checker: split monolithic rule into per-concern rules

checker/rules_authoritative.go

@@ -0,0 +1,54 @@
+package checker
+
+import (
+	"context"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// authoritativeRule flags nameservers that answer the zone's SOA without
+// setting the AA bit, i.e. they are not authoritative for the zone they
+// are delegated to serve.
+type authoritativeRule struct{}
+
+func (r *authoritativeRule) Name() string { return "ns_is_authoritative" }
+func (r *authoritativeRule) Description() string {
+	return "Verifies that nameservers answer authoritatively (AA bit set) for the zone"
+}
+
+func (r *authoritativeRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
+	report, errSt := loadReport(ctx, obs, "ns_authoritative_error")
+	if errSt != nil {
+		return []sdk.CheckState{*errSt}
+	}
+
+	servers := probedServers(report)
+	if len(servers) == 0 {
+		return []sdk.CheckState{noProbesState("ns_authoritative_skipped")}
+	}
+
+	out := make([]sdk.CheckState, 0, len(servers))
+	for _, srv := range servers {
+		state := sdk.CheckState{
+			Subject: serverLabel(srv),
+			Meta:    serverMeta(srv),
+		}
+		switch {
+		case srv.SOA.Error != "":
+			state.Status = sdk.StatusInfo
+			state.Code = "ns_authoritative_unknown"
+			state.Message = fmt.Sprintf("query failed: %s", srv.SOA.Error)
+		case srv.SOA.Authoritative:
+			state.Status = sdk.StatusOK
+			state.Code = "ns_authoritative_ok"
+			state.Message = "server is authoritative (AA bit set)"
+		default:
+			state.Status = sdk.StatusInfo
+			state.Code = "ns_authoritative_missing"
+			state.Message = "server is not authoritative (AA bit not set)"
+		}
+		out = append(out, state)
+	}
+	return out
+}