Initial commit

checker/rule.go

@@ -0,0 +1,46 @@
+package checker
+
+import (
+	"context"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// Rule returns the alias check rule.
+func Rule() sdk.CheckRule {
+	return &aliasRule{}
+}
+
+type aliasRule struct{}
+
+func (r *aliasRule) Name() string { return "alias_check" }
+
+func (r *aliasRule) Description() string {
+	return "Verifies a CNAME / DNAME / ALIAS chain: coexistence, loops, length, target resolvability, DNSSEC coverage."
+}
+
+func (r *aliasRule) ValidateOptions(opts sdk.CheckerOptions) error {
+	if v, ok := opts["maxChainLength"]; ok {
+		f, ok := v.(float64)
+		if !ok {
+			return fmt.Errorf("maxChainLength must be a number")
+		}
+		if f < 1 {
+			return fmt.Errorf("maxChainLength must be >= 1")
+		}
+	}
+	return nil
+}
+
+func (r *aliasRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, opts sdk.CheckerOptions) []sdk.CheckState {
+	var data AliasData
+	if err := obs.Get(ctx, ObservationKeyAlias, &data); err != nil {
+		return []sdk.CheckState{{
+			Status:  sdk.StatusError,
+			Message: fmt.Sprintf("failed to get alias data: %v", err),
+			Code:    "alias_error",
+		}}
+	}
+	return Evaluate(&data)
+}