Derive host Id from hostName for Linux consumption (#5507)

Author: divyagandhisethi

src/WebJobs.Script/Host/ScriptHostIdProvider.cs

@@ -48,8 +48,9 @@ internal static string GetDefaultHostId(IEnvironment environment, ScriptApplicat
             }
             else if (environment.IsLinuxConsumption())
             {
-                // The hostid is derived from the unique container name for Linux consumption.
-                hostId = environment.GetEnvironmentVariable(EnvironmentSettingNames.ContainerName);
+                // The hostid is derived from the hostname for Linux consumption.
+                string hostName = environment.GetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteHostName);
+                hostId = hostName?.Replace(".azurewebsites.net", string.Empty);
             }
             else
             {

test/WebJobs.Script.Tests.Integration/Host/StandbyManager/StandbyManagerE2ETests_Linux.cs

@@ -38,6 +38,7 @@ public async Task StandbyModeE2E_LinuxContainer()
             {
                 { EnvironmentSettingNames.AzureWebsitePlaceholderMode, "1" },
                 { EnvironmentSettingNames.ContainerName, containerName },
+                { EnvironmentSettingNames.AzureWebsiteHostName, "testapp.azurewebsites.net" },
                 { EnvironmentSettingNames.AzureWebsiteName, "TestApp" },
                 { EnvironmentSettingNames.ContainerEncryptionKey, encryptionKey },
                 { EnvironmentSettingNames.AzureWebsiteContainerReady, null },
@@ -97,7 +98,7 @@ public async Task StandbyModeE2E_LinuxContainer()
             response = await _httpClient.SendAsync(request);
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
 
-            string hostId = containerName.ToLowerInvariant();
+            string hostId = "testapp";
 
             // verify the expected logs
             var logLines = _loggerProvider.GetAllLogMessages().Where(p => p.FormattedMessage != null).Select(p => p.FormattedMessage).ToArray();

test/WebJobs.Script.Tests/ScriptHostIdProviderTests.cs

@@ -40,7 +40,7 @@ public async Task GetHostIdAsync_WithConfigurationHostId_ReturnsConfigurationHos
         [InlineData("TEST-FUNCTIONS--", "123123", "test-functions")]
         [InlineData("TEST-FUNCTIONS-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", "123123", "test-functions-xxxxxxxxxxxxxxxxx")]
         [InlineData("TEST-FUNCTIONS-XXXXXXXXXXXXXXXX-XXXX", "123123", "test-functions-xxxxxxxxxxxxxxxx")] /* 32nd character is a '-' */
-        [InlineData("TEST-FUNCTIONS-XXXXXXXXXXXXXXXX-XXXX", null, "f6c34226-637100850484032865")] // Linux consumption scenario where host id will be derived from the container name.
+        [InlineData("TEST-FUNCTIONS-XXXXXXXXXXXXXXXX-XXXX", null, "testsite")] // Linux consumption scenario where host id will be derived from the host name.
         [InlineData(null, "123123", null)]
         public void GetDefaultHostId_AzureHost_ReturnsExpectedResult(string siteName, string azureWebsiteInstanceId, string expected)
         {
@@ -52,7 +52,8 @@ public void GetDefaultHostId_AzureHost_ReturnsExpectedResult(string siteName, st
             var environment = new TestEnvironment();
             environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteInstanceId, azureWebsiteInstanceId);
             environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteName, siteName);
-            environment.SetEnvironmentVariable(EnvironmentSettingNames.ContainerName, "F6C34226-637100850484032865");
+            environment.SetEnvironmentVariable(EnvironmentSettingNames.ContainerName, "testContainer");
+            environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteHostName, "testsite.azurewebsites.net");
             string hostId = ScriptHostIdProvider.GetDefaultHostId(environment, options);
             Assert.Equal(expected, hostId);
         }