Merge pull request apache#527 from shapeblue/template_qcow2_validation

Template QCOW2 validation: added validation whether template file exists before validating template format.

Author: mprokopchuk

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStorageProcessor.java

@@ -2386,8 +2386,16 @@ public Answer handleDownloadTemplateToPrimaryStorage(DirectDownloadCommand cmd)
 
             template = storagePoolMgr.createPhysicalDiskFromDirectDownloadTemplate(tempFilePath, destTemplatePath, destPool, cmd.getFormat(), cmd.getWaitInMillSeconds());
 
-            String templatePath = template.getPath();
-            if (templatePath != null) {
+            String templatePath = null;
+            if (template != null) {
+                templatePath = template.getPath();
+            }
+            //Check template path is not empty and points to existing local file to validate
+            if (StringUtils.isEmpty(templatePath)) {
+                s_logger.warn(String.format("Skipped validation whether downloaded file is QCOW2 due to downloaded template path is empty for template %s", template.getName()));
+            } else if (!new File(templatePath).exists()) {
+                s_logger.warn(String.format("Skipped validation whether downloaded file for %s is QCOW2 due to downloaded template path is not valid: %s", template.getName(), templatePath));
+            } else {
                 try {
                     Qcow2Inspector.validateQcow2File(templatePath);
                 } catch (RuntimeException e) {