Log warning message if 'set_if' argument cannot be evaluated properly

fixes #6968

lib/icinga/pluginutility.cpp

@@ -94,8 +94,17 @@ void PluginUtility::ExecuteCommand(const Command::Ptr& commandObj, const Checkab
 					String set_if_resolved = MacroProcessor::ResolveMacros(set_if, macroResolvers,
 						cr, &missingMacro);
 
-					if (!missingMacro.IsEmpty() || !Convert::ToLong(set_if_resolved))
+					if (!missingMacro.IsEmpty())
 						continue;
+
+					try {
+						if (!Convert::ToLong(set_if_resolved))
+							continue;
+					} catch (const std::exception& ex) {
+						/* tried to convert a string */
+						Log(LogWarning, "PluginUtility", "Error evaluating set_if value '" + set_if_resolved + "': " + ex.what());
+						continue;
+					}
 				}
 			}
 			else
@@ -213,10 +222,10 @@ Value PluginUtility::ParsePerfdata(const String& perfdata)
 {
 	try {
 		Dictionary::Ptr result = make_shared<Dictionary>();
-	
+
 		size_t begin = 0;
 		String multi_prefix;
-		
+
 		for (;;) {
 			size_t eqp = perfdata.FindFirstOf('=', begin);
 

test/config/6968.conf

@@ -0,0 +1,28 @@
+object Host "6968-server" {
+  import "test-generic-host"
+  address = "127.0.0.1"
+}
+
+object Service "6968-test" {
+  import "test-generic-service"
+
+  host_name = "6968-server"
+  check_command = "6968-check_vmware"
+  vars.vmware_check = "vCenter_License_Status"
+}
+
+object CheckCommand "6968-check_vmware" {
+  import "plugin-check-command"
+
+  command = [ PluginDir + "/check_vmware.pl" ]
+  arguments = {
+    "--server" = "$address$" 
+    "--username" = "***" 
+    "--password" = "***" 
+    "--check" = { 
+      set_if = "$vmware_check$" 
+    }
+  }
+}
+
+