Make warmup execute once (#5137)

Author: ankitkumarr

src/WebJobs.Script.WebHost/Controllers/HostController.cs

@@ -48,6 +48,7 @@ public class HostController : Controller
         private readonly IEnvironment _environment;
         private readonly IScriptHostManager _scriptHostManager;
         private readonly IFunctionsSyncManager _functionsSyncManager;
+        private static int _warmupExecuted;
 
         public HostController(IOptions<ScriptApplicationHostOptions> applicationHostOptions,
             IOptions<JobHostOptions> hostOptions,
@@ -292,10 +293,20 @@ public IActionResult GetAdminToken()
         [HttpGet]
         [HttpPost]
         [Route("admin/warmup")]
-        [Authorize(Policy = PolicyNames.AdminAuthLevelOrInternal)]
         [RequiresRunningHost]
         public async Task<IActionResult> Warmup([FromServices] WebJobsScriptHostService hostService)
         {
+            // Endpoint only for Windows Elastic Premium or Linux App Service plans
+            if (!(_environment.IsLinuxAppService() || _environment.IsWindowsElasticPremium()))
+            {
+                return BadRequest("This API is not available for the current hosting plan");
+            }
+
+            if (Interlocked.CompareExchange(ref _warmupExecuted, 1, 0) != 0)
+            {
+                return Ok();
+            }
+
             var jobHost = hostService.Services?.GetService<IScriptJobHost>();
             if (jobHost == null)
             {

src/WebJobs.Script/Config/ScriptSettingsManager.cs

@@ -39,6 +39,8 @@ public static ScriptSettingsManager Instance
 
         public bool IsDynamicSku => WebsiteSku == ScriptConstants.DynamicSku;
 
+        public bool IsElasticPremiumSku => WebsiteSku == ScriptConstants.ElasticPremiumSku;
+
         public virtual string AzureWebsiteInstanceId
          {
              get

src/WebJobs.Script/Environment/EnvironmentExtensions.cs

@@ -134,6 +134,18 @@ public static bool IsWindowsConsumption(this IEnvironment environment)
             return string.Equals(value, ScriptConstants.DynamicSku, StringComparison.OrdinalIgnoreCase);
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the application is running in a Windows Elastic Premium
+        /// App Service environment.
+        /// </summary>
+        /// <param name="environment">The environment to verify</param>
+        /// <returns><see cref="true"/> if running in a Windows Elastic Premium app; otherwise, false.</returns>
+        public static bool IsWindowsElasticPremium(this IEnvironment environment)
+        {
+            string value = environment.GetEnvironmentVariable(AzureWebsiteSku);
+            return string.Equals(value, ScriptConstants.ElasticPremiumSku, StringComparison.OrdinalIgnoreCase);
+        }
+
         /// <summary>
         /// Gets a value indicating whether the application is running in an Azure Windows managed hosting environment
         /// (i.e. Windows Consumption or Windows Dedicated)

src/WebJobs.Script/ScriptConstants.cs

@@ -88,6 +88,7 @@ public static class ScriptConstants
         public const string AntaresColdStartHeaderName = "X-MS-COLDSTART";
         public const string SiteTokenHeaderName = "x-ms-site-restricted-token";
         public const string DynamicSku = "Dynamic";
+        public const string ElasticPremiumSku = "ElasticPremium";
         public const string DefaultProductionSlotName = "production";
 
         public const string AzureProxyFunctionLocalRedirectKey = "MS_ProxyLocalRedirectCount";

test/WebJobs.Script.Tests.Integration/Controllers/WarmupScenarios.cs

@@ -32,12 +32,17 @@ public async Task TestWarmupEndPoint_WhenHostStarts()
         {
             string testScriptPath = Path.Combine("TestScripts", "CSharp");
             string testLogPath = Path.Combine(TestHelpers.FunctionsTestDirectory, "Logs", Guid.NewGuid().ToString(), @"Functions");
+            var settings = new Dictionary<string, string>()
+            {
+                ["WEBSITE_SKU"] = "ElasticPremium"
+            };
+            var testEnvironment = new TestEnvironment(settings);
 
             _testHost = new TestFunctionHost(testScriptPath, testLogPath,
             configureWebHostServices: services =>
             {
                 services.AddSingleton<IScriptHostBuilder, PausingScriptHostBuilder>();
-
+                services.AddSingleton<IEnvironment>(testEnvironment);
                 services.AddSingleton<IConfigureBuilder<IWebJobsBuilder>>(new DelegatedConfigureBuilder<IWebJobsBuilder>(b =>
                 {
                     b.UseHostId("1234");
@@ -64,8 +69,7 @@ public async Task TestWarmupEndPoint_WhenHostStarts()
 
             // Let's make the warmup request and not wait for it to finish,
             // as warmup call needs the host to be running while the host is currently paused
-            string masterKey = await _testHost.GetMasterKeyAsync();
-            string uri = $"admin/warmup?code={masterKey}";
+            string uri = "admin/warmup";
             HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, uri);
             Task<HttpResponseMessage> responseTask = _testHost.HttpClient.SendAsync(request);