Deployment to Azure Functions


Deployment to Azure Functions

SelectPdf runs in Azure Functions (version 4, .NET isolated worker) on Windows and on Linux, on a Dedicated (App Service) plan of Basic or above, or on an Elastic Premium plan.

Hosting plans

Plan	SelectPdf
Dedicated (App Service), Basic or above	supported, Windows and Linux
Elastic Premium (EP1 and up)	supported, Windows and Linux
Consumption (Windows)	not supported
Flex Consumption (Linux)	not supported

A Windows Consumption plan cannot run the engine: the deployment does not fit the disk space the plan gives an application, Run From Package mounts the engine where it cannot be loaded, and the plan's sandbox stops the engine even when it is copied elsewhere. Flex Consumption always runs the application from the mounted, read-only package.

Packages

The same packages as a web application: SelectPdf.Universal with SelectPdf.Universal.Native.win-x64 on Windows, or with SelectPdf.Universal.Native.linux-x64 and SelectPdf.Universal.Fonts on Linux.

Step by step

1. Create a resource group, a storage account and a plan (--is-linux for Linux; --sku EP1 for Elastic Premium):

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az login
az group create --name selectpdf-rg --location westeurope
az storage account create --resource-group selectpdf-rg \
    --name selectpdfstorage --sku Standard_LRS
az functionapp plan create --resource-group selectpdf-rg \
    --name selectpdf-fnplan --sku P1v3 --is-linux

2. Create the function app on that plan, with Always On (a Dedicated plan option):

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az functionapp create --resource-group selectpdf-rg \
    --name selectpdf-fn --plan selectpdf-fnplan \
    --storage-account selectpdfstorage --functions-version 4 \
    --runtime dotnet-isolated --runtime-version 10 --os-type Linux
az functionapp config set --resource-group selectpdf-rg \
    --name selectpdf-fn --always-on true

On Windows use --os-type Windows and also pass --use-32bit-worker-process false to the second command.

3. Publish and deploy:

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dotnet publish -c Release -o publish
cd publish && zip -r ../fn.zip . && cd ..
az functionapp deployment source config-zip --resource-group selectpdf-rg \
    --name selectpdf-fn --src fn.zip

A function app on a Dedicated plan does not use Run From Package, and the zip deployment does not turn it on, so the engine runs from a writable folder as in a web application. Do not set WEBSITE_RUN_FROM_PACKAGE (see Azure App Service).

The function

A function that converts the page given in the query string:

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[Function("Convert")]
public static HttpResponseData Run(
    [HttpTrigger(AuthorizationLevel.Function, "get")] HttpRequestData req)
{
    string url = HttpUtility.ParseQueryString(req.Url.Query)["url"];
    HtmlToPdf converter = new HtmlToPdf();
    PdfDocument doc = converter.ConvertUrl(url);
    byte[] pdf = doc.Save();
    doc.Close();

    HttpResponseData response = req.CreateResponse(HttpStatusCode.OK);
    response.Headers.Add("Content-Type", "application/pdf");
    response.Body.Write(pdf, 0, pdf.Length);
    return response;
}

<[Function]("Convert")>
Public Shared Function Run(
    <HttpTrigger(AuthorizationLevel.Function, "get")> req As HttpRequestData
) As HttpResponseData
    Dim url As String = HttpUtility.ParseQueryString(req.Url.Query)("url")
    Dim converter As New HtmlToPdf()
    Dim doc As PdfDocument = converter.ConvertUrl(url)
    Dim pdf As Byte() = doc.Save()
    doc.Close()

    Dim response As HttpResponseData = req.CreateResponse(HttpStatusCode.OK)
    response.Headers.Add("Content-Type", "application/pdf")
    response.Body.Write(pdf, 0, pdf.Length)
    Return response
End Function

The official samples include a complete Azure Functions project for Windows and for Linux (windows/Functions, linux/Functions).

What to expect

Function apps run on the same machines as web applications, so the times of Azure App Service apply: on P1v3 a warm instance converts selectpdf.com in under 2 seconds, and Basic or Standard plans take several times longer.

Other Resources