Object to hashtable key comparison - powershell

Question

I'm looking for some help troubleshooting comparing .key values to objects.
Basically what's happening here is I'm connecting to two VMware vCenters and downloading a list of roles and putting those roles into two hash tables, then comparing them.
The problem comes down to the Process-Roles function where the comparing logic is flawed somewhere. It outputs all of the roles in both lists. I think the (-not .containskey) isn't working right. I've debugged in powerGUI and both hashtables and mstr_roles/slave_roles are all filled correctly.
The roles lists should be object lists, as they were filled with Get-VIRole.
The hash table should be object-in-key, value null lists. Is it possible to compare these two? I'm trying to check if the $role object in the roles list exists in the .key values list of the hash table.
$creds = Get-Credential
$mst = Read-Host "`n Master Server: "
$slv = Read-Host "`n Slave Server: "
$hsh_mstr_roles = #{}
$hsh_slave_roles = #{}
$mstr_roles = ""
$slave_roles = ""
Get-Roles -MasterServer $mst -SlaveServer $slv
Process-Roles
.
function Get-Roles() {
Param(
[Parameter(Mandatory=$True,Position=0)]
[string]$MasterServer,
[Parameter(Mandatory=$True,Position=1)]
[string]$SlaveServer
)
#Get Master Roles
Connect-VIServer $MasterServer -Credential $creds
$mstr_roles = Get-VIrole
foreach ($role in $mstr_roles) {
$hsh_mstr_roles.add($role, $null)
}
Disconnect-VIServer $MasterServer -Confirm:$false
#Get Slave Roles
Connect-VIServer $SlaveServer -Credential $creds
$slave_roles = Get-VIrole
foreach ($role in $slave_roles) {
$hsh_slave_roles.add($role, $null)
}
Disconnect-VIServer $SlaveServer -Confirm:$false
Write-Host "`n + Retrieved Roles Successfully"
}
.
function Process-Roles () {
#Get Roles on Master NOT ON SLAVE
Write-Host "`n"
foreach ($role in $mstr_roles){
if(-not $hsh_slave_roles.containsKey($role)){
Write-Host $role "doesn't exist on slave"
}
}
#Get Roles on Slave NOT ON MASTER
foreach ($role in $slave_roles){
if(-not $hsh_mstr_roles.containsKey($role)){
Write-Host $role "doesn't exist on master"
}
}
Write-Host "`n + Processed Roles Successfully"
}

Answer 1

The easiest way to do this is by finding the complement to one of the two sets of Keys that each hashtable has, using -notcontains:
function Process-Roles {
param(
[hashtable]$MasterRoles,
[hashtable]$SlaveRoles
)
# Complement to slave roles (those ONLY in $MasterRoles)
$MasterRoles.Keys |Where-Object { $SlaveRoles -notcontains $_ }|ForEach-Object {
Write-Host "$_ not in Slave Roles"
}
# and the other way around (those ONLY in $SlaveRoles)
$SlaveRoles.Keys |Where-Object { $MasterRoles -notcontains $_ }|ForEach-Object {
Write-Host "$_ not in Master Roles"
}
}
I'll have to add that your way of working with variables in different scopes is sub-optimal.
Define the parameters that the function needs in order to "do its job"
Return output from your functions where it make sense (any Get-* function should at least)
Depend on the Global and Script scopes as little as possible, preferably not at all
I would go with something like this instead:
Add a Credential parameter to the Get-Roles function and return the results rather than modifying a variable in a parent scope (here, using a Hashtable of role categories):
function Get-Roles {
Param(
[Parameter(Mandatory=$True,Position=0)]
[string]$MasterServer,
[Parameter(Mandatory=$True,Position=1)]
[string]$SlaveServer,
[Parameter(Mandatory=$True,Position=2)]
[pscredential]$Credential
)
$DiscoveredRoles = #{}
# Get Master Roles
Connect-VIServer $MasterServer -Credential $Credential
$DiscoveredRoles["MasterRoles"] = Get-VIRole
Disconnect-VIServer $MasterServer -Confirm:$false
#Get Slave Roles
Connect-VIServer $SlaveServer -Credential $Credential
$DiscoveredRoles["SlaveRoles"] = Get-VIrole
Disconnect-VIServer $SlaveServer -Confirm:$false
Write-Verbose "`n + Retrieved Roles Successfully"
return $DiscoveredRoles
}
Define parameters for the Process-Roles function, that match the hashtable you expect to generate from Get-Roles and do the same comparison of the role names as above, only this time we grab them directly from the Role objects:
function Process-Roles {
param(
[Parameter(Mandatory=$true)]
[ValidateScript({ $_.ContainsKey("MasterRoles") -and $_.ContainsKey("SlaveRoles") })]
[hashtable]$RoleTable
)
$MasterRoleNames = $RoleTable["MasterRoles"] |Select-Object -ExpandProperty Name
$SlaveRoleNames = $RoleTable["SlaveRoles"] |Select-Object -ExpandProperty Name
$MasterRoleNames |Where-Object { $SlaveRoleNames -notcontains $_ } |ForEach-Object {
Write-Host "$_ doesn't exist on slave"
}
$SlaveRoleNames |Where-Object { $MasterRoleNames -notcontains $_ } |ForEach-Object {
Write-Host "$_ doesn't exist on Master"
}
Write-Host "`n + Processed Roles Successfully"
}
Update your executing script with the new parameters:
$creds = Get-Credential
$MasterServer = Read-Host "`n Master Server: "
$SlaveServer = Read-Host "`n Slave Server: "
$RoleTable = Get-Roles -MasterServer $MasterServer -SlaveServer $SlaveServer -Credential $creds
Process-Roles -RoleTable $RoleTable
Next step would be to add pipeline support to the Process-Roles function, converting Write-Host statements to Write-Verbose and adding error handling, but I'll leave that as an exercise to OP :-)

Answer 2

try:
if(!$hsh_slave_roles.containsKey($role))