Log functionAppVersion during initialization

Author: kamperiadis

release_notes.md

@@ -4,3 +4,4 @@
 - My change description (#PR)
 -->
 - Add JitTrace Files for v4.1046
+- Log functionAppVersion during initialization to track rolling update progress (#11527)

src/WebJobs.Script.WebHost/Diagnostics/Extensions/ScriptHostServiceLoggerExtension.cs

@@ -204,6 +204,12 @@ public static class ScriptHostServiceLoggerExtension
                 new EventId(531, nameof(RequestAborted)),
                 "The request was aborted by the client (requestId: '{mS_ActivityId}').");
 
+        private static readonly Action<ILogger, string, Exception> _logFunctionAppVersion =
+            LoggerMessage.Define<string>(
+                LogLevel.Information,
+                new EventId(532, nameof(LogFunctionAppVersion)),
+                "Running following version from app configuration update or code content deployment: '{functionAppVersion}'.");
+
         public static void HostStateChanged(this ILogger logger, ScriptHostState previousHostState, ScriptHostState newHostState)
         {
             var newState = newHostState.ToString();
@@ -251,6 +257,11 @@ public static void Initialization(this ILogger logger, int attemptCount, int sta
             _initialization(logger, attemptCount, startCount, operationId, null);
         }
 
+        public static void LogFunctionAppVersion(this ILogger logger, string functionAppVersion)
+        {
+            _logFunctionAppVersion(logger, functionAppVersion, null);
+        }
+
         public static void InStandByMode(this ILogger logger, Guid operationId)
         {
             _inStandByMode(logger, operationId, null);

src/WebJobs.Script.WebHost/Models/HostAssignmentContext.cs

@@ -24,6 +24,9 @@ public class HostAssignmentContext
         [JsonProperty("lastModifiedTime")]
         public DateTime LastModifiedTime { get; set; }
 
+        [JsonProperty("functionAppVersion")]
+        public Guid FunctionAppVersion { get; set; }
+
         [JsonProperty("MSISpecializationPayload")]
         public MSIContext MSIContext { get; set; }
 
@@ -164,6 +167,11 @@ public void ApplyAppSettings(IEnvironment environment, ILogger logger)
                 }
                 environment.SetEnvironmentVariable(EnvironmentSettingNames.EasyAuthClientId, EasyAuthSettings.SiteAuthClientId);
             }
+
+            if (FunctionAppVersion != Guid.Empty)
+            {
+                environment.SetEnvironmentVariable(EnvironmentSettingNames.FunctionAppVersion, FunctionAppVersion.ToString());
+            }
         }
     }
 }

src/WebJobs.Script.WebHost/WebJobsScriptHostService.cs

@@ -798,6 +798,13 @@ private void LogInitialization(IHost host, bool isOffline, int attemptCount, int
                 logger.InStandByMode(operationId);
             }
 
+            // Log function app version for rolling update tracking
+            var functionAppVersion = _environment.GetFunctionAppVersion();
+            if (!string.IsNullOrEmpty(functionAppVersion))
+            {
+                logger.LogFunctionAppVersion(functionAppVersion);
+            }
+
             // Log settings
             var functionWorkerRuntime = _environment.GetEnvironmentVariable(FunctionWorkerRuntime);
             var functionWorkerRuntimeVersion = _environment.GetEnvironmentVariable(RpcWorkerConstants.FunctionWorkerRuntimeVersionSettingName);

src/WebJobs.Script/Environment/EnvironmentExtensions.cs

@@ -653,6 +653,11 @@ public static string GetFunctionsWorkerRuntime(this IEnvironment environment)
             return environment.GetEnvironmentVariableOrDefault(FunctionWorkerRuntime, string.Empty);
         }
 
+        public static string GetFunctionAppVersion(this IEnvironment environment)
+        {
+            return environment.GetEnvironmentVariableOrDefault(FunctionAppVersion, string.Empty);
+        }
+
         /// <summary>
         /// Gets a value indicating whether AzureFileShare should be mounted when specializing Linux Consumption workers.
         /// </summary>

src/WebJobs.Script/Environment/EnvironmentSettingNames.cs

@@ -35,6 +35,7 @@ public static class EnvironmentSettingNames
         public const string AppInsightsAgent = "APPLICATIONINSIGHTS_ENABLE_AGENT";
         public const string FunctionsExtensionVersion = "FUNCTIONS_EXTENSION_VERSION";
         public const string FunctionWorkerRuntime = "FUNCTIONS_WORKER_RUNTIME";
+        public const string FunctionAppVersion = "FUNCTION_APP_VERSION";
         public const string WorkerProbingPaths = "WORKER_PROBING_PATHS";
         public const string ContainerName = "CONTAINER_NAME";
         public const string WebsitePodName = "WEBSITE_POD_NAME";