+ Tighten LogViewer download

+ Harden Exception handling on Remote Exception

cr: Jakub (pending)

Author: lbwexler

grails-app/controllers/io/xh/hoist/admin/cluster/LogViewerAdminController.groovy

@@ -87,19 +87,19 @@ class LogViewerAdminController extends BaseController {
             return
         }
 
-        render(
-            file: ret.value,
-            fileName: filename,
-            contentType: 'application/octet-stream'
-        )
+        render(ret)
     }
 
-    static class Download extends ClusterRequest<File> {
+    static class Download extends ClusterRequest<Map> {
         String filename
-
-        File doCall() {
+        Map doCall() {
             if (!availableFiles[filename]) throwUnavailable(filename)
-            return appContext.logReaderService.get(filename)
+            def file = appContext.logReaderService.get(filename)
+            [
+                file: file.bytes,
+                fileName: filename,
+                contentType: 'application/octet-stream'
+            ]
         }
     }
 

src/main/groovy/io/xh/hoist/cluster/ClusterRequest.groovy

@@ -1,5 +1,6 @@
 package io.xh.hoist.cluster
 
+import io.xh.hoist.exception.ClusterExecutionException
 import io.xh.hoist.exception.InstanceNotAvailableException
 import io.xh.hoist.log.LogSupport
 
@@ -17,15 +18,17 @@ abstract class ClusterRequest<T> implements Callable<ClusterResponse<T>>, LogSup
             }
             return new ClusterResponse(value: doCall())
         } catch (Throwable t) {
+            def simpleName = this.class.simpleName
             try {
                 exceptionHandler.handleException(
                     exception: t,
                     logTo: this,
-                    logMessage: [_action: this.class.simpleName]
+                    logMessage: [_action: simpleName]
                 )
             } catch (Exception e) {
-                // Even logging failing -- just catch quietly and return neatly to calling member.
+                // Don't let logging ever prevent us from returning *actual* exception to caller.
             }
+            t = new ClusterExecutionException("Failed to execute ${simpleName}: ${t.message}", t)
             return new ClusterResponse(exception: t)
         }
     }

src/main/groovy/io/xh/hoist/exception/ClusterExecutionException.groovy

@@ -0,0 +1,24 @@
+/*
+ * This file belongs to Hoist, an application development toolkit
+ * developed by Extremely Heavy Industries (www.xh.io | [email protected])
+ *
+ * Copyright © 2023 Extremely Heavy Industries Inc.
+ */
+
+package io.xh.hoist.exception
+
+
+/**
+ *  Wrapper Exception to be returned from a failed ClusterResponse.
+ *
+ *  Exceptions are supposed to be serializable but can cause problems in practice, especially in
+ *  Kryo.  Note that we have already typically logged the actual exception on remote server.
+ */
+class ClusterExecutionException extends Exception {
+    String causeName
+
+    ClusterExecutionException(String msg, Throwable t) {
+        super(msg)
+        causeName = t.class.simpleName
+    }
+}