--- a/pkg/models/extservices.go	Sat Aug 06 00:46:21 2022 +0200
+++ b/pkg/models/extservices.go	Sat Aug 06 02:09:57 2022 +0200
@@ -23,22 +23,27 @@
 	"gemma.intevation.de/gemma/pkg/log"
 )
 
+// ExtEntry is an external WFS service.
 type ExtEntry struct {
 	Name string `json:"name"`
 	URL  string `json:"url"`
 	WFS  bool   `json:"wfs"`
 }
 
+// ExtServices is a list of the external services.
 type ExtServices struct {
 	mu      sync.Mutex
 	entries []ExtEntry
 }
 
+// ExternalServices is the list of external services
+// the Gemma server manages as proxies.
 var ExternalServices = &ExtServices{}
 
 const selectExternalServices = `SELECT local_name, remote_url, is_wfs
 FROM sys_admin.external_services ORDER BY local_name`
 
+// Find looks for a specific configures external service.
 func (es *ExtServices) Find(name string) (string, bool) {
 	es.mu.Lock()
 	defer es.mu.Unlock()
@@ -84,16 +89,24 @@
 		})
 }
 
+// Invalidate invalidate the list of external services.
 func (es *ExtServices) Invalidate() {
 	es.mu.Lock()
 	es.entries = nil
 	es.mu.Unlock()
 }
 
-func ExternalAll(ExtEntry) bool       { return true }
+// ExternalAll passes all external entries as filter.
+func ExternalAll(ExtEntry) bool { return true }
+
+// ExternalWMS passes only external entries which are not WFSs.
 func ExternalWMS(entry ExtEntry) bool { return !entry.WFS }
+
+// ExternalWFS passes only external enteries which are WFS.
 func ExternalWFS(entry ExtEntry) bool { return entry.WFS }
 
+// Filter returns a list of external services which met
+// the condition of the given accept filter.
 func (es *ExtServices) Filter(accept func(ExtEntry) bool) []ExtEntry {
 	es.mu.Lock()
 	defer es.mu.Unlock()