Merge pull request #256 from martinlindhe/mssql-clean-instance-names

Strip special chars from instance names

README.md

@@ -76,7 +76,10 @@ The prometheus metrics will be exposed on [localhost:9182](http://localhost:9182
 
     .\wmi_exporter.exe --collectors.enabled "process" --collector.process.processes-where "Name LIKE 'firefox%'"
 
-When there are multiple processes with the same name, WMI represents those after the first instance as `process-name#index`. So to get them all, rather than just the first one, the query needs to be a wildcard search.
+When there are multiple processes with the same name, WMI represents those after the first instance as `process-name#index`. So to get them all, rather than just the first one, the query needs to be a wildcard search using a `%` character.
+
+Please note that in Windows batch scripts (and when using the `cmd` command prompt), the `%` character is reserved, so it has to be escaped with another `%`. For example, the wildcard syntax for searching for all firefox processes is `firefox%%`.
+
 
 ## License
 

collector/mssql.go

@@ -66,7 +66,7 @@ func getMSSQLInstances() mssqlInstancesType {
 
 	instanceNames, err := k.ReadValueNames(0)
 	if err != nil {
-		log.Warn("Can't ReadSubKeyNames %#v", err)
+		log.Warnf("Can't ReadSubKeyNames %#v", err)
 		return sqlDefaultInstance
 	}
 
@@ -87,7 +87,15 @@ func getMSSQLInstances() mssqlInstancesType {
 func mssqlBuildWMIInstanceClass(suffix string, instance string) string {
 	instancePart := "MSSQLSERVER_SQLServer"
 	if instance != "MSSQLSERVER" {
-		instancePart = fmt.Sprintf("MSSQL%s_MSSQL%s", instance, instance)
+		// Instance names can contain some special characters, which are not supported in the WMI class name.
+		// We strip those out.
+		cleanedName := strings.Map(func(r rune) rune {
+			if r == '_' || r == '$' || r == '#' {
+				return -1
+			}
+			return r
+		}, instance)
+		instancePart = fmt.Sprintf("MSSQL%s_MSSQL%s", cleanedName, cleanedName)
 	}
 
 	return fmt.Sprintf("Win32_PerfRawData_%s%s", instancePart, suffix)