[CmdletBinding()]

Param(

[string] $ModuleName,

[string] $ModuleRegex,

[string] $OpenApiDocOutput,

[string] $GraphVersion,

[switch] $ForceRefresh,

[switch] $SingularizeOperationIds,

[int] $RequestCount = 1

)

if (-not (Test-Path $OpenApiDocOutput)) {

New-Item -Path $OpenApiDocOutput -Type Directory

}

$OpenApiBaseUrl = "https://devxapi-func-prod-eastus.azurewebsites.net"

$OpenApiServiceUrl = ("$OpenApiBaseUrl/`$openapi?tags={0}&title=$ModuleName&openapiversion=3&style=Powershell&fileName=powershell_v2&graphVersion=$GraphVersion" -f $ModuleRegex)

if ($ForceRefresh.IsPresent) {

$OpenApiServiceUrl = "$OpenApiServiceUrl&forceRefresh=true"

}

if ($SingularizeOperationIds.IsPresent) {

$OpenApiServiceUrl = "$OpenApiServiceUrl&singularizeOperationIds=true"

}

Write-Debug "[$RequestCount] Downloading OpenAPI doc for '$ModuleName' module: $OpenApiServiceUrl"

$Retries = 3

$Delay = 3

$Retrycount = 0

$Completed = $false

while (-not $Completed) {

try {

Invoke-WebRequest $OpenApiServiceUrl -OutFile "$OpenApiDocOutput\$ModuleName.yml"

$Completed = $true

}

catch {

$Exception = $_.Exception

switch ($Exception.Response.StatusCode.value__) {

{ @(429, 503, 504) -contains $_ } {

if ($Retrycount -ge $Retries) {

Write-Warning "Request to $OpenApiServiceUrl failed the maximum number of $Retrycount times."

throw

}

else {

[ref]$RetryAfterHeader = $null

if ($Exception.Response.Headers.TryGetValues("Retry-After", $RetryAfterHeader)) {

# Use Retry-After response header

$DelayInSeconds = $RetryAfterHeader.Value

}

else {

# Use exponential backoff

$mPow = [math]::Pow(2, $Retrycount)

$DelayInSeconds = $mPow * $Delay

}

Write-Warning "Request to $OpenApiServiceUrl failed. Retrying in $DelayInSeconds seconds."

Start-Sleep $DelayInSeconds

$Retrycount++

}

}

404 {

Write-Warning "Request to $OpenApiServiceUrl returned 404. Download will be skipped."

$Completed = $true

}

default {

# Get HTTP error message from DevX api, Re-throw error to be handled Upstream

$ErrorMessage = $Exception.Message

Write-Warning "[$RequestCount] Request for $ModuleName failed with error message: $ErrorMessage"

throw

}

}

}

}