feat: concurrently check and update all domains (#24)

Reviewed-on: #24
Co-authored-by: Timo Behrendt <t.behrendt@t00n.de>
Co-committed-by: Timo Behrendt <t.behrendt@t00n.de>

pkg/realDynDns/realDynDns.go

@@ -3,6 +3,7 @@ package realDynDns
 import (
 	"fmt"
 	"log/slog"
+	"sync"
 	"time"
 
 	"realdnydns/pkg/config"
@@ -70,10 +71,17 @@ func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
 		return 0, err
 	}
 
-	var numberUpdated int
+	var wg sync.WaitGroup
+
+	numberUpdatedChannel := make(chan int)
 
 	for _, domain := range c.domains {
 		for _, subdomain := range domain.Subdomains {
+			wg.Add(1)
+
+			go func(domain config.DomainConfig, subdomain string) {
+				defer wg.Done()
+
 				c.logger.Info("Checking record",
 					slog.String("tld", domain.TLD),
 					slog.String("subdomain", subdomain),
@@ -85,7 +93,7 @@ func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
 						slog.String("tld", domain.TLD),
 						slog.String("subdomain", subdomain),
 					)
-				continue
+					return
 				}
 
 				if currentRecord.IP != externalIp.String() {
@@ -104,7 +112,7 @@ func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
 						c.logger.Warn("Failed to send notification",
 							slog.String("error", err.Error()),
 						)
-					continue
+						return
 					}
 
 					c.logger.Info("Updating record",
@@ -120,11 +128,23 @@ func (c *ChangeDetector) detectAndApplyChanges() (int, error) {
 							slog.String("tld", domain.TLD),
 							slog.String("subdomain", subdomain),
 						)
-					continue
+						return
 					}
-				numberUpdated++
+
+					numberUpdatedChannel <- 1
+				}
+			}(domain, subdomain)
 		}
 	}
+
+	go func() {
+		wg.Wait()
+		close(numberUpdatedChannel)
+	}()
+
+	numberUpdated := 0
+	for v := range numberUpdatedChannel {
+		numberUpdated += v
 	}
 
 	c.logger.Info("Run completed", slog.Int("number_of_changes", numberUpdated))