Invoke-WebRequest with retry

As a continuation to a previous post where I was using Invoke-RestMethod to send some output to a Logic App’s callback URL I stumbled into an edge case wherein occassionally the callback would fail and rather than retry (because I was an idiot who forgot to put a try/ catch around it) the Function would fail.

Here’s an example error I get when calling the callback URL (this is not the entire message):

EXCEPTION: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (management.azure.com:443)

1	EXCEPTION: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (management.azure.com:443)

I could add a try/ catch, but more importantly I want to keep retrying until it succeeds. Turns out Invoke-RestMethod doesn’t give status code output so I had to resort to Invoke-WebRequest instead and do the following:

# Update the callback Url if present
# Using Invoke-WebRequest here so I can get the status code and keep retrying until this succeeds.
if ($RequestObj.callbackUrl.Length -ne 0) {
    $response = $null

    do {
        Write-Host "Pushing to the callback URL"
        try { 
            $response = Invoke-WebRequest -Uri $RequestObj.callbackUrl -UseBasicParsing -Body ($functionOutput | ConvertTo-Json -Depth 5) -Method POST -ContentType $contentType 
        } catch {}

        Start-Sleep -Seconds 60
    } until ($response -and ($response.StatusCode -eq 200))
}

# Update the callback Url if present

# Using Invoke-WebRequest here so I can get the status code and keep retrying until this succeeds.

if ($RequestObj.callbackUrl.Length -ne 0) {

$response = $null

do {

Write-Host "Pushing to the callback URL"

try {

$response = Invoke-WebRequest -Uri $RequestObj.callbackUrl -UseBasicParsing -Body ($functionOutput | ConvertTo-Json -Depth 5) -Method POST -ContentType $contentType

} catch {}

Start-Sleep -Seconds 60

} until ($response -and ($response.StatusCode -eq 200))

}

Now the Function keeps trying until it gets a 200 OK.

I should probably add some code/ counter to stop trying after a while. Doesn’t matter in this case as the Function has a timeout of 30 mins, while the webhook action is set to timeout after 60 mins, so the Function will timeout before that.