initial commit

internal/app/settings.go

@@ -0,0 +1,122 @@
+package app
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/owen/vibedns/internal/auditlog"
+	"github.com/owen/vibedns/internal/config"
+)
+
+// RestartRequired lists the settings that only take effect after a restart,
+// because they control a bound socket.
+var RestartRequired = map[string]string{
+	config.KeyDNSUDPListen: "DNS UDP listen address",
+	config.KeyDNSTCPListen: "DNS TCP listen address",
+	config.KeyHTTPListen:   "Management HTTP listen address",
+}
+
+// SettingsGroup names a page of the settings interface.
+type SettingsGroup string
+
+// Settings pages.
+const (
+	GroupDNS       SettingsGroup = "dns"
+	GroupResolver  SettingsGroup = "resolver"
+	GroupCache     SettingsGroup = "cache"
+	GroupLogging   SettingsGroup = "logging"
+	GroupHTTP      SettingsGroup = "http"
+	GroupBackup    SettingsGroup = "backup"
+	GroupRateLimit SettingsGroup = "ratelimit"
+)
+
+// SaveSettings validates and persists a complete settings object.
+//
+// Validation runs against the merged result rather than the submitted fields,
+// so a change that would leave the server in an unusable state — recursion on
+// with no upstreams, or an empty ACL — is rejected before it is stored.
+func (a *App) SaveSettings(ctx context.Context, actor auditlog.Actor, group SettingsGroup, next config.Settings) error {
+	next.Normalise()
+	if err := next.Validate(); err != nil {
+		return Invalid("%s", err.Error())
+	}
+
+	current := a.Settings()
+	changed := diffSettings(current.ToMap(), next.ToMap())
+	if len(changed) == 0 {
+		return nil
+	}
+
+	// Only the keys belonging to this group are written, so two administrators
+	// editing different pages cannot overwrite each other's work.
+	toWrite := map[string]string{}
+	full := next.ToMap()
+	for _, k := range changed {
+		toWrite[k] = full[k]
+	}
+
+	if err := a.DB.SetSettings(ctx, toWrite); err != nil {
+		return Internal(err, "The settings could not be saved.")
+	}
+
+	a.Audit.Record(ctx, actor, "settings.update", auditlog.ObjectSettings, string(group), string(group),
+		auditlog.Changes("keys", strings.Join(changed, " ")))
+
+	if err := a.Runtime.Reload(ctx); err != nil {
+		return Internal(err, "The settings were saved but could not be applied. Restart the server.")
+	}
+	return nil
+}
+
+// diffSettings returns the keys whose values differ.
+func diffSettings(before, after map[string]string) []string {
+	var changed []string
+	for k, v := range after {
+		if before[k] != v {
+			changed = append(changed, k)
+		}
+	}
+	sort.Strings(changed)
+	return changed
+}
+
+// PendingRestart reports which changed settings need a restart to take effect.
+func (a *App) PendingRestart(ctx context.Context) []string {
+	current := a.Settings()
+	udp, tcp := a.DNS.ListenAddrs()
+
+	var pending []string
+	if current.DNS.UDPListen != udp {
+		pending = append(pending, fmt.Sprintf("DNS UDP address (listening on %s, configured as %s)",
+			udp, current.DNS.UDPListen))
+	}
+	if current.DNS.TCPListen != tcp {
+		pending = append(pending, fmt.Sprintf("DNS TCP address (listening on %s, configured as %s)",
+			tcp, current.DNS.TCPListen))
+	}
+	return pending
+}
+
+// TestUpstream probes one upstream resolver on demand.
+func (a *App) TestUpstream(ctx context.Context, addr, qname string) (string, error) {
+	s := a.Settings()
+	if strings.TrimSpace(qname) == "" {
+		qname = "example.com"
+	}
+	upstreams := config.SplitLines(addr)
+	if len(upstreams) == 0 {
+		return "", Invalid("Enter an upstream resolver address.")
+	}
+	target := upstreams[0]
+	if !strings.Contains(target, ":") {
+		target += ":53"
+	}
+
+	rtt, rcode, err := resolverCheck(ctx, target, qname, s)
+	if err != nil {
+		return "", Invalid("%s", err.Error())
+	}
+	return fmt.Sprintf("%s answered %s in %.0f ms", target, rcode, float64(rtt.Microseconds())/1000), nil
+}