WIP

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/dns/write.go

@@ -0,0 +1,134 @@
+package dns
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/netip"
+	"sort"
+	"time"
+
+	"darvaza.org/core"
+	"github.com/libdns/libdns"
+)
+
+func (mgr *Manager) WriteTo(w io.Writer) (int64, error) {
+	var buf bytes.Buffer
+
+	var zones sort.StringSlice
+
+	// sort zones
+	for name := range mgr.zones {
+		zones = append(zones, name)
+	}
+	sort.Sort(zones)
+
+	for _, name := range zones {
+		z := mgr.zones[name]
+
+		if buf.Len() > 0 {
+			_, _ = buf.WriteRune('\n')
+		}
+
+		// servers
+		err := mgr.writeZoneMachinesToBuffer(&buf, name, z)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	return buf.WriteTo(w)
+}
+
+func (mgr *Manager) writeRecordsToBuffer(buf *bytes.Buffer, records ...libdns.Record) {
+	for _, rr := range records {
+		fqdn := fmt.Sprintf("%s.%s", rr.Name, mgr.domain)
+
+		_, _ = fmt.Fprintf(buf, "%s\t%v\tIN\t%s\t%v\n",
+			fqdn, int(rr.TTL/time.Second), rr.Type, rr.Value)
+	}
+}
+
+func (mgr *Manager) writeZoneMachinesToBuffer(buf *bytes.Buffer, zone_name string, z *Zone) error {
+	// title
+	_, _ = fmt.Fprintf(buf, ";\n; %s\n;\n", zone_name)
+
+	records := mgr.genMachineRecords(z)
+	mgr.writeRecordsToBuffer(buf, records...)
+
+	// zone alias
+	_, _ = fmt.Fprintf(buf, "; %s\n", zone_name)
+	records = mgr.genAliasRecords(zone_name, true, z)
+	mgr.Sort(records)
+	mgr.writeRecordsToBuffer(buf, records...)
+
+	return nil
+}
+
+func (mgr *Manager) genMachineRecords(z *Zone) []libdns.Record {
+	var out []libdns.Record
+
+	for _, p := range z.Machines {
+		pqdn := fmt.Sprintf("%s-%v%s", z.Name, p.ID, mgr.suffix)
+
+		for _, addr := range p.Addrs {
+			out = append(out, libdns.Record{
+				Name:  pqdn,
+				Type:  core.IIf(addr.Is6(), "AAAA", "A"),
+				TTL:   time.Second,
+				Value: addr.String(),
+			})
+		}
+	}
+
+	mgr.Sort(out)
+	return out
+}
+
+func (mgr *Manager) genAliasRecords(name string, activeOnly bool, zones ...*Zone) []libdns.Record {
+	var out []libdns.Record
+
+	fqdn := fmt.Sprintf("%s%s", name, mgr.suffix)
+	for _, z := range zones {
+		for _, p := range z.Machines {
+			if p.Active || !activeOnly {
+				for _, addr := range p.Addrs {
+					out = append(out, libdns.Record{
+						Name:  fqdn,
+						Type:  core.IIf(addr.Is6(), "AAAA", "A"),
+						TTL:   time.Second,
+						Value: addr.String(),
+					})
+				}
+			}
+		}
+	}
+
+	return out
+}
+
+func (mgr *Manager) Sort(records []libdns.Record) {
+	sort.SliceStable(records, func(i, j int) bool {
+		a := &records[i]
+		b := &records[j]
+		switch {
+		case a.Name < b.Name:
+			return true
+		case a.Name > b.Name:
+			return false
+		case a.Type < b.Type:
+			return true
+		case a.Type > b.Type:
+			return false
+		case a.Type == "A" || a.Type == "AAAA":
+			var aAddr, bAddr netip.Addr
+			aAddr.UnmarshalText([]byte(a.Value))
+			bAddr.UnmarshalText([]byte(b.Value))
+			return aAddr.Less(bAddr)
+		case a.Value < b.Value:
+			return true
+		default:
+			return false
+		}
+	})
+}