IgnoreReadOnlyProperties = $true
    $cgenericListSubResource = [System.Text.Json.JsonSerializer]::Serialize($listSubResource, "System.Collections.Generic.List[Microsoft.Azure.Management.Compute.Models.SubResource]", $options)
    $cgenericListSubResource = [System.Text.Json.JsonSerializer]::Deserialize($cgenericListSubResource, "System.Collections.Generic.List[Microsoft.Azure.Management.Compute.Models.SubResource]")
    # To preserve the original object type in the return we must use a , before the object to be returned
    return , [System.Collections.Generic.List[Microsoft.Azure.Management.Compute.Models.SubResource]]$cgenericListSubResource
}

function _MigrateNetworkInterfaceConfigurations {
    param (
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Network.Models.PSLoadBalancer] $BasicLoadBalancer,
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Network.Models.PSLoadBalancer] $StdLoadBalancer,
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet] $vmss,
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet] $refVmss
    )

    log -Message "[_MigrateNetworkInterfaceConfigurations] Adding InboundNATPool to VMSS $($vmss.Name)"
    foreach ($networkInterfaceConfiguration in $vmss.VirtualMachineProfile.NetworkProfile.NetworkInterfaceConfigurations) {
        $genericListSubResource = New-Object System.Collections.Generic.List[Microsoft.Azure.Management.Compute.Models.SubResource]
        foreach ($ipConfiguration in $networkInterfaceConfiguration.IpConfigurations) {
            If (![string]::IsNullOrEmpty($ipConfiguration.loadBalancerInboundNatPools)) {
                $genericListSubResource.AddRange($ipConfiguration.loadBalancerInboundNatPools)
            }

            foreach($InboundNatPool in $BasicLoadBalancer.InboundNatPools) {

                try {
                    # get the ipconfig from the VMSS as it was prior to starting the upgrade--we'll use this to determine which NAT Pools to assiciate with which ipconfig
                    $coorespondingRefVmssIpconfig = $refVmss.VirtualMachineProfile.NetworkProfile.NetworkInterfaceConfigurations | 
                        Where-Object {$_.Name -eq $networkInterfaceConfiguration.Name} | 
                        Select-Object -ExpandProperty IpConfigurations | 
                        Where-Object {$_.Name -eq $ipConfiguration.Name}
                    $coorespondingRefVmssIpconfigNatPoolNames = @()

                    #if ipconfig has associated nat pools, add their names to the array
                    If (![string]::IsNullOrEmpty($coorespondingRefVmssIpconfig.loadBalancerInboundNatPools)) {
                        $coorespondingRefVmssIpconfig.loadBalancerInboundNatPools | ForEach-Object {
                            log -Severity "Debug" -Message "Getting NAT Pool name from ID: '$($_.id)'" 
                            $coorespondingRefVmssIpconfigNatPoolNames += $_.Id.Split("/")[-1]
                        }
                    }

                    $message = "[_MigrateNetworkInterfaceConfigurations] Checking if VMSS '$($vmss.Name)' NIC '$($networkInterfaceConfiguration.Name)' IPConfig '$($ipConfiguration.Name)' should be associated with NAT Pool '$($InboundNatPool.Name)'"
                    log -Message $message
                    If ($null -ne $InboundNatPool -and $InboundNatPool.Id.split('/')[-1] -in $coorespondingRefVmssIpconfigNatPoolNames) {
                        $message = "[_MigrateNetworkInterfaceConfigurations] Adding NAT Pool '$($InboundNatPool.Name)' to IPConfig '$($ipConfiguration.Name)'"
                        log -Message $message
    
                        $subResource = New-Object Microsoft.Azure.Management.Compute.Models.SubResource
                        $subResource.Id = ($StdLoadBalancer.InboundNatPools | Where-Object { $_.Name -eq $InboundNatPool.Name }).Id
                        $genericListSubResource.Add($subResource)
                    }
                }
                catch {
                    $message = "[_MigrateNetworkInterfaceConfigurations] An error occured creating a new VMSS IP Config. To recover, address the cause of the following error, then follow the steps at https://aka.ms/basiclbupgradefailure to retry the migration. Error: $_"
                    log 'Error' $message -terminateOnError
                }
            }

            # if nat pools were found, associate them to the interface
            If (![string]::IsNullOrEmpty($genericListSubResource)) {
                # Taking a hard copy of the object and assigning, it's important because the object was passed by reference
                $ipConfiguration.loadBalancerInboundNatPools = _HardCopyObject -listSubResource $genericListSubResource
            }
            $genericListSubResource.Clear()
        }
    }
    log -Message "[_MigrateNetworkInterfaceConfigurations] Migrate NetworkInterface Configurations completed"
}
function InboundNatPoolsMigration {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Network.Models.PSLoadBalancer] $BasicLoadBalancer,
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Network.Models.PSLoadBalancer] $StdLoadBalancer,
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet] $refVmss
    )
    log -Message "[InboundNatPoolsMigration] Initiating Inbound NAT Pools Migration"

    $inboundNatPools = $BasicLoadBalancer.InboundNatPools
    foreach ($pool in $inboundNatPools) {
        log -Message "[InboundNatPoolsMigration] Adding Inbound NAT Pool $($pool.Name) to Standard Load Balancer"
        $frontEndIPConfig = Get-AzLoadBalancerFrontendIpConfig -LoadBalancer $StdLoadBalancer -Name ($pool.FrontEndIPConfiguration.Id.split('/')[-1])
        $inboundNatPoolConfig = @{
            Name                    = $pool.Name
            BackendPort             = $pool.backendPort
            Protocol                = $pool.Protocol
            EnableFloatingIP        = $pool.EnableFloatingIP
            EnableTcpReset          = $pool.EnableTcpReset
            FrontendIPConfiguration = $frontEndIPConfig
            FrontendPortRangeStart  = $pool.FrontendPortRangeStart
            FrontendPortRangeEnd    = $pool.FrontendPortRangeEnd
            IdleTimeoutInMinutes    = $pool.IdleTimeoutInMinutes
        }

        try {
            $ErrorActionPreference = 'Stop'
            $StdLoadBalancer | Add-AzLoadBalancerInboundNatPoolConfig @inboundNatPoolConfig > $null 
        }
        catch {
            $message = "[InboundNatPoolsMigration] An error occured when adding Inbound NAT Pool config '$($pool.name)' to the new Standard Load Balancer. The script will continue. MANUALLY CREATE THE FOLLOWING INBOUND NAT POOL CONFIG ONCE THE SCRIPT COMPLETES. `n$($inboundNatPoolConfig | ConvertTo-Json -Depth 5) $_"
            log 'Warning' $message
        }
    }
    log -Message "[InboundNatPoolsMigration] Saving Standard Load Balancer $($StdLoadBalancer.Name)"

    try {
        $ErrorActionPreference = 'Stop'
        $job = Set-AzLoadBalancer -LoadBalancer $StdLoadBalancer -AsJob

        While ($job.State -eq 'Running') {
            Start-Sleep -Seconds 15
            log -Message "[InboundNatPoolsMigration] Waiting for saving standard load balancer $($StdLoadBalancer.Name) job to complete..."
        }

        If ($job.Error -or $job.State -eq 'Failed') {
            Write-Error $job.error
        }
    }
    catch {
        $message = "[InboundNatPoolsMigration] An error occured when adding Inbound NAT Pool config '$($pool.name)' to the new Standard Load Balancer. The script will continue. MANUALLY CREATE THE FOLLOWING INBOUND NAT POOL CONFIG ONCE THE SCRIPT COMPLETES. `n$($StdLoadBalancer | Get-AzLoadBalancerInboundNatPoolConfig | ConvertTo-Json -Depth 5)$_"
        log 'Warning' $message
    }

    $vmss = GetVmssFromBasicLoadBalancer -BasicLoadBalancer $BasicLoadBalancer

    _MigrateNetworkInterfaceConfigurations -BasicLoadBalancer $BasicLoadBalancer -StdLoadBalancer $StdLoadBalancer -vmss $vmss -refVmss $refVmss

    # Update VMSS on Azure
    log -Message "[InboundNatPoolsMigration] Saving VMSS $($vmss.Name)"
    try {
        $ErrorActionPreference = 'Stop'

        Update-Vmss -Vmss $vmss
    }
    catch {
        $exceptionType = (($_.Exception.Message -split 'ErrorCode:')[1] -split 'ErrorMessage:')[0].Trim()
        if($exceptionType -eq "MaxUnhealthyInstancePercentExceededBeforeRollingUpgrade"){
            $message = "[InboundNatPoolsMigration] An error occured when attempting to update VMSS upgrade policy back to $($vmss.UpgradePolicy.Mode). Looks like some instances were not healthy and in orther to change the VMSS upgra policy the majority of instances must be healthy according to the upgrade policy. The module will continue but it will be required to change the VMSS Upgrade Policy manually. `nError message: $_"
            log 'Error' $message -terminateOnError
        }
        else {
            $message = "[InboundNatPoolsMigration] An error occured when attempting to update VMSS network config on the new Standard LB backend pool membership. To recover address the following error, and try again specifying the -FailedMigrationRetryFilePath parameter and Basic Load Balancer backup State file located either in this directory or the directory specified with -RecoveryBackupPath. `nError message: $_"
            log 'Error' $message -terminateOnError
        }
    }

    # Update Instances
    UpdateVmssInstances -vmss $vmss

    <#
    This will happen in the backend pool migration...
    # Restore VMSS Upgrade Policy Mode
    #_RestoreUpgradePolicyMode -vmss $vmss -refVmss $refVmss
 
    # Update VMSS on Azure
    #Update-Vmss -vmss $vmss
    #>


    log -Message "[InboundNatPoolsMigration] Inbound NAT Pools Migration Completed"
}
Export-ModuleMember -Function InboundNatPoolsMigration