hiding Azure Monitor behind app setting

Author: brettsam

src/WebJobs.Script.WebHost/WebScriptHostBuilderExtension.cs

@@ -57,7 +57,12 @@ public static IHostBuilder AddWebScriptHost(this IHostBuilder builder, IServiceP
                         IEnvironment environment = services.GetService<IEnvironment>();
                         IScriptWebHostEnvironment hostEnvironment = services.GetService<IScriptWebHostEnvironment>();
 
-                        if (!hostEnvironment.InStandbyMode &&
+                        // Temporarily hide Azure Monitor support behind an app setting.
+                        string monitorSetting = environment.GetEnvironmentVariable("AZURE_MONITOR_ENABLED");
+                        bool.TryParse(monitorSetting, out bool monitorenabled);
+
+                        if (monitorenabled &&
+                            !hostEnvironment.InStandbyMode &&
                             !string.IsNullOrEmpty(environment.GetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteHostName)))
                         {
                             IEventGenerator eventGenerator = services.GetService<IEventGenerator>();

test/WebJobs.Script.Tests/Configuration/LoggingConfigurationTests.cs

@@ -256,7 +256,7 @@ public void LoggerProviders_ApplicationInsights()
         }
 
         [Fact]
-        public void LoggerProviders_AzureMonitor()
+        public void LoggerProviders_AzureMonitor_NoAppSetting()
         {
             IHost host = new HostBuilder()
               .ConfigureDefaultTestWebScriptHost()
@@ -275,7 +275,43 @@ public void LoggerProviders_AzureMonitor()
             loggerProviders.OfType<HostFileLoggerProvider>().Single();
             loggerProviders.OfType<FunctionFileLoggerProvider>().Single();
             loggerProviders.OfType<UserLogMetricsLoggerProvider>().Single();
-            loggerProviders.OfType<AzureMonitorDiagnosticLoggerProvider>().Single();
+            loggerProviders.OfType<NullLoggerProvider>().Single();
+        }
+
+        [Theory]
+        [InlineData("1", false)] // only true/false are parsed
+        [InlineData("true", true)]
+        [InlineData("false", false)]
+        [InlineData("nonsense", false)]
+        public void LoggerProviders_AzureMonitor_AppSetting(string appSettingValue, bool expected)
+        {
+            IHost host = new HostBuilder()
+              .ConfigureDefaultTestWebScriptHost()
+              .ConfigureServices(s =>
+              {
+                  TestEnvironment environment = new TestEnvironment();
+                  environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteHostName, "something.azurewebsites.net");
+                  environment.SetEnvironmentVariable("AZURE_MONITOR_ENABLED", appSettingValue);
+                  s.AddSingleton<IEnvironment>(environment);
+              })
+              .Build();
+
+            IEnumerable<ILoggerProvider> loggerProviders = host.Services.GetService<IEnumerable<ILoggerProvider>>();
+
+            Assert.Equal(5, loggerProviders.Count());
+            loggerProviders.OfType<SystemLoggerProvider>().Single();
+            loggerProviders.OfType<HostFileLoggerProvider>().Single();
+            loggerProviders.OfType<FunctionFileLoggerProvider>().Single();
+            loggerProviders.OfType<UserLogMetricsLoggerProvider>().Single();
+
+            if (expected)
+            {
+                loggerProviders.OfType<AzureMonitorDiagnosticLoggerProvider>().Single();
+            }
+            else
+            {
+                loggerProviders.OfType<NullLoggerProvider>().Single();
+            }
         }
     }
 }