Add error details to RunFromPackage failure log (#9094)

* add file contents to log

* pr feedback

* Update release_notes.md

* consolidate log statements

Author: madelinegordon

release_notes.md

@@ -14,6 +14,7 @@
 - Update custom handlers to support trigger return values (#8874)
 - Send Workerwarmup request to warm up the worker code path before specialization (#9018)
 - Update PowerShell Worker 7.2 to 4.0.2673 [Release Note](https://github.com/Azure/azure-functions-powershell-worker/releases/tag/v4.0.2673)
+- Add error details to RunFromPackage failure log (#9094)
 
-**Release sprint:** Sprint 138
-[ [bugs](https://github.com/Azure/azure-functions-host/issues?q=is%3Aissue+milestone%3A%22Functions+Sprint+138%22+label%3Abug+is%3Aclosed) | [features](https://github.com/Azure/azure-functions-host/issues?q=is%3Aissue+milestone%3A%22Functions+Sprint+138%22+label%3Afeature+is%3Aclosed) ]
+**Release sprint:** Sprint 139
+[ [bugs](https://github.com/Azure/azure-functions-host/issues?q=is%3Aissue+milestone%3A%22Functions+Sprint+139%22+label%3Abug+is%3Aclosed) | [features](https://github.com/Azure/azure-functions-host/issues?q=is%3Aissue+milestone%3A%22Functions+Sprint+139%22+label%3Afeature+is%3Aclosed) ]

src/WebJobs.Script.WebHost/WebJobsScriptHostService.cs

@@ -200,9 +200,24 @@ private void CheckFileSystem()
                 // Check for marker file indicating a zip package failure, and if found stop the application.
                 // We never want to run with an incorrect file system.
                 string path = Path.Combine(_applicationHostOptions.CurrentValue.ScriptPath, ScriptConstants.RunFromPackageFailedFileName);
+
                 if (File.Exists(path))
                 {
-                    _logger.LogError($"Shutting down host due to presence of {path}");
+                    string errorPrefix = $"Shutting down host due to presence of {path}.";
+                    string errorSuffix = string.Empty;
+                    try
+                    {
+                        string fileContent = File.ReadAllText(path);
+                        errorSuffix = $" File content: {fileContent}";
+                    }
+                    catch (Exception ex)
+                    {
+                        errorSuffix = $" Error reading {ScriptConstants.RunFromPackageFailedFileName} file content: {ex.Message}";
+                    }
+                    finally
+                    {
+                        _logger.LogError(errorPrefix + errorSuffix);
+                    }
                     _applicationLifetime.StopApplication();
                 }
             }