ConvertTo-Json on VMWare objects doesn't work

Question

In powershell while converting VM objects to json , ($json = ConvertTo-Json $vm -Compress)

i am getting "An item with the same key has already been added" exception.

PS SQLSERVER:\> C:\Users\admin\Desktop\inventory.ps1
ConvertTo-Json : An item with the same key has already been added.
At C:\Users\huradmin\Desktop\inventory.ps1:68 char:31
+     if($vm -ne $null){$json = ConvertTo-Json $vm -Compress;      insertToElasticSearc ...
+                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [ConvertTo-Json], ArgumentException
+ FullyQualifiedErrorId : System.ArgumentException,Microsoft.PowerShell.Commands.ConvertToJsonCommand

insertToElasticSearch : Cannot bind argument to parameter 'json' because it is null.
At C:\Users\admin\Desktop\inventory.ps1:68 char:89
+ ... icSearch -json $json -info:$true -Verbose:$true}
+                    ~~~~~
+ CategoryInfo          : InvalidData: (:) [insertToElasticSearch], ParameterBindingValidationException
+ FullyQualifiedErrorId : ParameterArgumentValidationErrorNullNotAllowed,insertToElasticSearch

getVMHosts function returns a list of VM guests. Please find my code below.

function getVMHosts{
Param(
[Parameter(Mandatory=$True,Position=1)]
[string]$vcenter,
[Parameter(Mandatory=$False)]
[switch]$info=$false
)
try
{
    Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Importing VMWare modules" -verbose:$info
    Get-Module -ListAvailable -Name "VMware.*" | Import-Module
    Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Connecting to Vcenter:$vcenter" -verbose:$info
    [void]::$(Connect-VIServer -Server $vcenter -ErrorAction SilentlyContinue)
    Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Getting Data center servers" -verbose:$info
    $DCs = Get-Datacenter
    $VMs = $null
    foreach($dc in $DCs)
    {
        Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Getting VM servers for Data Center:$dc" -verbose:$info
        $VMs=$VMs+ $(Get-Datacenter -Name $dc.Name | Get-VM -Verbose:$info| Select PowerState,Name, NumCpu,MemoryMB,GuestId,VMHost, @{N="IP Address";E={@($_.guest.IPAddress[0])}})
    }
    Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Disconnecting from VCenter:$vcenter" -verbose:$info
    Disconnect-VIServer -Server $vcenter -ErrorAction SilentlyContinue -Confirm:$false
    Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Returning VM Lists" -verbose:$info
    return $VMs
}
catch
{
    $errorMessage = "$($_.Exception.Message)`n$(($_|select -ExpandProperty invocationinfo).PositionMessage)"
    Write-Warning -Message "Catched an exception in Function:$($MyInvocation.MyCommand)`n$errorMessage" -Verbose:$true
}
}
$vmHosts = getVMHosts -vcenter "vcenter"
$counter = 0
foreach($vm in $vmHosts)
{    
if($vm -ne $null){$json = ConvertTo-Json $vm -Compress;insertToElasticSearch json $json -info:$true -Verbose:$true}   
}

Answer 1

Try ConvertTo-JSON -Depth 1. Sounds like there are properties in the object that have the same name.

Answer 2

I don't have VCenter to verify the script, but I refactored yours a bit to make it more powershell-ly.

Notes:

CmdletBinding gives you -Verbose and other features
Any object not set to a variable is output to the pipeline by default
Return does not do what most developers would expect

function getVMHosts{
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory=$True,Position=1)]
        [string]$vcenter,
    )
    try
    {
        Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Importing VMWare modules"
        Get-Module -ListAvailable -Name "VMware.*" | Import-Module
        Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Connecting to Vcenter:$vcenter"
        [void]$(Connect-VIServer -Server $vcenter -ErrorAction SilentlyContinue)
        Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Getting Data center servers"
        Get-Datacenter |
            ForEach-Object {
                Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Getting VM servers for Data Center:$_"
                Get-Datacenter -Name $_.Name |
                    Get-VM -Verbose:$Verbose|
                    Select PowerState, Name, NumCpu, MemoryMB, GuestId, VMHost, @{N="IP Address";E={@($_.guest.IPAddress[0])}}
        }

        Write-Verbose "$(get-date -Format "dd/MM/yyyy HH:mm") - Function:$($MyInvocation.MyCommand) - Disconnecting from VCenter:$vcenter"
        [void]Disconnect-VIServer -Server $vcenter -ErrorAction SilentlyContinue -Confirm:$false
    }
    catch
    {
        $errorMessage = "$($_.Exception.Message)`n$(($_|select -ExpandProperty invocationinfo).PositionMessage)"
        Write-Warning -Message "Exception caught in Function:$($MyInvocation.MyCommand)`n$errorMessage"
    }
}

getVMHosts -vcenter "vcenter" |
    ForEach-Object {
        $json = ConvertTo-Json $_ -Compress;
        insertToElasticSearch json $json -info:$true -Verbose:$true
    }
}

Answer 3

As noam states there are objects in there causing this. Extract the base case as an example

get-vm <insertexamplevmname> | Select PowerState, Name, NumCpu, MemoryMB, GuestId, VMHost, @{N="IP Address";E={@($_.guest.IPAddress[0])}} | convertto-json -Depth 1

You will see that VMHost isn't just the name of the host it is running on but the actual host object which also has a Name property just like the VM has a Name.

So what you probably want is to extract the VMHost name as you have done for the IP addresses from the guest object.

get-vm <insertexamplevmname> | Select PowerState, Name, NumCpu, MemoryMB, GuestId, @{N="Hostname";E={@($_.VMhost.Name)}}, @{N="IP Address";E={@($_.guest.IPAddress[0])}} | convertto-json

Answer 4

After some fiddling, it appears to be a bug with convertto-json when the get-vm statement returns a single vm object. If more than one vm object is returned, convertto-json works. You can test yourself, replacing vm1 and vm2 with valid vm names:

get-vm -name 'vm1' | convertto-json -depth 1## fail
get-vm -name @('vm1') | convertto-json -depth 1 ## fail

get-vm -name 'vm2' | convertto-json -depth 1 ## fail
get-vm -name @('vm2') | convertto-json -depth 1 ## fail

get-vm -name @('vm1','vm2') | convertto-json -depth 1 ## success
get-vm -name @('vm2','vm1') | convertto-json -depth 1 ## success

One hackaround would be to ensure get-vm always returns two vms by including a known vm, then ignoring the known vm json element. Not recommending this solution, but may help someone in a bind.