Powershell cmdlet ignores an array parameter

Question

I am trying to use a PowerShell cmdlet to create a resource in Azure cloud:

$Gateway = New-AzApplicationGateway `
    -Name $GatewayName `
    -ResourceGroupName $ResourceGroupName `
    -Location $Location `
    -Sku $GatewaySku `
    -GatewayIPConfigurations $GatewayIPconfig `
    -FrontendIPConfigurations $FrontendIpConfig `
    -FrontendPorts $FrontEndPort `
    -Probes $HealthProbe `
    -BackendAddressPools $PlatformBackendPool, $ApiBackendPool `
    -BackendHttpSettingsCollection $PoolSettings `
    -Force

This, however, ends with:

cmdlet New-AzApplicationGateway at command pipeline position 1
Supply values for the following parameters:
(Type !? for Help.)
GatewayIPConfigurations[0]:

$GatewayIPconfig.GetType() yields

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    PSApplicationGatewayIPConfiguration      Microsoft.Azure.Commands.Network.Models.PSChildResource

and the documentation for the cmdlet states that the signature is

New-AzApplicationGateway
   ...
   -GatewayIPConfigurations <PSApplicationGatewayIPConfiguration[]>
   ...

Is this not the proper way to pass an array argument to a cmdlet?

marsze · Accepted Answer · 2020-10-26 17:00:27Z

2

It's just a guess, but do you maybe have a stray space or tab after -Sku $GatewaySku ' ? That might produce exactly the behavior you described. Basically that would be interpreted as:

$Gateway = New-AzApplicationGateway `
    -Name $GatewayName `
    -ResourceGroupName $ResourceGroupName `
    -Location $Location `
    -Sku $GatewaySku
# (the rest of the arguments will be missing)

It's a common pitfall when using the backtick that way. It is often recommended not to do it. It's because the backtick is not a continuation but an escape character, so anything after it will be escaped. When using it as you do, it's the line-break that is escaped, so you can put the arguments on separate lines, but if there's other whitespace in-between, this will break.

Best practice is to write everything in one line, or if there are too many arguments to keep it readable, you can use splatting:

$params = @{
    Name = $GatewayName
    ResourceGroupName = $ResourceGroupName
    Location = $Location
    Sku = $GatewaySku
    GatewayIPConfigurations = $GatewayIPconfig
    FrontendIPConfigurations = $FrontendIpConfig
    FrontendPorts = $FrontEndPort
    Probes = $HealthProbe
    BackendAddressPools = $PlatformBackendPool, $ApiBackendPool
    BackendHttpSettingsCollection = $PoolSettings
    Force = $true
}
$Gateway = New-AzApplicationGateway @params

edited Oct 26, 2020 at 17:00

answered Oct 26, 2020 at 16:21

marsze

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1 Comment

twoflower Over a year ago

Thank you @marsze, that was it! I was going crazy already. No more backticks from now on :)

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