Dynamically pass parameters to DSC resource? - powershell

Question

I was working on a composite resource when I came across the issue of being able to dynamically pass parameters to a DSC resource and wondered if there's another way to tackle this that I'm missing.
Basically, I have the an array (Below) that contains one PSObject per desired file-share. Each of these PSObjects has properties that are used as parameters for my DSC resource (In this case the cLocalFileShare community resource).
The issue is, not all of these objects have all of the parameters defined. For example, some of my shares don't have any users/groups assigned to the ReadAccess permission, but in my ForEach loop (Below), a $null value is being passed to the actual resource as this permissions isn't defined, and this causes the resource to error as it is trying to set ReadAccess permissions to user $null.
My issue is, how do I tackle this - for this resource and others?
I've tried splatting the parameters in the DSC resource, but this doesn't seem to be supported. If this worked, I could build a different parameter list and pass that.
Somebody on Reddit suggested passing a string that contained all of the parameters, but again this doesn't seem to be supported.
My worst fear is, I will have to edit each resource to support (and ultimately ignore) $null values which seems like a really bad way to tackle this.
So, here's my array containing a PSObject per file share.
$MyConfig = #(
#{
Path = 'D:\Shares\Accounting'
Name = 'Accounting'
Ensure = 'Present'
ChangeAccess = 'AccountingAdmins'
ReadAccess = 'AccountingInterns,FinanceDepartment'
}
#{
Path = 'D:\Shares\Software'
Name = 'Software$'
Ensure = 'Present'
ReadAccess = 'DomainUsers'
}
)
Now, within the actual DSC configuration...
configuration {
ForEach ($ShareProperties in $MyConfig) {
# Each resource is named after the Path specified, but with the colon replaced as that's not valid character for the resource name
cLocalFileShare $ShareProperties.Path.Replace(':','__') {
Path = $ShareProperties.Path
Name = $ShareProperties.Name
Ensure = $ShareProperties.Ensure
ChangeAccess = $ShareProperties.ChangeAccess
ReadAccess = $ShareProperties.ReadAccess
}
}
}

Answer 1

Not the most elegant solution. But you could use a conditional section within your ForEach loop.
configuration {
ForEach ($ShareProperties in $MyConfig) {
# Each resource is named after the Path specified, but with the colon replaced as that's not valid character for the resource name
if ($ShareProperties.ChangeAccess -eq $null) {
cLocalFileShare $ShareProperties.Path.Replace(':','__') {
Path = $ShareProperties.Path
Name = $ShareProperties.Name
Ensure = $ShareProperties.Ensure
ReadAccess = $ShareProperties.ReadAccess
}
}
else
{
cLocalFileShare $ShareProperties.Path.Replace(':','__') {
Path = $ShareProperties.Path
Name = $ShareProperties.Name
Ensure = $ShareProperties.Ensure
ChangeAccess = $ShareProperties.ChangeAccess
ReadAccess = $ShareProperties.ReadAccess
}
}
}
}