Only add / apply bundles configuration if file not present and file system is not readonly (#5580)

Author: soninaren

src/WebJobs.Script/Config/HostJsonFileConfigurationSource.cs

@@ -195,6 +195,9 @@ internal JObject LoadHostConfig(string configFilePath)
                         _logger.HostConfigNotFound();
 
                         hostConfigObject = GetDefaultHostConfigObject();
+
+                        // Add bundle configuration if no file exists and file system is not read only
+                        hostConfigObject = TryAddBundleConfiguration(hostConfigObject);
                         TryWriteHostJson(configFilePath, hostConfigObject);
                     }
 
@@ -204,7 +207,7 @@ internal JObject LoadHostConfig(string configFilePath)
 
             private JObject GetDefaultHostConfigObject()
             {
-                var hostJsonJObj = JObject.Parse("{'version': '2.0', 'extensionBundle': { 'id': 'Microsoft.Azure.Functions.ExtensionBundle', 'version': '[1.*, 2.0.0)'}}");
+                var hostJsonJObj = JObject.Parse("{'version': '2.0'}");
                 if (string.Equals(_configurationSource.Environment.GetEnvironmentVariable(RpcWorkerConstants.FunctionWorkerRuntimeSettingName), "powershell", StringComparison.InvariantCultureIgnoreCase)
                     && !_configurationSource.Environment.IsFileSystemReadOnly())
                 {
@@ -233,6 +236,17 @@ private void TryWriteHostJson(string filePath, JObject content)
                 }
             }
 
+            private JObject TryAddBundleConfiguration(JObject content)
+            {
+                if (!_configurationSource.Environment.IsFileSystemReadOnly())
+                {
+                    string bundleConfiguration = "{ 'id': 'Microsoft.Azure.Functions.ExtensionBundle', 'version': '[1.*, 2.0.0)'}";
+                    content.Add("extensionBundle", JToken.Parse(bundleConfiguration));
+                    _logger.AddingExtensionBundleConfiguration(bundleConfiguration);
+                }
+                return content;
+            }
+
             internal static string SanitizeHostJson(JObject hostJsonObject)
             {
                 JObject sanitizedObject = new JObject();

src/WebJobs.Script/Diagnostics/Extensions/HostLoggerExtension.cs

@@ -59,6 +59,12 @@ public static class HostLoggerExtension
             new EventId(207, nameof(DebugerManagerUnableToUpdateSentinelFile)),
             "Unable to update the debug sentinel file.");
 
+        private static readonly Action<ILogger, string, string, Exception> _addExtensionBundleConfiguration =
+           LoggerMessage.Define<string, string>(
+               LogLevel.Information,
+               new EventId(208, nameof(AddingExtensionBundleConfiguration)),
+               "Adding bundle configuration to default host configuration: {newLine}{bundleConfiguration}");
+
         public static void HostConfigApplied(this ILogger logger)
         {
             _hostConfigApplied(logger, null);
@@ -87,6 +93,12 @@ public static void HostConfigNotFound(this ILogger logger)
             _hostConfigNotFound(logger, fileName, null);
         }
 
+        public static void AddingExtensionBundleConfiguration(this ILogger logger, string bundleConfiguration)
+        {
+            string newLine = NewLine;
+            _addExtensionBundleConfiguration(logger, newLine, bundleConfiguration, null);
+        }
+
         public static void HostConfigCreationFailed(this ILogger logger)
         {
             string fileName = ScriptConstants.HostMetadataFileName;

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

@@ -18,7 +18,8 @@ namespace Microsoft.Azure.WebJobs.Script.Tests.Configuration
 {
     public class HostJsonFileConfigurationSourceTests
     {
-        private readonly string _defaultHostJson = "{\r\n  \"version\": \"2.0\",\r\n  \"extensionBundle\": {\r\n    \"id\": \"Microsoft.Azure.Functions.ExtensionBundle\",\r\n    \"version\": \"[1.*, 2.0.0)\"\r\n  }\r\n}";
+        private readonly string _hostJsonWithBundles = "{\r\n  \"version\": \"2.0\",\r\n  \"extensionBundle\": {\r\n    \"id\": \"Microsoft.Azure.Functions.ExtensionBundle\",\r\n    \"version\": \"[1.*, 2.0.0)\"\r\n  }\r\n}";
+        private readonly string _defaultHostJson = "{\r\n  \"version\": \"2.0\"\r\n}";
         private readonly ScriptApplicationHostOptions _options;
         private readonly string _hostJsonFile;
         private readonly TestLoggerProvider _loggerProvider = new TestLoggerProvider();
@@ -55,7 +56,7 @@ public void MissingHostJson_CreatesDefaultFile()
 
             AreExpectedMetricsGenerated(testMetricsLogger);
 
-            Assert.Equal(_defaultHostJson, File.ReadAllText(_hostJsonFile));
+            Assert.Equal(_hostJsonWithBundles, File.ReadAllText(_hostJsonFile));
 
             var log = _loggerProvider.GetAllLogMessages().Single(l => l.FormattedMessage == "No host configuration file found. Creating a default host.json file.");
             Assert.Equal(LogLevel.Information, log.Level);
@@ -108,7 +109,10 @@ public void ReadOnlyFileSystem_SkipsDefaultHostJsonCreation()
             TestMetricsLogger testMetricsLogger = new TestMetricsLogger();
             IConfiguration config = BuildHostJsonConfiguration(testMetricsLogger, environment);
             AreExpectedMetricsGenerated(testMetricsLogger);
+            var configList = config.AsEnumerable().ToList();
             Assert.Equal(config["AzureFunctionsJobHost:version"], "2.0");
+            Assert.Equal(configList.Count, 2);
+            Assert.True(configList.TrueForAll((k) => !k.Key.Contains("extensionBundle")));
 
             var log = _loggerProvider.GetAllLogMessages().Single(l => l.FormattedMessage == "No host configuration file found. Creating a default host.json file.");
             Assert.Equal(LogLevel.Information, log.Level);