Publish Azure App Service and Azure Function Apps on Linux

EvoPdf Chromium for .NET is a library that can be easily integrated in Azure App Service and Azure Functions for Linux to convert web pages and HTML strings to PDF or to image.

The HTML to PDF converter component of the library uses a rendering engine based on Chromium, which can render all modern HTML, CSS and JavaScript content in conformance with the latest standards.

EvoPdf Chromium for .NET can run in Azure App Service and Azure Functions Linux 64-bit applications. Before running your application in Azure App Service on Linux it is necessary to install additional dependency packages. The detailed installation instructions can be found below.

The .NET library targets the .NET Standard 2.0 and therefore it can be used in any .NET Core application which is compatible with this standard.

Create a new .NET project in Visual Studio and use the NuGet Package Manager from Visual Studio to add a reference to the EvoPdf.Chromium.Linux package from NuGet.

After the NuGet package has been installed, at the top of your C# source file add the using EvoPdf.Chromium; statement to include the EvoPdf.Chromium namespace in your application code and to make the library API available to your application.

// add this using statement at the top of your C# file
using EvoPdf.Chromium;

You are now ready to use the library to convert web pages and HTML code to PDF or to Image using EvoPdf Chromium for .NET.

With the code below you can convert a HTML string to a PDF document in a memory buffer and then save the data from buffer into a file.

// create the converter object in your code where you want to run conversion
HtmlToPdfConverter converter = new HtmlToPdfConverter();

// convert a HTML string to a memory buffer
byte[] htmlToPdfBuffer = converter.ConvertHtml("<b>Hello World</b> from EVO PDF !", null);

With the code below you can convert an URL to a PDF document in a memory buffer and then save the data from buffer into a file. The URL can also be a local file path prefixed by the 'file://' URI scheme.

// create the converter object in your code where you want to run conversion
HtmlToPdfConverter converter = new HtmlToPdfConverter();

// convert an URL to a memory buffer
string htmlPageURL = "http://www.evopdf.com";
byte[] urlToPdfBuffer = converter.ConvertUrl(htmlPageURL);

With the code below you can convert in your ASP.NET Core applications a HTML string to a PDF document in a memory buffer and then send it for download to browser.

// create the converter object in your code where you want to run conversion
HtmlToPdfConverter converter = new HtmlToPdfConverter();

// convert a HTML string to a memory buffer
byte[] htmlToPdfBuffer = converter.ConvertHtml("<b>Hello World</b> from EVO PDF !", null);

FileResult fileResult = new FileContentResult(htmlToPdfBuffer, "application/pdf");
fileResult.FileDownloadName = "HtmlToPdf.pdf";
return fileResult;

With the code below you can convert in your ASP.NET Core applications an URL to a PDF document in a memory buffer and then send it for download to browser. The URL can also be a local file path prefixed by the 'file://' URI scheme.

// create the converter object in your code where you want to run conversion
HtmlToPdfConverter converter = new HtmlToPdfConverter();

// convert an URL to a memory buffer
string htmlPageURL = "http://www.evopdf.com";
byte[] urlToPdfBuffer = converter.ConvertUrl(htmlPageURL);

FileResult fileResult = new FileContentResult(urlToPdfBuffer, "application/pdf");
fileResult.FileDownloadName = "UrlToPdf.pdf";
return fileResult;

The instructions from this section apply only if you publish an application in Azure App Service.

The minimum supported hosting plan size is Free F1. The recommended minimum hosting plan size is B2 (2 cores, 3.5 GB RAM) or a higher plan.

After the profile was created, before starting the publishing, select Portable as Target Runtime.

Publish the application in Azure App Service for Windows.

The instructions from this section apply only if you publish an Azure Function.

Running the converter in an Azure Function on Linux requires an additional configuration which is not necessary when deploying Azure Function Apps on Windows or Azure App Service applications on Linux.

Set HTML Loader Path

The file system is read only for Azure Functions on Linux (except a few directories like /tmp) and evopdf_loadhtml file is deployed without execution permission. In order to give the evopdf_loadhtml the execution permission, the converter runtime will be copied to /tmp directory in a later step described below.

Before publishing your application, set the full path of the evopdf_loadhtml executable in HtmlToPdfConverter object in your .NET application code using the following statement:

converter.HtmlLoaderFilePath = "/tmp/runtimes/linux-x64/native/evopdf_loadhtml";

Publish the Azure Function

For publishing, select the App service plan or Premium for Plan Type option in publish profile creation wizard in Visual Studio. The Consumption plan is not suitable for running the converter.

The minimum supported hosting plan size is B2 (2 cores, 3.5 GB RAM) or a higher plan. The Free plan is not suitable for running the converter in an Azure Function.

After the profile was created and before starting the publishing, select Portable as Target Runtime.

Publish the Azure Function application for Linux.

After the application was published and before installing the dependency packages for Linux, set the DISPLAY environment variable in your application. This environment variable is required by Xvfb dependency which will be installed later.

You can set the environment variable from Azure Portal. Open Settings->Environment Variables page of your application and in App settings panel click the +Add button to add a new environment variable. Use DISPLAY for name and :99 for value. Click Apply button, then Apply again and finally Confirm to set the environment variable and application restart.

You can now start installing the dependency packages for Linux.

The converter depends on various packages and it also requires an X11 display server to be installed and running.

From Azure portal open the Development Tools->SSH page of your application and click Go-> button to open the SSH console from where you can install the Linux packages for your application.

Install Dependency Packages

Install the dependency packages for Linux using the command below:

apt-get update && apt-get install -y --no-install-recommends libasound2 libatk1.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 libnss3 libgbm1

Install Xvfb Virtual Framebuffer

Install the Xvfb X virtual framebuffer using the command below:

apt-get update && apt-get install -y xvfb x11-apps x11-xkb-utils libx11-6 libx11-xcb1

Start the server to run in background as display number 99 using the command below:

Xvfb :99 -screen 0 1920x1280x24 -ac +extension GLX +render -noreset &

Install Windows Core Fonts

If the HTML pages you are converting use fonts generally available on Windows, it is also recommended to install the Microsoft Core Fonts package for Linux.

Change the current working directory to a directory with write access. For App Service application it can be any subdirectory of the /home directory. For Azure Functions you can use the /tmp directory because other directories might not be writeable.

Use the commands below to install Microsoft Core Fonts package:

wget http://ftp.de.debian.org/debian/pool/contrib/m/msttcorefonts/ttf-mscorefonts-installer_3.8_all.deb && apt-get install -y ./ttf-mscorefonts-installer_3.8_all.deb

The instructions from this section apply only if you publish an Azure Function.

In the case of Azure Functions the evopdf_loadhtml file is deployed without execution permission. In order to give the evopdf_loadhtml the execution permission, the file system must be writable and the runtime files must be copied to /tmp directory first.

Move Runtime and Set Execution Permission

This section does not apply to Azure App Service applications because in their case evopdf_loadhtml file has the execution permission is automatically granted.

When you published the Azure Function in a previous step, you set the full path to evopdf_loadhtml file in converter object. Now it's time to copy the published runtime files to /tmp directory using the command below:

cp -r /home/site/wwwroot/runtimes /tmp/runtimes

Give evopdf_htmltopdf file execution permission using the command below:

chmod +x /tmp/runtimes/linux-x64/native/evopdf_loadhtml

Everything should have been configured at this point and now you can run your application. Alternatively, you can follow the same instructions from this document to build and publish in Azure App Service for Linux our demo application for ASP.NET.

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