feat: init commit with main func

reconcile.go

@@ -0,0 +1,103 @@
+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"sync"
+)
+
+// reconcileMu ensures only one reconcile runs at a time.
+// TryLock is used so that concurrent triggers simply skip rather than queue.
+var reconcileMu sync.Mutex
+
+// Reconcile is the core reconciliation loop:
+//  1. Fetches the active router list from Traefik (source of truth).
+//  2. Pulls the DNS repository to ensure it is up to date.
+//  3. Writes desired zone files for each managed zone.
+//  4. Commits and pushes if anything changed.
+//
+// If Traefik is unreachable or git pull fails, the reconcile is aborted
+// without modifying any DNS files (safe-fail behaviour).
+func Reconcile(cfg *Config) {
+	if !reconcileMu.TryLock() {
+		slog.Info("reconcile already in progress, skipping")
+		return
+	}
+	defer reconcileMu.Unlock()
+
+	slog.Info("reconcile started")
+
+	routers, err := FetchRouters(cfg)
+	if err != nil {
+		slog.Error("failed to fetch Traefik routers — skipping reconcile to avoid stale DNS removal",
+			"error", err)
+		return
+	}
+	slog.Info("fetched routers from Traefik", "count", len(routers))
+
+	desired := FilterDomains(routers, cfg)
+
+	if err := GitPull(cfg); err != nil {
+		slog.Error("git pull failed — skipping reconcile", "error", err)
+		return
+	}
+
+	var total RecordStats
+	for zone, subdomains := range desired {
+		path := ZoneFilePath(cfg, zone)
+
+		current, err := ReadZoneFile(path)
+		if err != nil {
+			slog.Error("failed to read zone file", "zone", zone, "error", err)
+			return
+		}
+
+		newZF := BuildZoneFile(subdomains, cfg)
+		stats := DiffZoneFile(current, newZF)
+		total.Added += stats.Added
+		total.Removed += stats.Removed
+		total.Changed += stats.Changed
+
+		if err := WriteZoneFile(path, newZF); err != nil {
+			slog.Error("failed to write zone file", "zone", zone, "error", err)
+			return
+		}
+
+		if stats.Added+stats.Removed+stats.Changed > 0 {
+			slog.Info("zone updated",
+				"zone", zone,
+				"records", len(subdomains),
+				"added", stats.Added,
+				"removed", stats.Removed,
+				"changed", stats.Changed,
+			)
+		} else {
+			slog.Info("zone unchanged", "zone", zone, "records", len(subdomains))
+		}
+	}
+
+	changed, err := GitStatusChanged(cfg)
+	if err != nil {
+		slog.Error("git status check failed", "error", err)
+		return
+	}
+	if !changed {
+		slog.Info("reconcile complete — no changes to commit")
+		return
+	}
+
+	msg := fmt.Sprintf(
+		"chore(dns): reconcile dynamic records from traefik\n\nadded: %d, removed: %d, updated: %d",
+		total.Added, total.Removed, total.Changed,
+	)
+	if err := GitCommitAndPush(cfg, msg); err != nil {
+		slog.Error("failed to commit/push DNS changes", "error", err)
+		return
+	}
+
+	slog.Info("reconcile complete — changes pushed",
+		"added", total.Added,
+		"removed", total.Removed,
+		"updated", total.Changed,
+	)
+}