How to scale out web app base on custom metrics - JackyChiou/jackychiou.github.io GitHub Wiki

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.Azure.Management.ResourceManager.Fluent;
using Microsoft.IdentityModel.Clients.ActiveDirectory;
using Microsoft.Rest;
using System.Linq;
 
namespace ScaleWebAppFunction
{
    public static class Function1
    {
        [FunctionName("ScaleWebApp")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");
 
            int capacity;
 
            if (!string.IsNullOrEmpty(req.Query["capacity"]) && int.TryParse(req.Query["capacity"], out capacity))
            {
                log.LogInformation("You want to chagne the capacity to "+ capacity.ToString());
                // Step1. How to: Use the portal to create an Azure AD application and service principal that can access resources
                //      https://docs.microsoft.com/en-us/azure/active-directory/develop/howto-create-service-principal-portal
 
                // Step2. How to: Add app roles in your application and receive them in the token
                //      https://docs.microsoft.com/en-us/azure/active-directory/develop/howto-add-app-roles-in-azure-ad-apps
                // For security concerns, I only give the resource group => contributor 
                //                          and the service plan read permission
 
                var subscriptionId = "Your subscription id";
                var appId = "e6f6d231-Your-App_id";
                var secretKey = "2z]pj0vy2JRapjo:R@TJSoW1AmOCC=o8";
                var tenantId = "72f988bf-Your-Tenant-Id";
                var resourceGroup = "jackywebl1rg";
                var servicePlanName = "ASP-jackywebl1rg-81ee";
 
 
                // Step 3. change capacity
                var context = new AuthenticationContext("https://login.windows.net/" + tenantId);
                ClientCredential clientCredential = new ClientCredential(appId, secretKey);
                var tokenResponse = context.AcquireTokenAsync("https://management.azure.com/", clientCredential).Result;
                var accessToken = tokenResponse.AccessToken;
                TokenCredentials credential = new TokenCredentials(accessToken);
                var webSiteManagementClient = new Microsoft.Azure.Management.WebSites.WebSiteManagementClient(credential);
                webSiteManagementClient.SubscriptionId = subscriptionId;
                var servicePlan = webSiteManagementClient.AppServicePlans.ListByResourceGroupWithHttpMessagesAsync(resourceGroup).Result.Body.Where(x => x.Name.Equals(servicePlanName)).FirstOrDefault();
 
                var appServicePlanRequest = await webSiteManagementClient.AppServicePlans.ListByResourceGroupWithHttpMessagesAsync(resourceGroup);
                appServicePlanRequest.Body.ToList().ForEach(x => log.LogInformation($">>>{x.Name}"));
                var appServicePlan = appServicePlanRequest.Body.Where(x => x.Name.Equals(servicePlanName)).FirstOrDefault();
                if (appServicePlan == null)
                {
                    log.LogError("Could not find app service plan.");
                }
 
                //scale up/down
                //servicePlan.Sku.Family = "P";
                //servicePlan.Sku.Name = "P1v2";
                //servicePlan.Sku.Size = "P1v2";
                //servicePlan.Sku.Tier = "PremiumV2";
                servicePlan.Sku.Capacity = capacity; // scale out: number of instances 
                var updateResult = webSiteManagementClient.AppServicePlans.CreateOrUpdateWithHttpMessagesAsync(resourceGroup, servicePlanName, servicePlan).Result;
                log.LogInformation("Completed!!");
                return (ActionResult)new OkObjectResult($"Hello, {capacity} {updateResult.Response.StatusCode}");
            }
            else
            {
                return new BadRequestObjectResult("Please pass a capacity on the query string or in the request body");
            }
            
        }
    }
}