Tuesday, October 4, 2016

Azure: Web App Environment Variables

This posting will present a class that can be used to retrieve the environment variables associated with an Azure Web Application. A complete list of the pertinent environment variables for an Azure Web App can be found at Azure runtime environment | Environment | Website Environment Variables. An example of the environment variables associated with an Azure Web App are as follows


The specific environment variable I was interested in was WEBSITE_SITE_NAME. The web site name was need in order to write a piece of code that read the web site's application log. For this particular web application the application log was written to a storage container of type blob (see below):

Navigating to the specific blob containing shows the following

Notice above that the blob container contains a folder with the same name as the Web App. The application log for the Web App, SWPBlogAnotherWebApp01, is contained in the folder of the same name. So in order to write code that read the logs for an Azure Web App, the underlying code needs to know the name of the Web App, e.g.:

string websiteName = 

A class the reads all the environment variables discussed is as follows:

using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;

using static System.Environment;

namespace SoftwarePronto.Azure.Utility.Master
     * https://github.com/projectkudu/kudu/wiki/Azure-runtime-environment
     * WEBSITE_SITE_NAME - The name of the site.
     * WEBSITE_SKU - The sku of the site 
     *   (Possible values: Free, Shared, Basic, Standard).
     * WEBSITE_COMPUTE_MODE - Specifies whether website is on a dedicated
     *   or shared VM/s (Possible values: Shared, Dedicated).
     * WEBSITE_HOSTNAME - The Azure Website's primary host name for the 
     *   site (For example: site.azurewebsites.net). Note that 
     *   custom hostnames are not accounted for here.
     * WEBSITE_INSTANCE_ID - The id representing the VM that the site 
     *   is running on (If site runs on multiple instances, 
     *   each instance will have a different id).
     * WEBSITE_NODE_DEFAULT_VERSION - The default node version this 
     *   website is using.
     * WEBSOCKET_CONCURRENT_REQUEST_LIMIT - The limit for websocket's 
     *   concurrent requests.
    public static class WebAppEnviroment
      public static string _envNameWEBSITE_SITE_NAME = 

      public static string _envNameWEBSITE_SKU = "WEBSITE_SKU";

      public static string _envNameWEBSITE_COMPUTE_MODE = 

      public static string _envNameWEBSITE_INSTANCE_ID = 

      public static string _envNameWEBSITE_NODE_DEFAULT_VERSION = 

      public static string _envNameWEBSOCKET_CONCURRENT_REQUEST_LIMIT = 

      public static string WebSiteName =>

      public static string WebSKU =>

      public static string WebSitComputeMode =>

      public static string WebSiteInstanceId =>

      public static string WebSiteNodeDefaultVersion =>

      public static string WebSiteSocketConcurrentRequestLimit =>

      public static Dictionary<string, string> Get() =>
        new Dictionary<string, string>
          [_envNameWEBSITE_SITE_NAME] = WebSiteName,
          [_envNameWEBSITE_SKU] = WebSKU,
          [_envNameWEBSITE_COMPUTE_MODE] = WebSitComputeMode,
          [_envNameWEBSITE_INSTANCE_ID] = WebSitComputeMode,

      public static string GetAsText()
        StringBuilder result = new StringBuilder();

        Get().ToList().ForEach(wsv =>
           result.AppendLine($"{wsv.Key}: {wsv.Value ?? String.Empty}"));

        return result.ToString();

The source code can be found in github.com:

The solution can be found in the SoftwarePronto.Azure.Utility.Master folder.